test Flashcards
existence of two or more distinct alleles at a given locus in a population’s gene pool
genetic polymorphism
ancestral structure that has become obsolete; for example the hind limbs found in transitional whale fossils
vestigial character
graded variation in a trait that parallels a gradient in the environment
Cline
mutational change that results in individuals with more than two sets of chromosomes, sometimes leading to a distinct species
Poly ploidy
variation in the relative rates of growth of various parts of the body (during development), which helps shape the organism
heterochrony
Two individuals in an asexual population have distinct, beneficial mutations. When their descendants compete with each other, one of those mutations is lost to extinctions. This phenomenon is called
clonal interference
Most models of sympatric speciation postulate the existence of
disruptive selection based on resource use.
How does artificial selection produce rapid changes in the phenotype of organisms?
by changing the frequency of alleles and selecting for new combinations of traits
Which mode of speciation involves intermediate levels of gene flow?
Parapatric speciation
When we say that mutation is random, we mean that
we cannot predict which gene copy will undergo a mutation, and environments do not induce adaptive mutations
If a gene is described as polymorphic, how many alleles does it have?
two or more.
Many temperate plant taxa have not adapted to tropical environments, and many animal species shifted their ranges during the Pleistocene rather than adapting to climate change. These observations are consistent with
phylogenetic niche conservatism.
