Reproduction by Dale Hill by Dale Hill

Reproduction: The Basics

dale_hill — 2014-06-27 00:20:55 UTC

Since every living thing comes from another living thing, every organism has at least one parent. The parent passes genetic material to its offspring. That genetic material controls how the organism will look and function. The genetic material determines an organisms traits, or characteristics.

Survival advantages of each type of reproduction

dale_hill — 2014-06-27 00:25:37 UTC

Advantages of asexual reproduction: Only one organism is needed. It's a fast method of reproduction, since some species can reproduce every 10 minutes.

Advantages of sexual reproduction: Since these organisms have 2 parents, they can adapt to better fit into a changing environment.

Fungi Reproduction

dale_hill — 2014-06-27 00:27:11 UTC

Yeast, a unicellular fungi, reproduces asexually through budding.

Multicellular fungi, such as mushrooms, can reproduce asexually through spores. The fungus is deep under the surface of the ground, and may be extremely large. The part we see above the ground is just the reproductive structure. Soon after it releases its spores, it will die away, but the fungus is still alive under the surface.

This amazing video shows several fruiting bodies emerge and grow from their fungi. It also shows spore release and death of a fruiting body. How did these fungi get where they are in the first place?

Vegetative Propagation: asexual reproduction

dale_hill — 2014-06-27 00:27:34 UTC

Plants can reproduce asexually through their leaves, roots, or stems. A root may grow under or on top of the ground, and other plants spring up from that same root. Most grasses reproduce this way.

I have a beautiful angel begonia that my aunt gave me. She broke off a small part of the stem, plopped it in water, and gave it to me. That stem produces new roots and a new plant. Her original plant is still thriving.

The photo below is a Mother of Thousands, a succulent that reproduces through vegetative propagation by its leaves. All those little "ruffles" are leaves that will fall off and become new plants. What other type of reproduction does bring to mind?

Other Types of Asexual Reproduction in Animals

dale_hill — 2014-06-27 00:28:22 UTC

The honeybee (along with other insects, fish, frogs, and lizards) can reproduce sexually OR asexually with eggs. The queen bee lays all the eggs. The unfertilized ones grow into male drones, while the fertilized ones grow into female workers.

Budding: Asexual Reproduction

dale_hill — 2014-06-27 00:29:14 UTC

Budding is the funniest type of reproduction to imagine humans doing. In budding, the offspring just begins to grow on the adult. When it gets large enough, it can break off the adult to be its own organism. Sometimes the offspring stays attached to the adult, as in coral.

This video begins with sexual reproduction of the sea slug, followed by 4 different organisms reproducing asexually: hydra, paramecium, anemone, and volvox colony. Take notes during the video to help you decide what kind of asexual reproduction each organism is using.

Splitting: Asexual Reproduction

dale_hill — 2014-06-27 00:29:35 UTC

Most unicellular protists and bacteria reproduce by splitting. Internally, all the genetic material or DNA doubles and splits, then the one organism splits into two.

To calculate just how quickly splitting organisms can take over the world, check out the math challenge on p.81 of your textbook.

This sea anemonia, a member of the animal kingdom (class Cnidaria), is reproducing asexually in this video.

Asexual Reproduction

dale_hill — 2014-06-27 00:29:48 UTC

We'll discuss at least 4 types of asexual reproduction. Three of them are splitting, budding, and vegetative propagation.

Most fungi and many plants can reproduce both asexually and sexually.

Sexual Reproduction

dale_hill — 2014-06-27 00:31:31 UTC

Two parents combine their genetic material to produce an offspring. This process of joining the sperm cell and egg cell, called fertilization, produces an embryo. The embryo is the beginning of the new organism. Since the offspring of sexual reproduction is a combination of the two parents' genetic material, it isn't identical to either parent.
Only multicellular organisms can reproduce sexually. Why? The egg and the sperm are each a cell. Just the required sex cells are more than "unicell" or "one cell."

Excellent video on seed germination:

Seeds and Fruit

dale_hill — 2014-06-27 00:32:20 UTC

When you eat a fruit, you're actually eating a plant's ovary or reproductive structure. It's designed to attract an animal that will carry the seed far away from the parent. That way, the offspring won't have to compete with the parent for resources.

Animal Eggs

dale_hill — 2014-06-27 00:32:43 UTC

Animals that reproduce sexually begin as fertilized egg cells that grow into embryos, just like plants. The animal may lay the egg or keep it inside the female to develop.

Development of chicken embryo: