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Parent cells that undergo mitosis produce two identical daughter cells. This occurs in humans and other multicellular organisms producing new cells. It is also how many single-celled organisms asexually reproduce.

In organisms that reproduce sexually, meiosis produces sex cells with half the number of chromosomes found in other cells. You will see animations of these processes, along with movies of actual cells undergoing mitosis and meiosis. In each phase for both processes, you will determine what happens to the genetic material of the cell.

As you watch the mitosis animation and then the film, record your observations as instructed on your student sheet. Use the large orange arrows to go forward or back in the animation and view particular phases.

STOP HERE! Once you have completed the Mitosis portion of this simulation, return to your student book to finish Activity 3, "Mitosis and Asexual Reproduction."
Do not continue to the next portion of the simulation. You will complete the rest of the simulation when you are working on Activity 13, "Meiosis and Sexual Reproduction."

As you watch the meiosis animation and then the film, record your observations as instructed on your student sheet.

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Parent cells that undergo mitosis produce two identical daughter cells. This occurs in humans and other multicellular organisms producing new cells. It is also how many single-celled organisms asexually reproduce. In organisms that reproduce sexually, meiosis produces sex cells with half the number of chromosomes found in other cells.

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Our objective is to show experimentally that light is necessary for photosynthesis.

Photosynthesis is the process in which light energy is converted into chemical energy. Using the energy of light, carbohydrates such as sugars are synthesised from carbon dioxide and water.

The name photosynthesis is derived from the Greek words, photo for 'light' and synthesis meaning 'putting together'. Oxygen is also released, as a waste product. Light is the major factor for photosynthesis to take place and by doing this experiment we need to prove that light is necessary for photosynthesis.

The Process of Photosynthesis

The process of photosynthesis occurs when green plants use the energy of light to convert carbon dioxide (CO ₂) and water (H ₂ O) into carbohydrates. Light energy is absorbed by chlorophyll, a photosynthetic pigment of the plant, while air containing carbon dioxide and oxygen enters the plant through the leaf stomata. An extremely important by-product of photosynthesis is oxygen, on which most organisms depend.

Glucose, a carbohydrate processed during photosynthesis, is mostly used by plants as an energy source to build leaves, flowers, fruits, and seeds. Molecules of glucose later combine with each other to form more complex carbohydrates such as starch and cellulose. The cellulose is the structural material used in plant cell walls. Photosynthesis provides the basic energy source for virtually all organisms.

We can express the overall reaction of photosynthesis as:

Where does Photosynthesis occur?

Photosynthesis takes place primarily in leaves and little to none occurs in stems. It takes place within specialised cell structures called chloroplasts. A leaf has a petiole or the stalk and a lamina, the flat portion of the leaf. As its area is broad, the lamina helps in the absorption of sunlight and carbon dioxide during photosynthesis. Photosynthesis takes place in the chloroplasts that have chlorophyll present in them. It is the chlorophyll that absorbs light energy from the sun. There are tiny pores called stomata that function as roadways for carbon dioxide to enter and oxygen to leave the plant.

Role of the colour of light during Photosynthesis

Did you know that the colour of light plays an important role during photosynthesis? Yes, it does. Plants use only certain colours from light for the process of photosynthesis. The chlorophyll absorbs blue, red and violet light rays. Photosynthesis occurs more in blue and red light rays and less, or not at all, in green light rays.

The light that is absorbed the best is blue, so this shows the highest rate of photosynthesis, after which comes red light. Green light cannot be absorbed by the plant, and thus cannot be used for photosynthesis. Chlorophyll looks green because it absorbs red and blue light, making these colours unavailable to be seen by our eyes. It is the green light which is not absorbed that finally reaches our eyes, making the chlorophyll appear green.

Factors affecting Photosynthesis

For a constant rate of photosynthesis, various factors are needed at an optimum level. Here are some of the factors affecting photosynthesis.

Light Intensity:An increased light intensity leads to a high rate of photosynthesis and a low light intensity would mean low rate of photosynthesis.

Concentration of CO₂: Higher carbon dioxide concentration increases the rate of photosynthesis. Normally the carbon dioxide concentration of 0.03 to 0.04 percent is sufficient for photosynthesis.

Temperature:An efficient photosynthesis requires an optimum temperature range between 25 to 35oC.

Water: Water is an essential factor for photosynthesis. The lack of water also leads to a problem for carbon dioxide intake. If water is scarce, the leaves refuse to open their stomata to keep water they have stored inside.

Polluted Atmosphere:The pollutants and gases (impure carbon) settle on leaves and block the stomata, making it difficult to take in carbon dioxide. A polluted atmosphere can lead to a 15 percent decrease in the rate of photosynthesis.

Students understand the concept that light is necessary for photosynthesis.

Students understand the principle of photosynthesis and the factors affecting photosynthesis.

Students will be able to do the experiment more accurately in the real lab once they understand the steps through the animation and simulation.

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Importance of Light in Photosynthesis (Theory) : Class 10 : Biology : Amrita Online Lab

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Our objective is to show experimentally that light is necessary for photosynthesis. Photosynthesis is the process in which light energy is converted into chemical energy. Using the energy of light, carbohydrates such as sugars are synthesised from carbon dioxide and water. The name photosynthesis is derived from the Greek words, photo for 'light' and synthesis meaning 'putting together'.

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Video computer games, virtual labs and activities for learning and reviewing biology content. Great for students and teachers.

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Start

Directions: On the next page, you will see multiple "stations" to complete. Please start with Evolution Station One, but from there you can go in any order!Watch all videos, read all articles, and complete all activities!

Evidence for Evolution

Click the eye to return to the directions

Comparative Embryology

Vestigial Structures

homologous & analogous structures

Fossil Records

Common Ancestry

START HERE!

Evolution Station one

Evidence For Evolution Stations

Charles Darwin

Isaac Newton

Albert Einstein

The theory of evolution is one of the most important concepts in biology.Click the naturalist below who first described evolution by natural selection.

Evolution station one

Click on the animal on this slide with the best traits for this environment

Right! Charles Darwin first described evolution! He noticed that populations of organisms change over time and become better suited to survive and reproduce in their specific environments.

In this environment, which organism is "fittest"?

Yes, the grasshopper has the best traits because of its camouflage! Evolution is sometimes summarized with the phrase "survival of the fittest." Living things compete for resources. Those organisms that are more fit to do this will survive and reproduce better than others. These organisms will become more numerous.

Which of the following organisms has a body structure most similar to a lion?

Not many people would suggest a shark is "fitter" than the Hulk, but in this case it definitely is! So how does evolution happen? Speciation is the process of one species branching into two. In some cases, differences in ability to get food or to escape from predators can lead to speciation. ​These species usually have similar traits, but can no longer breed.

Key Word:Tiger

Write the key word on your answer sheet. Then continue onto your next station using the home button in the top right corner!

Right! Lions and tigers have similar body structures and traits. This leads scientists to consider that they may have a common ancestor. Continue through the stations to learn more!

Or is it more likely that they all evolved from the same species?

Is it more likely that thousands of mammal species evolved furry coats at different times?

An ancestor is a species from which a modern species evolved. In some ways, this is a probability problem. For example, all mammals have fur and birds always have wings.

Common Ancestry

A cladogram branches off as a species develops new traits. Click on the organism closest related to the fish.

Correct! This species would be a common ancestor of all living mammals with fur. One way to informally organize common ancestors is to use a cladogram.

Drag and drop the organisms into their placement on the following Cladogram! When you're done, click the arrow to check your answers

The salamander is the closest related organism! However, one difference is that the salamander has lungs!

Key Word: Fish

Your cladogram on the last page should look like this! Great job on this station! The other stations will describe the types of evidence we have for common ancestors. Write the key word on your answer sheet. Then continue onto your next station using the home button in the bottom left corner!

Check Your Answers!

We now know that many species evolved from common ancestors.But how do we know what those ancestors looked like? Click on the diagram of the fossil record to continue.

Fossil Records

below is a link to a gallery of fossil horses. Take a few minutes to check out the differences! when you're ready, click the arrow to move to the next page.

the Fossil record analyzes, dates, and organizes fossils. The fossil record helps paleontologists, archaeologists, and geologists place important events and species in the appropriate geologic era. We can learn about the changes in species over time by analyzing the fossil remains.

Notice the differences between the species of horses over time! take a look at it's feet- notice it had toes 50 million years ago, and now they have hooves! did you notice the difference in size? click on the modern day horse to move on.

Click on the transitional species in the diagram

for example, as amphibians evolved from fish, we should see evidence of a transitional species, having traits of both fish and amphibians.

Transitional species are species that are intermediate (a mix) between two different species.

Click on its flattened head to learn more!

However, it also had a flattened body and head- which fish do not have!

Right! That is a tiktaalik! The tiktaalik lived about 375 million years ago. It had fins, scales, and gills- all signs that it was a fish.

key word: record

Write the key word on your answer sheet. Then continue to the other stations using the home button in the bottom left corner!

Using fossil records is just one type of evidence we have of common ancestors. check out the other stations for more types!

The tiktaalik also had a neck that separated its head from its body, digits on its forelimbs, and eyes on the top of its head. It was clear it had features of a land animal.

Homologous Structures and Analogous Structures provide evidence for common ancestors. Watch the video below for an introduction about these structures. When you're done, click on the HOMOLOGOUS Structures to the right.

homologous and anaologous structures

Homologous Structures are organs, limbs, and other structures that look similar in structure, but may have different functions.If you look closely at the picture of the limbs on these animals, you will see some have a completely different function, but have all evolved from a common ancestor. They all have a humerus that leads to a radius and ulna, which leads to the carpals and metacarpals and finally phalanges. Click on the Whale's phalanges (fingers) to move to the next page.

Yes, the forelimbs of various animals in the picture is an example of Homologous Structures!Let's take a more detailed look!

Click on one of the analogous structures that help an organism fly to practice analyzing these structures!

Analogous structures are the opposite. They have different structures, but serve the same function. Take a look at the examples to the right.These do not provide evidence because the structures formed independently to serve the same purpose without a common ancestor.

Dorsal fin of a dolphin and shark

Ankle bone of a pig and deer

A platypus and duck both lay eggs

Human and turtle heart

Drag the following pictures to the correct type of structure.Click the arrow to move on when you're done!

ANALOGOUS STRUCTURES

HOMOLOGOUS STRUCTURES

ANALOGOUS STRUCTURES

HOMOLOGOUS STRUCTURES

Giraffes and humans both have 7 vertebrae in our necks!Which type of structures does this give evidence for?

Key Word:Giraffe

Great job on this station! Write the key word on your answer sheet. Then continue onto your next station using the home button below!

That's right! Giraffes and humans have similar structure of vertebrae provides evidence for homologous structures. This suggests we have a common ancestor!

NO

YES

Do you have one?! Try it out! Put your pinky and thumb together as shown. Does your tendon stick out?

As organisms evolve, there are often remaining structures that haven't fully disappeared. But they have lost most or all of their original purpose.

Vestigial Structures

Ear Rotation Muscles

Wisdom Teeth

Goosebumps

Click the buttons on the rainbow to check out multiple vestigial structures.When you're done, click the arrow below!

