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ASEXUAL REPRODUCTION

ASEXUAL REPRODUCTION. There are many forms of asexual reproduction All have 3 things in common Only one parent involved All offspring are genetically identical to the parent This means they contain identical DNA

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ASEXUAL REPRODUCTION

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  1. ASEXUAL REPRODUCTION

  2. There are many forms of asexual reproduction • All have 3 things in common • Only one parent involved • All offspring are genetically identical to the parent • This means they contain identical DNA • The cell(s) that produce the offspring are not specialized for reproduction

  3. Methods of asexual reproduction **Remember that the parent DNA is first duplicated so that** the offspring receives an identical copy Binary Fission • Organism splits into 2 equal-sized offspring • Occurs primarily in single celled organisms • Is the usual method of reproduction for bacteria and protists • http://www.youtube.com/watch?v=K0ZP8VtxUZ0

  4. Budding • Offspring begins as a growth (called a bud) on the parent • Once bud has developed to point where can survive on own, it detaches • Occurs in both single and multi-celled organisms • Offspring is not physically identical to parent, but is genetically identical

  5. http://www.youtube.com/watch?v=489CSop00sY

  6. Spore Formation • Organism produces spore cells • Cells that are some-what specialized for reproduction • Spores are spread by the elements (wind, water, etc.) • If a spore lands in a favourable environment it will develop into a new organism.

  7. http://www.youtube.com/watch?v=VWgm322uKWI&playnext=1&list=PL92A4B063B588C056http://www.youtube.com/watch?v=VWgm322uKWI&playnext=1&list=PL92A4B063B588C056

  8. Fragmentation • Pieces (fragments) of the parent body break off • The fragments then grow into whole, new organisms • Eg. Starfish and flatworms • http://www.youtube.com/watch?v=f7cXeWxxfD4

  9. Vegetative Reproduction • Occurs only in plants • Special stems are sent out • Offspring emerge from these stems at specific intervals • Stems travel on the surface  runners • Stems travel underground  rhizomes • Eg. Spider plants

  10. Outcome of asexual reproduction • Clone – identical offspring produced by asexual reproduction • How could having populations of entirely identical organisms be beneficial? • How could it be harmful?

  11. Human Assisted Cloning • Humans use all the asexual cloning methods in order toproduce desired results with organisms. This is done in several ways: • Reproductive cloning - purpose is to produce a genetic duplicate of an existing or dead organism. Steps involved: • Remove nucleus from an egg cell • A mammary gland cell is removedfrom an adult female • Electricity fuses mammary and egg cell • Fused cell begins dividing • Dividing embryo is inserted intosurrogate mother

  12. Human Assisted Cloning • Therapeutic cloning - purpose is to correct health problems • Very important to therapeutic cloning are stem cells - cells that can become different types of cells • Stem cells can be used to replace cellsdamaged from injuries or disease • Diabetes, spinal injuries, Parkinson’sdisease are only a few that canbenefit from stem cell therapy • Controversial because the beststem cells are from embryos whichare destroyed when harvesting cells Mouse Stem Cells

  13. Review Questions Complete the Check Your Understanding questions page 183 #1-14 Complete the Chapter Review page 184-185#1-26

  14. Oysters are a major part of the diet of starfish. Because of this, people who catch oysters for a living used to try to kill starfish by cutting them up and throwing them back into the sea. Why might this practice not reduce the numbers of starfish?

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