INTRODUCTION TO EVOLUTION AP BIOLOGY MR. ORNDORFF FEB. 2004

Special Creation vs. Evolution Species distinct and created separately by a divine being. Earth is thousands of years old. Humans present at original creation. Must be accepted on faith (religion). Species are all related through “descent with modification.” Earth is billions of years old. Humans appeared late in earth’s history. Must be testable and supported with evidence (science).

Microevolution vs. macroevolution Small-scale evolution (change within a species). Examples: Darwin’s Finches Pesticide resistant insects Grand-scale evolution (mass extinction and creation of new species) Examples: Eu- from prokaryotes Extinction of dinosaurs Adaptive radiation of mammals

Evidence for macroevolution Biogeography (no placental mammals in Australia). Fossil Record (vertebrate skeletons) (Whale Fossils-http://www.pbs.org/wgbh/evolution/library/11/2/e_s_3.html) Comparative anatomy (homologous structures and vestigial organs). Comparative embryology. (Embryology Film Clip- http://www.pbs.org/wgbh/evolution/library/04/2/quicktime/l_042_02.html) Molecular biology (DNA and proteins).

Fossil formation (Fig. 22.2)

Homologous structures (Fig. 22.9)

Molecular data and vertebrate evolution (Fig. 22.11)

Mechanisms for Evolution Lamarck (1744-1829) Organisms “feel a need” to adapt. Use and disuse idea (e.g. blacksmith biceps and giraffe neck). Inheritance of acquired characteristics theory. Darwin (1809-1882) Individuals vary (e.g. pigeons and dogs). Like tends to beget like. Limited resources allow few offspring to survive. Theory of natural selection.

Subtleties of Natural Selection Individual organisms do not evolve. A population is the smallest unit that evolves. Natural selection acts only on hereditable variations (i.e. genetically controlled traits). Natural selection acts differently as environmental factors vary from place to place and time to time.

Natural selection in action (Fig. 22.7)