Question 1

Which one of the links in the food chain shown below does the garden spider represent?
Grass-cricket-garden spider-blue jay-red-tailed hawk
A)producer
B)primary producer
C)primary consumer
D)secondary consumer
E)tertiary consumer

Accepted Answer

The garden spider represents the secondary consumer in this food chain, as it eats the primary consumer (cricket) and is then consumed by the tertiary consumer (red-tailed hawk).

Question 2

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%. A)4,000 kcal/m²/yr B)400 kcal/m²/yr C)40 kcal/m²/yr D)4 kcal/m²/yr E)0.4 kcal/m²/yr

Accepted Answer

With a 10% efficiency at each trophic level, the energy available at the top level (fourth level) is calculated as follows: 40,000 kcal * 0.1 * 0.1 * 0.1 = 40 kcal/m^2/yr.

Question 3

Which one of the links in the food chain shown below is the producer?
Grass-cricket-garden spider-blue jay-red-tailed hawk
A)grass
B)cricket
C)garden spider
D)blue jay
E)red-tailed hawk

Accepted Answer

The producer in a food chain is the organism that produces its own food through photosynthesis. In the given food chain, grass is the producer as it produces its own food through photosynthesis.

Question 4

What feature do the carbon and nitrogen cycles have in common?
A)a large atmospheric component
B)involvement in global climate change
C)often a limiting nutrient
D)mostly local cycling
E)many microbes involved in cycling

Accepted Answer

The answer of What feature do the carbon and nitrogen...

Question 5

Which one of the following cycles is characterized by often being a limiting nutrient in ecosystems and having no atmospheric component in its cycle?
A)phosphorus
B)carbon
C)nitrogen
D)iron
E)water

Accepted Answer

The phosphorus cycle is often limited in ecosystems and does not have an atmospheric component. Phosphorus is mostly found in rocks and minerals and must be weathered and dissolved before it can enter the biotic environment.

Question 6

A Viceroy caterpillar feeds on a leaf.If a day's feeding gains the caterpillar a total of 1000 calories and 50% is lost in its feces and 33% of the energy is used through cellular respiration,how many calories of the original intake are available for caterpillar biomass?
A)830 calories
B)670 calories
C)500 calories
D)330 calories
E)170 calories

Accepted Answer

After losing 50% to feces (500 calories), 500 calories remain. Of these, 33% are used in cellular respiration (165 calories), leaving 335 calories for biomass. However, the correct calculation should be 1000 - 500 - 165 = 335, but since the closest option is 170, it seems there might be a mistake in the options or calculations.

Question 7

Which of the following terms could be used by you as you explain to your teacher your understanding of the total amount of organic matter produced in a community in a given time that is available for heterotroph consumption?
A)primary productivity
B)secondary productivity
C)primary production
D)net primary production
E)net secondary production

Accepted Answer

Net primary production is the total amount of organic matter produced in a community over a given period of time, minus the energy used by plants in respiration. This represents the amount of energy available for heterotroph consumption.

Question 8

Which one of the following quantities best represents the respiratory heat lost by plants in an ecosystem?
A)gross primary productivity
B)net primary productivity
C)gross primary productivity - net primary productivity
D)gross primary productivity - standing crop biomass
E)gross primary productivity - secondary productivity

Accepted Answer

Respiratory heat is the energy lost during respiration, which is the process of breaking down organic molecules to release energy for cellular processes. This energy is not stored in the plant's tissues but rather released as heat. Net primary productivity (B) represents the amount of organic material produced by plants after respiration, so it does not accurately represent respiratory heat loss. Gross primary productivity (A) represents the total amount of organic material produced by plants, which includes both the energy stored in the tissues and the respiratory heat lost, so it is not specific to respiratory heat loss. Standing crop biomass (D) represents the total amount of organic material in a given area at a given time, regardless of whether it has been used for respiration or stored in plant tissues. Secondary productivity (E) refers to the amount of biomass produced by consumers in a food chain, not the amount of respiratory heat lost by plants. Therefore, the best option is C, which subtracts the net primary productivity from the gross primary productivity to specifically account for respiratory heat loss.

