Q: Which equation correctly represents the calculation of production efficiency in consumers?

$$ \text{Production Efficiency} = \frac{\text{Biomass produced}}{\text{Assimilated energy}} \times 100 $$

Q: If the net primary production (NPP) in a grassland is $$1500\ \text{g/m}^2/\text{year}$$ and the biomass of primary consumers is $$150\ \text{g/m}^2/\text{year}$$, what is the trophic efficiency from producers to primary consumers?

$$ \frac{150}{1500} \times 100 = 10\% $$

Question 1

Which of the following best describes Net Primary Production (NPP) in an ecosystem?

Accepted Answer

The energy available to consumers after accounting for the energy used by producers for respiration.

Question 2

In a trophic pyramid, why is the biomass of primary producers typically much greater than that of tertiary consumers?

Accepted Answer

Energy transfer between trophic levels is inefficient, with only about 10% of energy passed on to the next level.

Question 3

Which equation correctly represents the calculation of production efficiency in consumers?

Accepted Answer

$$ 	ext{Production Efficiency} = \frac{	ext{Biomass produced}}{	ext{Assimilated energy}} 	imes 100 $$

Question 4

Mercury pollution in the ocean leads to biomagnification. Which of the following best explains why humans are at greater risk for mercury toxicity than algae?

Accepted Answer

Mercury concentrations increase at higher trophic levels due to biomagnification.

Question 5

Which of the following is an example of resource partitioning?

Accepted Answer

Different warbler species foraging at different heights in the same tree to reduce competition.

Question 6

According to the Competitive Exclusion Principle, what is the likely outcome if two species occupy the exact same ecological niche?

Accepted Answer

One species will outcompete and exclude the other from the community.

Question 7

Sea otters are considered a keystone species in kelp forest ecosystems. What is the most direct effect of removing sea otters from this ecosystem?

Accepted Answer

A dramatic increase in sea urchin populations, leading to kelp decline.

Question 8

Which of the following best describes an ecosystem engineer?

Accepted Answer

A species that directly or indirectly modifies the physical environment, affecting resource availability for other species.

Question 9

If the net primary production (NPP) in a grassland is $$1500\ 	ext{g/m}^2/	ext{year}$$ and the biomass of primary consumers is $$150\ 	ext{g/m}^2/	ext{year}$$, what is the trophic efficiency from producers to primary consumers?

Accepted Answer

$$ \frac{150}{1500} 	imes 100 = 10\% $$

Question 10

Which of the following is a consequence of interspecific competition in a community?

Accepted Answer

Exclusion of one species from the community or alteration of species' resource use.

Question 11

Why must toxin levels in the environment be kept very low to protect human health?

Accepted Answer

Toxins biomagnify, so even low environmental concentrations can become highly concentrated in top predators like humans.

Question 12

Which of the following scenarios best illustrates the concept of niche partitioning?

Accepted Answer

Two species of finches with different beak sizes feeding on different seed types in the same habitat.

Question 13

Which of the following is NOT a likely effect of removing a keystone species from an ecosystem?

Accepted Answer

An increase in the abundance of the keystone species.

Question 14

Which of the following best explains why energy transfer between trophic levels is typically only about 10% efficient?

Accepted Answer

Most energy is lost as heat through respiration and metabolic processes.

Question 15

A beaver builds a dam, creating a pond that supports new plant and animal species. In this scenario, the beaver is acting as:

Accepted Answer

An ecosystem engineer

Question 16

Which of the following is a direct consequence of biomagnification in aquatic food webs?

Accepted Answer

Top predators, such as humans, accumulate the highest concentrations of toxins.

Question 17

Which of the following best describes the role of decomposers in a trophic pyramid?

Accepted Answer

They recycle nutrients by breaking down dead organic matter.

Question 18

If two species of Paramecium are grown together in a limited resource environment and one species outcompetes the other, this is an example of:

Accepted Answer

Competitive exclusion

Question 19

Which of the following is a likely outcome if a top predator is removed from a food web?

Accepted Answer

An increase in the abundance of herbivores, leading to overgrazing of primary producers.

Ecosystem Energy Flow, Trophic Structure, and Community Interactions

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