Timeline of Earth by Jocelyn Cach-Xec

The Great Oxidation

jcach27_1 — 2023-10-24 18:29:30 UTC

(524 million years ago)

The Great Oxygenation was when free oxygen filled the atmosphere. Cyanobacteria are prokaryotes, which are known to be the earliest forms of life. Long ago, oceanic cyanobacteria evolved to carry out photosynthesis to make energy for themselves. Over time, these cyanobacteria released oxygen as a waste product. So much oxygen, that it kept building up in the oceans. Free oxygen had intense effects on the planet. It triggered an oxygen crisis, it froze over the whole planet and it rusted iron to form banded iron formations. The reason why this event is called an “oxygen crisis” is that they threatened their own existence. Cyanobacteria didn’t completely vanish. By hiding in low-oxygen environments, cyanobacteria avoided a mass extinction. Eventually, life evolved to use this oxygen and now the ecosystem keeps itself in balance this way.

The Cambrian Explosion

jcach27_1 — 2023-10-25 01:52:16 UTC

"Biology's Big Bang" - 524 million years ago, the most developed organisms were simple animals living in the oceans. Over a period of 20 million years, at the beginning of a period called the Cambrian, an explosion of new animals developed below water's surface. The cause of the Cambrian Explosion however is still unknown. This caused a wide variety of animals to burst onto the evolutionary scene. In perhaps as few as 10 million years, marine animals evolved most of the basic body forms that we observe in modern groups. Among the organisms preserved in fossils from this time are relatives of crustaceans and starfish, sponges, mollusks, worms, chordates, and algae, exemplified by these taxa from the Burgess Shale. Cambrian animals didn’t just pop up out of nowhere. Early animal fossils from the pre-Cambrian era have been discovered. Around 575 million years ago, there was a mysterious group of animals living in the oceans called the “Ediacarans.” While there is little we know about these creatures, it’s possible that they may have included some of the ancestors of the lineage we know today as the “Cambrian explosion.”

Compartments

jcach27_1 — 2023-10-25 01:53:41 UTC

Compartments - This transition takes us from self-replicating molecules to self-replicating molecules in 'compartments' -membranes of some sort. A compartment separates 'self' from 'other', and it's crucial to life as we know it. When did this happen? About 4.4 billion years ago, when the Earth first got a solid crust. Probably after 3.85 billion years ago, when the Late Heavy Bombardment ended. Before 3.3 billion years ago, which is the age of the Isua greenstone belt- a formation that contains graphite specks with less carbon-13 than average, a hint of life.

End Ordovician (444 million of years ago)

jcach27_1 — 2023-10-25 01:54:17 UTC

There were two distinct extinctions roughly a million years apart. Together, these extinctions may have removed about 85 percent of species of marine animals. The evidence indicates that climate change caused the extinctions. A major ice age is known to have occurred in the southern hemisphere and climates cooled worldwide. The first wave of extinctions happened as the climate became colder and a second pulse occurred as climates warmed at the end of the ice age.

1. The Cenozoic Era

jcach27_1 — 2023-10-25 01:54:29 UTC

Dinosaurs evolved from a group of dog and horse-sized creatures into their enormous size over time.

Some Dinosaurs even shrank over time and evolved into birds, when that happened only the non-avian dinosaurs went extinct.
The dinosaurs first appeared in the Triassic period more than 200 million years ago.
These dinosaurs roamed the supercontinent of Pangea.

Major evolutionary changes that lead to humans dominating their environment and becoming more intelligent

jcach27_1 — 2023-10-25 01:57:24 UTC

Humans were first able to evolve because of the last major mass extinction, the asteroid that killed the dinosaurs, without this mammals wouldn't have gotten a chance to evolve and thrive, eventually creating humans also.
There were once several other species of humans alive, but we were able to survive amongst the others, we do not know for sure why they went extinct but there is an assumption that environment changes and homo sapiens have more desirable traits would have been the cause for our success and their demise.
We were able to become more intelligent because of our social environment, and we evolve because of this, being able to share information quickly through language unlike other animals have to show it visually, as time passed, humans evolved and created new tools, and language improved and become more complex allowing for even better cooperation, and that got us to where we are today.

