Q: A population of rabbits is growing exponentially. The population size at time $$t is $$given by $$N(t) = N_0$ e$$^{rt}$$, where N_0$ is the initial population and r$ is the intrinsic rate of increase. If N_0$ = 100$$ and $$r = 0.2$$, what will the population be after 5 years?

$$N(5) = 100 e$$^{0.2 \times 5}$$ = 100 e$$^{1}$$ \approx 271.8$$

Question 1

Which of the following best explains why cancer is usually not inherited, even though mutations can be passed from parent to offspring?

Accepted Answer

Most cancer-causing mutations occur in somatic cells, not gametes.

Question 2

A population of rabbits is growing exponentially. The population size at time $$t is $$given by $$N(t) = N_0$ e$$^{rt}$$, where N_0$ is the initial population and r$ is the intrinsic rate of increase. If N_0$ = 100$$ and $$r = 0.2$$, what will the population be after 5 years?

Accepted Answer

$$N(5) = 100 e$$^{0.2 	imes 5}$$ = 100 e$$^{1}$$ \approx 271.8$$

Question 3

Which of the following best describes the difference between exponential and logistic growth in populations?

Accepted Answer

Exponential growth occurs when resources are unlimited, while logistic growth includes the effect of carrying capacity, $$K$$, limiting population size.

Question 4

Which of the following is a correct statement about proto-oncogenes and tumor-suppressor genes?

Accepted Answer

Proto-oncogenes stimulate cell division, while tumor-suppressor genes inhibit it.

Question 5

Which of the following is an example of a keystone species and its impact on an ecosystem?

Accepted Answer

Wolves in Yellowstone control elk populations, which allows vegetation and other species to thrive.

Question 6

Which of the following best explains why only about 10% of energy is transferred from one trophic level to the next in an ecosystem?

Accepted Answer

Most energy is lost as heat due to metabolism and cellular respiration at each trophic level.

Question 7

A scientist is studying a lake and observes that oxygen levels are highest in the summer and lowest in the winter. Which of the following best explains this pattern?

Accepted Answer

Increased photosynthesis by aquatic plants in summer raises oxygen levels.

Question 8

Which of the following is a correct distinction between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.

Question 9

Which of the following best describes the concept of biological magnification?

Accepted Answer

Toxic substances become more concentrated in organisms at higher trophic levels.

Question 10

Which of the following is the best example of resource partitioning in a community?

Accepted Answer

Two bird species feed on insects in different parts of the same tree.

Question 11

Which of the following is a correct statement about the three domains of life?

Accepted Answer

The three domains are Bacteria, Archaea, and Eukarya.

Question 12

A population of deer has a carrying capacity $$K of 500. If $$the current population is 400 and the intrinsic rate of increase $$r is 0.1$$, what is the expected change in population size in one year according to the logistic growth equation $$\Delta N = rN \left(1 - \frac{N}{K}\right)$$?

Accepted Answer

$$\Delta N = 0.1 	imes 400 	imes \left(1 - \frac{400}{500}ight) = 0.1 	imes 400 	imes 0.2 = 8$$

Question 13

Which of the following best describes the process of competitive exclusion?

Accepted Answer

Two species competing for the same limiting resource cannot coexist indefinitely.

Question 14

Which of the following is a correct statement about the carbon cycle?

Accepted Answer

Carbon is cycled globally through processes such as photosynthesis and respiration.

Question 15

Which of the following is a correct example of mutualism?

Accepted Answer

Bees pollinate flowers while obtaining nectar for food.

Question 16

Which of the following best explains why the introduction of wolves to Yellowstone National Park led to changes in river structure?

Accepted Answer

Wolves reduced elk populations, allowing vegetation to recover, which stabilized riverbanks.

Question 17

Which of the following is a correct statement about the basic structure of a biological membrane?

Accepted Answer

A membrane is composed of a phospholipid bilayer with embedded proteins.

Question 18

Which of the following best describes the difference between fundamental and realized niches?

Accepted Answer

A fundamental niche is the full range of conditions a species can occupy, while a realized niche is where it actually lives due to competition.

Question 19

Which of the following is a correct example of Batesian mimicry?

Accepted Answer

A harmless butterfly species resembles a toxic butterfly species to avoid predation.

Question 20

Which of the following best explains why phosphorus is often a limiting nutrient in ecosystems?

Accepted Answer

Phosphorus cycles locally and is not abundant in the atmosphere.

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