Question 9

Which one of the following explanations for why the tropics have greater species diversity than the temperate zone is least convincing?
A)Seasonality variability is less in the tropics.
B)Niches are narrower in the tropics.
C)Fewer predators in the tropics allow more prey species to flourish.
D)Greater spatial heterogeneity in the tropics creates more niches.
E)The tropics have greater plant production,which supports greater overall species richness.

Accepted Answer

The idea that there are fewer predators in the tropics is not convincing because the tropics are known for having a high diversity of both predators and prey, contributing to complex food webs and ecological interactions.

Question 10

Which one of the following ecosystems is most likely to show an inverted biomass pyramid but a normal energy pyramid?
A)grassland
B)open ocean
C)intertidal
D)tropical forest
E)desert

Accepted Answer

The open ocean is the best choice for this scenario because it is home to phytoplankton, which have high rates of production and turnover, resulting in a large amount of energy being available at the base of the food chain. However, the biomass of individual phytoplankton is very small, leading to a lower overall biomass of primary producers compared to the higher trophic levels. This results in an inverted biomass pyramid, where the biomass of consumers outweighs that of primary producers, but a normal energy pyramid, where energy flows from the base of the food chain to the apex predators.

Question 11

In a marine ecosystem with an inverted biomass pyramid,which trophic level should have the smallest number of organisms?
A)phytoplankton
B)zooplankton
C)primary carnivores (sardines)
D)secondary carnivores (tuna)
E)detritivores

Accepted Answer

In an inverted biomass pyramid, the biomass of higher trophic levels is greater than the biomass of lower trophic levels. This means that there are fewer organisms in higher trophic levels than in lower trophic levels. Therefore, the secondary carnivores (tuna) should have the smallest number of organisms in this ecosystem.

Question 12

The following figure shows studies in a stream where enclosures were setup either with trout or with no trout.Which statement is a correct interpretation of the graph about trout,invertebrates,and algae? 
A)If trout are present in a system,alga production is low and invertebrate population levels are also low.
B)If trout are present in a system,alga production is high and invertebrate population levels are also high.
C)If trout are present in a system,alga production is high and invertebrate population levels are low.
D)Trout do not seem to affect the alga production;only the invertebrate populations are affecteD.
E)Trout do affect the alga production but not the invertebrate populations.

Accepted Answer

The graph shows that when trout are present in a system, alga production is high while invertebrate population levels are low. This suggests that the presence of trout can lead to increased grazing on invertebrates, which in turn leads to lower invertebrate population levels and reduced grazing pressure on algae. Thus, trout affect alga production, indirectly, by reducing the invertebrate populations that consume algae.

Question 13

Addition of a primary carnivore to an ecosystem can sometimes influence the whole ecosystem.This process is called
A)a top-down effect.
B)a bottom-up effect.
C)species turnover.
D)disruption.
E)a trophic cascadE.

Accepted Answer

A trophic cascade occurs when a top predator influences the structure and population dynamics of the ecosystem, affecting multiple trophic levels below it.

Question 14

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 primary consumers? (Use an energy transfer rate of 10%. ) A)4.8 kcal/m²/yr B)48 kcal/m²/yr C)480 kcal/m²/yr D)4,800 kcal/m²/yr E)48,000 kcal/m²/yr

Accepted Answer

The energy transfer rate is 10%, so each trophic level has 10 times the energy of the level above it. The top level has 48 kcal/m²/yr, so the level below it (secondary consumers) has 480 kcal/m²/yr, and the primary consumers have 4,800 kcal/m²/yr.

Question 15

According to MacArthur and Wilson's island biogeography theory,which of the following would be expected to have the smallest species diversity?
A)the mainland
B)a large island near the mainland
C)a large island far from the mainland
D)a small island near the mainland
E)a small island far from the mainland

Accepted Answer

According to MacArthur and Wilson's theory, smaller and more isolated islands are expected to have lower species diversity due to their smaller size and lower immigration rates. Therefore, a small island far from the mainland (Option E) would be expected to have the smallest species diversity.

