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4.1.2-.4 Natural Selection Evolution of mammals

4.1.2-.4 Natural Selection Evolution of mammals. http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html. Darwin and Evolution. Evolution are the changes in the gene pool of a population over time.

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4.1.2-.4 Natural Selection Evolution of mammals

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  1. 4.1.2-.4 Natural Selection Evolution of mammals

  2. http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.htmlhttp://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html

  3. Darwin and Evolution

  4. Evolution are the changes in the gene pool of a population over time. Natural selection process by which individuals that are better suited to their environment survive and reproduce most successfully. Adaptation is an inherited characteristic that increases an organism’s chance of survival.

  5. Darwin Wolf Pinta Genovesa Marchena Santiago Bartolomé Seymour Råbida Baltra Pin zon Fernandia Santa Cruz Santa Fe Tortuga San Cristobal Española Floreana EQUATOR Galåpagos Islands Isabela

  6. Marine Iguana Land Iguana

  7. KONA FINCH extinct KAUAI AKIALAOA AMAKIHI LAYSAN FINCH IIWI AKIAPOLAAU APAPANE MAUI PARROTBILL fruit and seed eaters insect and nectar eaters FOUNDER SPECIES

  8. Based on his observations, Darwin proposed that EVOLUTION occurs by NATURAL SELECTION.

  9. Darwin’s Postulates • Variation within populations. • Overproduction of offspring. • Struggle for existence. • Unequal survival and reproduction rates. http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html

  10. Population of organisms Mutations & Sexual reproduction produces variations among offspring. Overproduction of offspring Limited resources leads to a struggle for survival between offspring. Survivors reproduce more successfully. Population changes over time.

  11. Evolution of Mammals

  12. DISPERSAL OF HIGHLY EVOLVED PLACENTAL MAMMALS South America Extinctions of many marsupials and early placental mammals About 5 million years ago, during the Pliocene Fig. 27.19d, p. 471

  13. Nonvertebrate chordates Jawless fishes Cartilaginous fishes Bony fishes Amphibians Reptiles Birds Mammals

  14. Eurasia North America MONOTREMES, MARSUPIALS EVOLVE AND MIGRATE THROUGH PANGEA South America Africa India Australia Antarctica About 150 million years ago, during the Jurassic Fig. 27.19a, p. 471

  15. MONOTREMES Platypus Spiny anteater

  16. MARSUPIALS Koala Tasmanian Devil

  17. PLACENTAL MAMMALS EVOLVE; ADAPTIVE RADIATIONS BEGIN Isolation of the early monotremes, marsupials on this land mass Between 100 and 85 million years ago, during the Cretaceous Fig. 27.19b, p. 471

  18. PLACENTAL MAMMALS Bat Arctic Fox Walruses Manatee

  19. Beaver Beaver Muskrat Beaver andMuskrat Coypu Capybara Coypu andCapybara NORTH AMERICA Muskrat Capybara SOUTH AMERICA Coypu

  20. ADAPTIVE RADIATIONS OF MORE EVOLVED PLACENTAL MAMMALS North America Eurasia South America Continued isolation of early monotremes and marsupials Africa Extinctions of mammals Antarctica About 20 million years ago, during the Miocene Fig. 27.19c, p. 471

  21. SPECTACLED BEAR SLOTH BEAR SUN BEAR BLACK BEAR POLAR BEAR BROWN BEAR RACCOON RED PANDA GIANT PANDA DIVERGENCE 15-20 million years ago DIVERGENCE approximately 40 million years ago Fig. 20.10, p. 319

  22. What is a Species? A group of potentially or actually interbreeding populations, with a common gene pool, which are reproductively isolated from other groups

  23. The problem with the species definition The species concept is a human construct used to make sense of the natural world. While extraordinarily helpful in understanding life, it fails to capture the full complex reality of continually evolving populations of organisms.

  24. Sibling Species Species that can’t interbreed, but have no significant differences in appearance.

  25. Very different appearance that can interbreed?!

  26. Two tigons (male to the left, female to the right)

  27. A Liger-Lion/Tiger

  28. A "boblynx" -- a hybrid of bobcat and lynx;

  29. A "zonkey" -- a hybrid of zebra and donkey;

  30. The "Toast of Botswana",  -- a hybrid of a female goat to a male sheep;A "cama" -- a hybrid of camel and llama;A "yakalo" - a hybrid of buffalo or bison and yak;A "cattalo" (or "beefalo") -- a cross of a bison with a domestic cattle;A "coywolf" -- a hybrid of coyote and wolf; A "wholphin" -- a hybrid of a bottlenose dolphin mother and a false killer whale father. Same situation like with the "pumapard" (parents belong to different genera).Some intraspecies hybrids (both genders fertile):A "wig" -- a cross of a wild and a domestic pig;An unnamed cross of a Siberian and a Manchurian tiger.

  31. tulips

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