Question 1

Which one of the following illustrates interspecific competition?
A)The largest wolves in a pack are the first to feed on a freshly killed deer.
B)Two honeybees from the same colony converge on a flower to collect pollen and nectar.
C)Advertising its nectar with red colors,a columbine flower attracts a hummingbird for a meal.
D)Caterpillars of two different species of moth are feeding on the same plant's leaves.

Accepted Answer

Interspecific competition occurs when individuals of different species compete for the same resources. In this case, the caterpillars of two different species of moth are competing for the same plant's leaves, which is an example of interspecific competition. Options A, B, and C all involve individuals of the same species interacting with each other or with different species in a way that does not directly involve competition for resources.

Question 2

In general,it is rare for a parasite to
A)feed on a host.
B)kill its host.
C)spread from one host to another.
D)compete with other parasites for access to a host.

Accepted Answer

It is rare for a parasite to kill its host because doing so would eliminate its source of sustenance and therefore reduce its chances of survival. Most parasites have evolved to coexist with their hosts, using them as a source of food and shelter without causing fatal damage.

Question 3

Which of the following represents a type of top-down regulation for wildflowers living in a forest?
A)types of minerals in the soil
B)amount and timing of precipitation
C)strength and frequency of sunlight
D)herbivores in the region

Accepted Answer

The presence and behavior of herbivores in the region can act as a top-down regulation on the population of wildflowers. For example, if a forest has a high population of deer that prefer to eat wildflowers, this can limit the abundance of wildflowers in the area.

Question 4

Dung beetles live in regions where cattle graze,quickly burying and recycling cattle droppings.Because of the dung beetle's activities,breeding habitats and resources for disease-carrying flies are reduced and the plants upon which cattle feed are nourished.
-The relationship between the dung beetles and the disease-carrying flies is a type of
A)mutualism.
B)commensalism.
C)intraspecific competition.
D)interspecific competition.

Accepted Answer

Dung beetles and disease-carrying flies are in interspecific competition because they compete for the same resource (cattle droppings) but are different species.

Question 5

A grasshopper population in a prairie is limited in large part by the number of birds in the region.Following a terrible storm that killed many of the birds,the grasshopper population exhibits exponential growth.This happens because the grasshoppers experienced
A)a new biotic potential with steady environmental resistance.
B)a new much lower biotic potential with decreased environmental resistance.
C)a steady biotic potential but suddenly decreased environmental resistance.
D)a decreased biotic potential and decreased environmental resistance.

Accepted Answer

The grasshopper population exhibits exponential growth primarily due to the sudden decrease in environmental resistance (predation pressure from birds), while their biotic potential (intrinsic rate of increase) remains unchanged.

Question 6

Many predator-prey relationships do not result in the complete elimination of the prey because
A)predators cannot catch all of the healthy adults.
B)the predator population is limited by the availability of territorial space.
C)the prey do not provide enough nutrition.
D)the prey populations are always far below carrying capacity.

Accepted Answer

Predators may not be able to catch all healthy adults of the prey species, allowing some individuals to survive and potentially reproduce. Additionally, predators may target specific individuals or prey species, leaving other populations relatively untouched. This can lead to a cyclical relationship between predator and prey populations, rather than complete elimination.

Question 7

In a mature forest in a national park,maple trees grow very large and live more than 80 years.Over an average lifetime,a tree produces more than 100,000 seeds,of which only 2-3 sprout and grow to maturity.This maple tree is
A)K-selected and exhibits a type I survivorship curve.
B)K-selected and exhibits a type III survivorship curve.
C)r-selected and exhibits a type I survivorship curve.
D)r-selected and exhibits a type III survivorship curve.

Accepted Answer

Maple trees are K-selected species because they grow large, live long, and invest in fewer offspring with higher survival rates. They exhibit a type III survivorship curve, where many seeds are produced but few survive to maturity.

Question 8

Parasites
A)affect their hosts in a density-independent manner.
B)and their hosts represent a type of intraspecific competition.
C)occur in animals but not plants.
D)may live inside or outside of their host.

