Practice Problems

Which of these is the BEST working definition of a population?

A. Members of different species interacting with each other in a given locality

B. Members of the same species interacting with each other in a given locality

C. Individuals with similar traits interacting with each other in a given locality

D. All the different species plus all the nonliving parts interacting in a given locality

B

Why might dispersion (spacing pattern) of individuals in a population be clumped?

A. Resources are scattered everywhere

B. Aggressive, defense of territory

C. Social behavior like mating or hunting

D. Random chance

C

Why might dispersion (spacing pattern) of individuals in a population be uniform?

A. Resources are scattered everywhere

B. Aggressive, defense of territory

C. Social behavior like mating or hunting

D. Random chance

B

You are studying a population of beetles of size (N0) is 3000. During a one-month period, you record 600 births and 300 deaths in this population. Estimate b, d, and r for that first month (What would N1 be?) and then project that population’s size (N2) after a second month at the same rates.

So, b = ? d = ? r = ?

N0 = 3000

N1 = ?

If same rates, then after the second month, N2 = ?

A. 3000

B. 3300

C. 3600

D. 3630

E. None of these is correct

D

According to the logistic growth equation

A. the number of individuals added per unit time is greatest when N is close to zero.

B. the per capita growth rate (r) increases as N approaches K

C. population growth rate is zero when N equals K

D. the population grows exponentially when K is small

E. the death rate (d) approaches zero as N approaches K

C

What does Balanus’ fundamental niche look like?

A. the same as its realized niche

B. much larger than its realized niche

C. cannot be determined

A

Which of the following is MORE true about the two different types of niches?

A. The realized niche is larger than the fundamental niche.

B. The fundamental niche is determined primarily by competitors.

C. The realized niche is affected primarily by abiotic resources.

D. Individuals will be found only in the realized niche.

E. There are no differences between the realized niche and fundamental niche.

D

What type of population regulation is shown in the fluctuating predator-prey graph?

A. density-independence

B. density-dependence

B

Which of the following is NOT a correct portrayal of community interactions?

A. Commensalism 0 +

B. Mutualism + +

C. Predation + -

D. Competition + -

D

Which of the following is the best example of a commensalism (+/0) ?

A. Mycorrhizal fungi residing in plant roots

B. Acacia tree ants that live inside the thorns and defend the trees

C. Cattle egret birds eating insects stirred up by grazing cows

D. Monarch butterfly caterpillars feeding on milkweed plants

C

The video of the food web in the Yellowstone National Park talked about different species interactions. When the wolf populations increased, the deer populations grazed less in the valleys and the aspens grew taller. This would be an example of what?

A. Top-down control

B. Bottom-up control

A

When wolves went extinct in Yellowstone Park, which species GREATLY increased in number?

A. Grizzly bear

B. Elk

C. Bison

D. Coyote

B

A population size of 720 bluebonnets is being studied by a group of botanists. During a one month period, they recorded 50 births and 40 deaths in this population. What will be the approximate population size after 3 months at the same growth rate?

A. 728

B. 740

C. 750

D. 758

C

In the Pacific Northwest, fireweed is known to be the FIRST vegetation to grow after the burning of a forest. What kind of succession allows for vegetation to bloom after a wildfire burns, and why?

A. Primary succession, because pioneer species are resistant to calamities

B. Primary succession, because some vegetation requires fire for seeds to germinate

C. Secondary succession, because the disaster left behind nutrient-rich soil from the organic debris

D. Secondary succession, because some vegetation requires fire to release its seeds

D

In the food web shown, identify the interspecific interaction between bird and the snake, the trophic level(s) that the bird occupies, and assuming that the clover plants have 1000 kcal of energy available, approximate the amount of energy that is available to the snake after consuming the rabbit?

A. Predation (+/-); Primary Consumer; 10 kcal

B. Competition (-,-); Primary and Tertiary Consumer; 100 kcal

C. Predation (+,-); Primary and Secondary Consumer; 10 kcal

D. Commensalism (+, 0); Primary and Secondary Consumer; 100 kcal

C

As you move from lower on the food chain towards higher on the food chain in a particular community with contaminants (DDT), which trend would you see?

A. greater biomass and greater tissue concentration of contaminants

B. greater biomass and lower tissue concentration of contaminants

C. lower biomass and greater tissue concentration of contaminants

D. lower biomass and lower tissue concentration of contaminants

C

The transfer of energy in an ecosystem is referred to as

A. energy flow, because energy enters and exits an ecosystem

B. energy flow, because most energy is transferred directly at each step of the food chain

C. energy cycling, because energy is transferred back and forth between biotic and abiotic forms

D. energy cycling, because energy is transferred at different steps of the food chain and back to producers

A

In an ecosystem facing increasing drought, the carrying capacity of the population of mice who inhabit the ecosystem is likely to…

A. Increase exponentially

B. Decrease

C. Increase steadily

D. Remain steady

B

Canyon tree frogs camouflage themselves to hide from potential predators? Which type of defense mechanism is this?

A. Cryptic coloration

B. Aposematic coloration

C. Batesian mimicry

D. Mullerian mimicry

A

A golden jackal trails behind a tiger after being rejected from its pack in order to feed on the leftovers of the tiger’s kills. This is an example of…

A. Mutualism

B. Commensalism

C. Competition

D. parasitism

B

Which of the following interactions could be considered an intraspecific interaction?

A. A lion kills and eats a zebra

B. A hyena eats the leftovers of a lion

C. A lion competes with another lion for a mate

D. A hyena has a tapeworm

C

Which of the following statements is TRUE about niches?

A. The realized niche is larger than the fundamental niche.

B. The fundamental niche is determined by competitors.

C. The realized niche is affected primarily by abiotic resources.

D. Individuals will be found only in the realized niche.

D

When a nearby chemical spill disrupts the soil and plant growth of a nearby national park, less snails and caterpillars are seen in the subsequent generations. Years later, park officials noticed a decline in the coyote population. Which model does this represent?

A. Bottom-up Model

B. Top-down Model

C. Neither

A

A sea otter in a kelp forest is an example of …

A. Invasive species

B. Foundation species

C. Keystone Species

D. Ecosystem Engineers

C

True or False: Primary Succession occurs when an existing community has been cleared by a disturbance that leaves the soil intact.

A. True

B. False

B

True or False: The first law of thermodynamics states that Every exchange of energy increases the entropy of the universe

A. Ture

B. False

B

The amount of energy from light (or chemicals) converted to the chemical energy of organic molecules per unit time is known as

A. Net Primary Production (NPP)

B. Gross Primary Production (GPP)

B

True or False: Trophic Efficiency is the percentage of energy stored in assimilated food that is used for growth and reproduction, not respiration

A. True

B. False

B

As you move from lower on the food chain towards higher on the food chain in a particular community with contaminants (DDT), which trend would you see?

A. greater biomass and greater tissue concentration of contaminants

B. greater biomass and lower tissue concentration of contaminants

C. lower biomass and greater tissue concentration of contaminants

D. lower biomass and lower tissue concentration of contaminants

C