Question 1

An organic farmer releases parasitic wasps to eat the aphids that are attacking the leaves of his plants.This form of plant management is known as _______.

Accepted Answer

The answer of An organic farmer releases parasitic wasps to...

Question 2

A city has been trying to control its rat population by poisoning them.This kills up to 50 percent of the population, but the remaining rats then reproduce more rapidly, rebuilding the population.Given this response, a more effective method of rat control might be to

Accepted Answer

Since the availability of food is a limiting factor for the rat population, drastically reducing the amount of garbage available for food will limit their reproductive capacity and force them to disperse outside of the city limits in search of food. This will effectively reduce the rat population in the city. Setting rat traps and increasing the city's population of feral cats may help to control the population in the short term, but reducing the availability of food will be a more effective long-term solution. Poisoning a larger percentage of the rats may increase the rate of rebound reproduction, so it is not a viable solution. Letting the rat population reach its carrying capacity would lead to an unsustainable population that will cause further issues.

Question 3

An ecologist wishes to study the distribution of a plant species along a gradient of elevation up a mountainside.At various places around the base of the mountain, she attaches ropes, which she extends in a straight line up the mountainside.She then counts the number of plants present along each foot of the rope lines.This method of measuring the plant's population size is known as a(n) _______.

Accepted Answer

The answer of An ecologist wishes to study the distribution...

Question 4

Some members of a species live in a cold environment.They spend much of their energy on maintaining body temperature and finding food, and they have few offspring.Members of the same species living in a more moderate environment allocate more of their energy to reproduction and have more offspring.The two species groups are illustrating the use of _______ to optimize their survival in different habitats.

Accepted Answer

The answer of Some members of a species live in...

Question 5

The black rockfish has indeterminate growth, and female fecundity is directly proportional to size and age.Larvae produced by older females have better nutrition and grow faster.How does the fact that fishermen prefer to catch larger fish affect the management of the rockfish population?

Accepted Answer

Since female fecundity is directly proportional to size and age, removing larger females results in fewer eggs, slower-growing larvae, and ultimately lower population sizes. This negatively impacts the management of the rockfish population as it reduces the reproductive potential of the population and may lead to long-term population decline.

Question 6

Both schools of sardines and flocks of starlings move together as a group, which confuses predators.This behavior is more effective with more individuals in the group.This illustrates the _______ effect.

Accepted Answer

The answer of Both schools of sardines and flocks of...

Question 7

The poisonous cane toad was introduced to Australia to control cane beetles.It had no effect on the beetles, but in the absence of predators, it has been consuming many other native species.This is an example of

Accepted Answer

The introduction of the cane toad to Australia was intended to be a biological control of the cane beetle but it ended up becoming a pest itself and consuming many other native species. This is an example of an intended biological control organism becoming a pest.

Question 8

Most humans live close together in cities, and the rest are scattered in small towns and rural areas.Overall, the human population could be said to have a(n) _______ dispersion pattern.

Accepted Answer

The answer of Most humans live close together in cities,...

Question 9

A metapopulation of wood thrushes is found in an area of the Midwest.Individual thrush populations exist in forest patches interspersed with farm fields.Monitoring over several years showed several types of populations: 
I.Populations with negative birth rates that went extinct
II. New populations that occasionally formed in previously bare patches
III. Populations with positive birth rates that maintained population equilibrium
Which of these types would be considered source populations, and which would be considered sink populations?

Accepted Answer

Sink populations are those with negative population growth that require influxes of individuals from source populations to maintain viability. Both populations with negative birth rates that went extinct (Type I) and new populations that occasionally formed in previously bare patches (Type II) fit this definition and are likely sink populations. Populations with positive birth rates that maintained population equilibrium (Type III) could act as source populations, providing individuals to maintain or establish sink populations. Therefore, I and II are likely sink populations, while III might be a source population.

Question 10

How will harvesting affect a population with density-dependent growth?

Accepted Answer

The answer of How will harvesting affect a population with...

Question 11

Ecologists measure population characteristics over several years in a metapopulation of insects.They find that, in Population A, birth rates exceed death rates.In Populations B and C, death rates exceed birth rates.The sizes of Populations A and C remain relatively stable, whereas Population B declines and eventually goes extinct.How could these three populations best be described?

Accepted Answer

Population A, where birth rates exceed death rates, acts as a source population by potentially providing individuals to other populations. Populations B and C, where death rates exceed birth rates, are sink populations, but Population C remains stable possibly due to immigration from Population A, while Population B declines and goes extinct without sufficient immigration to offset its losses.

Question 12

What difference, if any, is there in the management of r-strategist and K-strategist populations?

Accepted Answer

The management of r-strategist and K-strategist populations differs due to their different reproductive strategies. R-strategist species reproduce quickly and have high population growth rates, while K-strategist species reproduce slowly and have lower population growth rates. As a result, K-strategists are more vulnerable to overharvesting and take longer to recover from population declines compared to r-strategists. Therefore, management strategies for K-strategists must focus on reducing or controlling the stressors that impact their reproductive success, while management strategies for r-strategists can focus more on population control measures.

Question 13

One population lives in an area with abundant food and allocates a large percentage of its available energy to reproduction.Another lives in an area where resources are scarce.Individuals spend more energy finding food and have fewer offspring.These populations are showing a difference in their _______ strategies.

Accepted Answer

The answer of One population lives in an area with...

Question 14

Species have differing life history strategies, based on the predictability of their environments.Organisms that reproduce only once during their life spans but have large numbers of offspring to ensure high population growth are called _______.

Accepted Answer

The answer of Species have differing life history strategies, based...

Question 15

As a population's resources become limited, it begins to display a pattern called _______ growth.

Accepted Answer

The answer of As a population's resources become limited, it...

Question 16

Individuals of a species that interact with one another within a given area at a particular time are known as a(n) _______.

Accepted Answer

The answer of Individuals of a species that interact with...

Question 17

Which organism is not correctly matched with its dispersion pattern?

Accepted Answer

Ragweed seeds, which disperse by wind, are more likely to exhibit a random dispersion pattern rather than a clumped one. This is because wind dispersal scatters seeds in unpredictable directions and distances, leading to a distribution where plants grow in various locations without a clear pattern of clumping.

Question 18

A study of pikas in a mountainous region of California finds 50 discrete population patches.Counts of the number of individuals in each population are done every 5 years.These counts show that all populations are in decline.After 10 years, 7 populations have become extinct, and after 20 years, 21 have become extinct.None of the patches that went extinct at year 10 are populated again at year 20.This scenario illustrates

Accepted Answer

The answer of A study of pikas in a mountainous...

Question 19

In the Trinidad guppy populations studied by Reznick and colleagues, the differences in life-history strategies between high-predation and low-predation sites resulted from changes in the population's _______.

Accepted Answer

The answer of In the Trinidad guppy populations studied by...

Question 20

A ship accidentally discharges a species of rat onto an island.At first, resources are abundant, and the rat population grows rapidly.But, as population density increases and resources become increasingly scarce, the population size approaches its environment's _______.

Accepted Answer

The answer of A ship accidentally discharges a species of...

Quiz 54: Populations