Collegeboard Unit 3
Which of the following best describes a difference between generalist species and specialist species? A Generalists use a large range of resources, while specialists have a limited range of resources they use to survive. B Generalists can thrive in a narrow range of environmental conditions, while specialists thrive in a variety of environmental conditions. C Generalists are often herbivores, while specialists are often omnivores. D Generalists are more prone to extinction than specialists are.
Answer A Correct. Generalist species can utilize a broad range of resources, while specialists utilize a much smaller range of resources.
Which of the following statements best describes why birth and death rates are changing in a country that is in Phase 2 of the demographic transition? A Individuals have better sanitation and access to clean drinking water. B Individuals have increased availability of birth control and have smaller family sizes. C The population has a high infant mortality rate because of the lack of health care. D The population size stops increasing and may decline if birth rates are lower than death rates.
Answer A Correct. In phase 2, there is rapid population growth as the result of better access to clean drinking water, food, vaccinations, and other medical care.
A country is currently in the second stage of the demographic transition. Currently the country has a birth rate of 37.9 births per 1,000 individuals and a death rate of 13.4 deaths per 1,000 individuals. Which of the following changes would indicate that the country is moving from the second stage into the third stage of the demographic transition? A The birth rate declines to 25.3 births per 1,000 individuals. B The birth rate declines to 13.1 births per 1,000 individuals. C The birth rate rises to 43.1 births per 1,000 individuals. D The death rate rises to 37.9 deaths per 1,000 individuals.
Answer A Correct. The birth rate falls but does not yet match the death rate during the third stage.
The rule of 70 can be used to determine a population's doubling time. Doubling time is a measure of the A population growth rate B environmental impact of each individual in a population C length of time an individual born in a population is expected to live D average age of the first reproductive event per 1,000 women in a country
Answer A Correct. The rule of 70 states that dividing the number 70 by the percentage population growth rate approximates the population's doubling time.
Based on current trends and patterns, which of the following statements best predicts how the human population will change over the next 50 years? A As the amount of available food and drinking water increases, the population size will also increase. B As the population density increases, there will be an increase in disease transmission, leading to increased mortality. C A decrease in the number and magnitude of earthquakes and tsunamis will decrease the amount of land available for agriculture, leading to decreased fecundity. D As educational and economic opportunities increase for women in less developed countries, both the total fertility rate and the population size will increase.
Answer B Correct. Diseases that occurred locally will spread rapidly among a growing population with high population density.
A scientist is studying a biome that experiences large seasonal fluctuations in both temperature and precipitation patterns. Which of the following would best characterize the organisms that inhabit the biome? A Habitat specialists would be most abundant, because they have broad niches. B Generalists would be most abundant, because the resources available would be constantly changing. C Generalists that feed only on animals would be more abundant in the summer months, while generalists that feed only on plants would be more abundant in the winter months. D Specialists that live in trees would be more abundant in the summer months, whereas specialists that live in caves would be more abundant in the winter months.
Answer B Correct. Generalists have an advantage in habitats that are changing; they are capable of surviving in a wide range of conditions and use a wide range of food resources.
Which of the following claims best supports the classification of bees as an organism that displays a Type II survivorship curve, as shown in the graph above? A Queen bees are capable of laying up to 2,000 eggs in one day. B Away from the colony, bees experience a constant probability of death per unit time as a foraging species. C Bees communicate using chemical signals and exchange information through vibration of their wings. D Populations of bees are declining in North America due to habitat loss and pesticide use.
Answer B Correct. Type II species have a constant mortality rate throughout their lifetimes. Bees demonstrate this survivorship curve.
Which of the following density-independent factors can affect the size of a human population? A Disease B Availability of food C Heat waves D Access to clean water
Answer C Correct. Heat waves will affect people if there are few or many in an area; the effects are independent of population density.
Which of the following is a characteristic of an organism that displays a Type III survivorship curve, as shown in the graph above? A The organism has a fairly constant mortality rate over time. B The organism reaches reproductive maturity after many years. C The organism produces large numbers of offspring every time it reproduces. D The organism provides constant parental care to its offspring for several years.
Answer C Correct. Type III organisms (including many marine invertebrates and other r-selected species) have large numbers of offspring.
A variety of plants and animals inhabit a forest ecosystem. Which statement correctly explains why certain organisms would be more likely to survive than others if a forest fire burned the area? A Specialist species are more likely to survive because they can thrive in a narrow range of environmental conditions and they have a limited diet. B Specialist species are more likely to survive because they can thrive in a large range of environmental conditions and can make use of a variety of different resources. C Generalist species are more likely to survive because they can thrive in a narrow range of environmental conditions and they have a limited diet. D Generalist species are more likely to survive because they can thrive in a wide variety of environmental conditions and can make use of a variety of different resources.
Answer D Correct. A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources. A specialist species can thrive only in a narrow range of environmental conditions or has a limited diet. Loss of habitat leads to a loss of specialist species before a loss of generalist species.
The demographic transition model describes population change over time as a country becomes more developed. Age-structure diagrams describe how populations are distributed across age ranges. Which of the following age-structure diagrams best displays the age ranges in a country that is in stage 2 of the demographic transition? A A stationary age-structure diagram B An inverted pyramid age-structure diagram C A constrictive age-structure diagram D An expansive pyramid age-structure diagram
Answer D Correct. Stage 2 in the demographic transition has high birth rates and fairly high death rates, with a rapidly growing population. This is illustrated by high numbers of prereproductive-age individuals in the age-structure diagram, leading to a pyramid shape.
