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Evidence for Evolution

Evidence for Evolution. Species Numbers. Exploration brought increased realization of the ENORMOUS NUMBER OF SPECIES in the world. Fossil Evidence. Similar fossils were found in geographically isolated locations. Fossil Evidence. Fossil Evidence.

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Evidence for Evolution

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  1. Evidence for Evolution

  2. Species Numbers • Exploration brought increased realization of the ENORMOUS NUMBER OF SPECIES in the world

  3. Fossil Evidence

  4. Similar fossils were found in geographically isolated locations

  5. Fossil Evidence

  6. Fossil Evidence • Sea animal fossils can be found at high land elevations showing great land movement

  7. Homologous structures evolved from a common ancestor Divergent Evolution swim grasp run claw fly fly

  8. Vestigial Structures

  9. Compara-tive Embryo Evidence

  10. Embryo Evidence

  11. Animals and plants in different locations but similar niches tend to look or act the same Convergent Evolution

  12. Convergent Evolution due to similar niches Analogous structures formed

  13. Convergent Evolution

  14. Drug Resistant Bacteria • Many strains of bacteria have developed mutations that make them resistant to antibiotics

  15. Biochemical Analysis • May show similarities and differences between groups of organisms using: • DNA sequencing • Cytochrome C patterns • Amino acid sequencing • (Hemoglobin especially useful) • Mitochondrial DNA analysis

  16. We Can Separate Species Based On % Of Shared Dna How Much of a difference is needed to call 2 organisms separate species?

  17. Recombinent DNA • Can now demonstrate the effects of mutations precisely.

  18. ADAPTIVE RADIATION • Massive explosions of new species • Usually followsmass extinctions

  19. What are the Limits to Adaptation? • Genetic Drift • Limited Genetic Variability in Population • Compromises in Evolution • Time Delays • Reproductive Capacity

  20. Extinction • The elimination a species from the earth • Background Extinction Rate - relatively constant rate of extinction in the fossil record • Mass Extinction - major loss of species: climate change, humans, catastrophies

  21. Extinctions Today • Since 1600 • 1138 extinctions documented • Estimate • 10,000 x greater than background extinction • If extinction rate is 0.5%/yr • 1 million spcies lost in 2-40yrs

  22. CRITICAL QUESTION:How Do Humans Affect Extinction Rates?

  23. extinction Root Causes of • Population Growth • Economic Policies that do not support the environment • High per Capita Resource Use leading to degradation of the environment

  24. How Do Humans Affect Extinction Rates? • Simplify ecosystems • (monocultures/disturbed habitats) • Strengthen pest populations • Eliminate predators (can create new pests)

  25. How Do Humans Affect Extinction Rates? • Introduce new species (starlings) • Overharvest • Interfer with chemical cycling and energy flow (UV/ozone, heat pollution)

  26. Designed by Anne F. Maben These images are for viewing only and may not be published in any form

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