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Unformatted text preview: — whole clades affected or not.
Morphological selectivity — individuals possessing certain morphological
easy to visualize, difficult to interpret
features are more vulnerable
Ecological selectivity — spets affected more than generalists
Biogeographic selectivity — widespread taxa tend to survive more than
geographically restricted taxa
tropic > temperate
Periodicity of extinctions
Pattern of 26 million year cycles in families of marine invertebrates
(Raup and Sepkoski, 1984)
- Is it real?
Implies a common cause for mass extinctions - is there evidence? carnivores > herbivores
large > small all patterns dependent on quality of
stratigraphic record; FADs and LADs assumed
true Part 2: Mass Extinctions
Patterns of mass extinctions, attributed to various causes:
Abrupt and global changes cause synchronous extinctions at a geological
boundary, with few if any survivors
Stepped mass extinction
Groups of species sensitive to change become extinct first, with more robust
groups becoming extinct in subsequent episodes
Graded mass extinction
Rate of extinction increases beyond bac...
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This note was uploaded on 04/02/2014 for the course GEL 107 taught by Professor Motani during the Spring '08 term at UC Davis.
- Spring '08