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17-4 Patterns of Evolution

17-4 Patterns of Evolution. Evolution. Macroevolution Big changes over long periods of time. Mammals replace Dinosaurs Microevolution Changes within a species. Allele frequency change. Macroevolution. Extinction Adaptive radiation Convergent evolution Co-evolution

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17-4 Patterns of Evolution

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  1. 17-4 Patterns of Evolution

  2. Evolution • Macroevolution Big changes over long periods of time. Mammals replace Dinosaurs • Microevolution Changes within a species. Allele frequency change

  3. Macroevolution • Extinction • Adaptive radiation • Convergent evolution • Co-evolution • Punctuated equilibrium • Changes in developmental genes

  4. Extinction • Environment changes, species disappear Some species have variations allowing them to survive. Other species can no longer successfully compete for resources. Environmental collapse (asteroid) normal natural selection can’t function.

  5. Adaptive Radiation • Single species or small group gives rise to diverse groups that live in different ways.

  6. Convergent evolution • Unrelated organisms look alike because they face similar environmental demands. • Structures of similar function are analogous, not homologous. • They do the same job but made up of parts that do not share a common ancestry. shark fish Different Ancestors Similar appearance Same Environment, mammal dolphin

  7. Convergent

  8. Divergent

  9. Co-Evolution • Process by which two species evolve in response to changes in each other over time. Plants and pollinators

  10. Coevolution

  11. Speed of evolution Gradualism Biological change that is slow and steady over time. Punctuated Equilibrium Change occur rapidly after a long period of being stable.

  12. Developmental Genes • Changes (mutations) in the genes that control early development can produce transformations in the organisms. • Hox genes – master control genes that guide development of major body structures in animals.

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