Dog's Dew Claw

Appendix

It does, however, provide evidence that they may share common ancestry with other organisms that do use that body part, organ, or structure!

80-85% of people do have this tendon, though, because if a structure isn't negatively affecting the organism, it most likely won't disappear entirely!

About 10-15% of people don't have this tendon!This tendon has no effect on grip strength or really anything else. It is completely useless!

The dewclaw is present on many animals.It's something that has evolved into a thumb in others. Ancient ancestors to the dog once used this structure to climb trees, but as dogs evolved to run on the ground and stand more on their digits than their whole foot, their dewclaw became mostly useless.

Dog's Dewclaw

How about for people though?Useless! We have so many little hair on our bodies that goosebumps do nothing to keep us warm.

What's the point of these?Most animals that have fur can lift these muscles up to stand up their fur. This allows more air to be trapped in their fur for insulation and keeping warm. Goosebumps also happen when an animal gets scared or feels threatened to make its hair stand up.

Goosebumps

Humans have an appendix which many believe serves as a housing for good bacteria in our intestines, so it may actually serve a purpose for us- but it is believed that the original pupose of the appendix may have changed. The appendix helps many other animals in digesting cullulose-rich diets, such as grass.

Appendix

Now one in four people are missing at least one wisdom tooth.It wouldn't be surprising if no one had any wisdom teeth another million years from now!

Some humans have wisdom teeth. They hardly fit into most of our skulls nowadays, which is why some people have to have them removed!Human skulls have changed over milions of years. They used to be longer, allowing more room for teeth in the jaw. Once humans could cut foods, cook foods softer, and use agriculture, our need for stronger jaws decreased.

Wisdom Teeth

Some animals have the ability to rotate their ear 90 degrees or more to help them locate the direction of sounds and hear better.Studies show that our brains subconsciously tell our ears to turn towards sounds, too, even though they no longer rotate!

Can you move your ears? If so, probably just slightly.We still have ear rotation muscles, but they are have lost their original function.

Ear Rotation Muscles

A bird's beak

Human's fingers

A cat's tail

A whale's leg bones

Now that you've learned about a few examples, answer the following question! Which of the circles describes a vestigial structure?

Vestigial Structures

Key Word:Whale

Congrats! You've completed the station! Write the key word on your answer sheet. Then continue onto your next station using the home button in the top right corner!

Great job! A whale's leg bones are vestigial structures that suggest that they have a common ancestor that once lived on land. The species adapted and gradually lost their legs, but retained the vestigial bones.

Click the embryos above to see more examples

Embryology is the study of the development of embryos (an organism before it's born or hatched) across different species. Scientists have found that organisms with a common ancestor have similar traits during early embryological development.

Embryological Evidence

Click Here When You're Done!

Chick

Fish

Salamander

Tortoise

Hog

Calf

Human

Rabbit

How similar are they? Try to pin each organism's name under its early embryo

Click Here When You're Done!

Chick

Fish

Salamander

Tortoise

Hog

Calf

Human

Rabbit

How about now? Try to pin each organism's name under its late stage embryo

Click on the embryos that were HARDER to label!

Yes! It was very difficult to tell the early embryos apart! That's because of how similar the traits are in all of these organisms! All vertebrate embryos essentially have the same parts to start.

However, as they continue to grow, they change drastically due to their adaptations that help them survive in their environment. Click the early human embryo to move on

Click the arrow to find out what the pharyngeal arches become.

All vertebrate embryos also have what looks like "gill slits," but are not actually gills. These structures in embryos are called pharyngeal arches. These are exposed (visible outside) early in embryo development but eventually they close in many species.​

Key Word:Baby

This is the end of the station! Write the key word on your answer sheet. Then continue onto your next station using the home button in the top right corner!

Only in fish and in larval amphibians do pharyngeal arches develop into gills.​ In mammals, the tissue within the first two gill slits forms part of the lower jaw and the bones of the inner ear.

Watch the video in the link below and take note of the characteristics that were more advantageous in some species and how humans' ancestors became more advanced as time passed. When you're done, click the arrow to learn more!

Hominids are a family of primates that walk upright on two legs, including today's humans and our extinct ancestors! Hominids first evolved about 6 millions years ago. Humans are the only hominids alive today! Like most organisms, we are a part of a large and diverse family tree that has many branches, with many changes along the way.

Changes in Hominids

Click on the Australopithecus aferensis skeleton "Lucy" to learn more!

Scientists have measured the heights of fossil skeletons and the patterns of their fossil footprints Over time, ancestors got taller and their feet changed as they got better adapted to walking on the ground

The earliest hominid skeletal fossil dates back 6 million years to Ardipithecus ramidus These early ancestors could walk upright, but had huge big toes, which allowed it to mostly live in trees

Click the skull of the earliest hominid fossil.

Over time, hominid skulls have changed in the following ways... -Jaws and teeth have decreased in size because straw jaws were no longer needed as we began cooking softer foods -Brain size has TRIPLED to develop the precise motor skills needed to make and use tools, to track and predict movements of the animals they hunted, and to develop spoken language

Fossils of Skulls

Using tools

Yes! Did you notice how the skulls have changed? Here are some other changes that hominids have gone through over time!

Wider pelvic bones

Working cooperatively with each other

Increased height and weight

Key Word: Sapiens

Write the key word on your answer sheet. Then continue onto your next station using the home button in the bottom left corner!Before you go, check out the chart below!

How cool is it that hominids have changed so much? Well, that's it for this station!

If you are on this page, this means that you have completed EVERY OTHER STATION already! If that is the case, let's learn about coevolution!

If we find two species that can NOT survive without their dependence on each other, this is considered evidence of Coevolution. These two species changed and evolved together over time. Click on the bees and flower above to learn more!

Bonus: coevolution

Think About It: -Pollination by animals is critical to the reproduction of most plants -Bees are the most familiar pollinators This coevolution created a mutually beneficial relationship: Bees were safe from predators Bees got food Flowers were able to produce more seeds Click on the bee for another example.

Bees and flowers are popular examples of coevolution.

Click the Mimic Butterfly to test your knowledge!

Other examples are common among predator-prety and host-parasite pairs.

Here's another example!

Bees see yellow and blue well. Bee-pollinated flowers are usually yellow and blue with a narrow tube.

Ostriches and giraffes are both native to the savannahs and have a very long neck.

Whales and penguins have fins/flippers for moving in water.

Click the circle below that shows an example of coevolution.

Key Word: Bee

You've made it to the end of this station! Write the key word on your answer sheet. Then continue onto the very last station using the home button in the bottom right corner!

Great job finding the example of coevolution!

If you are on this page, this means that you have completed EVERY OTHER STATION already! If that is the case, feel free to practice our topic using the Blooket link in the icon below!

Bonus: Blooket

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Aerobic and Anaerobic Respiration Review

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Aerobic and Anaerobic Respiration Review

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Anaerobic vs Aerobic Respiration | Genially

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https://kidwings.com/explores/online-labs/barn-owls/

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Virtual Pellet. Everyone should experience the fun and discovery of dissecting an owl pellet. Kids and adults alike can dissect a pellet online and learn many of the bones found inside a real pellet. It's a perfect way to inform parents, introduce teaching assistants, and even use when your budget prevents buying real owl pellets!

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The Theory of Evolution by  Natural Selection | Evolution | Biology | FuseSchool

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Punnett Square Basics | Mendelian Genetic Crosses

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Cellular Respiration Escape room

Witchcraft Manual

Start

Lesson 01

Haunted Forest: Venture forth and reach the end of the path.

Magical Progress

To break down ATP in order to harness its energy to produce glucose.

To break down sugar in the presence of oxygen to release energy in the form of ATP.

To produce oxygen from breaking down water and carbon dioxide.

To make glucose by converting light energy from the sun into chemical energy.

Question 1/4

What is the purpose of cellular respiration?

Question 2/4

What is the energy molecule that is made during cellular respiration?

NAD+

ATP

FAD

ADP

Question 3/4

Which formula is cellular respiration?

Question 4/4

Where in the cell does glycolysis occur?

Chloroplast

Nucleus

Mitochondria

Cytoplasm

Well done!

Lesson learned!

Continue

You fell!

Back

Lesson 02

Potions. Drag the circleover the potions tofind the correct letter or number.

Magical progress

Question 1/4

In glycolysis, glucose is broken down into two molecules of what? A. Pyruvate B. Lactate C. Acetyl-CoA

Drag the circle and findthe letter.

Question 2/4

What is the net gain of ATP at the end of glycolysis?

Drag the circle and findthe letter.

Question 3/4

Which of the following statements is false? A. Glycolysis can occur with or without oxygen. B. Glycolysis is the first step for anaerobic respiration, but not aerobic respiration. C. Glycolysis produces 2ATP, 2 NADH, and 2 pyruvate.

Drag the circle and findthe letter.

What is the order of the steps of aerobic respiration? A. Kreb' Cycle, Glycolysis, ETC B. Glycolysis, ETC, Kreb's Cycle C. Glycolysis, Kreb's Cycle, ETC

Question 4/4

Drag the circle and findthe letter.

Well done!

Lesson learned!

Continue

Oh no! You have added the wrong ingredient to the mixture and created poison, go back to correct the mixture.

It's poison!

Back

Lesson 03

Divination. Can you predict the future by looking at a single card?

Magical Progress

Question 1/4

Where in a eukaryotic cell does the Kreb's cycle occur?

Clue

Nucleus

Chloroplast

00:10

Cytosol

Mitochondria

Question 2/4

Which of the following is a product of the Kreb's cycle?

Clue

NADH and FADH2

CO2

00:10

2 ATP

All of the above

Question 3/4

What are NADH and FADH2 used for?

Clue

Act as electron carriers to give e- to the ETC

Give energy to break down glucose

00:10

Nothing, they are waste products

They break down into ATP

Question 4/4

What is produced when oxygen is reduced in the electron transport chain?

Clue

ATP

H2O

00:10

NAD+

CO2

Well done!

Lesson learned!

Continue

Bad omen!

Back

Lesson 04

Enchantments Which of these options is the best choice?

Magical progress

Krebs cycle

Glycolysis

Oxidative phosphorylation

Fermentation

Question 1/4

What is the electron transport chain known as?

Outer membrane

Inner membrane

Matrix

Cytosol

Question 2/4

Where in the mitochondria does the electron transport chain occur?

Hydrogen ions flow through ATP synthase, producing ATP

Water is the final electron acceptor and breaks down into oxygen which is released

Energy from electrons forms an electrochemical gradient

NADH and FADH2 lose electrons

Question 3/4

What does NOT happen as electrons flow down the electron transport chain?

Krebs cycle

Glycolysis

Pyruvate oxidation

Electron Transport Chain

Question 4/4

Which of the following processes generates the most ATP?

Badchoice!

Back

You've escaped the cat's claws.

Move on to the last step of the journey...

Magical progress

Lesson 05

Haunted Forest: You have one last part of the forest to fly through until you reach the end.

Oxidative phosphorylation

Photosynthesis

Fermentation/ Anaerobic respiration

Aerobic respiration

Question 1/4

When oxygen is not present, what process is used to break down pyruvate?

