Why is life on Earth so diverse - PowerPoint PPT Presentation

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Why is life on Earth so diverse

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    1. Why is life on Earth so diverse???

    2. EVOLUTION Not only a change over time Defined as descent with modification Genetic traits which are passed to offspring

    3. Charles Darwin & The Voyage of the Beagle In 1831 he traveled around the world on a ship called the Beagle He noticed that there was great diversity in organisms even in very similar environments The Galapagos Islands had the biggest impact on Darwins studies.

    4. Darwins Journey

    5. What did Darwin see?????

    6. What did Darwin see?????

    7. Evidence of Evolution Darwin saw many things which influenced his theories Fossil Record, the Earth was really old( estimated at 4.5 billion years) Lamarks misconceptions on use and disuse of adaptations Populations did not grow out of control, bean counting lab.

    8. Evidence of Evolution Fossil Records-fossils being discovered were evidence that the world was much older that once thought.

    9. Fossils show history of life on Earth Relative Dating -The layering of rock can show which fossils are older.

    10. Fossils show history of life on Earth

    11. Lamarks Theory Lamark believed organisms could adapt to fit their environment (ex: fiddler crab)

    12. Darwins Observations: 1. organisms produce so many offspring that their population size would increase exponentially if all individuals that are born reproduce successfully. (Green bean activity) 2. populations tend to remain stable in size, except for seasonal fluctuations. 3. environmental resources are limited.

    13. ORIGIN OF SPECIES In 1859, after 25 years of work, Darwin publishes his work to much ridicule.

    14. Darwins Theory is supported by. ARTIFICIAL SELECTION Nature provides variation but humans decide what traits are selected and passed on. Hybridization brings about new variations

    15. Darwin new there was much variation in nature. Descent with Modification

    16. Reasons for. Descent with Modifications Reason for Genetic Variability Sexual reproduction Mutations Migrations Natural Selection Genetic Drift

    17. Other Evidence for Evolution Embryology Embryos tend to look very similar at early stages and cells develop into homologous structures.

    18. Other Evidence for Evolution Homologous Structures

    19. Analagous Structures Analogous Structures: structures similar in function, but not inherited from a common ancestor. Share similar environments. Same function, different structure

    20. Other Evidence for Evolution Vestigial Organs Traces of organs, inherited from ancestors, that seem to have no functional purpose Appendix Hip joint in whales, snakes Ear muscles in humans Male nipples Tailbone

    21. Other Evidence for Evolution Geographic Distribution When similar environments produce similar looking organisms that are unrelated.

    22. Other Evidence for Evolution Biochemical Evidence