ERSC 1F90 Lecture Notes - Lecture 7: Cosmic Ray, Permafrost, Cenozoic
9 Apr 2015
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Document Summary
Occurs when all members of a species have died. It is a scientific certainty when there aren"t enough surviving for reproduction. A species is functionally extinct when there are only a few and chances of reproduction are slim. Genetics and demographics: small population = increased risk at extinction, mutations, causes a flux in natural selection, beneficial genetic traits are overruled. Loss of genetic diversity: shallow gene pools promote massive inbreeding. Habit degradation: one of the most influential, sometimes caused by humans, sometimes not. Mass extinction (whole species get wiped out) Planned extinction (bringing in a new species) Toxicity: kills off species directly through food/water. Indirectly through sterilization: can occur in short life spans (one generation, can occur over generations, increasing toxicity, increasing competition for habitat resources. Destruction of habitat: elimination of living spaces, change in habitat, rainforest to pasture lands, leads to diminishing resources, increases competition, can be caused by natural processes, volcanoes, floods, drought, etc.