Accepted Answer

Parasites may live inside or outside of their host. Some parasites live on the host's skin or attach themselves to the host's external surface, while others live inside the host's body.

Question 9

The most stable predator-prey relationships typically involve
A)a prey species and several natural predators.
B)two species of carnivores eating each other.
C)only bottom-up population regulation.
D)only top-down population regulation.

Accepted Answer

The most stable predator-prey relationships often involve a prey species and several natural predators. This diversity in predators can prevent any single predator from decimating the prey population, leading to a more balanced and stable ecosystem.

Question 10

Sumatran rhino populations have declined steadily to a point near extinction.Because of its population decline,this unusual forest-dwelling rhino is near its
A)carrying capacity and is officially listed as threatened.
B)carrying capacity and is officially listed as endangered.
C)critical number and is officially listed as threatened.
D)critical number and is officially listed as endangered.

Accepted Answer

The decline in Sumatran rhino populations has brought them to a critical number, which means that even a slight additional decline could lead to extinction. Therefore, the Sumatran rhino is officially listed as endangered.

Question 11

A population of catfish in a muddy pond reaches its maximum size as the food supplies start to run low.Without any new sources of food,the catfish population remains steady.This population represents
A)density-dependent logistic growth.
B)density-independent logistic growth.
C)density-dependent exponential growth.
D)density-independent exponential growth.

Accepted Answer

The catfish population reaches its maximum size due to limited food supplies, which is a density-dependent factor. The population's growth stabilizes, indicating logistic growth, where the population size levels off at the carrying capacity of the environment.

Question 12

In general,K-strategists have a
A)type I survivorship pattern,and r-strategists have a type III survivorship pattern.
B)type II survivorship pattern,and r-strategists have a type I survivorship pattern.
C)type II survivorship pattern,and r-strategists have a type III survivorship pattern.
D)type III survivorship pattern,and r-strategists have a type II survivorship pattern.

Accepted Answer

K-strategists typically exhibit a type I survivorship pattern, characterized by high survival rates of the young and middle-aged and a high mortality rate only for older individuals. This is because K-strategists invest heavily in fewer offspring, providing care and ensuring their survival. On the other hand, r-strategists are associated with a type III survivorship pattern, where there is a high mortality rate at the early stages of life due to producing a large number of offspring with minimal investment in each, leading to only a few surviving to adulthood.

Question 13

Density-independent factors such as earthquakes and hurricanes are
A)abiotic factors that maintain a population near equilibrium.
B)biotic factors that maintain a population near equilibrium.
C)abiotic factors that are not involved in maintaining a population near its equilibrium.
D)biotic factors that are not involved in maintaining a population near its equilibrium.

Accepted Answer

Density-independent factors are not affected by the size of a population and do not maintain a population near its equilibrium. Instead, they can cause fluctuations or even drastic changes in the population size. Earthquakes and hurricanes are abiotic factors that fall under this category.

Question 14

Which of the following represents a type of mutualism?
A)A red-tailed hawk pounces on a field mouse for dinner.
B)A large herd of zebra graze lazily across the broad savannah.
C)A mosquito draws a blood meal from the back of an elk.
D)A honeybee feeds on nectar at a flower on an orange tree and pollinates the flower.

Accepted Answer

Mutualism is a type of interaction between two species where both species benefit from the relationship. In this case, the honeybee benefits by feeding on the nectar, while the flower benefits by being pollinated, leading to reproduction.

Question 15

Walking through a national park,you step off a well-marked trail to take a photograph and accidentally trample a rare orchid.This is an example of
A)commensalism.
B)mutualism.
C)predation.
D)amensalism.

Accepted Answer

Amensalism is a type of interspecific interaction in which one species is harmed and the other remains unaffected. In this case, the rare orchid was harmed by the accidental trampling while the individual who trampled it was unaffected. The other options do not apply as there is no benefit or harm to both species (commensalism), both species benefit (mutualism), or one species benefits and the other is harmed (predation).

Question 16

The relationship between the moose and wolf populations on Isle Royale reveals
A)intraspecific competition.
B)top-down and bottom-up population regulation.
C)the high and steady environmental resistance on wolves.
D)the high and steady environmental resistance on moose.

