Question 1

Which of the following best describes the difference between biotic and abiotic factors in an ecosystem?

Accepted Answer

Biotic factors are living or once-living components, while abiotic factors are non-living components of an ecosystem.

Question 2

A food web is more stable than a food chain because:

Accepted Answer

It shows multiple pathways for energy flow, allowing for greater ecosystem resilience.

Question 3

According to the 10% rule of energy transfer in ecosystems, if a plant stores 5,000 J of energy, how much energy is available to the primary consumer?

Accepted Answer

$$5000 	imes 0.1 = 500 J$$

Question 4

Which of the following is an example of a density-independent factor affecting a population?

Accepted Answer

A volcanic eruption

Question 5

Which survivorship curve is most characteristic of humans and other large mammals?

Accepted Answer

Type I

Question 6

A population of 100 rabbits experiences 20 births and 5 deaths in a year. What is the growth rate $$r$$?

Accepted Answer

$$r = \frac{20-5}{100} = 0.15$$

Question 7

Which of the following best describes an ecological niche?

Accepted Answer

The role a species plays in its ecosystem, including its diet, habitat, and interactions.

Question 8

If a corn field has a GPP of 2,000 J/m$$^2/$$day and 1,200 J/m$$^2/$$day is used for respiration, what is the NPP?

Accepted Answer

$$NPP = 2,000 - 1,200 = 800 J/m$^2/$$day

Question 9

Which of the following is an example of mutualism?

Accepted Answer

Bees pollinating flowers while collecting nectar

Question 10

A community contains 4 species with the following numbers: A: 50, B: 30, C: 10, D: 10. Calculate Simpson’s Diversity Index $$D$$ using $$D = 1 - \sum (n/N)^2$.

Accepted Answer

$$D = 1 - [(50/100)^2$ + (30/100)^2$ + (10/100)^2$ + (10/100)^2$] = 1 - [0.25 + 0.09 + 0.01 + 0.01] = 1 - 0.36 = 0.64$$

Question 11

Which of the following best describes a keystone species?

Accepted Answer

A species that has a disproportionately large effect on its ecosystem relative to its abundance.

Question 12

Which of the following is an example of Batesian mimicry?

Accepted Answer

A harmless butterfly resembling a toxic butterfly.

Question 13

Which growth model is represented by the equation $$dN/dt = rN$$?

Accepted Answer

Exponential growth

Question 14

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

Accepted Answer

Produce few, large offspring with significant parental care

Question 15

If the primary producers in an ecosystem produce 20,000 J/m$$^2/$$day and the primary consumers receive 2,000 J/m$$^2/$$day, what is the ecological efficiency?

Accepted Answer

$$Ecological\ Efficiency = \frac{2,000}{20,000} = 0.1 = 10\%$$

Question 16

Which of the following best describes kin selection?

Accepted Answer

When an animal sacrifices its own fitness to increase the survival of close relatives.

Question 17

Which of the following is an example of a density-dependent factor?

Accepted Answer

Predation

Question 18

Which of the following best describes the difference between taxis and kinesis?

Accepted Answer

Taxis is a directed movement toward or away from a stimulus, while kinesis is a random change in movement rate in response to a stimulus.

Question 19

Which of the following is a likely consequence of introducing an invasive species into an ecosystem?

Accepted Answer

Disruption of food webs and decline of native species

Ecology: Principles, Energy Flow, Biodiversity, and Population Dynamics

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