Question 1

In logistic growth (an S-shaped curve),how does population growth change as the population nears its carrying capacity?

Accepted Answer

As a population approaches its carrying capacity, the available resources become more limited and competition for resources increases which leads to a decline in population growth rate. Eventually, the population will stabilize or reach a plateau at its carrying capacity, resulting in no net growth.

Question 2

Some beetles escape from a ship and fly to a small island covered with grass but with no trees or beetle predators.As the beetles feed,they destroy all the grasses.But with abundant food,the beetle population soars,doubling in size every month.After about a year,the population crashes as thousands of beetles have destroyed almost all of the plants and there is little left to feed the large population.This scenario best illustrates

Accepted Answer

The scenario describes exponential growth of the beetle population as it doubles in size every month due to the abundant food on the island. However, at the end of a year, the population crashes due to the depletion of their food source, which is shown through the destruction of almost all plant life on the island. This is a classic example of population growth followed by a sudden population crash, which is characteristic of exponential growth.

Question 3

A squirrel population in an oak forest in Indiana is limited by hawk predators,the amount of acorns produced annually,nesting sites in the trees,and cold winter temperatures.
-Which of the following is an abiotic factor limiting this squirrel population?

Accepted Answer

Cold winter temperatures are an example of an abiotic (non-living) factor that can limit the squirrel population. The other factors mentioned (hawks, amount of acorns, nesting sites) are all biotic (living) factors that could also limit the population.

Question 4

A stable population would remain at equilibrium if

Accepted Answer

A stable population requires that the number of births and deaths are equal in order to maintain a constant population size. Therefore, if births and deaths increase by the same number of organisms, the population will remain at equilibrium. The other options involve changes to only one factor (birth rate, death rate, emigration rate, or immigration rate) which will cause a shift in population size and therefore not maintain equilibrium.

Question 5

The population of game fish in a lake is under heavy fishing pressure.If too many fish are caught,the population will crash and future years of fishing will suffer.The game fish can exhibit logistic growth under certain circumstances.Assuming logistic growth,it would be best to manage this game fish population by permitting the harvesting of just enough fish to keep the game fish population

Accepted Answer

The carrying capacity is the maximum population size that can be sustained by the environment. If too many fish are caught, the population will crash and future years of fishing will suffer. To avoid this, the best management practice for game fish population would be to permit the harvesting of just enough fish to keep the population at half its carrying capacity. This would ensure that the population is not overexploited and allows for a sustainable fishery over the long term. Harvesting the population at its full carrying capacity or above can also lead to a crash in the future if environmental conditions change.

Question 6

Which one of the following is characteristic of a K-selected species?

Accepted Answer

K-selected species are characterized by a slow reproductive rate and investment in fewer, larger offspring, which often requires a larger body size. This strategy is favored in stable environments where competition for resources is high, and there is low mortality among adults.

Question 7

Which of the following organisms is most likely a K-strategist?

Accepted Answer

K-strategists are organisms that have a longer lifespan, reproduce later in life, and produce fewer offspring with greater parental care. Oak trees exhibit all of these characteristics, making them a good example of a K-strategist. Bacteria and puffball mushrooms are examples of r-strategists, which have short lifespans, reproduce early and often, and produce many offspring with little parental care. Fruit flies are somewhere in between, but are generally considered closer to r-strategists than K-strategists.

Question 8

A group of frogs in a rain forest represents a population if the frogs

Accepted Answer

A population is defined as a group of individuals of the same species living in the same region and potentially able to interbreed with each other. Therefore, choice A is the best answer as it describes a group of frogs living in the same region and capable of interbreeding, which makes them a population. While choices B, C, and D may be true characteristics of a population, they do not fully define the concept of a population.

Question 9

Golden frog populations would be more likely to survive the current threats if

Accepted Answer

If golden frog populations were more widely distributed across Central and South America, it would be less likely that a single event would impact their entire population. This would increase their overall chances of survival.

Question 10

Sustainable populations

Accepted Answer

Sustainable populations are those that can be maintained over long periods of time without causing significant negative impacts on the environment. These populations are often near their carrying capacity, which is the maximum number of individuals that an environment can sustain. Therefore, choice A is the correct answer. Choices B, C, and D are incorrect as they do not reflect the characteristics of sustainable populations.

Question 11

A population that is at equilibrium

Accepted Answer

A population at equilibrium means that the birth rate is equal to the death rate and there are no significant factors causing the population to grow or decline. Therefore, the population is staying at about the same size.

Question 12

In North America,a toxic weed called leafy spurge was accidentally introduced and has grown and spread rapidly,covering millions of acres in north central United States and south central Canada.Leafy spurge is generally avoided by cattle and horses and may be toxic to them.Thus,rangeland where leafy spurge has spread has been damaged by the invasion of this plant.
-Plants such as leafy spurge can double their population size every year in part because of their efficient production of large amounts of seeds.Populations that can double every year,such as leafy spurge,

Accepted Answer

Populations that can double every year exhibit exponential growth as they spread to new regions. This means that their growth rate doesn't slow down as they spread, unlike logistic growth patterns where the growth rate slows as the population approaches its carrying capacity. Therefore, option D is the most appropriate answer. Option A is incorrect because populations that can double their size every year cannot achieve global distribution due to resource limitations. Option B is incorrect because leafy spurge is not an example of logistic growth. Option C is also incorrect because there is no evidence to suggest that leafy spurge has more predators than other species.

