1. Macroevolution refers to changes in populations of plants and animals so that new species develop from old ones. Microevolution refers to changes in allele frequencies within a species.
2. Adaptation results from the possession of features that promote the chance of an organism's survival and reproduction. The natural selection of Darwin's concept of evolution is the process, and adaptation is the result.
3. Genetic polymorphism refers to genes that have more variation than can be explained by mutation. Invertebrates are more polymorphic than vertebrates. The variation provided by genetic polymorphism is a significant source of raw material upon which natural selection can act.
4. (p + q)2 = p2 + 2pq + q2, where p2 is the frequency of individuals homozygous for the more common allele, q2 is the frequency of individuals homozygous for the less common allele, and 2pq is the frequency of heterozygous individuals.
5. p = 54/100 = 0.54 q = 1 - p = 0.46. Therefore, heterozygous: 2pq = 2(0.54 _ 0.46) = 0.4968 = 5/10; homozygous dominant: p2 = 0.54 _ 0.54 = 0.29 = 3/10; homozygous recessive: q2 = 0.46 _ 0.46 = 0.21 = 2/10; CHECK: 5/10 + 3/10 + 2/10 = 10/10.
6. Migration, mutation, genetic drift, nonrandom mating, and selection will cause a shift in the Hardy-Weinberg equilibrium. Only selection produces an adaptive change; the rest of the phenomena are independent of environmental pressures.
7. Gene flow is the movement of genes from one population to another through migration or hybridization. Gene flow is affected by the distance between populations, how much individuals move during or before they reach reproductive age, and the distance over which mating takes place.
8. Genetic drift is loss of an allele from a population. This is more likely to occur if a population is small because the loss of a single breeding individual will greatly affect gene frequencies.
9. The only alleles the subsequent population can build on are those few present in the population originators (the "founders"). If a population should become catastrophically reduced in size (through earthquakes, etc.), subsequent alleles in the population will only be those of the survivors, a phenomenon called the bottleneck effect.
10. Nonrandom mating increases the proportion of homozygotes. Inbreeding has no effect on allele frequencies. Inbreeding tends to throw deleterious recessive alleles together, which is typically not favored by natural selection. Marriage between close relatives contributes to inbreeding.
11. Selection is the ultimate success of an organism so that it survives to leave more offspring and hence pass on more of its genetic material. The ``successful'' organisms will leave more offspring and hence more of their own genes, skewing the allele frequencies, even if only slightly. Directional selection eliminates one extreme from a range of phenotypes, such as the elimination of Drosophila individuals in a population that move toward light. Stabilizing selection eliminates both extremes from a range of phenotypes, such as reduced survival values in duck eggs at the higher and lower extremes of weight. Disruptive selection actually eliminates some of the intermediate forms instead of extremes, as seen in increased predation on nonmimic butterflies in Africa.
12. Few traits are completely independent of others, and their interactions increase with successive matings; selection can only act on traits in which the homozygotes and heterozygotes are clearly phenotypically distinguishable.