Late Devonian (360 million of years ago)

rcast272_1 — 2023-10-26 04:05:34 UTC

Animals that went extinct in the Late Devonian are jawless fish, brachiopods, ammonites, and trilobites. The Devonian is known as the Age of Fishes, as it spawned a remarkable variety of fish. The Devonian period ended with a tragic extinction event, particularly devastating to warm-water marine communities. The Late Devonian, changes in sea level and ocean anoxia, possibly triggered by global cooling or oceanic volcanism.

End Permian (250 million of years ago)

rcast272_1 — 2023-10-26 04:15:01 UTC

The main cause of this extinction was the flood basalt volcanic eruptions that created the Siberian Traps, which released sulfur dioxide and carbon dioxide, resulting in euxinia and anoxia, elevating global temperatures, and acidifying the oceans. Animals that survived the Permian are ancestors of mammals and birds, as well as tetrapods like synapsids and archosaurs. At the end of the Permian 90 percent of the planet's species.

End Triassic (200 million years ago)

rcast272_1 — 2023-10-26 04:15:36 UTC

All major groups of marine invertebrates survived this extinction. The causes of this are still unknown, but what is now the Atlantic Ocean experienced massive volcanic activity. People thought that this is when dinosaurs were killed but it's not true. What ended the End Triassic is the volcanic eruptions in the Central Atlantic Magmatic Province. The end-Triassic extinction particularly affected the ammonoids and conodonts. Animals that survived the End Triassic are Alligators, Crocodiles, Birds, Frogs and Salamanders. These decimated 76 percent of marine and terrestrial species.

End Cretaceous (65 million years ago)

rcast272_1 — 2023-10-26 04:16:01 UTC

The event that killed all the dinosaurs except the birds. The Frogs and salamanders survived these. Cretaceous period suggests that mass extinction only took about 32,000 years. Tardigrades are the only ones that survived all the 5 extinctions. After the dinosaurs died the Pantolambdas took over.

2. The Paleozoic Era

alope278_3_1 — 2023-10-26 18:03:27 UTC

A creature on earth that roamed this era about 541 million years ago was the trilobite.
They lived in this era for around 300 million years, they were some of the first multicellular animals to live in the ocean.
The name comes from the distinctive three-fold longitudinal division of the dorsal exoskeleton into a central axis flanked on either side by latera areas.
The body of the trilobite has a head-shield which is made up of fused segments.
The reason the trilobites were an interesting species was because they served as index fossils, which allowed scientists to date the age of rocks that were nearby.

3. The Mesozoic Era

alope278_3_1 — 2023-10-26 18:05:07 UTC

The Repenomamus Robustus was one of the "largest" known mammals in the Mesozoic Era.
This animal weighed around 5kg and was about the size of 50 cm in overall length.
These animals fed on dinosaurs whether they were alive or dead they were their food supply.
The Repenomamus Robustus had epipubic bones, meaning that it gave birth to undeveloped young or laid eggs like marsupials nowadays.
This animal was interesting in the Mesozoic Era because it would feed on dinosaurs.

Groups of genes

acama27_1 — 2023-10-26 18:18:02 UTC

This transition takes us from independent self-replicating molecules to self-replicating molecules linked into long chains, probably RNA. This could have happened roughly about 4.4 or 3.3 billion years ago.

Genetic code

acama27_1 — 2023-10-26 18:29:40 UTC

This transition takes us from a world where RNA both stored information and catalyzed reactions to a world where DNA stores the information used to build for protiens, which catalyze reactions. This also could have happened 3.3 to 4.4 billion years ago.

Eukaryotes

acama27_1 — 2023-10-26 18:32:36 UTC

This transition takes us from prokaryotes to eukaryotes. Prokaryotes, like bacteria and archaea, have relatively simple cells like the picture above.

