Name: __________________________________ BI103 – General Ecology 1.) 2.) Lecture Exam IV April 28, 2022 In Michael Huston’s studies of Costa Rican forest diversity, the highest tree diversity was found on soils with a. very high fertility. b. moderate fertility. c. very low fertility. d. either high or low, but not moderate fertility. Pocket gophers change the nitrogen cycle in prairies because they a. excavate nitrogen-rich subsoil to the surface. b. selectively remove nitrogen-fixing legumes from plant communities. c. cultivate nitrogen-fixing bacteria in burrow chambers. d. excavate nitrogen-poor subsoil to the surface. 3.) 4.) Mycorrhizal fungi (directly) help their plant partners acquire a. sugars. b. sunlight. c. seed dispersal. d. soil nutrients. In most ecological communities, we find a. more rare species than moderately common or very common ones. b. more very common species than moderately common or rare ones. c. no rare species—apparently “rare” species are artifacts of incomplete sampling. d. more moderately common species than rare or very common ones. 5.) Liebig’s “Law of the Minimum” stated that a. the lowest primary productivity occurs in the coldest ecosystems. b. primary productivity is typically controlled by climate. c. primary productivity is typically controlled by both climate and soil nutrients. d. a single soil nutrient typically limits primary productivity. 6.) In soil and water fertilization experiments, increasing fertilization tends to reduce the number of limiting resources for plant growth until a single resource limits growth of all species. This “ultimate” limiting resource tends to be a. carbon. b. light. c. phosphorus. d. oxygen. 7.) 8.) The breakdown of organic matter accompanied by the release of carbon dioxide is called? a. mineralization b. decomposition c. nutrient cycling d. disturbance The interaction between honeyguide birds and the Boran people of Kena a. is an obligate mutualism. b. is a facultative mutualism. c. is exploitative, with humans benefitting but honeyguides are exploited. d. represents the only way a honeyguide can gain access to a beehive. 9.) The major source of nutrients in surface waters of the open ocean is a. mixing of subsurface with surface waters. b. deposition from the atmosphere. c. addition by ocean currents bringing nutrients from nearshore waters. d. decomposition of dead organic material. 10.) Cyanide and nitrates are residual contaminants left over from extracting gold. What was added to the environment to help bacteria remove these so they are not pollutants? a. nitrogen b. carbon dioxide c. ammonia d. sucrose 11.) The most serious human-caused threat to endangered species worldwide is a. pollution. b. the introduction of invasive species. c. habitat destruction. d. the pet trade. 12.) ________ mutualism describes a relationship where species are so dependent on their mutualistic relationship they cannot live in its absence. a. Obligate b. Critical c. Facultative d. Dispensable 13.) In general, among solitary predators, ______ is/are often the determining factor in prey selection. a. age b. size c. numbers d. health 14.) Herbivores, carnivores, and detritivores are all a. omnivores. b. autotrophs. c. heterotrophs. d. browsers. 15.) The major benefit obtained by aspen sunflower, Helianthella quinquenervis, from its ant mutualists is a. reduced losses of seeds to seed predators. b. reduced loss of leaf tissue to herbivorous insects. c. more efficient extraction of soil nutrients. d. more rapid growth early in the growing season. 16.) Robert MacArthur’s study of forest warblers suggested that a. fewer warbler species can survive in more complex habitats. b. warbler species diversity increases with habitat complexity. c. warbler species diversity decreases with habitat complexity d. most warblers have rather similar foraging niches. 17.) Generally, as predator size decreases, prey size _________________________. 18.) Soil fertilization should favor mycorrhizal fungi that are a. less aggressive at obtaining sugars from their plant hosts. b. more aggressive at extracting inorganic nutrients from soils. c. more efficient at extracting inorganic nutrients from soils. d. more efficient at extracting sugars from soils. 19.) Joseph Connell’s “intermediate disturbance hypothesis” proposes that a. species diversity is highest at intermediate frequencies of disturbance. b. species diversity is lowest at intermediate frequencies of disturbance. c. population growth rates are highest at intermediate frequencies of disturbance. d. competitive exclusion is fastest at intermediate levels of disturbance. 20.) __________________ is the process of increased nutrient inputs into an ecosystem resulting in increased primary productivity and reduced biodiversity. 21.) Nitrogen export was greatest in streams draining watersheds from a. forested areas. b. agricultural areas. c. suburban areas. d. urban areas. 22.) A relatively discrete ecological event that kills or damages organisms or alters the physical or biological environment is called a ______________________. 23.) Actual evapotranspiration rates are highest in ___________ climates. a. warm, moist b. cold, moist c. warm, dry d. cold, dry 24.) Carnivores that feed on herbivores (or on detritivores) are referred to as a. primary producers. b. primary consumers. c. secondary consumers. d. keystone species. 25.) Which aspects of the biology of zooxanthellae are controlled by their coral hosts? a. Their cell wall chemistry b. The release of photosynthetic products from their cells c. Their mortality rate d. The rate at which they absorb sugars from their hosts 26.) A community is defined as a. a group of organisms that all make their living in a similar way. b. a group of individuals of a single species inhabiting a defined area. c. the portion of a defined area that supports life. d. an association of interacting species inhabiting a defined area. 27.) The number of trophic levels in an ecosystem is limited by a. the number of tertiary consumers. b. the loss of energy with each transfer between trophic levels. c. the gain of energy with each transfer between trophic levels. d. the rate at which organisms can recycle energy within the ecosystem. 28.) A set of species that have similar ways of making their living make up a _________________. 29.) Scientists have studied nutrient cycles and determined that these cycles affect the health of the biosphere. Which cycles are of most concern? a. Carbon and nitrogen b. Nitrogen and phosphorus c. Carbon and phosphorus d. Carbon, nitrogen, and phosphorus 31.) The main force in the development and refinement of prey defenses is/are a. nutrition. b. predators. c. the prey themselves. d. mate choices 32.) ___________ is the movement of nutrients between pools of an ecosystem and influences the distribution of nutrients. a. Nutrient shedding b. Nutrient cruising c. Nutrient sink d. Nutrient flux 33.) To test if a nutrient limits ecosystem productivity, you should a. analyze nutrient availability. b. measure ecosystem productivity. c. add nutrients. d. add different nutrients and measure productivity. 34.) The largest reservoir of phosphorus in most ecosystems is phosphorus a. in the atmosphere. b. dissolved in water. c. in rocks and sediments. d. bound in animal tissues. 35.) How do nutrients and energy move through ecosystems? a. Nutrients move one direction while energy gets recycled. b. Nutrients get recycled while energy moves one direction. c. Nutrients and energy both get recycled. d. Nutrients and energy both move one direction. 36.) Ant-acacia trees provide several services to their mutualistic ant partners. These include a. enlarged thorns to host any colonies. b. nectar from foliar nectaries. c. nectar from floral nectaries. d. both enlarged thorns to host ant colonies and nectar from foliar nectaries. 37.) The production of new organic matter, or biomass, by autotrophs in a system is called _____. a. primary production. b. primary construction. c. trophic production. d. trophic gain. 38.) In aquatic ecosystems, leaves with high lignin content decompose a. rapidly because lignin is a nutrient-rich compound. b. rapidly because lignin enhances colonization by decomposing fungi. c. slowly because lignin reduces colonization by decomposing fungi. d. slowly because lignin is a carbon-poor compound. 39.) Which of the following are nitrogen fixing organisms?
