Natural Selection and Evolution of mammals http://www.youtube.com/watch?v=FNz9aHUTAT8 6:40

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. 13:13 http://www.youtube.com/watch?NR=1&v=svHQ4BQY__o&feature=endscreen

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

Marine Iguana Land Iguana

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

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

Darwin’s Postulates 1. Individuals within populations vary. 2. Some of these variations are passed on to offspring. 3. In every generation some individuals are more successful in surviving or reproducing than others. 4. Survival and reproduction are not random. Individuals with the most favorable variations are more likely to survive and reproduce.

MONOTREMES Platypus Spiny anteater

MARSUPIALS Koala Tasmanian Devil

PLACENTAL MAMMALS Bat Arctic Fox Walruses Manatee

DIVERGENCE approximately 40 million years ago 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