EARTH 7 Lecture Notes - Lecture 5: Common Descent, Selective Breeding, Uniformitarianism
Document Summary
Species: a group of viably interbreeding organisms (if two organisms cannot viably produce offspring, therefore they are the same species)(hybrid animals do not prove this wrong. Divergence (speciation): when a lineage splits. (they will split into two, and each will split and so on) Change of species over time (evolution) was not darwin"s original idea. There was lamarck who had ideas on evolution before darwin. Steno figured out what fossils were and how they formed. Darwin started thinking about evolution after observing the birds and turtles in the galapagos. He spent 20 years gathering notes and information to make sure his idea is honed and coherent, writing the origin of species. Darwin"s two ideas: common descent with modification and natural selection. Common descent with modification: all living organisms are related, descending from a single common ancestor. Diversity is the result of divergence of lineage. Similiarity between species is the result of close ancestry.
