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REPRODUCTION AND DEVELOPMENT. Every species depends on it for survival!. Reproduction can be…. Asexual *think mitosis, one parent, genetically identical! Sexual *think meiosis, two parents, variation!. All organisms…. Will have either asexual or sexual reproduction
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REPRODUCTION AND DEVELOPMENT Every species depends on it for survival!
Reproduction can be… • Asexual *think mitosis, one parent, genetically identical! • Sexual *think meiosis, two parents, variation!
All organisms… • Will have either asexual or sexual reproduction • Typically the less complex you are, the less variety you have (so asexual) • Typically the more complex you are, the more variation you have (so sexual reproduction)
Examples of different types of asexual reproduction • Binary fission (two equal cells) *ameoba • Budding (unequal division) *yeast • Spore formation *fungus & mold • Budding (new individual on the parent) *hydra & some plants
Examples of different types of sexual reproduction • Conjunction *Swapping a small portion of genetic material (paramecium) • Fertilization *Joining of two cells
Cloning • A type of asexual reproduction • Individual is identical to one “parent” • Possible in some plants (cuttings) and animals that normally reproduce sexually
A donor cell is taken from a sheep’s udder. Donor Nucleus These two cells are fused using an electric shock. Fused Cell Egg Cell The nucleus of the egg cell is removed. An egg cell is taken from an adult female sheep. The fused cell begins dividing normally. Embryo Cloned Lamb The embryo is placed in the uterus of a foster mother. The embryo develops normally into a lamb—Dolly Foster Mother
Mitosis • No variation • Occurs in all body cells • Required for growth & development & repair • Diploid to diploid • Genetic number never varies
Meiosis • Creates variation (crossing over, four cells to choose from) • ONLY occurs in sex cells • Required for sexual reproduction • Diploid to haploid (monoploid) • Genetic number cut in half (needs to be in order for the number to be restored after fertilization)
Human Male System • Testes – where sperm cells mature • Testosterone – hormone produced by testes
Plant male system • Stamen – produces the mature sperm cell (poll) • Known as pollination
Human female system • Ovaries – where immature eggs are stored and mature • Estrogen & progesterone – hormone produced by the ovaries Oviducts – where fertilization occurs Uterus – where placenta and embryo develop
Plant female system • Pistal (stigma) – where fertilization occurs / at base is ovary • Embryo is surrounded by nutrients (fruit)
Development in plants • Pollination – fertilization - germination
Development in humans • Gametogenesis – fertilization – zygote - embryo • Differentiation • Female hormonal / menstral cycle
The Menstrual Cycle Section 39-3
Application of Reproductive Technology • Cloning • In Vitro techniques • Genetically altered plants • Endangered species “help” • Stem cell research • Chromosome screening