Question 2/4

What molecule is produced when muscles start fermentation and causes cramps?

Lactic acid

Ethanol

Methanol

Pyruvic acid

Question 3/4

What molecule is produced during the fermentation of yeast?

Lactic acid

Methanol

Ethanol

Pyruvic acid

Question 4/4

How much ATP do both types of fermentation produce?

You fell!

Back

Well done!

Lesson learned!

Continue

Manual completed

Congratulations!

Magical progress

You can nowpractice sorcery!

Are you sure you want to exit?

Your progress will be lost and you will not learn witchcraft

Exit

Continue

Become an expertin witchcraft!

To do this, you must complete the wizardry manual by overcoming each of the 4 lessons you will find: · Bewitched Forest· Potions· Divination· Enchantments. Test your magical skills and try not to fail or you will have to retakethe test.

Become an expertin witchcraft!

To do this, you must complete the wizardry manual by overcoming each of the 4 lessons you will find: · Bewitched Forest· Potions· Divination· Enchantments. Test your magical skills and try not to fail or you will have to retakethe test.

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Homologous Structures vs Analogous Structures | Key Differences

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Homozygous vs Heterozygous Alleles | Punnet Square Tips

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Energy & Matter in Ecosystems | Genially

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Protein Synthesis Race

You are using the Free Version of this Game (with ads). If you want to use the Ad-Free Member Version, click the button below. Please note: This will open in a new tab/window! Please save your progress before proceeding!

Topics Covered: Protein synthesis, transcription, translation, amino acids, ribosomes, tRNA, mRNA, nucleotides etc.

Check out the worksheet that goes along with the game, courtesy of Ms. Julie Olson!

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Video computer games, virtual labs and activities for learning and reviewing biology content. Great for students and teachers.

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RESPIRATION - AEROBIC VS ANAEROBIC RESPIRATION - OXYGEN DEBT

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Convergent Evolution vs Divergent Evolution | Shared Traits Explained

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Genotype vs Phenotype | Understanding Alleles

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Codominance and Incomplete dominance- Non mendelian 

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Codominance and Incomplete dominance- Non mendelian 

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Codominance and Incomplete Dominance: Non-Mendelian Genetics

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Human Impacts on Biodiversity | Ecology and Environment | Biology | FuseSchool

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Peppered moths are common insects living in England, Europe, and North America. They are small moths, only 1.5 to 2.5 inches across. Their light wings are "peppered" with small dark spots.

Life Cycle

Light and dark peppered moth larvae. Image by Rockpocket via Wikimedia Commons.

Peppered moth eggs hatch during mid summer. Larvae (caterpillars) feed on the leaves of birch, willow, and oak trees. The larvae look much like a small branch. Having a body that looks like a stick helps the larvae hide from predators. The larvae can even adjust their color from brown to green to best match the branches they are feeding on.

Cold weather is difficult for insects. To avoid death, peppered moth larvae change into pupae (cocoons) for the winter. In April and May the pupae open to reveal a new adult moth. These adults will lay eggs and die by the end of summer. No peppered moth lives for more than one year.

Peppered moth pupae

While the typical peppered moth is light, and is given the name typica, some moths have dark, almost black, bodies. These moths are given the name carbonaria. Others are somewhere in the middle and have many more dark spots than the light peppered moth. This middle color (or morph) is called insularia. In the past, darker moths were very rare. But that changed around 150 years ago. Continue onto the next section about natural selection to find out why.

Predators

Light and dark peppered moth. Image by Martinowksy via Wikimedia Commons.

Predators of the peppered moth include flycatchers, nuthatches, and the European robin. Like most moths, peppered moths avoids predators that hunt in daylight by flying at night and resting during the day. Any animal sitting still is harder to see than a moving one.

Peppered moths have extra camouflage to help them hide. The trees they live in have light-colored bark and are covered with small lichens, organisms that are part fungus and part algae or bacteria. The pattern on peppered moth wings looks very similar to lichens.

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Peppered moths are common insects living in England, Europe, and North America. They are small moths, only 1.5 to 2.5 inches across. Their light wings are "peppered" with small dark spots. Light and dark peppered moth larvae. Image by Rockpocket via Wikimedia Commons. Peppered moth eggs hatch during mid summer.

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This interactive module explores the phases, checkpoints, and protein regulators of the cell cycle. The module also shows how mutations in genes that encode cell cycle regulators can lead to the development of cancer.

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By closing this banner and using MolView, you agree with the Terms of Use! read the Terms of Use We need your support to create more cool stuff! Donate Allow MolView to collect annonymous usage data ( details)

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1, 2, 3 Photosynthesis! (The Photosynthesis Song)

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A song I made for extra credit in biology class! To the song "3" by Britney spears. Lyrics/Vocals - David Levitz

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Carbon Quest!

Topics Covered: Be Carbon in the Carbon Cycle! Nutrient Cycling, Carbon Cycle. Photosynthesis, Respiration, Combustion, Fossil fuels, Fossilization, Decomposition.

Next Generation Science Standards (NGSS): HS-LS2-5 Ecosystems: Interactions, Energy, and Dynamics-- Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.

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Video computer games, virtual labs and activities for learning and reviewing biology content. Great for students and teachers.

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PI: Pedigree Investigator, On the Case of Nicotine Addiction

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PI: Pedigree Investigator, On the Case of Nicotine Addiction [Internet]. Salt Lake City (UT): Genetic Science Learning Center; 2013 [cited 2023 Sep 22] Available from https://learn.genetics.utah.edu/content/addiction/pi/

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This simulation explores the survival of prey species individuals based on their coloring and the environment. The user controls the predator in the simulation and “eats” the prey by clicking on them.

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Five fingers of evolution - Paul Andersen

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Photosynthesis and Respiration

Photosynthesis is how plants make food for themselves and for the rest of us! Respiration is how animals and other organisms break down food to release energy that cells can use! This special energy is called ATP!

Photosynthesis and Respiration Video Games, Virtual Labs & Activities

Build molecular models that illustrate key principles of energy transfer through the chemical reactions of photosynthesis and respiration. Also, use a model to show how carbohydrates can be used to build other important biomolecules. This activity was designed for the Next Generation Science Standards (NGSS), specifically HS-LS1-5, HS-LS1-6, and HS-LS1-7 (From Molecules to Organisms: Structures and Processes).

Learn how photosynthesis works by performing the light-dependent reactions and the Calvin cycle yourself. It this interactive, the biochemistry of photosynthesis comes alive! Also, learn about the anatomy of the leaf and where exactly the reactions of photosynthesis take place.

Jump to collect oxygen and glucose to keep the man alive through respiration! Then collect carbon dioxide and water to help the tree do photosynthesis! Don't fall off the screen and watch out for enemy hermit crabs and jumping fish! By the time your done, you'll be an expert on the basics of photosynthesis and respiration!

Test your knowledge of photosynthesis and respiration! These quizzes can be submitted online to your registered teacher. Please note: A quiz will not end until you have successfully answered all questions.

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Photosynthesis and Respiration Photosynthesis is how plants make food for themselves and for the rest of us! Respiration is how animals and other organisms break down food to release energy that cells can use! This special energy is called ATP!

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This activity will have students identifying the monomer, polymer, function, elements, and examples for the following four macromolecules (1) carbohydrates, (2) lipids, (3) proteins, and (4) nucleic acids.

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This activity will have students identifying the monomer, polymer, function, elements, and examples for the following four macromolecules (1) carbohydrates, (2) lipids, (3) proteins, and (4) nucleic acids.

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Video computer games, virtual labs and activities for learning and reviewing biology content. Great for students and teachers.

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Succession Interactive!

Topics Covered: Ecological succession, Primary succession, Secondary succession, abiotic and biotic factors, pioneer species, critical thinking, graph analysis, NGSS (Next Generation Science Standards), pheonomena. For NGSS, see LS2.C: Ecosystem Dynamics, Functioning, and Resilience specifically.

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Video computer games, virtual labs and activities for learning and reviewing biology content. Great for students and teachers.

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The two strands of a DNA molecule are held together through complementary base pairing: A pairs with T, and C pairs with G.

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A hurricane has hit the island and some of your birds have been blown to three new areas!

Each area has a unique environment. Work with your group to create the Northeast environment. The other two environments will be created for you.

The simulation in the next part will stop every 50,000 years beginning at 500,000 years and ending at 1,000,000 years. This will give you a snapshot of the major changes in the bird populations and the environment during that time. While there are many other changes that could be occuring in the environment and the bird populations, they are not shown in this simulation.

Each time the simulation stops

Observe and record on the Student Sheet the changes that have occurred in you assigned area.

Then click "Next" and
Discuss with your group the changes that occurred and the reasons for the changes.

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A hurricane has hit the island and some of your birds have been blown to three new areas! Each area has a unique environment. Work with your group to create the Northeast environment. The other two environments will be created for you.

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How Mendel's pea plants helped us understand genetics - Hortensia Jiménez Díaz

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Since nucleic acids make up just a small proportion of the nutrients in our food, we don't detail their breakdown or storage in Metabolic Pathways or Building, Burning & Storing. But that's not to say they're unimportant. ATP is a nucleic acid, and it plays a role in just about every cellular process. Nucleic acids are also used for building DNA and RNA, as well as the carrier molecules NAD, FAD, and Coenzyme A.

Related content

To see how nutrients from our food are further processed by our cells, visit Metabolic Pathways.

Fats are transported in packages

We are made mostly of water. It accounts for about 65% of our body weight and more than 90% of our blood. And water makes up the bulk of our food and drink.

The breakdown products of proteins, carbohydrates, and nucleic acids dissolve in water. They can travel easily in the watery contents of our digestive system, bloodstream, and cells. But when it comes to fats, oil and water don't mix. Fats require special handling.

In fat breakdown, above, you can see how bile salts help break fats from food into small droplets, giving them a greater surface area so that digestive enzymes can break them apart. In fat absorption, you can see how fats are packaged into chylomicrons and transported through the lymphatic system to the bloodstream.

This theme of wrapping fats in coated packages continues. Once they're nearly empty, chylomicrons are taken up by the liver. Their remaining cargo is combined with fats that are made in the liver along with other lipids (including cholesterol) and packaged into VLDLs, or very low-density lipoproteins. VLDLs travel to all the tissues of the body, delivering their cargo where it is needed. As fats are removed, VLDLs shrink, and they become more dense (remember, fat floats on water). They soon become LDLs, or low-density lipoproteins. Eventually, when most of their fat is gone and they contain mainly cholesterol, they become HDLs, or high-density lipoproteins, which return to the liver.

Good and bad cholesterol

You may have heard of LDLs and HDLs in the context of cholesterol. LDLs are often called "bad cholesterol" and HDLs are often called "good cholesterol." What's important to remember is that low-density and high-density lipoproteins are packages that carry cholesterol and other lipids, not the cholesterol itself. Cholesterol is cholesterol, and all of our cells need it.

What's different is the characteristics of the packages. LDLs are out to deliver their contents, including cholesterol, to the tissue of the body. When LDL levels are high, they can get stuck on the walls of blood vessels, forming "plaques." This build-up can reduce blood flow, leading to heart attack or stroke. HDLs, on the other hand, are picking up cargo, including cholesterol, from the rest of the body and bringing it to the liver.