Accepted Answer

The relationship between the moose and wolf populations on Isle Royale shows top-down and bottom-up population regulation where the wolf population acts as the top predator controlling the moose population which in turn controls the plant population, providing bottom-up regulation.

Question 17

Which of the following represents a type of top-down regulation for rattlesnakes living in Arizona?
A)the availability of fresh water
B)the number of mice in the region
C)abundance of rocks under which snakes can hide
D)the number of snake-eating hawks in the region

Accepted Answer

The presence of snake-eating hawks is a top-down regulation factor because their existence at higher trophic levels affects the population of rattlesnakes.

Question 18

Dung beetles live in regions where cattle graze,quickly burying and recycling cattle droppings.Because of the dung beetle's activities,breeding habitats and resources for disease-carrying flies are reduced and the plants upon which cattle feed are nourished.
-The relationship between the dung beetles and the cattle is a type of
A)mutualism.
B)parasitism.
C)intraspecific competition.
D)interspecific competition.

Accepted Answer

The relationship between the dung beetles and the cattle benefits both parties. The beetles receive food and habitat from the cattle droppings, while the cattle benefit from the reduction of disease-carrying flies and improved plant growth. This is a classic example of mutualism, where both species benefit from their interaction.

Question 19

Which of the following is analogous to a mutualistic relationship?
A)A basketball player is paid by a company to wear its particular brand of shoes.
B)A deer hunter stalks and kills a large buck.
C)A thief breaks into a store and steals some precious jewels.
D)Young lovers leave their initials carved onto a tree,which then gets diseased and dies.

Accepted Answer

A mutualistic relationship is one in which both parties benefit. In this scenario, the basketball player benefits from receiving payment while the shoe company benefits from increased brand exposure. Both parties benefit, making it analogous to a mutualistic relationship.

Option B is an example of predation as the hunter kills the deer for his own benefit. Option C is an example of theft and Option D is an example of harm or negative impact, neither of which are analogous to mutualism.

Question 20

Threatened and endangered species receive special protection from human activities such as hunting and habitat destruction because these activities may continue despite the species' low numbers.These human activities therefore
A)are density independent.
B)are density dependent.
C)represent bottom-up regulation.
D)represent harmful abiotic resistance.

Accepted Answer

Human activities like hunting and habitat destruction are considered density independent because they can occur regardless of the population size of the species in question. These activities impact species regardless of their density, unlike density-dependent factors which change in intensity according to the population size.

Quiz 4: Populations and Communities

Which one of the following illustrates interspecific competition?

In general,it is rare for a parasite to

Which of the following represents a type of top-down regulation for wildflowers living in a forest?

A grasshopper population in a prairie is limited in large part by the number of birds in the region.Following a terrible storm that killed many of the birds,the grasshopper population exhibits exponential growth.This happens because the grasshoppers experienced

Many predator-prey relationships do not result in the complete elimination of the prey because

In a mature forest in a national park,maple trees grow very large and live more than 80 years.Over an average lifetime,a tree produces more than 100,000 seeds,of which only 2-3 sprout and grow to maturity.This maple tree is

Parasites

The most stable predator-prey relationships typically involve

Sumatran rhino populations have declined steadily to a point near extinction.Because of its population decline,this unusual forest-dwelling rhino is near its

A population of catfish in a muddy pond reaches its maximum size as the food supplies start to run low.Without any new sources of food,the catfish population remains steady.This population represents

In general,K-strategists have a

Density-independent factors such as earthquakes and hurricanes are

Which of the following represents a type of mutualism?

Walking through a national park,you step off a well-marked trail to take a photograph and accidentally trample a rare orchid.This is an example of

The relationship between the moose and wolf populations on Isle Royale reveals

Which of the following represents a type of top-down regulation for rattlesnakes living in Arizona?

Which of the following is analogous to a mutualistic relationship?

Threatened and endangered species receive special protection from human activities such as hunting and habitat destruction because these activities may continue despite the species' low numbers.These human activities therefore