NATS 1840 Chapter 5: 5.4- Speciation, Extinction, and Biodiversity
8 Feb 2019
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Speciation: two species arise from one, occurs when some members of a population can no longer produce fertile offspring breeding with others. If this divergence process continues long enough, members of the isolated population become so different that they can no longer reproduce live, fertile offspring . (divergent evolution) Sympatric speciation: creation of new species when groups in a population living close together are unable to interbreed because of mutation or behavioural changes e. g : when different types of plants are eaten, causing mutation. Extinction : when an entire species ceases to exist. Causes by continents moving apart, have been flooded. Background extinction: as local environmental conditions change, a certain number of species disappear at a low rate. Mass extinction: a significant rise in extinction rates, often global and catastrophic. Mass depletion: extinction rates are higher than normal but not high enough to classify as a mass extinction. Humans have become a major force in the premature extinction of species.
