BIO 263 Lecture Notes - Lecture 4: Archaeopteryx, Devonian, Tiktaalik
Document Summary
Earliest life was 3. 4-3. 8 billion years ago. Earliest forms of life were all unicellular prokaryotes. Ediacaran fauna 570-540 mya after ice age. First multicellular life was found around this area. Were all marine organisms that were filter feeders. Entire phyla in this area came and went. Advent of hox genes appeared around this time. Many of the animal behaviors came in this era. All ancestors of modern arthropods came to existence. Comes from rock layers with younger rock layers higher up while lower rock layers further down. Island naiveness led to not be afraid of various predators. Darwin pointed out extinction is evidence that species are dynamic. 99% of species to have ever lived are now extinct. Extinct species and living species in same region are very similar. In some ways every species is a transitional form. Transitional form are species which have traits that make them the transitional species in between two species.
