BIO SCI 94 Lecture Notes - Lecture 8: Tiktaalik, Archaeopteryx, Marsupial

• School: UC-Irvine
• Department: Biological Sciences
• Course: BIO SCI 94
• Professor: Brandon Stuart Gaut

Document Summary

Prediction 1: there should be evidence of extinction. Fossils: pieces of physical evidence from an organism that lived in the past. Species go extinct due to ongoing environmental change, predation, diseases, etc. o. 98% of all species have gone extinct (98% of the things that lived on the earth are no longer around: some of these represent dead-end evolutionary lineages, other extinct species have descendants that are still around today. 5 major episodes of mass extinction (marked increase in extinction rates: during each mass extinction, at least 60% of the species died out, largest --> 250 million yrs ago: end-permian event. Marine organisms were especially hard hit: late triassic --> many amphibians & reptiles went extinct. Set the stage for the rise of dinosaurs: end-cretaceous (aka k-p extinction) --> 65 million yrs ago. Many other terrestrial and marine species also became extinct: now; ongoing extinction events.