Extinction - Extinction succumb to changing habitat Mass...

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Extinction 1. Types of extinction Extinction – no longer in existence Taxonomic Extinction species evolution Homo erectus to H. sapiens True extinction --loss of taxonomic species loss of species T. rex loss of genus
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2. Principles of Extinction A. Extinction can be: e.g. Local – Horse in North America e.g. Global -- T. rex B. Extinction can be up to any taxon Group to Species to Genus to family to Phylum Most common Most rare
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A. Extinction is a “natural” process Extinction is the loss or significant reduction of fitness of a group of organisms in their habitat Extinction of one group opens the path for other groups. Large ferns and Angiosperms Dinosaurs and birds + mammals Epicardians and arthropods Extinction rates vary
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3. How does Extinction occur? When Environment or habitat changes– three possibilities Migration –depending on ability to leave and to move out of … Evolution – depending on the availability preadapted alleles i.e. degree of biological variability
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Unformatted text preview: Extinction succumb to changing habitat Mass extinctions I. Very early extinction of anaerobic bacteria: Result of Oxygen revolution II. Later extinction of the Stromolite bacterial populations Result of possible increase in predation III.End of Precambrian era and possibly led to Cambrian explosion. Result: possibly associated with plate tectonics. Mass extinctions cont Phanerozoic mass extinctions 5 major extinctions The end-Ordovician extinction ~440 mya The Late Devonian extinction ~365 mya End Permian ~250 mya End-Triassic ~215 mya K-T Cretaceous Tertiary extinction~ 65 mya Mass extinctions cont Late Permian Pangea formed Greatly reduced oceanic current flows and sea-level dropped precipitously Build-up of Organic decay Anoxic Massive die-off of estuarine organisms K-T Asteroid impact near Carribean Large die-off in North America Modern extinctions...
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This note was uploaded on 12/09/2009 for the course BIO 200 taught by Professor Herreid during the Spring '07 term at SUNY Buffalo.

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Extinction - Extinction succumb to changing habitat Mass...

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