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