Download
1 / 26
280 likes | 307 Vues
Asexual Reproduction. Are you two twins?. Asexual Reproduction : Used by many unicellular organisms, plants, and lower animals. Involves only mitotic cell division = each offspring has exactly the same heredity as its parent. Usually rapid compared to sexual reproduction.
E N D
Are you two twins? • Asexual Reproduction: • Used by many unicellular organisms, plants, and lower animals. • Involves only mitotic cell division = each offspring has exactly the same heredity as its parent. • Usually rapid compared to sexual reproduction. • Types of Asexual Reproduction Include: • Binary fission • Budding • Spore formation • Regeneration • Vegetative Reproduction
Cut it in half! • Binary Fission = simplest form of asexual reproduction. Parent organism divides into two • Approximately equal parts. Each daughter cell becomes a new individual.
Bacteria (prokaryotic single cell organism) • No organized nucleus. • Genetic material in the form a single circular chromosome. • Before division starts chromosome is replicated then each daughter cell gets one copy of the chromosome. • Can occur every 20-min.
Protozoan (eukaryotic single cell organism) • Mitosis occurs. • Cytoplasm pinches in and divides the organism in half. • Each half has a copy of the genetic material.
They were best buds… • Budding = Parent organism divides into two unequal parts. • The new organism is created as a smaller out growth or bud on the outside of the parent. • Buds will break off and live independently or remain attached and form a colony.
Yeast – Once the yeast cell reaches a certain size it undergoes mitosis. • Once the genetic material is replicated budding begins. • Hydra – Cells on the outside of the parent hydra begin to undergo mitotic division creating a small group of cells. Those cells continue to divide until in a completely new hydra is formed. Can also reproduce sexually.
Yeast budding: • http://https://www.youtube.com/watch?v=iOvrq6ssy2Y
Can I have some spore? • Spore Formation – spores = small specialized cells that contain a nucleus and cytoplasm surrounded by a thick outside wall which protects the spore. • Under the right conditions the spore can rise to a new organism. Found in bacteria, molds, yeast, mushrooms, mosses, ferns and some protozoans.
Don’t try this at home • Regeneration = The ability to re-grow lost or damaged body parts. Hydra, planaria, starfish, and earthworm • More complex animals less able to re-grow parts. • Crab can re-grow a claw. Some reptiles can re-grow a tail. • Most mammals can repair damaged tissue but can not re-grow missing parts.
Bulb = Short underground stem surrounded by thick leaves. Contain stored food. As the plant grows it produces new bulbs which will grow into new plants. Tulips, onions, and lilies.
Corms= Similar to bulbs but do not contain leaves, just under-ground stems. Water chestnuts.
Tuber= enlarged part of an underground stem that contains stored food. Potatoes are tubers. “Eyes” = tiny buds that can form a new potato plant.
Runner or stolen= horizontal stem above the ground with buds. If a bud touches the ground it will form roots and stems and start a new plant. Strawberries.
Rhizome = horizontal stem that grows underground. Thick and contains stored food. Upper portion form nodes which will form buds which will form new plants. Lower portion forms roots. Ferns, cattails, and water lilies.
Watch out for those old ladies. • Cutting= use a portion of a developed plant to make a new plant. Roses, ivy, and grapevines are reproduced in this way.
Layering = a stem is bent so that it is covered with soil. Once the branch forms roots it is disconnected from the original plant. Raspberries and roses.
Grafting= Bud or stem of one plant is permanently attached to the stem or trunk of a very similar plant. The cambium layers grow together and form a single plant. Apple trees.
Why Bother?? • Advantages to artificial vegetative propagation: 1. Plants that grow from seed are not always exactly the same as their parents. 2. Takes less time to artificially propagate. 3. Can create seedless fruits. 4. Grafting can be used to generate higher levels of fruit and nut production.