HDLs are considered "good" for a few reasons. First, some evidence suggests they can pick up cholesterol deposits from blood vessel walls, decreasing plaque build-up. Second, HDLs take cholesterol out of circulation. When they return to the liver, their cholesterol is converted into bile. Bile is dumped into the digestive tract, and some of it leaves in our feces-the only way we have of getting rid of cholesterol for good.

An emulsifier breaks oil into tiny droplets that can stay suspended in water. In the digestive tract, bile acts as an emulsifier. The proteins in chylomicrons and blood lipoproteins also act as emulsifiers, surrounding small droplets of lipids.

Fats and other lipids travel through the bloodstream in a variety of packages.

Taking up vitamins and minerals

In addition to the nutrients described above, our food contains "micronutrients"-vitamins and minerals that our bodies need to stay healthy. The digestive system absorbs these micronutrients, sending them to the bloodstream where they can travel to all of our cells.

Water-soluble micronutrients, such as vitamins B and C, dissolve easily in the watery contents of our digestive tract. The cells that line the gut take up these nutrients and transport them to the bloodstream.

Fat-soluble micronutrients, such as vitamins A and D, do not dissolve in water. Instead, they hitch a ride with fats, traveling in chylomicrons and VLDLs as described above. Eating a little fat with our food makes it possible to absorb these vitamins.

Some vitamins, such as K and B12, are made by microbes that live in the large intestine. They travel through the cells that line the large intestine and out to the rest of the body.

Water-soluble vitamins and other nutrients flow freely in the blood and digestive tract. Fat-soluble vitamins travel in packages with fats.

Alcohol absorbtion and breakdown

Ethanol from alcoholic beverages is absorbed directly through the lining of the digestive tract, mostly the stomach and small intestine. It is a small molecule, so it doesn't need further breakdown before it can be absorbed. Ethanol mixes with water, and it travels readily through cell membranes. It diffuses easily in and out of capillaries and cells, from areas of higher concentration to areas of lower concentration.

Some ethanol leaves the body in the urine and through the skin, but most is broken down in the liver. Just like any other carbon-based fuel, ethanol is oxidized to form carbon dioxide and water, releasing energy in the process.

Liver cells can burn ethanol for energy.

Hydrolysis: the chemical reaction

Most food is broken down through a chemical reaction called hydrolysis. In Greek, "hydro" means water, and "lysis" means releasing, hydrolysis means releasing with water.

When two sugars are separated, or a chain of amino acids is taken apart, a molecule of water is added for each bond that is broken. Hydrolysis reactions are carried out by enzymes. Water wouldn't react with these bonds on their own, but the enzymes make it more energetically favorable.

The reverse of this reaction is called dehydration synthesis: water is taken away as two molecules are bound together.

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PBS Airdate: February 17, 2021

DAVID POGUE (Science and Technology Author): What's it take to make our modern world?

Ah!

Dah!

That's amazing!

I'm David Pogue. Join me on a high-speed chase through the elements and beyond.

Oh, my god.

As we smash our way into the materials, molecules and reactions...

AMANDA CAVANAGH (University Of Illinois, Realizing Increased Photosynthetic Efficiency [RIPE)]): It's a really cool enzyme, because it makes life on Earth possible.

DAVID POGUE: ...that make the places we live, the bodies we live in and the stuff we can't seem to live without.

The only thing between me and certain death is chemistry? From killer snails...

MANDË HOLFORD (Hunter College): Just when you think you've heard of everything, nature will surprise you.

DAVID POGUE: ...and exploding glass to the price a pepper-eating Pogue pays...

There's got to be some easier way to learn about molecules.

...we'll dig into the surprising way different elements combine together and blow apart.

In this hour, we tackle one of the biggest mysteries of all: the origin of life.

JACK SZOSTAK (Massachusetts General Hospital/Nobel Laureate): How do a bunch of chemicals get together and start acting like a cell?

DAVID POGUE: Part of the answer might be soap?

Cell division!

We explore how the chemistry of life transformed the planet...

LISA AINSWORTH (United States Department of Agriculture, Agricultural Research Service Scientist, University of Illinois): So, everything that we eat, the air that we breathe, all have to do with the process of photosynthesis.

DAVID POGUE: All right, so let's find the lipids aisle.

...I go shopping for the macromolecules of my body...

You're telling me that that's only half the amount of fats in my body?

MONICA HALL-PORTER (University Of Texas, Austin): Absolutely.

DAVID POGUE: ...and I meet an engineer who uses nature's tools to invent new molecules.

FRANCES ARNOLD (California Institute of Technology/Nobel Laureate): Humans have been using microbes to make beer and wine. Instead of making sake, we make jet fuel.

DAVID POGUE: It's Beyond the Elements: Life, right now, on NOVA.

The world we live in is made of atoms, all listed here as elements on the Periodic Table. They're the building blocks of everything around us. And putting atoms together to make molecules and compounds is what we call "chemistry."

And maybe the strangest event in the history of chemistry is the birth of biology. How do a bunch of chemicals somehow get together to form life? And if you look back at the conditions on early Earth, how did life get off the starting block?

There was a turning point, the evolution of a transformative series of chemical reactions that, over time, remade the planet, even allowing us to come along.

But first, let's take a trip back to Life 1.0.

So here's the ad: "Planet available, recently scoured by asteroids. New construction. Now with many water views. The atmosphere? A fixer-upper, devoid of oxygen. Likely full of whatever the volcanoes spewed forth, gases like hydrogen sulfide, and methane."

Somehow, in that very harsh environment, primitive life got its start. But the going stayed tough. Food, molecules and minerals that early organisms could use for energy, consisted of whatever was left over from Earth's formation or was welling up from the earth's core, at places like deep sea vents. But in a surprisingly short amount of time, perhaps 500-million years, a new survival strategy evolved, possibly the most important chemical process for life on Earth today: "photosynthesis," the ability to turn sunlight into fuel.

Life now had access to the vast power of the sun. In the words of one biologist, "When photosynthesis entered the picture, life connected up to the cosmos."

LISA AINSWORTH: So, everything that we eat, what we wear, the air that we breathe, the ecosystem services that we rely on, so, things like having clean water, all have to do with the process of photosynthesis. So, it's an incredibly important, probably the most important process on the planet.

DAVID POGUE: Photosynthesis harnesses the power of sunlight to break down water molecules. Discarding the oxygen, it uses the electrons from the hydrogen atoms to power the assembly of carbon dioxide molecules into carbohydrates, which become both building blocks and long-term energy storage.

DONALD ORT (University Of Illinois, Realizing Increased Photosynthetic Efficiency [RIPE)]): It's not an overstatement to say that all life on this planet depends on photosynthesis.

STEVE LONG (University Of Illinois, Realizing Increased Photosynthetic Efficiency [RIPE)]): It's exactly where all of our food comes from, directly or indirectly. So, understanding how this process works is so important to humanity.

DAVID POGUE: Steve Long and Don Ort, two plant biologists at the University of Illinois at Urbana-Champaign, along with thousands of other scientists, from around the world, have spent decades teasing apart the workings of photosynthesis.

DON ORT: Light intensity is 900, right now?

STUDENT: Right now, yeah.

CARL BERNACCHI: Oh, yeah. That makes sense.

DAVID POGUE: Now, with that knowledge in hand, there is a new international research effort, based here at the university, with an audacious goal. The program's called RIPE: Realizing Increased Photosynthetic Efficiency.

AMANDA CAVANAUGH: This year was a huge hit for the canola farmers, because it was too wet.

STEVE LONG: So, I've been wondering whether it would be worth trying to find a substitute as our testbed.

DON ORT: That'd be perfect.

DAVID POGUE: These folks want to hack photosynthesis.

But why would you want to do that? Because experts think the earth is about to get a whole lot more people. Today, the world's population is close to eight-billion, and that's forecast to hit 9.7-billion by 2050, raising the question: will there be enough food?

STEVE LONG: If you look at the current rate at which we are improving crop productivity per acre of land, we are not going to get there.

DON ORT: Part of the answer is going to be redesigning photosynthesis.

DAVID POGUE: To learn more about RIPE's plans, I've joined Lisa Ainsworth, a U.S.D.A. scientist and professor at the University of Illinois...

LISA AINSWORTH: You can see just how different the height is.

DAVID POGUE: Wow.

....on an early morning tour of a field that contains 600 different varieties of soybeans.

Usually, you hear about efficiency, like of a gas engine, measured in terms of percentage, how much fuel is ultimately converted to energy. What's the percentage efficiency for a plant?

LISA AINSWORTH: Well, in terms of how much of the light energy it turns into sugar, it's pretty low, maybe around three percent.

DAVID POGUE: Three percent? That's terrible. But you guys are going to help it?

LISA AINSWORTH: That's the plan.

DAVID POGUE: To improve photosynthesis, two other researchers with RIPE, Amanda Cavanagh and Paul South, have focused on one of its key molecules. It has a very catchy name.

AMANDA CAVANAGH: So, the molecule is what we biologists call an enzyme. And so, it does the work. Enzymes are like biological workers. And the enzyme's called "RUBISCO."

PAUL SOUTH (Louisiana State University, Realizing Increased Photosynthetic Efficiency [RIPE)]): It's R.U.B.P., or "ribulose bisphosphate carboxylase oxygenase."

AMANDA CAVANAGH: And it's, for most plant biologists, one of our favorite enzymes on the planet.

PAUL SOUTH: Yeah, rubisco is our shortened term for it.

DAVID POGUE: Mainly because it's fun to say?

AMANDA CAVANAGH: Well, it's super fun to say.

DAVID POGUE: Rubisco.

AMANDA CAVANAGH: Of course, rubisco. But, it is also a really cool enzyme, because it makes life on Earth possible.

DAVID POGUE: Rubisco may not look so special, but it is arguably the most important enzyme on the planet, because of its critical role in photosynthesis. Rubisco's job is to grab a molecule of carbon dioxide and feed it into a molecular machine that's building carbon chains.

That means, any carbon atom that's part of any plant, anywhere, got there thanks to rubisco or one of its close variants. And because we eat plants or animals that ate plants, that also includes just about every carbon atom in your body. All approximately eight-hundred-million-billion-billion of them. That's 26 zeroes.

Not bad rubisco, not bad.

PAUL SOUTH: Yeah, so if it's ever come from a plant, it had to have gone through that enzyme of rubisco.

DAVID POGUE: That's wild. How come there's not a memorial to rubisco in Washington? It seems like, sort of important.

Rubisco is important, and that's why it's the most plentiful protein on Earth. But just because you're important, doesn't mean you're entirely competent.

PAUL SOUTH: It's, in this case, not the best enzyme in the world.

AMANDA CAVANAGH: It's got a hard job, so it's doing its best, but at the same time it exists in an atmosphere that's not predominantly carbon dioxide, it's mostly oxygen.

PAUL SOUTH: And about one in every four or five reactions, it grabs oxygen instead of carbon dioxide.

DAVID POGUE: That's right. Rubisco screws up about a fifth of the time. Instead of attaching a carbon dioxide, it attaches an oxygen molecule, and that's trouble.

