Chapter 19.2 (Pgs. 546-551): Patterns and Processes of Evolution.
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Transcript of Chapter 19.2 (Pgs. 546-551): Patterns and Processes of Evolution.
Chapter 19.2 (Pgs. 546-551):Patterns and Processes of Evolution
Microevolution*- Is evolution that happens on a small
scale
- Includes natural selection and genetic drift
- Can involve the speciation of a few species from a common ancestor
Macroevolution- Is large changes in anatomy and
behavior over long periods of time
- Is the evolution of many new species from an ancient ancestor
Extinction- Occurs when an organism is no
longer fit for its environment
- Background extinction is a normal extinction rate of species
- Mass extinction is the extinction of a large number of species at one time
- Usually due to a natural disaster or rapidly changing climate conditions
Rate of Evolution
- Can change for different organisms at different periods in time
- Gradualism- Slow, steady changes accumulate
over time
- Punctuated Equilibrium- Long periods of very slow change
are punctuated by periods of rapid change
Adaptive Radiation
- A single or a few species rapidly evolves into many new species
- Can occur when a species migrates into a new area
- Can occur after extinction, and new habitats have become available