chapter 12 Flashcards
(45 cards)
what is the key to natural population?
variation
what is the simplest example of variation?
allele
two different forms of alleles
dimorfysm
multiple forms of alleles for a particular gene
polymorfysm
what are sources of variation?
mutation, sexual reproduction
set of all alleles of all genes in a population
gene pool
changes in allele frequency
microevolution
what are the modes of selection?
directional, stabalizing, disruptive, character
individuals toward one end of variation are favored
directional selection
intermediate phenotypes are favored- extremes are weeded out
stabalizing selection
individuals of extreme phenotypes are favored at both ends of the spectrum
disruptive selection
evolutionary change that reduces competition between two species, incompletely overlapping ranges
character displacement
population species ranges overlap
sympatric
region where species occur seperatly
allopatric
maintance of multiple alleles in a population
balanced polymorphsym
“mate choosiness”
sexual selection
random changes in allele frequencies in populations due to change event (can result in fixation or lost)
genetic drift
what type of population does genetic drift effect the most?
smaller populations
drastic reduction in population size by chance event
bottleneck effect
difference in allele frequencies of a new population started from subsets of original population due to smaller population size and chance
founder effect
common disease in old order amish
ellis van creveld syndrome
formation of a new species
speciation
species are groups of interbreeding natural populations that are reproductively isolated from other such groups
biological species concept
end to gene flow between population
reproductively isolated
