The correct answer is A. Disruptive selection selects against the mean. Stabilizing selection favors the mean at the expense of the extremes. Directional selection is one phenotypic extreme selected over another, causing a shift in the overall mean in one direction or the other. Normal is not a type of selection, but refers to the normal bell-shaped curve in ideal situations.

C is the correct answer. Choice A refers to the morphological species concept. Choice B refers to the mate recognition species concept. Choice D refers to the phylogenetic, or evolutionary, species concept.

C is the correct answer. Disruptive selection is pressure acting upon the middle of the trait distribution. Natural selection is the process of one genotype leaving more offspring than another genotype. Stabilizing selection occurs when selective pressures cull out the two extremes in a population.

D is the correct answer. Gregor Mendel observed variations across several generations of pea plants. He formulated the law of independent assortment and law of segregation. Darwin developed the concept of natural selection central to the theory of evolution. Dobzansky and Mayr introduced the evolutionary theory that shifted focus on populations, genetics, and phenotypes.

The correct answer is B. Turnover pulse is a hypothesis constructed by Elisabeth Vrba explaining an extensive evolutionary shift worldwide. The theory of evolution states the process of variation and natural selection. Gradualism is the belief that change is slowly cumulative, yet continuous.

The correct answer is B. The bottleneck effect refers to a species being reduced to a very small population, resulting in reduced genetic diversity. Genetic drift is the random variation in gene frequency from one generation to another. Geographic isolation, or allopatry, refers to a part of a population becoming geographically isolated and evolving different characteristics over time.

The correct answer is A. Populations of species may share bordering territory without sharing genetic information. Allopatric speciation occurs when individuals become geographically isolated and evolve into a distinctly different species. Sympatric refers to closely related species occupying the same area without interbreeding. Symbiotic refers to a relationship between two organisms with one or both benefiting.

C is the correct answer. Comparative anatomy is the study of evolutionary biology, phylogeny, paleontology, and anatomy to identify evidence of evolution. Choices A, B, and D are ideas within comparative anatomy.

A is the correct answer. Fossil remains indicate that there have been geologically brief periods of time when entire species have disappeared. Mass extinctions have opened the way for new species to emerge and succeed. Punctuated equilibrium is the evolutionary theory that speciation occurs quickly with long periods of very little change. Gradualism refers to evolution and states that species' modifications occur over time. Genetic drift is the random variation in gene frequency from one generation to another.