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2 ANSWERS 46 Population Ecology 13. Consider a population undergoing logistic growth. When (K N)/K = 0, what does that imply about the birth rate (b) and death rate (d)? A) b > d B) b < d C) b = d D) It is not possible to make an inference about b and d from this information. 14. As a population approaches its carrying capacity, how does its growth change? A) The growth rate slows until N is 0. B) The growth rate slows until N is close to K. C) The growth rate slows until N is close to r. D) The growth rate stays the same. E) r changes until it is close to K. 15. Population is the number of individuals of a species per unit of habitat area or volume at a given time A) dispersion B) density C) survivorship D) age structure E) demographics 16. Draw the survivorship curve of humans. Then draw the survivorship curve of a dandelion (small flower; r-strategist species).! 1!

3 17. Consider the data in the Figure above illustrating the age structure of France and India. In many parts of the world, the average age of reproductive maturity is increasing as humans move from urban to rural environments. Suppose that the current average age of first reproduction is 15 years in India and 20 years in France. How would a 5-year increase in the average age of reproductive maturity in both countries be expected to affect the per capita birth rate? A) increase in per capita birth rate B) decrease in per capita birth rate 18. Consider the data in the Figure above illustrating the age structure of France and India. Which population is undergoing more rapid growth? How can you tell? India is growing more rapidly, You can tell because there are a high proportion of young people so you know the birth rate is high 19. If the major food source of the seals declines due to pollution or overfishing, which of the following would likely occur? A) The carrying capacity of seals would decrease, as would be the seal population!! B) The carrying capacity of seals would decrease, but the seal population would remain the same. C) The carrying capacity of seals would increase, as would the seal population D) The number of seal deaths would increase, but the number of birds would also increase, so the population size would remain the same. 20. Species that have many offspring at one time are usually: A) r-selected B) K-selected 21. Give an example of how density-dependent and density-independent factors might interact. If there is a drought (density-independent) it could lead to intense competition for food or water (density dependent)!!! 2!

4 ! The!figures!above!represent!three!hypothetical!populations;!each!circle!is!an!organism.!Write! the!letter!(a,!b,!or!c)!of!the!pattern!that!you!would!expect!to!find!in!situations!listed!in! questions!22!!25.!! 22.!Individuals!establish!exclusive!territories!to!secure!access!to!resources.!!A! 23.!Individuals!are!distributed!randomly!within!the!environment.!C! 24.!Food!is!most!abundant!near!waterholes!in!the!desert.!B! 25.!This!is!a!social!species.!B!! 26. Fill in the cohort life table below.! Age Class Population Size Mortality Survivorship Communities, Species Interactions & Ecosystems 27. How might a food web change if all decomposers were eliminated from it? Many important nutrients (from dead organisms) would not be returned to the soil. This could potentially limit plant growth and in turn the effect might be seen at all trophic levels. 28. A symbiotic association in which organisms are beneficial to one another is known as A) predation B) interspecific competition C) intra specific competition D) commensalism E) mutualism! 3!

5 29. Bright coloration that warns predators of prey toxicity is called A) aposematism. B) crypsis. C) homotypy. D) amensalism. E) character displacement. 30. Although a species might be physiologically able to live under a wide range of resource conditions, competitors may restrict its use of resources in a particular location. This is known as A) mutualism. B) interference competition. C) fundamental niche. D) realized niche. E) character displacement. 31. Organisms higher in a food web eat everything that is lower in the food web. (TRUE OR FALSE) 32. There are more herbivores than carnivores because of the decreasing amount of energy available at each level of the food web. (TRUE OR FALSE) 33. Which of the following best describes the kind of resource for which individuals may compete? A) It will most likely be food or some form of nutrient. B) It will most likely be related to space or shelter. C) It will most likely be related to reproduction, such as access to mates. D) It will most likely be related either to food, nutrients, space, or shelter. E) It can be any resource that is limited in the environment. 34. Tropical leafcutter ants collect leaf cuttings which they transport to special underground chambers. There, they chew the leaves to create nursery beds on which they grow a species of fungus they use for food. When ant queens disperse to establish new colonies, they carry the fungus with them, dispersing it as well (this benefits the fungus). In the ants nest, the fungus is at risk of being destroyed by another fungal species that is able to grow in the same habitat, using the same limited resources. On their bodies, the ants carry and provide a home for bacteria that produce antibiotics the ants use to kill this second fungus and thereby protect their food supply. In this system, the relationship between the two fungal species is: A) interspecific competition. B) mutualism. C) predation. D) parasitism. E) commensalism. 35. In a coevolutionary arms race, after a plant evolves a novel chemical defense against an herbivore, A) the herbivore can be expected to go extinct. B) the herbivore can be expected to disperse to new habitats. C) the herbivore can be expected to evolve resistance to the plant's defense. D) the plant can be expected to colonize new habitats. E) the plant can be expected to outcompete all other plants in the same environment.! 4!

