Specific Evolution Terms

adaptive radiation

speciation occurs at an accelerated rate in a new environment

allopatric speciation

populations are physically isolated from each other

allopolyploidy

chromosomes duplicated between species and are fertile

autopolyploidy

chromosomes double within a species and are often infertile, except in plants and fungi

bottleneck

reduction in alleles due to catastrophe, genetic variation decreases

founder effect

reduction in alleles due to starting a new population, genetic variation decreases

convergent evolution

multiple organisms independently evolve the same characteristic

gene flow

movement of alleles across different populations which increases genetic diversity

genetic drift

random change in allele frequency due to chance event

homologous structure

indicate divergent evolution from a common ancestor

analogous structures/homoplasy

indicate convergent evolution, no recent common ancestor

hybrid zone

different species come in contact and mate resulting in reinforcement, fusion, or stability

paraphyletic

include some but not descendants from a common ancestor

polyphyletic

do not have a recent common ancestor and are placed in different taxa

monophyletic

all descendants of a common ancestor

polyploidy

more than one pair of homologous chromosomes

qualitative variation

discrete variation with distinct states

quantitative variation

continuous variation in appearance or function that is measured and controlled by many genes

sympatric speciation

occurs without a geographical border