Question 16

Which one of the following statements about the carbon cycle is false? A)Carbon and nitrogen fixation have analogous functions in their cycles. B)Burning of fossil fuels has lead to the current imbalance in the carbon cycle. C)Cutting down rainforests decreases atmospheric CO₂ levels. D)In water,inorganic carbon exists in two different forms,both of which can be used by autotrophs. E)Carbon cycles globally.

Accepted Answer

Cutting down rainforests actually increases atmospheric CO2 levels because trees absorb CO2 during photosynthesis and release oxygen. When trees are cut down, they no longer absorb CO2 and can release the stored carbon back into the atmosphere when they are burned or decompose.

Question 17

What feature do the carbon and phosphorus cycles have in common?
A)involvement in acid rain
B)large mineral deposits
C)involvement in eutrophication
D)large atmospheric component
E)often a limiting nutrient

Accepted Answer

The answer of What feature do the carbon and phosphorus...

Question 18

In a pond ecosystem,a crayfish feeds on three species of algae.It in turn is preyed on by one species of fish and a heron.The heron also preys upon the fish.What is the minimum number of food chains in this food web?
A)2
B)3
C)4
D)5
E)6

Accepted Answer

In the food web, there are three algae species, each forming a separate food chain with the crayfish. The crayfish is then preyed upon by the fish and the heron, creating two more chains for each algae species. Additionally, the fish is preyed upon by the heron, adding another chain. Thus, the minimum number of food chains is 3 (algae-crayfish-fish) + 3 (algae-crayfish-heron) = 6.

Question 19

Which one of the links in the food chain shown below does the cricket represent?
Grass-cricket-garden spider-blue jay-red-tailed hawk
A)producer
B)primary producer
C)primary consumer
D)secondary consumer
E)tertiary consumer

Accepted Answer

The cricket is consuming the grass, which makes it a primary consumer in this food chain.

Question 20

Which one of the following observations was not an outcome of studies by David Tilman and coworkers at Cedar Creek,Minnesota on ecosystem stability?
A)Plots with more species showed less year-to-year variation in biomass.
B)Species rich plots were less affected by drought than species poor plots.
C)More diverse plots were less susceptible to invasion by new species.
D)Nitrogen uptake and total biomass produced were negatively correlated to species richness.
E)Overyielding was observed in more recent work at Cedar Creek.

Accepted Answer

The observation that nitrogen uptake and total biomass produced were negatively correlated to species richness was not an outcome of studies by David Tilman and coworkers at Cedar Creek on ecosystem stability.

Quiz 58: Dynamics of Ecosystems

Which one of the links in the food chain shown below does the garden spider represent? Grass-cricket-garden spider-blue jay-red-tailed hawk

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%.

Which one of the links in the food chain shown below is the producer? Grass-cricket-garden spider-blue jay-red-tailed hawk

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

Which one of the following cycles is characterized by often being a limiting nutrient in ecosystems and having no atmospheric component in its cycle?

A Viceroy caterpillar feeds on a leaf.If a day's feeding gains the caterpillar a total of 1000 calories and 50% is lost in its feces and 33% of the energy is used through cellular respiration,how many calories of the original intake are available for caterpillar biomass?

Which of the following terms could be used by you as you explain to your teacher your understanding of the total amount of organic matter produced in a community in a given time that is available for heterotroph consumption?

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

Which one of the following explanations for why the tropics have greater species diversity than the temperate zone is least convincing?

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

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

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

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

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 primary consumers? (Use an energy transfer rate of 10%. )

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

Which one of the following statements about the carbon cycle is false?

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

In a pond ecosystem,a crayfish feeds on three species of algae.It in turn is preyed on by one species of fish and a heron.The heron also preys upon the fish.What is the minimum number of food chains in this food web?

Which one of the links in the food chain shown below does the cricket represent? Grass-cricket-garden spider-blue jay-red-tailed hawk

Which one of the following observations was not an outcome of studies by David Tilman and coworkers at Cedar Creek,Minnesota on ecosystem stability?

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%.

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 primary consumers? (Use an energy transfer rate of 10%. )