You're saying nature has created a screwed-up little worker enzyme?

PAUL SOUTH: Yeah. So 400-million years ago, when this enzyme evolved, there wasn't very much oxygen in the air.

DAVID POGUE: All right. So, I'm the little rubisco enzyme and, like, on the conveyor belt, here. And like carbon dioxide, carbon dioxide, carbon dioxide, carbon dioxide, oxygen. And I, I don't notice I accidentally grabbed oxygen out of the box.

PAUL SOUTH: And it produces compounds that are inhibitory to photosynthesis. So, it kind of starts to shut things down.

DAVID POGUE: I mean it's been going on for billions of years and nobody has cared.

AMANDA CAVANAGH: Yeah, well.

DAVID POGUE: I mean, it all basically works.

AMANDA CAVANAGH: Photosynthesis, right now, is sort of a victim of its own success. Rubisco certainly is. So, by oxygenating the atmosphere via photosynthesis, you now have a huge amount of oxygen in the atmosphere, but you need a carbon dioxide to make the reaction work.

DAVID POGUE: So, what happens when rubisco screws up? The result gets shipped out through a couple other parts of the cell to where the mess is taken apart and recycled, all of which consumes a lot of energy.

So, if you could fix this inefficiency problem, the plant might make more soybeans, corn, whatever it is?

AMANDA CAVANAGH: That's exactly it. Then they will have that energy to put towards something that we will consider useful, like making more food for us to eat.

DAVID POGUE: Is this just a crazy theory or is there some indication that this could actually work?

AMANDA CAVANAGH: There is quite a bit of evidence that this is working. So, right now, we have this tested in a couple of model species.

DAVID POGUE: It is tropical in here.

Amanda and Paul take me to the greenhouse to see one example. Using two genes, one from algae and the other from a pumpkin, they've modified tobacco plants to address rubisco's "sloppy work."

And why are we using tobacco plants?

AMANDA CAVANAGH: Yeah, tobacco's a really useful model crop for us.

DAVID POGUE: Why tobacco? Turns out, it's one of the easiest plants to genetically manipulate, which makes it a common test subject.

PAUL SOUTH: They have definitely shown improvements in plant growth and total biomass. And we've been studying the rates of photosynthesis, and we are pretty confident, now, that our model crop is successful in this pathway. And now we're really interested in moving these into something we like to eat.

DAVID POGUE: Reducing the energy penalty crops pay for rubisco's mistakes could be huge. In soybeans, a 25 percent reduction could result in plants that produce more than 60-million more bushels a year.

AMANDA CAVANAGH: This, to a lot of people, is an idea that might be out there. But if we can get it, if we can get this moonshot approach to work, then we're going to have more food. And so that's really what drives what I do.

DAVID POGUE: The RIPE program is international. And likely, so will be the reach of any of its discoveries. But work like theirs is not without controversy. Some of RIPE's solutions depend on crossbreeding plants, chosen for their genes; but other solutions, like the rubisco work, depend on genetic engineering, also called genetic modification or G.M., adding new genes from other types of plants, or even organisms, entirely.

The laws governing genetically modified crops vary from country to country, especially when it comes to labeling their use in food, and there have been objections to some companies that patent their new crops and control who can plant them. But the general scientific consensus is that they are no more dangerous than conventional crops, though they need to be carefully studied for potential health and environmental effects.

The U.S., unlike Europe, has largely adopted G.M. plants. An overwhelming percentage of corn, soybeans and cotton grown in the United States is genetically modified.

STEVE LONG: I understand there are concerns. As a scientist, I feel those concerns have very little validity, although clearly people have become very concerned, particularly in Europe. Of course, in this part of the world, genetically modified crops have been grown for over 20 years. This technology has spread throughout the Americas.

DAVID POGUE: In fact, as the global population grows, it's in poorer countries that RIPE's work may end up having the greatest impact, especially if genetically modified foods gain acceptance.

STEVE LONG: The place where I see the technology needed most is actually in sub-Saharan Africa. And this opposition to G.M. is having quite an influence in Africa. It's keeping the science, which is needed, out. And I fear that this could risk people starving when we could actually be giving them seed which would allow them to feed themselves into the future.

DAVID POGUE: Even if scientists succeed in improving photosynthesis, it won't have anywhere near the dramatic impact of the original version introduced about three-billion years ago. Back then, scientists believe, photosynthetic cyanobacteria began cranking out oxygen as a waste product. Eventually, bacteria produced enough oxygen that it started to accumulate in the atmosphere, which, in turn, gave rise to one of life's underappreciated molecular allies, the ozone layer.

It's in the lowest level of the stratosphere, between, roughly, eight and 22 miles up. Atmospheric research planes venture up here but not much else. The ozone comes from a process even higher up in the stratosphere. There, solar radiation busts up O2 molecules into individual oxygen atoms. They drift down to the ozone layer, where they convert O2 into O3, ozone.

Despite the name, there's not that much ozone in the ozone layer, less than 10 parts per million, yet it's had a profound effect on the evolution of life on Earth.

To find out more...

So, ozone is O3, right?

KERRY HANSON (University of California, Riverside): Ozone is O3.

DAVID POGUE: ...I travel to the University of California, Riverside, to meet Kerry Hanson...

KERRY HANSON: We came alive because...

DAVID POGUE: ...a research chemist who studies how molecules like ozone and those in sunscreens interact with light.

KERRY HANSON: Any molecule can absorb light.

DAVID POGUE: It turns out the ozone layer and sunscreens have a lot in common. This O3 gas is out there in the atmosphere in such quantity that there's an envelope around the whole planet?

KERRY HANSON: Yeah. It's a layer. Think of, like, a sunscreen, you know, how we use sunscreen on our skin?

DAVID POGUE: Yeah.

KERRY HANSON: It's the exact the same thing. The ozone layer is Earth's sunscreen.

DAVID POGUE: Both the ozone layer and sunscreens protect us from the harmful effects of ultraviolet radiation or U.V., a kind of sunlight that, unlike the colors of the rainbow, we can't see. On the electromagnetic spectrum, visible light sits here, but U.V. sits up here, at a higher energy.

Scientists divide it roughly into three kinds, A, B and C. And while A and B aren't good for you, and they're the reason to wear sunscreen, it's C that's the big problem for living things. Because it's particularly destructive to D.N.A. Kerry tells me how all this relates to ozone.

Just another Sunday, and it's kind of like volleyball...

KERRY HANSON: Oh, he's good.

DAVID POGUE: ...well, if the balls were different kinds of U.V.

In the early days of life on Earth, before photosynthetic bacteria oxygenated our atmosphere...

Get it, get it, get it! Yeah, yeah, yeah!

...there was no ozone layer and no global defense against ultra violet radiation.

Aw....

The most dangerous kind, U.V.C., bathed the planet, which may have effectively limited where life could grow. But oxygen accumulating in the atmosphere and the rise of the ozone layer changed all that. The layer blocks all the U.V.C. and most of the U.V.B. from reaching the earth's surface.

KERRY HANSON: Oh, good block.

DAVID POGUE: Here's how it works: when U.V. radiation hits a molecule of ozone, it splits it into an oxygen atom and a molecule of O2; the U.V. light has been absorbed and neutralized; the lone atom quickly rejoins another molecule of O2, to reform ozone. The net result is a conversion of that harmful radiation into heat. Despite the ozone layer, we can still get hit by unhealthy amounts of U.V. And that's why it is a good idea to use sunscreen.

KERRY HANSON: If you read the label and if it says broad spectrum, that means it's blocking U.V.B. and U.V.A.

DAVID POGUE: Wow.

KERRY HANSON: Not U.V.C., like ozone, but U.V.A. and B.

DAVID POGUE: Just like we use sunscreen to block harmful U.V.A. and B radiation from our skin, the ozone layer protects planet Earth from harmful U.V.C. radiation that would destroy the building blocks of life, D.N.A.

KERRY HANSON: Without the blocking of U.V.C. by the ozone layer, life would not have been able to come out of those oceans, come up onto land, and you and I wouldn't be talking here today.

DAVID POGUE: Thanks, ozone!

Without that global protection, the grand story of evolution that began from single-cell ocean-dwelling life and led to the wondrous complexity of multicellular animals occupying land, sea and sky would probably never have been told.

And yada yada yada.

Yeah, yeah. I know, the evolution of life is important, but let's talk about something really important: me; or, at least, me and my molecules.

I know what elements I'm made of: C.H.N.O.P.S.: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. C.H.N.O.P.S. There are other elements in the human body, but these are the main six. And, of course, a good chunk of me, by mass, is good old H2O.

But if you take that water away, most of what's left is macromolecules, mostly big, long polymers,chains of smaller molecules.

Yeah, so I once went "chnopping." That's C, H, N, O, P, S.

To learn more about them, biologist Monica Hall-Porter, formerly at Lasell University, now at the University of Texas, offers to show me around a local...supermarket?

It's kind of weird. I ask you about the molecules of my body and you bring us to a grocery store.

MONICA HALL-PORTER: Yeah, so today's shopping trip is about the macromolecules that actually make up the human body: specifically protein, lipids or fats, carbohydrates and nucleic acids. And if you take a look around the grocery store, there are many examples of those macromolecules here.

DAVID POGUE: All right, show me the ropes.

MONICA HALL-PORTER: Let's go shopping.

DAVID POGUE: Our first objective? Protein molecules.

Monica tells me, by weight, that's about 20 percent of my body.

Does that mean pure masculine muscle? Is that what you're saying?

MONICA HALL-PORTER: Well, not necessarily muscle. Proteins are the molecules that actually do work in cells, so, not just composing muscle, but also the proteins that serve as the structural proteins in our hair and our fingernails.

DAVID POGUE: The most abundant protein in your body is collagen, making up fibrous tissues like skin, tendons and ligaments. There's also collagen in teeth and bone.

But even though there are tens of thousands of different proteins in the human body, maybe millions-no one is sure, amazingly-they're all made from stringing together about 20 different kinds of small molecules called "amino acids," which we get by breaking down the proteins we eat in a variety of foods.

MONICA HALL-PORTER: And so, when we consume protein, like in turkey for example...

DAVID POGUE: Whoa.

MONICA HALL-PORTER: ...our body breaks the amino acids down, and then the amino acids are incorporated into proteins that our body synthesizes or makes.

Yep, there you go.

DAVID POGUE: Handsome little gobbler. Next on the macromolecule shopping list, lipids.

All right let's find the lipids aisle.

MONICA HALL-PORTER: There is no lipids aisle, but we can get oils and fats. So, let's head down this way.

DAVID POGUE: All right.

MONICA HALL-PORTER: And let's get some oil.

DAVID POGUE: This is massive. How much fats are we getting?

MONICA HALL-PORTER: A lot.

DAVID POGUE: Oh, man. This seems like we've got 15 pounds of fats here. And you're telling me that's only half the amount in my body?

MONICA HALL-PORTER: Absolutely; you're about 30 pounds of fat.

DAVID POGUE: Now, I have to say I find that a little insulting.

MONICA HALL-PORTER: Well, you shouldn't.

