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Patterns in evolution: 17-2, 17-4

Patterns in evolution: 17-2, 17-4. Endosymbiotic theory. Proposes that complex cells arose from smaller prokaryotes invading the larger eukaryotes. The cells that used oxygen to make ATP became mitochondria . Those that could photosynthesize became chloroplasts.

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Patterns in evolution: 17-2, 17-4

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  1. Patterns in evolution: 17-2, 17-4

  2. Endosymbiotic theory • Proposes that complex cells arose from smaller prokaryotes invading the larger eukaryotes. • The cells that used oxygen to make ATP became mitochondria. • Those that could photosynthesize became chloroplasts. • Evidence: both contain DNA different from nuclear DNA

  3. Sexual reproduction • Eukaryotic cells begin to reproduce sexually. • The reshuffling of genes greatly increases gene combinations and variation. • This increaseddiversity and the speed of evolutionary change Tetrahymenathermophila

  4. Multicellularism • Began a few million years after sexual reproduction. • Life became multicellular, experiencing great diversity over time. • All developed in the sea. • Because of their soft bodies, few fossils remain. microfossils hydra

  5. Big ideas of evolution: Extinction • 99% of all species once living are now extinct • Most succumb to natural selection • Mass extinctions have several causes • Survivors experience a burst of evolution, producing many new species Diatrymas: 55-65 MYA stood 2 m tall

  6. Adaptiveradiation Anole lizards of the Caribbean islands • A single species or a small group of species evolve into many diverse forms, living in different niches.

  7. Convergent evolution • Unrelated organisms can develop to look similar to others if they adapt to the same environment • Ex: all species that swim in the water are streamlined, with paddles for locomotion Shark, dolphin, and penguin represent aquatic fish, mammal, and bird species

  8. Coevolution • Organisms that are closely connected often evolve together • Occurs often in flowers and their pollinators • Plants evolve poisons to ward off insects that eat them, who become immune over time.

  9. Gradualism • The idea that evolution happens at a slow, steady pace. • Exception: horseshoe crabs have changed little from their fossils.

  10. Punctuated equilibrium • Evolution can proceed at different rates • There can be long periods of stability, then brief periods of more rapid change

  11. Developmental genes and body plans • Master control genes guide the development of major body parts in animals • Small changes in the expression of developmental genes can cause large changes in the adult Antennapedia and wingless fruit flies

  12. Plant and animal mutations

  13. The human evolutionary tree

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