Unit 11 - VI. + VII. Patterns and Rates of Evolution

Coevolution

joint change in 2 or more species in close interaction

• e.g. predators/prey or plants/pollinators

Convergent evolution

unrelated species become more & more alike in appearance as they adapt to similar environmental pressures

• e.g. different plants displaying similar adaptations to desert climate

Divergent evolution

process by which 2 related species become more dissimilar over time as they adapt to separate environments

Adaptive radiation (type of divergent evolution)

process by which a single species develops simultaneously into many different species

Gradualism

proposes evolution is a slow, gradual & continuous change

• fossils show slight changes in organisms between rock layers

Punctuated equilibrium

proposes that species have long periods of genetic equilibrium interrupted by geologically brief periods of rapid evolutionary change