34. _________ is the ability of a community or ecosystem to maintain structure in the face of potential disturbance.
(A) Resilience
(B) Elasticity
(C) Resistance
(D) Plasticity
(E) Flexibility

30. Which of the following represents a difference between viruses and viroids? (A) Viruses contain introns; viroids have only exons. (B) Viruses infect many types of cells, whereas viroids infect only prokaryotic cells. (C) Viruses always have genomes composed of DNA, whereas viroids always have genomes composed of RNA. (D) Viruses have capsids composed of protein, whereas viroids have no capsids. (E) Viruses cannot pass through plasmodesmata; viroids can.

31. What may lead to alternations of chromosome number? (A) nondisjunction during meiosis. (B) hybridization. (C) chromosome breakage. (D) genetic recombination. (E) genetic exchange.

32. A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of (A) the influence of environment on development. (B) paedomorphosis. (C) a change in a developmental gene or in its regulation that altered the spatial organization of body parts. (D) heterochrony. (E) gene duplication.

33. The chain lengths in food webs are limited by (A) the amount of energy such as sunlight available in an ecosystem. (B) the efficiency of energy transfers that occur between trophic levels. (C) catastrophes. (D) all of the above. (E) A and B only.

35. Some bacteria are metabolically active in hot springs because (A) they are able to maintain a cooler internal temperature. (B) high temperatures make catalysis unnecessary. (C) their enzymes have high optimal temperatures. (D) their enzymes are completely insensitive to temperature. (E) they use molecules other than proteins or RNAs as their main catalysts.

36. The Shannon diversity index is a measure of (A) the number of different species in a community. (B) the abundance of a species in a community. (C) the types of species found in a typical climate. (D) the number of different species and their relative abundance in a community. (E) the distribution of members of a species in a community.

37. Divergence in morphology that is a result of competition between species is termed (A) competitive exclusion. (B) resource partitioning. (C) character displacement. (D) amensalism. (E) mutualism.

38. When each female in the population mates with several males, but each male mates with only one female, the mating system is referred to as (A) polygamy. (B) polyandry. (C) polygyny. (D) monogamy. (E) harem mating.

39. Which of the following cannot be determined using a fecundity schedule combined with a life table? (A) per capital rate of increase. (B) net reproductive rate. (C) mean generation time. (D) dispersal rates. (E) geometric rate of increase.

40. The __________ defines the physical conditions under which a species might live, in the absence of interaction with other species. (A) functional niche (B) realized niche (C) principle niche (D) fundamental niche (E) primary niche