Exam 1: Multiple Choice

a

A species of fish is found to require a certain water temperature, a particular oxygen content of the water, a particular depth, a rocky substrate on the bottom, and a variety of nutrients in the form of microscopic plants and animals to thrive. These requirements describe the fish's: a. ecological niche b. prime habitat c. resource partition d. dimensional profile e. home base

d

According to the figure, which species is more successful in competing for seeds? a. species 1 b. species 2 c. These species do not compete for seeds d. This figure does not illustrate which species is more successful.

d

Assuming these age structure diagrams describe human populations, which population is likely to experience zero population growth (ZPG)? a. I b. II c. III d. I and II e. II and III

c

In a population that is exhibiting the effects of density dependence, you would expect that as density increases: a. organisms would always devote more energy to reproduction than to growth or survival. b. carrying capacity decreases. c. birth rates would decrease and mortality rates would increase. d. birth rates would stay the same and mortality rates would decrease. e. fundamental niches would get smaller.

a

Looking at the data in the figure, what can be said about survival and clutch size? a. High clutch sizes tend to produce animals with low survival. b. Animals with high fecundity tend to live longer. c. Animals with high fecundity tend to not live as long as animals with low fecundity. d. Animals with low survival tend to have small clutch sizes.

c

Natural selection has led to the evolution of diverse life history strategies, which have in common: a. limitation only by density-independent limiting factors. b. adaptation to stable environments. c. maximum lifetime reproductive success. d. relatively large offspring. e. many offspring per reproductive episode.

b

The competitive exclusion principle states that ___________________. a. it is possible for two species with different niches to coexist. b. it is not possible for two species with the same niche to coexist. c. it is possible for two species with the same niche to coexist. d. it is not possible for two species with different niches to coexist.

d

The intertidal zone is habitat for many different sessile organisms that compete for space on rocks; however, one species of mussel (Mytilus) is a strong competitor for space and will overgrow and "choke out" all other species attached to the rocks. Choose the statement below that best describes how starfish interact with Mytilus and the consequences of this interaction. a. Starfish and Mytilus have a high amount of overlap in the food they eat, but starfish can produce more offspring using fewer resources, which enables them to out-compete Mytilus and reduce the numbers of Mytilus in the populations. A lower abundance of Mytilus means there are more resources available for other species. b. Starfish and Mytilus are mutualists and when they occur together, the fitness of both organisms increases to the point that they dominate the intertidal community. c. Starfish have adapted a chemical defense against Mytilus and prevent it from establishing wherever starfish are present. This allows for establishment of other intertidal species. d. Starfish preferentially prey on Mytilus and reduce its abundance to the point that enough resources (space) are available to allower weaker competitors against Mytilus to maintain small populations.

d

The observation that members of a population are uniformly distributed suggests that: a. the density of the population is low. b. the size of the area occupied by the population is increasing. c. resources are distributed evenly. d. the members of the population are competing for access to a resource. e. the members of the population are neither attracted nor propelled by one another.

e

When we say that an individual organism has a greater fitness than another individual, we specifically mean that the organism: a. competes for resources more successfully than other of its species. b. mates more frequently than others of its species. c. utilizes resources more efficiently than other species occupying similar niches. d. lives longer than others of its species. e. leaves more viable offspring than others of its species.

b

Which is a true statement concerning genetic variation? a. It arises in response to environmental changes. b. It must be present in a population before natural selection can act upon the population. c. It is created by the direct action of natural selection. d. It tends to be reduced by the process involved when diploid organisms produce gametes. e. A population that has higher average heterozygosity has less genetic variation than one with a larger average heterozygosity.

b

Which of the following are important biotic factors that can affect the structure and organization of biological communities? a. nutrient availability; soil pH b. predation; competition c. temperature; water d. precipitation; wind e. light intensity; seasonality

e

Which of the following characterizes relatively K-selected populations? a. many offspring per reproductive episode. b. small offspring. c. a high intrinsic rate of increase. d. early age of first reproduction. e. offspring with good chances of survival.

c

Which of the following is *true*? a. r-selection occurs in populations whose densities are very near carrying capacity. b. Different populations of the same species will be consistently r- or K-selected. c. r- and K-selection are two extremes of a range of life history strategies. d. K-selection operates in populations where populations fluctuate well below carrying capacity. e. r-selection tends to maximize population size, not the rate of increase in population size.

d

Which of the following is an example of Mullerian mimicry? a. a day-flying hawkmoth that looks like a wasp b. a chameleon that changes color to like a dead leaf c. two species of rattlesnake that both rattle their tails d. two species of unpalatable butterfly that have the same color pattern e. two species of moths with wing spots that look like an owls eyes

b

Which of the following is an example of cryptic coloration? a. bands on a coral snake b. a "walking stick" insect that resembles a twig c. brown color of tree bark d. markings of a viceroy butterfly e. colors of an insect-pollinated flower

a

Which of the following pairs of reproductive strategies is consistent with energetic trade-off and reproductive success? a. Female rabbits that suffer high predation rates may produce several litters per breeding season, and coconuts produce few fruits, but most survive when they encounter proper growing conditions. b. Pioneer species of plants produce many very small, highly airborne seeds, while large elephants that are very good parents produce many offspring. c. Species that have to broadcast to distant habitats tend to produce seeds with heavy protective seed coats, and animals that are caring parents produce fewer offspring with lower infant mortality. d. Free-living insects lay thousands of eggs and provide no parental care, while flowers take good care of their seeds until they are ready to germinate. e. Some mammals will not reproduce when environmental resources are low so they can survive until conditions get better, and plants that produce many small seeds are likely found in stable environments.

a

Which of the following statements best summarizes evolution as it is viewed today? a. It is the differential survival and reproduction of the most-fit phenotypes. b. It is goal-directed. c. It represents the result of selection for acquired characteristics. d. It is synonymous with the process of gene flow. e. It is the descent of humans from the present-day great apes.

c

Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in heritable traits Condition 2: Some heritable traits must increase reproductive success Condition 3: Individuals must pass on all traits they acquire during their lifetime a. Condition 1 only b. Condition 2 only c. Conditions 1 and 2 d. Conditions 2 and 3 e. Conditions 1, 2, and 3

a

Which of these is the smallest unit that natural selection can change? a. a population's gene frequency b. an individual's genome c. an individual's genotype d. a species' gene frequency e. an individual's phenotype

c

Which population appears to be stable? a. I b. II c. III d. I and II e. II and III

b

Which population is in the process of decreasing? a. I b. II c. III d. I and II e. II and III

c

Which would be the best way to directly test the hypothesis that C. stellatus (a species of barnacle) is competitively excluded from the lower intertidal zone by B. balanoides (another species of barnacle). a. Remover all C. stellatus from the upper tidal zone. b. Place individuals of each species in a jar and see which species survives. c. Remove all B. balanoides from the lower intertidal zone. d. Transplant B. balanoides to the upper intertidal zone. e. Clear rocks in an entire area and document recolonization events.

c

White-breasted nuthatches and Downy woodpeckers both eat insects that hide in the furrows of bark in hardwood trees. The Downy woodpecker searches for insects by hunting from the bottom of the tree trunk to the top, while White-breasted nuthatch searches from the top of the trunk down. These hunting behaviors best illustrate which of the following ecological concepts? a. individualistic hypothesis b. competitive exclusion c. resource partitioning d. character displacement e. keystone species

c

You are observing a population of lizards when you notice that the number of adults has increased and is higher than observed during the previous week. One explanation for such an observation would include: a. increased birth rate. b. reduction in death rate. c. increased immigration. d. increased emigration. e. decreased emigration.