evolution Flashcards
what is darwins theory of natural selection
Darwin accepted that populations change over time and individuals with traits that help them survive are
more likely to survive. This is called the Survival of the Fittest
survival of the fittest
organisms compete for limited resources. Organisms with favourable traits that helps them survive and will have an increased chance of reproduction. If they reproduce, a growing number of the population will have these traits in later generations
stabilizing selection
favors an intermediate phenotype and selects against extreme variants of the phenotype
directional selection
favors phenotypes at one extreme over the other
disruptive selection
favors extreme phenotypes rather than intermediate phenotypes
homologous structures
Similar body (origin) different function
analogous structures
Similar function, different body (origin)
vestigial structures
A structure that is a reduced version of a structure that was functional in the organism’s ancestors
mimicry
harmless species resemble (mimic) a harmful species so predators will avoid them because they think they are harmful
camouflage
a defense or tactic that organisms use to disguise their appearance, usually to blend in with their surroundings
fitness
the contribution an individual makes to the gene pool of the next generation by producing offspring that can survive long enough to reproduce
behavioural isolation
behaviours that prevent other spp. from recognizing or selecting them for mating
temporal isolation
Two species that live in the same habitat or the same niche but have different mating seasons due to varying reproductive cycles
ecological isolation
two species that live in same general area but in different habitats
mechanical isolation
structural differences in reproductive organs that prevent fertilization