DAVID POGUE: Compared to proteins, lipids, or fats, do get a bad rap. But in addition to their role in cell membranes and long-term energy storage, you know, body fat, they also provide protection for internal organs.

Oh, and don't forget the lipids in earwax.

MONICA HALL-PORTER: And so, literally, there's fat in every part of you.

DAVID POGUE: So, even a slim, lean, handsome physically fit person could have 30 pounds of fat in him?

MONICA HALL-PORTER: Absolutely.

DAVID POGUE: Next up, the third most common macromolecule type...

Oh, this is my kind of food group.

...carbohydrates.

Sugar.

MONICA HALL-PORTER: Sugar.

DAVID POGUE: Does this count as carbs?

MONICA HALL-PORTER: Absolutely.

DAVID POGUE: While I would have thought I was sweeter, turns out, on average, there's only about two pounds of carbs in me.

Glucose is the most abundant carb in the human body. It circulates to provide energy for cells.

Now we're talking carbs, carb city, carb heaven, carb central.

MONICA HALL-PORTER: We are in the bread aisle, my friend.

DAVID POGUE: I like it.

MONICA HALL-PORTER: We can toast this up and put some butter on it.

DAVID POGUE: Many glucose molecules joined together can make a plant starch, the kind you find in cereals and root vegetables. It's the most common carb in the human diet.

So, did I under...

DAVID POGUE: Hey! We're working here.

MONICA HALL-PORTER: So, we've got lipids...

DAVID POGUE: Yeah.

MONICA HALL-PORTER: ...proteins...

DAVID POGUE: Yeah.

MONICA HALL-PORTER: ...and carbohydrates.

DAVID POGUE: Yeah, the three macromolecules of the human body.

MONICA HALL-PORTER: Right, but we are missing one.

DAVID POGUE: There's another one?

MONICA HALL-PORTER: Yeah, we don't have anything that's representative of nucleic acids.

DAVID POGUE: Nucleic acids are better known as D.N.A. and R.N.A. D.N.A. is the famous double helix. It's usually two long chains of molecules that wrap around each other. It contains genetic instructions for making proteins.

R.N.A. is often a long molecular chain, as well. If D.N.A. is the cookbook, R.N.A. is the chef, reading D.N.A.'s instructions for proteins, gathering the ingredient amino acids and assembling them in the right order, in a macromolecular "protein printing" machine called a "ribosome."

Life on Earth exists in a spectacular variety of forms, but in the end, it all depends on the arrangement of a handful of different small molecules, the nucleotides in the nucleic acids D.N.A. and R.N.A.

And we are now arriving at the D.N.A. aisle.

MONICA HALL-PORTER: Alrighty.

DAVID POGUE: And why strawberries?

MONICA HALL-PORTER: Well, strawberries actually have eight copies of each chromosome per cell, so, relative to other fruits, strawberries are actually very rich in D.N.A.

DAVID POGUE: Wow. All right. Here's our "D.N.A.e-berries."

MONICA HALL-PORTER: Alrighty.

DAVID POGUE: Actually seeing D.N.A., you know, the code of life has always seemed beyond the reach of ordinary folks. You can't just find some, can you?

So, when you said we were going to extract D.N.A. from strawberries, I figured we would go to some humming, high-tech lab with millions of dollars of equipment.

MONICA HALL-PORTER: No, actually D.N.A. extraction from strawberries is something that can be achieved at home.

DAVID POGUE: As it turns out, using some easily available household items, like plastic bags, detergent, rubbing alcohol, cheesecloth and strawberries, along with a little bit of waiting time, you, too, can catch a glimpse of the code of life, D.N.A.

MONICA HALL-PORTER: There it is. You'll actually see an accumulation of white, stringy substance.

That's actually a very crude prep of D.N.A.

Basically, what's going to happen is it's going to clump on the end of your glass rod.

DAVID POGUE: Strawberry D.N.A. slime, right there.

Pretty amazing! And so are the other three macromolecules that make up my body. But all their wondrous complexity raises a deeply mysterious question: How did chemistry give rise to biology?

How did life get its start?

A famous experiment, in 1952, suggested the answer might not be that hard to find. At the University of Chicago, graduate student Stanley Miller, with help from his doctoral advisor, Harold Urey, mixed what were then thought to be the dominant ingredients of Earth's early atmosphere: methane, ammonia and hydrogen, inside some sealed glassware. Boiling water added water vapor to the mix. Then, Miller created sparks between electrodes, simulating lightning, and let the mixture cool and condense.

After running the experiment for a week, Miller found five amino acids, some of them critical building blocks of proteins.

JACK SZOSTAK: You know, it was a dramatic breakthrough, at the time, for people to realize amino acids could be made in such a simple way.

DAVID POGUE: At Massachusetts General Hospital, Jack Szostak runs one of the several research labs around the world that are trying to figure out how chemistry gave rise to biology.

ANNA WANG (UNSW Sydney): So, this is like increasing the amount of sodium hydroxide. And so, increasing...

JACK SZOSTAK: Oh, okay.

DAVID POGUE: Today, it's clear even the Miller-Urey experiment, while groundbreaking, just scratched the surface of the problem.

JACK SZOSTAK: In retrospect, it kind of fooled people into thinking that the answer might be easier than it turned out to be.

And once you've got the right chemicals, then what?

DAVID POGUE: Right, right.

JACK SZOSTAK: How do a bunch of chemicals get together and start acting like a cell?

DAVID POGUE: A key requirement seems to be a container. All life on Earth, from the simplest to the most complex, is made of cells with outer membranes.

So, on the road to life, how did that happen?

Scientists like Anna Wang, a former postdoc in Jack Szostak's lab, now a professor at UNSW, Sydney, have been working with a simple molecule that is one of the prime suspects.

It's also present here...

ANNA WANG: Wow.

DAVID POGUE: ...shaped into bars, in a wide variety of colors and scents...

Smells good in here.

ANNA WANG: Smells amazing.

DAVID POGUE: ...at Molly's Apothecary, outside of Boston.

ANNA WANG: Oh, that's wonderful.

DAVID POGUE: That's right: soap.

Soap's interesting, because a soap molecule is a combination of two different types of molecules, called polar and non-polar. For example, water molecules are polar. Each one has a concentration of electrons in one part, making it negative, which leaves another part more positive. That's polarity. And it makes water molecules want to stick together, each negative part attracted to another molecule's positive part.

An oil molecule, made up of carbon and hydrogen, is an example of a non-polar molecule. It has an even distribution of electrons: no polarity and less stickiness between molecules. In fact, polarity is why oil and water don't mix. The polar water molecules stick together, keeping the oil molecules at bay. The less dense oil floats on top.

That's also why trying to clean oily grease off your hands with water alone, doesn't work very well.

It actually won't come off, it's super oily.

The two just don't interact. And that's where soap molecules come in. They're hybrids. At one end, are some negatively charged, electron-rich oxygens, ready to interact with polar molecules, like water, but the rest is a long, non-polar hydrocarbon tail, with no positive or negative charge. It's more comfortable mixing with other non-polar molecules, like grease.

Put some soap on your greasy hands...

Soapy!

...and the soap's non-polar tails stick into the grease, while its polar heads act like handles, ready to interact with the water, taking the grease along for the ride.

Here's another interesting soap fact. Drop some soap into water and the molecules form little balls called "micelles," with their water-loving polar heads sticking out and their water-hating non-polar tails sticking in.

That naturally occurring little container has piqued the interest of scientists like Anna. Back at the lab, she adds some soap molecules to water containing short fragments of R.N.A. They've been tagged with a molecule that makes them glow.

Why R.N.A.? The current scientific consensus is that a primitive form of R.N.A. may have been the first molecule with the ability to replicate itself, jump-starting evolution.

Next stop...

ANNA WANG: Now, we're going to go look at it under the microscope.

DAVID POGUE: ...the microscope room...

ANNA WANG: Let's go.

DAVID POGUE: ...where Anna loads up a sample she prepared yesterday.

ANNA WANG: So, this is what our soap molecules have self-assembled into overnight.

DAVID POGUE: What are they? Bubbles?

ANNA WANG: Yes, they are almost like bubbles. And so, what we are looking at here is not the soap molecules themselves but what they've been able to trap inside these cell-sized structures.

DAVID POGUE: Overnight, the soap micelles have self-assembled into larger spheres, trapping the fluorescing R.N.A. inside. And if we could zoom into one of them, we'd see that it actually consists of two layers of soap molecules, arranged with the water-loving heads toward the inside and outside, and the water-hating tails brought together.

ANNA WANG: When you have molecules that have a polar head group and a non-polar tail, but you don't give them any oil to interact with, the oily tails actually want to interact with each other, and so you end up forming these bilayer structures.

DAVID POGUE: Wait, so these are soap molecules and these are also soap molecules?

ANNA WANG: Yeah.

DAVID POGUE: And they like to assemble into this position?

ANNA WANG: Yeah, that's right. So, they like to form these really thin envelopes, and you can imagine this structure extending onwards and onwards and curving around and forming a sphere. And that's what we're seeing here. We're seeing this bilayer structure, encapsulating some green-dyed R.N.A. molecules.

DAVID POGUE: This lipid bi-layer structure isn't alive, but it's familiar to biologists. It's similar to the bilayer structure of the membranes that surrounds something that is alive, cells.

Of course, those are much more complicated and more stable containers, better at keeping things in or out, though that feature comes at a price.

ANNA WANG: If you take the membranes that we have now, but get rid of all the highly evolved protein machinery, what you're left with is just an inert sack. It can't grow, it can't divide. It can't even get nutrients in and out.

DAVID POGUE: That's why, in the days of proto-life, less-stable membranes built out of simpler molecules, like soap, may have been an advantage.

Anna shows me an example.

ANNA WANG: So, what I am about to do is I have some soapy water in here, and I'm just going to add it. What happens is the soap molecules start incorporating onto the existing membrane.

DAVID POGUE: Look at this. Look at this.

ANNA WANG: Yeah.

DAVID POGUE: It just split.

ANNA WANG: They look pretty spherical now, but they're starting to wiggle a bit. And all of a sudden, it looks like they might melt.

DAVID POGUE: Cell division.

Wow.

Our cells grow and divide, because we have something giving instructions.

ANNA WANG: Yes.

DAVID POGUE: But you're saying that, billions of years ago, none of that existed.

ANNA WANG: There's none of that in here. So, what we're kind of simulating is a condition where maybe these protocells have floated somewhere down the stream, and they've come across a pool of excess soap molecules, and these soap molecules can join the membrane and grow it.

So, I think what it means is that we can still get simple cells to divide by purely physical mechanisms, and that's what we're trying to understand in the field, like how do you get to do things that kind of seem like life and mimic life but without any biology?

DAVID POGUE: In the early days of Earth, soap or similar molecules may have self-assembled into cell-like containers.

Do they have the bilayer thing already?

JACK SZOSTAK: They have the bilayer membrane.

DAVID POGUE: But Jack Szostak realizes that's just a start. There are many more steps on the road from chemistry to biology.

JACK SZOSTAK: Once you got the right kinds of molecules, which are pretty simple, they can assemble into membranes. But they can't actually start to do anything interesting in terms of, like, getting more complicated and being more, like, more and more advanced life, until you have genetics.

