1	genetic variation		_____	those with too few or too many chromosomes
2	epistasis		_____	Single gene influences many traits (can have multiple phenotypic effects)
3	polygenic inheritance		_____	ultimate source of genetic variation
4	pleiotropy		_____	failure of homologous chromosomes to separate
5	non-disjuction		_____	opinions regarding the struggle to survive helped to inspire Charles Darwin in his development of the Theory of Natural Selection
6	Lamarck		_____	extreme phenotype is favored over other phenotypes
7	Malthus		_____	one gene affects the action of another gene
8	gene flow		_____	process in which an individual organism adjusts to a gradual change in its environment (such as a change in temperature, humidity, photoperiod, or pH)
9	genetic drift		_____	refer to differences between individuals or to differences between populations
10	heterozygote advantage		_____	Characters in a population vary in gradations along a continuum; referred to as quantitative characters
11	co-evolution		_____	trisomy
12	directional selection		_____	the transfer of alleles or genes from one population to another
13	stabilizing selection		_____	heterozygote genotype has a higher relative fitness than either the homozygote dominant or homozygote recessive genotype
14	disruptive selection		_____	mechanism to explain evolution: inheritance of acquired characters
15	acclimation		_____	he change of a biological object triggered by the change of a related object
16	mutation		_____	example of epistasis
17	aneuploid zygotes		_____	variation in the relative frequency of different genotypes
18	Down Syndrome		_____	select against extreme values
19	Fur Coloration		_____	extreme values for a trait are favored over intermediate values