Question

Of the following evolutionary forces; crossing over, directional selection, mutation, speciation, stabilizing selection, sex, gene flow and genetic drift which promote or maintain genetic variation within a population?

a) crossing over only b) directional selection and sex c) directional selection, mutation, and speciation d) crossing over, mutation, sex, and gene flow e) only sex

Of the following evolutionary forces, crossing over, directional selection, mutation, speciation, stabilizing selection, sex, gene flow and genetic drift which promote genetic differentiation (divergence) among populations?

a) directional selection, speciation, and genetic drift b) crossing over, directional selection, stabilizing selection, and sex c) sex and gene flow d) mutation, gene flow, and genetic drift e) crossing over, mutation, stabilizing selection, sex, and gene flow

What factual evidence can be offered to indicate that geographic isolation promotes speciation?

a) related species are often separated by a conspicuous geographic boundary. b) speciation appears to occur more rapidly on islands. c) populations on the opposite sides of wide ranging species are often differentiated. d) all of the above (a, b and c). e) there can be no evidence offered since speciation is too slow to observe.

There are two alleles common at the zic-zac locus in a Caribbean snail. If the zic allele occurs at 40% and the zac allele occurs at 60%, how many zic-zac heterozygotes would you expect to observe in the populations?

20%, 24% ,10%, 48% 30%