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Asexual reproduction

Asexual reproduction. OVERVIEW. Clone : an identical genetic copy of its parents Bread mold comes from a single mold spore A duplicate tree growing from the bottom of another tree Asexual Reproduction : only 1 parent is required to produce offspring .

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Asexual reproduction

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  1. Asexual reproduction

  2. OVERVIEW Clone: an identical genetic copy of its parents • Bread mold comes from a single mold spore • A duplicate tree growing from the bottom of another tree Asexual Reproduction: only 1 parent is required to produce offspring

  3. Clones can also be created artificially (agricultural or horticultural industries, or biomedical labs) • Trying to create heartier breeds and increase plant production • Clone healthy genes to replace mutated ones • Potentially cloning the genes of extinct animals like Tasmanian Tigers! We might be able to use cloning to reproduce extinct species like Tasmanian tigers!

  4. Types of Asexual Reproduction There are 5 main methods of asexual reproduction: • Binary Fission • Budding • Fragmentation • Vegetative Reproduction • Spore Formation

  5. 1. Binary Fission • A single parent cell replicates its genetic material, dividing into 2 equal parts • Method used by small, one-celled eukaryotic organisms like amoeba Ex.: Amoebas • Have between 30-40 chromosomes • Chromosomes duplicated during mitosis

  6. Binary fission is the onlymethod of reproduction for some bacteria! • No nucleus = no mitosis! Instead, one ring of DNA is replicated... • Under ideal conditions, it can replicate every 20 min. Ex. Streptococcus bacteria

  7. Mutations can occur during binary fission! • Mutations in the DNA of bacteria can make it very resistance to antibiotics

  8. 2. Budding • Areas of an individual undergo mitosis and cell division, developing into an identical organism • Used by some multicellular organisms (hydras and sponges) that only have a few different cell types • The “buds” might detach from the parent and become a new individual OR remain attached

  9. 1. Hydra develops a “bud” 2. The bud develops a mouth and tentacles 3. When it’s fully formed the daughter hydra detaches from parent 4. The daughter is fully independent

  10. Budding is great for organisms like sponges because they attach to rocks and move very little. Colonies can grow in the same area or break off and colonize new locations.

  11. 3. Fragmentation • Occurs when a piece of an organism breaks apart (ex. injury) and each fragment develops into a clone of the parent Ex.: Starfish • If a broken arm contains enough DNA it can develop into an identical copy

  12. Plants can also reproduce by fragmentation IF the environment doesn’t change and IF there are enough nutrients available. Example: Eurasian milfoil • Introduced to North America • Chopped up by propellers and spread through lakes

  13. 4. Vegetative Reproduction • Occurs when special cells (usually in plant stems and roots) divide repeatedly to form structures that will eventually develop into an identical plant • Develop off of the bulb or as sprouts (“eyes”) Ex.: Tulips, daffodils, hyacinth bulbs, and potatoes

  14. Disadvantage • Daughter plants grow very close to parent plants • Will complete for soil, nutrients, and light

  15. Benefits of Vegetative Reproduction Potatoes • #1 tuber crop in world • Used globally Common Camas • An important part of the First Nations diet • Also used for trading

  16. Human Assisted Methods of Vegetative Reproduction • CUTTINGS • The plant grower removes a part of the stem (or leaf/root) and plants the cutting in a special growing medium • Plant hormones, which are chemical messengers, are often applied to the cut stem • Hormones signal nuclei to stimulate cell division, causing some cells to develop into root tissue • House plants can reproduce in this method

  17. 2. GRAFTING • Stems called “scions” are attached to the rotted stock (“rootstock”) of a similar plant • Often used for apple trees and rose plants • Another form called “budding” is used to grow apple trees

  18. Advantages: • Can help scion benefit from a more rigorous root system • Produce fruit within 2-3 years instead of 5-10 years • Helps control eventual size of plant

  19. 5. SPORE FORMATION • Method used by some bacteria, micro-organisms, fungi (ex. bread mold), mosses, and ferns • Reproduction through the formation of single-celled spores • Spores: a reproductive cell that grows into a new individual by mitosis • Very light in weight • Rely on wind or water for transportation

  20. If conditions are right (enough moisture and food, and proper temperature) a new individual will grow wherever it lands • Many spores have tough outer coatings that allow them to survive in harsh conditions (drought or extreme temp.) until the conditions are right

  21. Summary of Asexual Reproduction

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