Biology 1001A Lecture 21: LEC 21 - Phylogeny II and Evolutionary Ecology.pdf
11 Feb 2014
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Lec 21 - phylogeny ii and evolutionary ecology. End of the cretaceous, 65 mya, most dinosaurs and large marine reptiles died out. Iridium (rare element, found in asteroids) found worldwide in stratum at the cretaceous-tertiary boundary. When dinos became extinct, this opened up niche for new life. Origination of new ecosystems due to earlier continental drift and evolution of other groups. May be local, specific nd not result in extinction of species. May eliminate a the species in a region or ecosystem. May be of much larger scale, eliminating most of the species n a continent or on earth. Particles in air, dust clouds interfere w/ photosynthesis food chain may collapse. Heat can start raging forest fires nitrous oxides acid rain destroy vegetation and marine organisms. Over half of species and reptiles became extinct. For many animals, species/genetic diversity was still low after 5-10 mil years later.
