Evolution Flashcards
Evolution
Change in the genetic composition of a population during successive generations as a result of natural selection acting on the genetic variation among individuals and resulting in the development of new species
phylogenetic tree
a branching diagram used to model evolution and describe the evolutionary relationship between species
speciation
formation of new species through evolution
species
a group of organisms that are capable of breeding with one another and are incapable of breeding with other species
evolutionary fitness
the better-adaptedness of individual organisms to their environment that allows them to live and reproduce, ensuring that their genes are apart of their populations next generation
natural selection
According to Darwin’s theory on evolution
Only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics in increasing numbers to succeeding generations, while those less adapted tend to be eliminated
selective pressure
any cause that reduces reproductive success (fitness) in a portion of the population
this is what drives evolution
gene pool
the total genetic makeup of a population
genetic drift
the random fluctuations in the frequency of the appearance of a gene in a small isolated population, presumably owing to chance, rather than natural selection
microevolution
small-scale evolutionary changes over relatively short periods of time
macroevolution
large-scale patterns of evolution within biological organisms over long periods of time
extinction
the death of an entire species; permeant inactivity
biological extinction
true extermination of a species; no individuals of this species are left on the planet
ecological extinction
the condition in which there are so few individuals of a species that the species can no longer perform its ecological function
commercial/economic extinction
a few individuals exist but the effort needed to locate and harvest them is not worth the expense
population
a group of organisms of the same species that live in the same area
community
formed from populations of different species occupying the same geographic area
niche
the total sum of a species use of biotic and abiotic resources in it’s enviornmet
habitat
the area or environment where an organism or ecological community normally lives or occurs
specialist
a species that has a narrow niche and can only live in a certain habitat
generalist
a species that has a broad niche, is highly adaptable, and can live in varied habitats
competition
the relationship that exists when two individuals - of the same species or of different species - compete for resources in the same environmet
intrapspecific competition
competition between individuals of the same species
interspecific competition
competition between individuals of different species
Gause’s principle
states that no two species can occupy the same niche at the same time, and that the species that is less fit to live in the environment will either relocate die out, or occupy another niche
realized niche
the compromised niche a species occupies- smaller than the niche it would occupy in the absence of competition
fundamental niche
the niche a species would have if there were no competition
resource partitioning
when different species rely on the resource but use slightly different parts of the resource to avoid direct competition
predation
when one species feeds on another
predator
a species that feeds on another species
prey
a species that’s subject to predation by another species
symbiotic relationship
close, prolonged associations between two or more different organisms of different species that may, but do not necessarily, benefit the other members
mutualism
a symbiotic relationship in which both species benefit
commensalism
symbiotic relationship in which one organism benefits while the other is neither helped nor hurt
parasitism
a symbiotic relationship in which one member is helped by the association and the other is harmed
