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the principle that events in the past occurred suddenly and were caused by mechanisms different from those operating in the present
use and disuse
lyell's idea that parts of the body that are used become larger and those that are not used deteriorate
hardy weinberg principle
the frequencies of alleles and genotypes in a population will remain constant provided only mendelian segregation and recombination of alleles
chance events causing allele frequencies to fluctuate unpredictably from one generation to the next
when a few individuals become isolated from a larger population, their gene pool differs from the source population
after a severe drop in population size, the resultant population has a differing gene pool from that of the source population
transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes
the contribution an individual makes to the gene pool relative to the contribution of other individuals
individuals with certain inherited characteristics are more likely than other individuals to obtain mates
individuals who are heterozygous at particular alleles have a greater fitness than both homozygotes
the fitness of a phenotype declines if it becomes too common in a population
biological species concept
a species is defined as a group of populations that can interbreed to produce viable, fertile offspring but cannot do this with members of other group
the existence of biological barriers that impede members of two species from producing viable, fertile offspring
sperm of one species cannot fertilize eggs of another species (prezygotic barrier)
phylogenetic species concept
characterized species based on the smallest group of individuals that share a common ancestor
gene flow is interrupted when a population is divided into geographically isolated subpopulations, causing speciation
a species originating from accident in cell division that causes extra set of chromosomes
an individual that has more than two chromosome sets that are all derived from a single species
mitochondria and plastids were formerly small prokaryotes that bean living within larger cells
a discipline focused on classifying organisms and determining evolutionary relationships
the discipline that uses dna and other molecular data to determine evolutionary relationships
a species from an evolutionary lineage that is known to have diverged before the group of studied species
predicting that features shared by two groups of closely related organisms are present in their common ancestor
a yardstick for measuring the absolute time of evolutionary change based on the observation that some genes change more rapidly than others
much evolutionary change has no effect on fitness and is not influenced by darwinian selection
fixed action pattern
a sequence of unlearned acts that is unchangeable and carried to completion when triggered
a representation of the spatial relationships between objects in an animal's surroundings
the cognitive capacity of devising a method to proceed from one state to or another in the face of an obstacle
cross fostering study
the young of one species are placed in the care of adults from another species
the total effect an individual has on proliferating its own genes and by providing aid that enables close relatives to proliferate theirs
the natural selection that favors altruistic behavior by enhancing reproductive success of relatives
a system of information transfer through social learning that influences the behavior of individuals in a population
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