DAVID POGUE: Yeah.

JACK SZOSTAK: You needed hereditary materials, something like R.N.A. or D.N.A.

And once you've done that, you have cycles of replication, because that's got to go on inside this protocell. And it has got to happen just by chemistry and physics, because there were no enzymes. There was no evolved machinery, right?

DAVID POGUE: Right.

JACK SZOSTAK: So, in a sense, the answer has to be simple.

DAVID POGUE: Yeah.

JACK SZOSTAK: And we just have to figure out how it works.

DAVID POGUE: Scientists like Jack and Anna are searching for the mysterious road that led not only to life but to the mechanism that's allowed it to overcome adversity, evolution.

Today, some scientists wonder, what if we could harness evolution's creative power to solve some of our own challenges?

Wow.

FRANCES ARNOLD: Nature is constantly changing...

DAVID POGUE: Hi, boys.

FRANCES ARNOLD: ...because there is this tremendous effort to survive. And if you can harness that power, that innovation that nature is doing, and direct it in a beneficial way, then we can use that power of innovation to solve some of our really tough problems.

DAVID POGUE: Harnessing the innovative power of evolution is at the heart of the work of chemical engineer Frances Arnold, of Caltech, in Pasadena, California.

That could be a huge deal in the world.

FRANCES ARNOLD: I hope so.

DAVID POGUE: And she's used it to engineer new molecules to solve a wide range of problems, from the search for new antibiotics, or methods to convert waste into biofuels, to teaching cells to bond elements in ways never before seen in nature.

FRANCES ARNOLD: So, do come if you are interested in the process of protein engineering, because that's the future. So, all of you....

DAVID POGUE: She's achieved her successes by discovering new catalysts, the materials that speed up chemical reactions without getting consumed by them.

In living things, catalysts are called enzymes, for example the protein rubisco. Enzymes help facilitate the reactions that make life possible.

FRANCES ARNOLD: The reason that you and I can sit here and talk is that we have thousands of catalysts in us, proteins that can convert the food we eat into the thoughts that you think and the motor mouth, right? These are catalysts that do all this chemistry. These are chemical transformations that make life possible.

DAVID POGUE: In fact, they work so well, engineers and scientists have wanted to find a way to co-opt the idea, to create new enzymes that would do our bidding, assisting reactions that aren't found in nature at all.

The question is how?

FRANCES ARNOLD: Many scientists and engineers feel that in order to design a new product, you sit down and you calculate, you know, the right angles and the right weights and loads.

I come from a different point of view, that these very complicated things are the products of evolution. So, I say, "Let's just go straight to the answer, using this gift given to us."

DAVID POGUE: Frances uses an approach called "directed evolution."

FRANCES ARNOLD: One way to think about directing evolution is it's like breeding. It's like breeding cats or dogs.

DAVID POGUE: With a specific end goal in mind, she starts with D.N.A. that encodes for some protein catalysts that have some promising traits, depending on what she's looking for. The D.N.A. gets copied in a way that produces random mutations. She puts that into microorganisms that multiply and produce a variety of slightly different proteins.

FRANCES ARNOLD: So, you have a gene, the organism breeds the gene, makes the proteins, and they're all slightly different, just like your children. But now, I can decide who goes on to parent the next generation, because I measure what those proteins do.

DAVID POGUE: Frances tests the results to see if any represent a step in the right direction. If so, that becomes the new starting point, and she repeats the process.

FRANCES ARNOLD: To see how quickly you can train enzymes, that's what we're doing, we're training them, we're breeding them to do something that perhaps nature never did before.

When you discover that they've learned how to do that and they do it better than any human can do, it is so exciting.

DAVID POGUE: To see how directed evolution is applied outside the lab, Frances suggested that I contact one of her former students, Pedro Coelho. Along with a partner, she and Pedro founded a company, Provivi, based in Santa Monica. Pedro is the C.E.O.

Provivi makes a chemical to fight this agricultural pest, the fall armyworm.

PEDRO COELHO: It's a pest that is native to the Americas, but in the last three years, it's invaded all of Africa, and now, all of Asia, going from India to China. And it's a very difficult pest to control, because once it infests the corn, it hides inside of the corn plant where the insecticides can't touch it.

DAVID POGUE: But Provivi's chemical isn't a pesticide; it doesn't kill anything, instead, it disrupts the way fall armyworms mate.

Here's how it works: fall armyworms eventually become adult moths and that's when they mate.To attract males, female moths release a pheromone, a molecule that acts as a chemical signal.

PEDRO COELHO: So, the female moth will release a little bit of pheromone, and then the male will pick up that signal with his antenna and will fly towards her to mate and reproduce.

DAVID POGUE: She uses only a small amount, but it is incredibly potent. It can attract males from up to a mile away.

FRANCES ARNOLD: These are complicated molecules. These are the Chanel® No 5 of insects.

DAVID POGUE: But such a powerful "sex perfume" can be become a means of control.

FRANCES ARNOLD: So, imagine now you come with a bottle of Chanel No 5, and you spray it everywhere, then he can't find her, and they don't mate and have caterpillars.

DAVID POGUE: Provivi has figured out how to replicate the fall army pheromone and put it into a slow-release spray for crops, which you have to imagine is very confusing for the male moths.

They have so much trouble finding females that in the end there are fewer eggs and worms.

So, you're not killing these things, and you're not driving them away, you're just confusing them.

PEDRO COELHO: Yeah, so it's not a repellant, and it's not a kill agent, it's simply a mating disrupter.

DAVID POGUE: Pedro tells me using pheromones to combat pests isn't new, but until now, it's been expensive and therefore limited to high-value smaller crops like apples or grapes.

So, the real breakthrough at Provivi isn't using pheromones but making them inexpensively. They've studied the enzyme catalysts the insect uses to make the pheromone and moved the genes for those enzyme catalysts into yeast. Then, through directed evolution, they optimized those little yeast cell factories for larger scale production in vessels similar to those used for brewing beer.

PEDRO COELHO: And the key is that by just changing the microbe, we can make many different pheromones. But using the same infrastructure, which gives us the economies of scale, should make this cost effective.

DAVID POGUE: Making it possible to use on staple crops grown around the world, like corn and rice.

PEDRO COELHO: Our mission, very much, is to take this proven tool of pheromones to the largest markets of agriculture, which are the staples of humankind.

DAVID POGUE: Companies like Provivi aren't the only sign directed evolution and cell factories are having a big impact on manufacturing.

FRANCES ARNOLD: Well, I teach this course, called Reaction Engineering, which is how do you take chemical reactions and scale them up?

DAVID POGUE: In 2018, Frances Arnold won the Nobel Prize in Chemistry, for her pioneering work in directed evolution.

Is this idea of chemistry and biology to manufacture stuff, is that catching on these days?

FRANCES ARNOLD: It is. It most definitely is. I think the future is so exciting, because now what happens is with these tools of being able to manipulate D.N.A. and the code of life, really, we can now merge all these beautiful mechanisms of the biological world with the inventions of human chemistry. And that way it merges in new innovations.

DAVID POGUE: That both chemists and biologists have a lot to learn from each other should come as no surprise, but what is surprising is that biology would arise out of chemistry at all.

Look at this. Look at this. Cell division.

The blueprints of life.

The origin of life remains one of the great unsolved mysteries of science. Was the mix of chemicals on early Earth destined to give rise to life? And once it started, was the road that lead to the chemical complexity of photosynthesis and the harnessing of the power of the sun...

LISA AINSWORTH: Probably the most important process on the planet.

DAVID POGUE: ...the only road to be taken? Are we alone in the universe, or just the local branch of Cosmic Bio-Chem? The answers to questions like these will only be found through science, as we go Beyond the Elements.

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PBS Airdate: February 17, 2021 DAVID POGUE (Science and Technology Author): What's it take to make our modern world? Ah! Dah! That's amazing! I'm David Pogue. Join me on a high-speed chase through the elements and beyond. Oh, my god. As we smash our way into the materials, molecules and reactions...

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Transcription and Translation (Steps in Protein Synthesis) - Amoeba Sisters #Shorts

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Meet the animal influencers that play an oversize - and often surprising - role in shaping our world.

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Photosynthesis in plants and a few bacteria is responsible for feeding nearly all life on Earth. It allows energy from the sun to be converted into a storable form, usually glucose, which plants use to grow and thrive. Photosynthesis also generates the oxygen that animals need to survive. But here we animals repay the favor. We exhale the carbon dioxide that plants need for photosynthesis. Here, take a closer look at the oxygen/carbon dioxide cycle and the process of photosynthesis.

This feature originally appeared on the site for the NOVA program Methuselah Tree.

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Illuminating Photosynthesis - NOVA | PBS

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Photosynthesis in plants and a few bacteria is responsible for feeding nearly all life on Earth. It allows energy from the sun to be converted into a storable form, usually glucose, which plants use to grow and thrive. Photosynthesis also generates the oxygen that animals need to survive.

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What Is Evolution, Anyway? - 12 Days of Evolution #1 | It's Okay to Be Smart | PBS LearningMedia

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Some of the biggest evolution questions finally answered.

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Mitosis in Real Cells

Introduction:

To study mitosis, biologists often look at particular cells. Remember, that mitosis occurs only in areas of growth, so finding a good spot to study it can be challenging. Two specimens are commonly used by biologists to study mitosis: the blastula of a whitefish and the root tip of an onion.

The whitefish embryo is a good place to look at mitosis because these cells are rapidly dividing as the fish embryo is growing. The onion root is also a good place because this is the area where the plant is growing. Remember that when cells divide, each new cell needs an exact copy of the DNA in the parent cell. This is why mitosis is only visible in cells that are dividing, like the whitefish embryo and the onion root tip.

Mitosis can take several hours to complete. Scientists will make slides of cells that should be undergoing mitosis in order to find a particular cell in any of the stages - prophase, metaphase, anaphase, telophase. Remember that most cells you see will be in interphase, that's the cells "resting" state. Your task is to look at photographs of actual slides and identify the stages of mitosis. Answer the questions on each page in your lab notebook or print this first page and answer direction on it.

Tasks:

View slide images of a whitefish blastula and an onion root to see cells in various stages of mitosis. Answer the questions as you read the introduction and view the slides.

You may want to print this page out to answer the questions on it, or just answer questions (#1-5) on your own paper.

Introduction:

1. Why is the whitefish used to study mitosis?

2. What are the four stages of mitosis?

3. How long does it take for mitosis to complete? Why will most of the cells you view be in interphase?

View Cells

4. For each specimen list sketch and label the phases of mitosis

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To study mitosis, biologists often look at particular cells. Remember, that mitosis occurs only in areas of growth, so finding a good spot to study it can be challenging. Two specimens are commonly used by biologists to study mitosis: the blastula of a whitefish and the root tip of an onion.

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The DNA Song (Parody of Fetty Wap - Trap Queen)

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https://youtu.be/yYt_ioqLYtw?feature=shared

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What could you possibly have in common with a mushroom, or a dinosaur, or even a bacterium? More than you might think. In this Lab, you'll puzzle out the evolutionary relationships linking together a spectacular array of species. Explore the tree of life and get a front row seat to what some have called the greatest show on Earth. That show is evolution.

