Exam 3

73. Stratospheric ozone is important because it

blocks solar UV radiation.

In which of the following habitat types would species diversity be expected to be relatively low?

high environmental stress

54. Near the poles, what is generally the overriding climate factor?

temperature

32. Which country would be expected to have the greatest species richness per unit area?

Brazil

31. In accordance with the time hypothesis, which of the following countries would be expected to have the LEAST species richness?

Canada

53. Which of the following is an adaptation of black-tailed prairie dogs?

Modified digestive tracts easily digest seeds of grasses

4. Which of the following relationships is incorrectly paired?

Nesting seabirds—random dispersion

18. What is a typical feature of K-selected organisms?

a low productive rate

39. A linear depiction of energy flow in an ecosystem is a(n)

food chain

60. The most productive region of a lake is the ____ zone.

littoral

10. What term refers to the average rate at which organisms produce offspring?

natality

3. The best definition of population density is the number of individuals:

of one species in a given area at a given time.

22. Which scenario best describes facilitation?

An interaction between members of a population that enhances the local environment for other members of the same population

7. Which of the following consists of organisms, all of which share a common gene pool?

a population

Differentiate between the following terms: threatened species and endangered species.

"Endangered" means a species is in danger of extinction throughout all or a significant portion of its range. "Threatened" means a species is likely to become endangered within the foreseeable future.

37. Approximately what proportion of the radiant energy entering an ecosystem is used in photosynthesis?

1%

On average, clouds and surfaces, especially snow, ice, and the ocean, immediately reflect away

50. 30% of the solar radiation that falls on Earth.

Describe why identifying and conserving keystone species are important, provide an example of a keystone species

A keystone species helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether

58. What environment is characterized by high nutrient inputs and by relatively great fluctuations in salinity and temperature?

An estuary

Which statement best describes a typical food chain?

An owl has a positive impact on the grass population.

61. Which of the following applies to the deepest zone of a large lake?

Anaerobic conditions

62. The ____ realm has long been separated from other land masses and is the area in which marsupials are particularly common.

Australian

72. Between 1990 and 2010, which greenhouse gas increased the most to the warming effect of the planet?

Carbon dioxide

Differentiate between density-dependent and density-independent factors affecting population growth. Provide two examples for each, along with a brief explanation.

Density-dependent limiting factors depend on the size of a population. The Density-dependent limiting factors include disease, parasites, competition for food, water, and shelter, and predation. The Density-independent limiting factors include natural disasters, climate, and human activity.

69. Which action best illustrates in situ conservation?

Designating a large area as a national reserve

The primary reason that Earth experiences seasons is because of the

Earth's tilt on its axis.

A biological community and its abiotic environment together comprise which of the following?

Ecosystem

35. Based on latitude only, which of the following U.S. states would be expected to have the highest species richness?

Georgia

Describe the human impact on two aquatic ecosystems. How have these alterations impacted these ecosystems?

Human effects on aquatic ecosystems can result from pollution, changes to the landscape or hydrological systems, and larger-scale impacts such as global climate change

26. Many poisonous snakes share warning colors of red, yellow, and black. This is an example of:

Müllerian mimicry.

36. A lake in which of the following locations would be expected to have the highest species richness?

National forest

State two reasons why tropical rain forests are being destroyed today.

People cutting down wood for timber and road construction

66. Which of the following is reported to cause deformities in amphibians in the Sierra Nevadas of California?

Pesticides

2. Which of the following series correctly represents the hierarchical organization within ecology?

Population → community → ecosystem → biosphere

1. Which of the following is a correct statement regarding populations in biology?

Populations exhibit characteristics distinctive from those of the individuals of which they are composed.

Which of the following is NOT a condition that is likely to lead to uniform population dispersion?

Pressure from predation

38. Which pair best represents photosynthetic organisms?

Primary producer and autotroph

59. Which factor is most important in determining the distribution of organisms in aquatic biomes?

Salinity

71. What is a practice in which farmers often follow loggers' access roads, cut down the trees, burn the area, and plant crops immediately?

Slash-and-burn agriculture

Briefly describe where deserts develop and why.

Some deserts are found on the western edges of continents. They are caused by cold ocean currents, which run along the coast. They cool the air and make it harder for the air to hold moisture.

57. Currently, much commercial lumber and wood products come from which biome?

Temperate rain forest

52. What two abiotic factors are considered to most affect organisms?

Temperature and water

33. Which habitat would most likely have the greatest species richness?

Tropical Rainforest

Net primary productivity represents:

amount of biomass needed for cellular respiration

Density-independent factors:

are typically abiotic

Keystone species:

are typically not the most abundant species in the community.

at zero population growth:

b=d

8. Which of the following organisms would have the highest intrinsic rate of increase?

bacteria

The major components of Earth's atmosphere, from the lowest concentration to the greatest concentration, are

carbon dioxide, oxygen, and nitrogen

Traditionally, most ecologists have assumed that community stability is a consequence of:

community complexity

When the size of a population begins to approach K, we can expect that the growth rate will

decline

Which factors are an example of a negative feedback system?

density dependent

67. Today, the major danger to species is

destruction of habitats.

An organism's role within the structure and function of a particular community is its:

ecological niche.

30. A transitional zone where two or more communities meet is known as which of the following?

ecotone

40. What key factor limits the number of trophic levels in an ecosystem?

energy loss

63. The ability to meet humanity's current needs without compromising the ability of future generations to meet their needs is

environmental sustainability.

45. Which process plays the most important role in the phosphorous cycle?

erosion

65. When a species dies, the species is said to be

extinct

. Which organisms may be a keystone species in a tropical rain forest?

fig trees

64. Building roads, parking lots, buildings and bridges all contribute to

habitat destruction.

Organisms that eat plants exclusively are known as:

herbivores

23. Large-scale experiments conducted in oak forests of the northeastern United States linked bumper acorn crops to booming mouse populations. The conclusion from these experiments is that:

increased levels of first trophic level productivity cause an increase in disease vector activities.

48. The event in human history that changed the natural balance of the carbon cycle was the

industrial revolution

Two members of the same species compete for a limited resource, resulting in equal sharing of the limited resource. What is this called?

infraspecific

20. A population that is divided into several local populations among which individuals occasionally disperse (emigrate and immigrate) is known as a:

metapopulation

Which of the following would increase population size?

natality

47. Which of the following processes restores nitrogen to the air?

nitrification

49. The 'sun's energy is produced by

nuclear fusion reactions

56. There are no trees in the tundra because:

of limited root penetration due to permafrost.

An example of a density-dependent factor that influences the size of a population is:

parasites

Iteroparity is common in which of the following organisms?

perennial herbaceous plants

Natural selection acts most directly on

populations

68. The use of the principles of ecology to return a degraded environment to as functional a state as possible is called

restoration ecology

19. Generally, r-selected organisms exhibit:

short life spans and early maturity

70. Perhaps the biggest problem associated with the Endangered Species Act as it currently stands is that it

tends to protect a limited number of organisms.

46. Transpiration is most closely associated with

terrestrial plants

A habitat is best defined as:

the local environment in which a species lives.