BILD 3 Lecture : BILD 3.docx
Document Summary
History of evolutionary thinking and darwin"s arguments for descent with modification: origin of the species (1859, all organisms evolved from common ancestor- descent w/ modification (this was accepted soon after publication) Accepted easily b/c it could be reconciled with god. The thinking at the time: organisms didn"t change over time. Created by god, and variation = imperfections, species were made independently and creation was recent: mechanism- evolution by natural selection. This idea was rejected for about 50-60 years: observations darwin made on beagle, tropical diversity in brazil. Organisms there are similar to temperate parts of south america: discovered bones of extinct giant mammals, recognized similarity to extant forms, found sedimentary rock, experienced an earthquake. Changes in geography, mountain rising several meters, perhaps cause of natural selection as changes in geography separated species: colonization and divergence, observed 3 species of mockingbirds on 4 islands. Each species was different in appearance from each other: darwin pondered mysteries ~20 yrs.