BUILD A TREE & DEEP TREE ACTIVITIES
DEVELOPED BY THE LIFE ON EARTH PROJECT

Video Intro About this Lab Educator Guide

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What could you possibly have in common with a mushroom, or a dinosaur, or even a bacterium? More than you might think. In this Lab, you'll puzzle out the evolutionary relationships linking together a spectacular array of species. Explore the tree of life and get a front row seat to what some have called the greatest show on Earth.

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Video computer games, virtual labs and activities for learning and reviewing biology content. Great for students and teachers.

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The Origin of Species: The Beak of the Finch

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This film explores four decades of research on the evolution of Galápagos finches, which has illuminated how species form and diversify.

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Mammoth Science - DNA Replication to Protein Interactive Simulation

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DNA Replication to Protein Interactive Simulation

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Party With the DNA (DNA Replication and Protein Synthesis Song)

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Your Inner Fish
Our arms, legs, necks and lungs were bequeathed to us by a fish that lumbered onto land some 375 million years ago. The genetic legacy of this creature can be seen today in our own DNA, including the genes used to build our hands and limbs.

Aired: 04/09/14

Expires: 12/31/22

Rating: NR

Problems Playing Video? Report a Problem |

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Your Inner Fish Our arms, legs, necks and lungs were bequeathed to us by a fish that lumbered onto land some 375 million years ago. The genetic legacy of this creature can be seen today in our own DNA, including the genes used to build our hands and limbs.

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I hope this 4 minute animation on Evolution could come in handy when teaching it .. I have to add Sir David Attenborough approved of it!! | By Sheila Graber | Facebook

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1.4K views, 54 likes, 15 loves, 7 comments, 30 shares, Facebook Watch Videos from Sheila Graber: I hope this 4 minute animation on Evolution could come in handy when teaching it .. I have to add Sir...

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Genetic Engineering Will Change Everything Forever – CRISPR

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Hans Rosling: Global population growth, box by box

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Snurfle Meiosis and Genetics

Topics Covered: The connection between meiosis, fertilization and genetics, Meiosis, genes, alleles, chromosomes, phases of meiosis I and II (prophase, metaphase, anaphase and telophase), interphase, cytokinesis, homologous chromosomes, sister chromatids, fertilization, genetics, genetic terms (homozygous, heterozygous, genotype, phenotype etc.)

Check out the Worksheet that goes along with the game (courtesy of Ms. Pam Robinson)!

Here is another version of the Worksheet that goes along with the game (courtesy of Ms. Cindy Sutyak)!

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Video computer games, virtual labs and activities for learning and reviewing biology content. Great for students and teachers.

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Chasing Carbon Zero | Full Documentary | NOVA | PBS

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Overpopulation – The Human Explosion Explained

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Independent, Dependent, and Control Variables

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Independent, Dependent, and Control Variables

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How Do Cells Divide - Phases Of Mitosis - Cell Division And The Cell Cycle - Cellular Division

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Mitosis Bling (Science Hotline Bling Parody)

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Wordwall - Create better lessons quicker

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Maze chase - Run to the correct answer zone, whilst avoiding the enemies.

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Wordwall - Create better lessons quicker

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Labelled diagram - Drag and drop the pins to their correct place on the image.

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Breakout Mitosis & Meiosis

START

GO!

Using a special laser beam, your class has been shrunken down to enter and explore a dividing cell. However, in order to grow back to normal size, everyone must be located outside of the cell. You must use your knowledge of mitosis and meiosis to escape the cell. Answer the questions at each level and be sure to record each answer. Once allfour questions have been answered, use the decoder to progress to the next level. You must hurry to escape the cell before your entire class stays small forever!

MISSION 03

MISSION 04

MISSION 02

MISSION 01

CODE

MISSION 05

Click around the lab to see if there are any clues help you escape!

Take a GOOD look at the clock. You will need it to complete this mission!

Didn't mean to start mission 5? Click here to go back to the lab.

MISSION 01

START

Take a look at the clock

D. Telophase

C. Anaphase

B. Metaphase

A. Prophase

Identify this stage of mitosis:

Mission 1: Question 1

Take a look at the clock

D. Telophase

C. Anaphase

B. Metaphase

A. Prophase

Identify this stage of mitosis:

Mission 1: Question 2

Take a look at the clock

D. Telophase

C. Anaphase

B. Metaphase

A. Prophase

Identify this stage of mitosis:

Mission 1: Question 3

Take a look at the clock

Take a look above and compare your answers. You'll need it for the next page!

D. Telophase

C. Anaphase

B. Metaphase

A. Prophase

Identify this stage of mitosis:

Mission 1: Question 4

Using the clock, identify the correct code to escape this mission.

Compare the clock & your answers

Take a GOOD look at the yarn. You will need it to complete this mission!

Didn't mean to start mission 5? Click here to go back to the lab.

MISSION 02

START

D. Meiosis cells divide once

C. Meiosis produces identical cells

B. Mitosis only occurs in sex cells

A. Mitosis results in 2 cells, meiosis in 4

Which is correct about the difference between mitosis and meiosis?

D. Centrioles

C. Centromeres

B. Chromosomes

A. Centrosomes

What are the set of microtubules which move to opposite ends of the cell to aid in cell division called?

D. Spindle fibers form

C. Nuclear envelope dissolves

B. Centromeres divide

A. Chromosomes coil up

Which of the following does not occur during Prophase in mitosis?

Take a look above and compare your answers. You'll need it for the next page!

D. Parent cells

C. Daughter cells

B. Sister cells

A. Brother cells

What are the two resulting cells formed from a single cell called?

Look at the yarn & identify the correct code to escape this mission.

"ABCD" "1234" - find the code

TRY AGAIN

MISSION 03

Take a GOOD look at the dice. You will need it to complete this mission!

Didn't mean to start mission 3? Click here to go back to the lab.

START

Proteins

Enzymes

Ribonucleic acid

Deoxyribonucleic acid

What types of genetic information must be copied for the next generation of cells?

Telophase

Anaphase

Metaphase

Prophase

During which stage of mitosis do chromosomes separate?

Chromosomes begin to move toward opposite poles

Spindle fibers dissolve

Chromosomes uncoil

Nuclear envelope forms

Which of the following does not occur during Telophase?

Take a look above and compare your answers. You'll need it for the next page!

Flagella

Kinetochores

Spindle fibers

Cilia

The protein fibers that extend from centrioles and attach to chromosomes to pull them apart are called

Look at the dice & identify the correct code to escape this mission.

Hint:Compare the dice and your answers.

MISSION 04

Take a GOOD look at the shapes. You will need this to complete this mission!

Didn't mean to start mission 4? Click here to go back to the lab.

START

Mission 4: Question 1

None of these

They are both involved in cell division

All organisms go through both mitosis and meiosis

Both occur in only animal cells

Which is true regarding both mitosis and meiosis?

Mission 4: Question 2

All of these

Unicellular organisms

Sperm cells

Liver cells

Which of the following undergo meiosis?

Mission 4: Question 3

Centriole: DNA & Sugar

Centromere: Protein & Fat

Centriole: DNA & Proteincells

Chromosome: DNA & Protein

Which correctly pairs this structure with what its made from?

Take a look to the left and compare your answers. You'll need it for the next page!

Mission 4: Question 4

Nuclear envelope dissolves

Spindle fibers pull on the chromosomes

Chromosomes move towards opposite poles

Centromeres divide

Which of the following does not occur during Anaphase?

Look at the shapes & identify the correct code to escape this mission.

Compare the shapes and your answers.

MISSION 05

Take a GOOD look at the puzzle. You will need this to complete this mission!

Didn't mean to start mission 5? Click here to go back to the lab.

START

D. Requires a male and a female to reproduce

C. Muscle cells reproduce in this way

B. More complex than mitosis

A. Final cells have half of the DNA

Which of the following is not true about meiosis?

D. . Meiosis

C. . Criss-Crossing

B. Independent assortment

A. Crossing over

What is the exchange of genes between homologous chromosomes called?

D. . Independent Assortment

C. . Crossing over

B. Recombination

A. Crossing over

What is the random distribution of chromosomes during meiosis called?

D. Mitosis: 2 sets of 46 chromosomes

C. Mitosis: 1 set of 23 chromosomes

B. Meiosis: 1 set of 23 chromosomes

A. Meiosis: 2 sets of 23 chromosomes

Which is correctly matched with the appropriate number of chromosomes in each daughter cell?

Look at the puzzle & identify the correct code to escape this mission.

Compare the puzzle and your answers.

You have reached the last step to unlock the laboratory 🧪, go ahead!

Code you gathered along your way

TRY AGAIN

EMERGENCY

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This game is all about punnett squares and genotypes.

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start

evolution ESCAPE ROOM

Welcome to the

PARADISE

??

DESERT OF DOUBTS

VALLEY OF THE LOST LETTERS

FIREDOOR

03

02

01

Embryology

Homologous

Analogous

TEST 01

What evidence of evolution would apply to the image below?

TEST 01

What evidence of evolution would apply to the image below?

Embryology

Fossil Record

Biogeography

TEST 01

What evidence of evolution would apply to the image below?

DNA Sequences Differences

Vestigial Structures

Homologous

TEST 01

What evidence of evolution would apply to the image below?

DNA Sequences Differences

Biogeography

Fossil Record

right!

Continue

back

WRONG. Watch the video to help you.

PARADISE

DESERT OF DOUBTS

VALLEY OF THE LOST LETTERS

FIREDOOR

??

03

02

01

each wing has differing structure but similar function

Each wing has similar structure and similar function

Each wing has similar structure but differing function

How do we know this is evidence of evolution is an analogous structure?

test 02

How do we know this is evidence of evolution is embryology?

TEST 02

The embryos are similar in the beginning stages of formation up to a certain period during gestation.

The embryos have similarities throughout the entire period of development.

The embryos are similar in the ending stages of formation where it is more evident of common ancestry.

Look at the figure below of the fossil record of a whale. Their transition to an aquatic lifestyle occurred long before they eliminated their hind limbs. During the transition, their limbs became smaller, but they kept the same number and arrangement of hind limb bones as their terrestrial ancestors. According to the image below, is this a true or false statement?

TEST 02

True

False

Continue

right!

back

wrong. Watch the video to help you.

PARADISE

DESERT OF DOUBTS

VALLEY OF THE LOST LETTERS

FIREDOOR

??

03

02

01

Which picture below shows a vestigal structure?

test 03

TEST 03

Which picture below shows a homologous structure?

According to these DNA sequences, which one is least likely to be part of the genome?

TEST 03

orangutan

Chimpanzee

Gorilla

Continue

right!

back

wrong. Watch the video to help you.

03

02

01

PARADISE

DESERT OF DOUBTS

VALLEY OF THE LOST LETTERS

FIREDOOR

??

FINAL TEST

Memorize the secret key to continue

REward

Start with the arrow and use the clue from the previous screen to determine which green box is your exit.

Click here for the clue again.

FINAL TEST

back

wrong!

FINAL TEST

exit

YOU'VE ARRIVED IN PARADISE!

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Human Impact on the Environment | Genially

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