80 likes | 588 Vues
Patterns of Evolution. Patterns in Evolution. Natural selection leads to many predictable outcomes On a grander scale, these predictable outcomes produce recognizable patterns in evolution. Divergent Evolution Convergent Evolution Coevolution. Divergent Evolution.
E N D
Patterns in Evolution • Natural selection leads to many predictable outcomes • On a grander scale, these predictable outcomes produce recognizable patterns in evolution Divergent Evolution Convergent Evolution Coevolution
Divergent Evolution • Divergent evolution is alsocalled adaptive radiation • A common ancestor gives rise to many different species that each fill a different ecological niche. • Niche: All factors related to the role of an organism in the environment (predators, prey, habitat, nocturnal/diurnal, etc)
Divergent Evolution (cont) • Examples: • Ontario rodents • Galapagos finches
Convergent Evolution • Different species that do not share a recent common ancestor have evolved similar traits because they experience the same selective pressures (analogous features) Ex. 1 Eyes of spiders and humans Ex. 2 Streamlined body shape of sharks and dolphins
Coevolution • Two species evolve simultaneously when the survival of one species is influenced by the other • Examples: • Predator-Prey: “evolutionary arms race” • Flowering plants and pollinators • Species that rely on mimicry for survival will continue to evolve if the species they mimic changes
Video • Evolutionary arms race between snakes and newts • http://www.pbs.org/wgbh/evolution/library/01/3/l_013_07.html