Question 13

In North America,a toxic weed called leafy spurge was accidentally introduced and has grown and spread rapidly,covering millions of acres in north central United States and south central Canada.Leafy spurge is generally avoided by cattle and horses and may be toxic to them.Thus,rangeland where leafy spurge has spread has been damaged by the invasion of this plant.
-Leafy spurge has spread completely across many US states.If left uncontrolled in these states,leafy spurge populations will

Accepted Answer

If left uncontrolled, leafy spurge populations will continue to grow until they eventually reach their carrying capacity, meaning the maximum number of individuals that the environment can support. As the plant spreads and occupies more area, it will deplete resources and compete with other plants, eventually leading to stabilization of the population size at the carrying capacity.

Question 14

A population would be expected to grow if

Accepted Answer

Immigration is the key factor that would increase the population size. If immigration increases and both deaths and emigration decrease, then the net growth rate would be positive leading to an increase in population size. None of the other options suggest an increase in immigration or a decrease in deaths and emigration, which are necessary for population growth.

Question 15

A squirrel population in an oak forest in Indiana is limited by hawk predators,the amount of acorns produced annually,nesting sites in the trees,and cold winter temperatures.
-A population of bullfrogs in a pond produces many thousands of eggs each spring that hatch out into tadpoles.However,only about 1% of the tadpoles survive to reproduce.This population of frogs is experiencing

Accepted Answer

The fact that only 1% of tadpoles survive to reproduce indicates that the bullfrog population is experiencing low levels of recruitment. This means that the population growth is limited by factors that prevent new individuals from joining the population, such as predation, disease, competition, or environmental conditions. It does not imply low environmental resistance, unlimited growth, or exponential growth.

Question 16

Flea beetles alone are unlikely to eliminate all of the leafy spurge in a region.Instead,the number of leafy spurge plants and the number of flea beetles in a particular community may stabilize.At this point,the leafy spurge and flea beetle populations

Accepted Answer

The presence of environmental resistance, likely from factors such as food availability or climate, would prevent the populations from experiencing exponential growth and instead stabilize at a certain level.

Question 17

Along the shoreline of a pond,Canadian geese,American toads,and grass frogs search for food while bluegill and bass prey on small fish in the shallow water.These species,living and feeding in this particular location,represent one

Accepted Answer

The presence of multiple species interacting with each other (predator-prey relationships) indicates a community of organisms living in a particular location. Choice A is incorrect because there are multiple species involved, not just one. Choice B is incorrect because a population refers to a group of individuals of the same species living in a particular location, not multiple species. Choice D is incorrect because an ecosystem refers to the interaction between living and nonliving components in a particular location, which extends beyond just the organisms mentioned in the scenario.

Question 18

A squirrel population in an oak forest in Indiana is limited by hawk predators,the amount of acorns produced annually,nesting sites in the trees,and cold winter temperatures.
-The many factors listed above that can affect the squirrel population represent

Accepted Answer

The factors listed above, such as hawk predators, acorn production, nesting sites, and winter temperatures, all represent various forms of environmental resistance that can limit the growth and size of the squirrel population. Environmental resistance refers to any external factors in the environment that can limit the growth or abundance of a particular species or population.

Question 19

It is common to hear about the huge reproductive potential of some organisms.Perhaps someone has mentioned that if all of the eggs of houseflies were to survive to maturity,the world would soon be covered in flies.This does not happen because,in reality,

Accepted Answer

Biotic potential refers to the maximum reproductive capacity of an organism under favorable conditions. However, in reality, there are limiting factors or environmental resistances such as availability of resources, habitat, competition, predation, and disease that prevent the exponential growth of populations. Therefore, the biotic potential of houseflies would be limited by environmental resistance, and not all eggs would survive to maturity.

Question 20

Many strategies have been used to control leafy spurge,including the deliberate introduction of different species of flea beetles that feed on leafy spurge.Each flea beetle female may lay about 200 eggs in her only year of life.In places where flea beetle introductions have quickly established large populations that have grown and stabilized,the population growth of these beetles most likely looked like

Accepted Answer

An S-shaped curve (also known as a logistic growth curve) is the most likely shape for the population growth of flea beetles. This is because their growth is initially slow, but as the population grows and reaches a certain size, it stabilizes and growth slows down due to limiting factors such as available food and habitat.

Quiz 4: Populations and Communities

In logistic growth (an S-shaped curve) ,how does population growth change as the population nears its carrying capacity?

A squirrel population in an oak forest in Indiana is limited by hawk predators,the amount of acorns produced annually,nesting sites in the trees,and cold winter temperatures. -Which of the following is an abiotic factor limiting this squirrel population?