6 36. Some argue that any members of the microbiota that take up space on our body surfaces and do no harm are actually providing us a service, because they prevent the colonization of harmful species. From this point of view, the relationship between the microbiota and their human is. A) mutualism B) an antagonistic relationship C) commensalism D) predation 25 Carbon Cycle 37. If plants consume CO 2 during photosynthesis, why hasn t all the atmospheric CO 2 been used up? (Select all that apply.) A) Photosynthesis also produces CO 2 as a product. B) Respiration produces CO 2 as a product. C) Both photosynthesis and respiration produce CO 2 as a product. D) Plants actually don t use CO 2 during photosynthesis, they use O 2. E) Photosynthesis and respiration use one another s products as reactants. 38. Which of the diagrams below best depicts the flow of carbon between primary producers, consumers, and decomposers? A) primary producers! consumers! decomposers B) consumers! primary producers! decomposers C) decomposers! consumers! primary producers 39. Photosynthesis results in the fixation of A) carbon. B) water. C) nitrogen. D) oxygen. E) None of the above 26.4 Nitrogen Cycle What would be the most likely effect on most plants (lacking symbiont microorganisms) if they were given additional nitrogen gas? A) The additional nitrogen gas would increase their growth rate. B) The additional nitrogen gas would interfere with their photosynthesis, and thus would decrease their growth rate. C) The additional nitrogen gas would accelerate their metabolic rate. D) There would be no effect, because plants do not require nitrogen. E) There would be no effect, because plants cannot use nitrogen gas. 41. A rise in aquatic nitrogen and phosphorus levels leads to a strong increase in the population growth rate of algae and cyanobacteria. This suggests that nitrogen and phosphorus are typically in aquatic habitats. A) always abundant B) not at all present C) the limiting factors for planktonic growth D) unnecessary for planktonic growth! 5!

7 42. Explain how eutrophication leads to a decrease in oxygen in a body of water. Increase N = Increased algae growth = increase decomposition = decrease oxygen 48 Global Climate Change & Conservation Biology 43. Consider the characteristics of biomes. Would you expect more biomass in a trophic pyramid from the tropical rainforest compared to one from the tundra? A) Yes, because there is higher productivity at the equator than at the poles. B) Yes, because there is higher fungal diversity cycling carbon at the equator than at the poles. C) Yes, because there are higher numbers of predators at the equator than at the poles. D) No, because there are photosynthetic organisms in both biomes that support the trophic pyramids. E) No, because there are other producers at the poles that don t require sunlight so make up the difference in biomass that would be there if only sunlight was used as an energy source. 44. Climate change occurs because A) carbon dioxide an other greenhouse gases react chemically to produce excess heat B) earth has too many greenhouse and other glassed buildings C) volcanic eruptions produce large quantities of sulfur and other greenhouse gases D) carbon dioxide and other greenhouse gases trap infrared radiation in the atmosphere E) carbon dioxide and other greenhouse gases allow excess heat to pass out of the atmosphere 45. Why might captive-breeding programs that reintroduce species into natural environments fail? Many reasons One is that species might become too reliant on humans. Also, you might relseas organisms back to the wild, but if the original threat is still there, then they still may not be able to survive 46. Which of the following processes increase(s) the amount of atmospheric carbon in the carbon cycle? A) photosynthesis B) cellular respiration C) combustion D) A & C E) B & C 47. Introduced species that spread widely and become unduly abundant are known as species. A) spreader B) invasive C) super D) extravagant E) hammerhead 48. The American Prairie Foundation's practice of buying up ranches in Montana with the aim of reintroducing bison and other species is an example of A) habitat preservation. B) restoration ecology. C) invasive ecology. D) biocontrol. E) None of the above! 6!

8 49. The practice of using exploited lands in ways that sustain biodiversity is known as A) restoration ecology. B) reconciliation ecology. C) reparative ecology. D) fragmentation ecology. E) Kubrick's principle. 50. The rate of absorption of carbon dioxide in the oceans is causing them to become more. A) decreasing; acidic B) decreasing, alkaline C) decreasing; productive D) increasing; acidic E) increasing; productive 51. Which of the following will be a likely result of global warming? A) Temperate-zone diseases moving to the tropics B) Tropical diseases expanding to the temperate zone C) Insects moving from high altitudes of the temperate zone to lowland areas D) Both a and c E) None of the above 52. If the oceans were able to absorb more carbon dioxide, the rate at which the Arctic sea ice melts would likely DECREASE. 53. Name three sources of atmospheric carbon. Respiration Burning of Fossil Fuels Deforestation! 7!