Eukaryotes - like animals, plants, fungi, and protists - have cells with lots of internal parts called organelles. It is believed that some organelles were originally independent prokaryotes that got swallowed up but survived as symbiotic partners: so-called endosymbionts. This occurred around 1.85 billion years ago.

1. The Cenozoic

jcach27_1 — 2023-10-27 18:20:25 UTC

The Cenozoic is the youngest era. Cenozoic means recent life. During this era, plants and animals looked most like those on Earth today.

-The Cenozoic Era is the age of mammals. They evolved to fill virtually all the niches vacated by dinosaurs.

-The ice ages of the Quaternary Period of the Cenozoic led to many extinctions.

-The last ice age ended 12,000 years ago. By that time, Homo sapiens had evolved.

2. The Paleozoic Era

jcach27_1 — 2023-10-27 18:22:35 UTC

Fish diversified and marine organisms were very abundant. During the Paleozoic Era, which lasted 289 million years, plants and reptiles began moving from the sea to the land.
The Paleozoic Era began with the Cambrian explosion. It ended with the Permian extinction. During the era, invertebrate animals diversified in the oceans. The Paleozoic Era began with the Cambrian explosion. It ended with the Permian extinction. During the era, invertebrate animals diversified in the oceans.

-The Paleozoic Era began with the Cambrian explosion. It ended with the Permian extinction.

-During the era, invertebrate animals diversified in the oceans. Plants, amphibians, and reptiles also moved to the land.

3. Mesozoic Era

jcach27_1 — 2023-10-27 18:22:48 UTC

The Mesozoic is divided into three time periods: the Triassic (245-208 Million Years Ago), the Jurassic (208-146 Million Years Ago), and the Cretaceous (146-65 Million Years Ago). During the Jurassic and Cretaceous Periods, the dinosaurs ruled the earth. Both plants and animals reached giant proportions during the Mesozoic. During the 180 million years of the Era, reptiles lived on land, in seas, and in the air. Small mammals, although insignificant during that time, did exist during this era. Dinosaurs appeared and disappeared during the Mesozoic Era, which lasted 186 million years. Seas covered western and central Kansas during the late Cretaceous Period. Fossilized marine rocks found at the surface include the Greenhorn Limestone in central Kansas and the Niobrara Chalk to the west. Shale and sandstone deposited during this period are found underground in western Kansas. Fossils from this period have not been found in Kansas.

Sex

acama27_1 — 2023-10-27 18:33:28 UTC

This transition takes us from populations of sexually reproducing clones to populations that reproduce sexually. This occurred around the time eukaryotes arose.

Archaeopteryx

jmaga27_2 — 2023-10-30 03:59:50 UTC

The Archaeopteryx is one of the most well known transitional fossils and also gives evidence for evolution, specifically the evolution from dinosaurs to birds.

Pakicetus

jmaga27_2 — 2023-10-30 04:27:06 UTC

This fossil provides evidence that the earliest relatives of large whales were small land animals, this animal made their permanent translation to the ocean about 50 million years ago.

A timeline of what human evolution is suspected to look like

jmaga27_2 — 2023-10-30 04:31:22 UTC

Cell differentiation

acama27_1 — 2023-10-31 05:16:43 UTC

This transition takes us from single-celled protists to multi-celled animals, plants and fungi where different cells specialize to play different roles. The oldest known animal fossils are some early sponges in the Trezona Formation in South Australia ... going back 665 million yeasrs. Plants go back 1.2 billion years, and fungi around 1.4 billion years.

Social colonies

acama27_1 — 2023-10-31 05:23:23 UTC

This transition takes us from solitary individuals to social organizations such as colonies of ants, bees, and termites, or the societies of birds and mammals. Sociality has risen independently many times, but its hard to say for lack of fossil evidence. By the late Triassic, there is evidence for social behavior among termites.

Language

acama27_1 — 2023-10-31 05:31:47 UTC

This is the transition from societies without language to societies with. Some scholars assume the development of primitive language-like systems as early as Homo habilis, while others place the development of primitive symbolic communication only with Homo erectus or Homo heidelbergenisis and the development of language proper with Homo sapiens sapiens less than 100,000 years ago.