Question 1

A Viceroy caterpillar feeds on a leaf.One day's feeding consumes 1000 calories worth of leaves.50% of the calories are lost in its feces and 33% of the calories are used in cellular respiration.How many calories of the original intake are available to add to the caterpillar's biomass each day?

Accepted Answer

The answer of A Viceroy caterpillar feeds on a leaf.One...

Question 2

In an ecosystem

Accepted Answer

The answer of In an ecosystem
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Question 3

According to MacArthur and Wilson's island biogeography theory, which of the following would be expected to have the smallest species richness?

Accepted Answer

According to MacArthur and Wilson's theory, small and isolated islands are expected to have smaller species richness due to their limited resources and smaller habitats. Therefore, a small island far from the mainland would be expected to have the smallest species richness compared to the other options.

Question 4

In an ecosystem, the amount of organic matter produced in a given time that is available for heterotrophs is known as

Accepted Answer

Net primary productivity is the amount of organic matter produced by producers that is available for consumption by heterotrophs after accounting for the energy used in respiration.

Question 5

The net weight of all of the organisms living in an ecosystem is its

Accepted Answer

Biomass is the total mass of living organisms in an ecosystem.

Question 6

Which one of the following quantities best represents the respiratory heat lost by plants in an ecosystem?

Accepted Answer

Respiratory heat loss by plants is the energy used in respiration, which is the difference between gross primary productivity (total energy captured by photosynthesis) and net primary productivity (energy remaining after respiration).

Question 7

In the food chain below, what does the blue jay represent? crabgrass-cricket-garden spider-blue jay-red-tailed hawk

Accepted Answer

The blue jay is a secondary carnivore because it feeds on the garden spider, which is a primary carnivore that eats crickets.

Question 8

During the 1960s, a group of scientists in the northeastern United States conducted an experiment at Hubbard Brook, New Hampshire.A 38-acre watershed was completely deforested and the runoff (water flow) monitored for several years.It was compared to an adjacent watershed that was left untouched.The scientists collected data during those years and found

Accepted Answer

The experiment conducted at Hubbard Brook, New Hampshire showed a tremendous increase in both the amount of runoff and nitrogen release from the deforested watershed compared to the adjacent untouched watershed. Therefore, the best choice is D.

Question 9

In a food chain with four trophic levels, what would be the energy in the top trophic level if the energy contained in the primary producer level is 40,000 kcal/m²/yr? Assume a trophic level transfer efficiency of 10%.

Accepted Answer

The energy decreases by 90% at each trophic level due to the 10% transfer efficiency. Starting with 40,000 kcal/m²/yr, the energy at each level would be: 1st level (producers) = 40,000 kcal, 2nd level = 4,000 kcal, 3rd level = 400 kcal, and 4th level (top) = 40 kcal.

Question 10

Which one of the following ecosystems is most likely to show an inverted biomass pyramid but a normal energy pyramid?

Accepted Answer

In open ocean ecosystems, the biomass of primary producers (phytoplankton) is less than that of the primary consumers (zooplankton), leading to an inverted biomass pyramid. However, the energy pyramid remains normal because energy flow follows the typical pattern from producers to consumers.

Question 11

In a food chain consisting of four trophic levels, if the energy present in the top level is 48 kcal/m2/yr, how much energy do you expect in herbivores? (Use an energy transfer rate of 10%.)

Accepted Answer

The answer of In a food chain consisting of four...

Question 12

Which one of the following factors would NOT influence the productivity of an ocean community?

Accepted Answer

The amount of rainfall would not significantly influence the productivity of an ocean community as the source of water for marine organisms comes primarily from the ocean itself, not from rainfall. The other factors listed can affect the availability of nutrients and energy within the community, and therefore influence productivity.

Question 13

Addition of a primary carnivore to an ecosystem can sometimes influence the whole ecosystem.This process is called

Accepted Answer

The addition of a primary carnivore to an ecosystem can trigger a trophic cascade, where the decrease or increase in abundance of one trophic level can lead to changes in the abundance of other levels. This can ultimately influence the whole ecosystem.

Question 14

A good average value for the amount of energy that reaches the next trophic level is about

Accepted Answer

Typically, about 10% of the energy at one trophic level is transferred to the next level in an ecosystem. This is known as the 10% rule in ecology.

Question 15

The following figure shows studies in a stream where enclosures were set up either with trout or with no trout.Which statement is a correct interpretation of the graph about trout, invertebrates, and algae?

Accepted Answer

The answer of The following figure shows studies in a...

Question 16

The rate of production of new biomass by heterotrophs is called

Accepted Answer

Secondary productivity refers to the rate at which heterotrophs (such as animals) produce new biomass from consuming other organisms.

Question 17

What feature do the carbon and nitrogen cycles have in common?

Accepted Answer

Both the carbon and nitrogen cycles have a large atmospheric component, as carbon dioxide and nitrogen gas are both present in the atmosphere and play significant roles in these cycles.

Question 18

In a marine ecosystem with an inverted biomass pyramid, which trophic level should have the smallest number of organisms?

Accepted Answer

In an inverted biomass pyramid, the trophic level with the smallest number of organisms is typically the top trophic level. In this case, the top trophic level is the secondary carnivores (tuna).

Question 19

In the food chain below, what does the garden spider represent? crabgrass-cricket-garden spider-blue jay-red-tailed hawk

Accepted Answer

The garden spider is a primary carnivore because it feeds on crickets, which are herbivores.

Question 20

Energy enters most ecosystems by the process of

Accepted Answer

Energy enters most ecosystems primarily through photosynthesis, where plants and other autotrophs convert sunlight into chemical energy.

Quiz 57: Dynamics of Ecosystems