Elements of Ecology, 8e (Smith/Smith) Chapter 13 Species Interactions, Population Dynamics, and Natural Selection 13.1 Short Answer Questions 1) In most flowering plants, successful reproduction requires that ________ (male gametes) from one individual be transported to the female organ (stigma) of another flowering individual. Answer: pollen Topic: Introduction to Part 4 2) When each of two species benefits from their interaction, the relationship is referred to as ________. Answer: mutualism Topic: Section 13.1 3) When one species reduces or adversely affects the population of another, but the affected species has no influence in return, the relationship is referred to as ________. Answer: amensalism Topic: Section 13.1 4) When one species feeds on another prey species, typically killing it, the relationship between the two interacting species is referred to as ________. Answer: predation Topic: Section 13.1 5) When individuals of two species interact, the nature of the interaction can be classified qualitatively as positive, negative, or ________. Answer: neutral Topic: Section 13.2 6) ________ occurs when two species undergo reciprocal evolutionary change through natural selection. Answer: Coevolution Topic: Section 13.3 7) Under certain conditions, ________ fungi live in the roots of many species of plants and have a mutually beneficial relationship with the plants. Answer: mycorrhizal Topic: Section 13.4 8) The process in which a network of species undergoes reciprocal evolutionary change through natural selection is referred to as ________. Answer: diffuse coevolution Topic: Section 13.5
1 Copyright © 2012 Pearson Education, Inc.
9) The range of physical and chemical conditions under which each species can persist (survive and reproduce) and the array of essential resources it utilizes are referred to as its ecological ________. Answer: niche Topic: Section 13.6 13.2 Multiple-Choice Questions 1) When the trunk or limb of a tree provides the substrate on which an epiphytic orchid grows, the arrangement benefits the orchid, which gets nutrients from the air and moisture from aerial roots, while the tree is unaffected. The relationship is referred to as A) amensalism. B) comensalism. C) competition. D) parasitoidism. Answer: B Topic: Section 13.1 2) When the relationship between two interacting species is detrimental to the populations of both species, the interaction is referred to as A) parasitism. B) mutualism. C) competition. D) amensalism. Answer: C Topic: Section 13.1 3) As the population of a predator increases, the A) population of the prey species decreases. B) birthrate of the prey species increases. C) mortality rate of the prey species decreases. D) proportion of the prey population that is captured and consumed decreases. Answer: A Topic: Section 13.2 4) When a species of bird preys upon the seeds of a plant and favors the smallest seeds, A) the prey species functions as an agent of natural selection on the predator. B) natural selection favors individual plants that produce the largest seeds. C) the plants compensate for their losses by producing proportionately more smaller seeds. D) the bird species is unaffected when directional selection favors plants that produce the largest seeds. Answer: B Topic: Section 13.3
2 Copyright © 2012 Pearson Education, Inc.
5) Mycorrhizal fungi have a mutually beneficial relationship with plants in environments with soils that A) are saturated with water. B) have a high clay content. C) are acidic. D) are low in nutrients. Answer: D Topic: Section 13.4 6) In most plant-pollinator interactions, plants species are pollinated by A) one animal species, and each animal species pollinates one plant species. B) one animal species, and each animal species pollinates multiple plant species. C) multiple animal species, and each animal species pollinates one plant species. D) multiple animal species, and each animal species pollinates multiple plant species. Answer: D Topic: Section 13.5 7) Two species of cattail (Typha) live in shallow water along the shoreline of ponds. Although T. agustifolia can live by itself in water 0—20 cm deep, in the presence of T. latifolia, it occurs only in water > 20 cm deep, whereas T. latifolia occurs in shallower water. In this example, T. agustifolia is limited by competition exploiting its A) ecological niche. B) fundamental niche. C) realized niche. D) physiological niche. Answer: C Topic: Section 13.6 13.3 True/False Questions 1) The flower of an orchid species is pollinated by a species of wasp that is deceived by the orchid into thinking it is mating with another wasp. Answer: TRUE Topic: Introduction to Part 4 2) Predation always has a negative effect on the individual prey. Answer: TRUE Topic: Section 13.1 3) In a parasitic relationship between two species, the host species usually dies. Answer: FALSE Topic: Section 13.1 4) Parasitoidism is a form of mutualism. Answer: FALSE Topic: Section 13.1 3 Copyright © 2012 Pearson Education, Inc.
5) When the population size of a prey species increases, the birthrate of a predator species should also increase. Answer: TRUE Topic: Section 13.2 6) The interaction between two species usually influences all individuals within the respective populations equally. Answer: FALSE Topic: Section 13.3 7) The relationship between nectar-producing flowers and nectar-feeding birds is a mutually beneficial interaction. Answer: TRUE Topic: Section 13.3 8) Species having wide geographic distributions generally encounter a broader range of physical environmental conditions than species whose distribution is more restricted. Answer: TRUE Topic: Section 13.4 9) Most interspecific interactions are exclusive, involving only two species. Answer: FALSE Topic: Section 13.5 10) An organism's realized niche is always smaller than its fundamental niche. Answer: FALSE Topic: Section 13.6 11) Adaptive radiation can result from divergent adaptations to avoid predators. Answer: TRUE Topic: Section 13.7 13.4 Essay Questions 1) Define five types of species interactions based on their reciprocal effects. Topic: Section 13.1 2) Describe an example of how coevolution between a predator and a prey can lead to specialization. Topic: Section 13.3 3) Define diffuse coevolution. Do most interspecific interactions occur exclusively between two species? Provide an explanation for your answer. Topic: Section 13.5
4 Copyright © 2012 Pearson Education, Inc.
4) Define a fundamental niche and a realized niche, and provide an example illustrating each. Is one always larger than the other? Explain your answer. Topic: Section 13.6
5 Copyright © 2012 Pearson Education, Inc.
