Topic 9 - Keystone Sample Quiz | Attempts: 854 - Trivia , Flashcards & Questions

2.

A volcanic eruption destroyed a forest, covering the soil with volcanic ash. For many years, only small plants could grow. Slowly, soil formed in which shrubs and trees could grow. These changes are an example of

Manipulation of genes
Evolution of a species
Ecological succession
Equilibrium

Correct Answer

A. Ecological succession

Explanation

The given scenario describes the process of ecological succession. Ecological succession refers to the gradual and predictable changes in the composition and structure of an ecological community over time. In this case, the volcanic eruption destroyed the existing forest, leaving behind a barren landscape covered in volcanic ash. Over the years, small plants were able to grow in the ash, which eventually led to the formation of soil. As the soil developed, shrubs and trees were able to grow, resulting in the establishment of a new forest ecosystem. This sequence of changes exemplifies ecological succession, where a new community gradually replaces the previous one in a disturbed or barren area.

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3.

A major reason that humans can have such a significant impact on an ecological community is that humans

Can modify their environment through technology
Reproduce faster than most other species
Are able to increase the amount of finite resources available
Remove large amounts of carbon dioxide from the air

Correct Answer

A. Can modify their environment through technology

Explanation

Humans can have a significant impact on an ecological community because they have the ability to modify their environment through technology. This means that humans have the power to alter their surroundings, such as building structures, manipulating landscapes, and creating new resources. By utilizing technology, humans can change the natural balance of an ecosystem, which can have both positive and negative effects on the community. This ability to modify the environment sets humans apart from other species and allows them to have a greater influence on the ecological systems they inhabit.

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4.

Abandoned railroad tracks are overgrown with weeds. Ten years later there are small aspen trees growing in the middle of the tracks. This change is an example of

Ecological succession
Biological evolution
Genetic variation
Heterotrophic nutrition

Correct Answer

A. Ecological succession

Explanation

The change of abandoned railroad tracks being overgrown with weeds and later having small aspen trees growing in the middle is an example of ecological succession. Ecological succession refers to the process of gradual and predictable changes in the composition and structure of an ecosystem over time. In this case, the initial colonization of weeds is followed by the establishment of aspen trees, indicating a succession of plant species in response to changing environmental conditions. This process is a natural progression of ecological communities and demonstrates how ecosystems can adapt and evolve over time.

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5.

Why is a mushroom considered a heterotroph?

It manufactures its own food.
It divides by mitosis.
It transforms light energy into chemical energy.
It obtains nutrients from its environment.

Correct Answer

A. It obtains nutrients from its environment.

Explanation

A mushroom is considered a heterotroph because it obtains nutrients from its environment. Unlike autotrophs that can produce their own food through photosynthesis, mushrooms cannot produce their own energy or nutrients. Instead, they rely on obtaining organic matter from their surroundings, such as decaying plant material or dead organisms. This makes them dependent on external sources for their nutrition, classifying them as heterotrophs.

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6.

Decomposers are necessary in an ecosystem because they

Produce food for plants by the process of photosynthesis
Provide energy for plants by the process of decay
Can rapidly reproduce and evolve
Make inorganic materials available to plants

Correct Answer

A. Make inorganic materials available to plants

Explanation

Decomposers are necessary in an ecosystem because they make inorganic materials available to plants. Decomposers break down dead organic matter, such as dead plants and animals, into simpler inorganic compounds like nitrogen, phosphorus, and carbon dioxide. These inorganic materials are then recycled back into the soil, making them accessible to plants for growth and development. Without decomposers, organic matter would accumulate and nutrients would become locked up, hindering plant growth and disrupting the balance of the ecosystem.

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7.

An energy pyramid is shown below. Which graph best represents the relative energy content of the levels of this pyramid?

Graph 1
Graph 2
Graph 3
Graph 4

Correct Answer

A. Graph 4

Explanation

Graph 4 best represents the relative energy content of the levels of the energy pyramid. In an energy pyramid, each level represents a trophic level, with producers at the bottom and higher-level consumers at the top. The energy content decreases as you move up the pyramid due to the loss of energy through metabolic processes and heat. Graph 4 shows a clear decrease in energy content as you move up the levels, indicating the correct representation of the energy pyramid.

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8.

The graph below represents the amount of available energy at successive nutrition levels in a particular food web. The Xs in the diagram represent the amount of energy that was most likely

Changed into inorganic compounds
Changed into organic compounds
Recycled back to the producers
Lost as heat to the environment

Correct Answer

A. Lost as heat to the environment

Explanation

The graph shows a decrease in available energy as you move up the nutrition levels in the food web. This suggests that energy is being lost at each level. The only option that explains this loss of energy is "lost as heat to the environment". This means that as energy is transferred from one level to another, some of it is lost as heat and is not available for the organisms in the food web to use.

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9.

The diagram below represents an energy pyramid constructed from data collected from an aquatic ecosystem. Which statement best describes this ecosystem?

The ecosystem is most likely unstable.
Long-term stability of this ecosystem will continue.
The herbivore populations will continue to increase in size for many years.
The producer organisms outnumber the consumer organisms.

Correct Answer

A. The ecosystem is most likely unstable.

Explanation

The energy pyramid represents the flow of energy in an ecosystem, with each level containing less energy than the one below it. In a stable ecosystem, there should be a large base of producers (plants) to support the energy needs of the consumers (herbivores and carnivores). However, in this diagram, the producer organisms are outnumbered by the consumer organisms, indicating an imbalance in the ecosystem. This suggests that there may not be enough energy available to sustain the higher trophic levels, making the ecosystem likely to be unstable.

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10.

Two food chains are represented below. Decomposers are important for supplying energy for

Food chain A, only
Food chain B, only
Both food chain A and food chain B
Neither food chain A nor food chain B

Correct Answer

A. Both food chain A and food chain B

Explanation

Decomposers are important for supplying energy in both food chain A and food chain B. Decomposers break down dead organic matter and release nutrients back into the environment, which can then be used by producers to create energy through photosynthesis. In food chain A, the decomposers break down dead plants and animals, releasing nutrients that are used by primary consumers (herbivores) and then passed on to secondary consumers (carnivores). In food chain B, the decomposers break down dead marine organisms, releasing nutrients that are used by primary consumers (zooplankton) and then passed on to secondary consumers (fish). Therefore, decomposers play a crucial role in supplying energy in both food chains.

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Topic 9 - Keystone Sample Quiz

Young birds that have been raised in isolation from members of their species build nests characteristic of their species. This suggests that the nest-building behavior is

Quiz Preview

A volcanic eruption destroyed a forest, covering the soil with volcanic ash. For many years, only small plants could grow. Slowly, soil formed in which shrubs and trees could grow. These changes are an example of

A major reason that humans can have such a significant impact on an ecological community is that humans

Abandoned railroad tracks are overgrown with weeds. Ten years later there are small aspen trees growing in the middle of the tracks. This change is an example of

Why is a mushroom considered a heterotroph?

Decomposers are necessary in an ecosystem because they

An energy pyramid is shown below. Which graph best represents the relative energy content of the levels of this pyramid?

The graph below represents the amount of available energy at successive nutrition levels in a particular food web. The Xs in the diagram represent the amount of energy that was most likely

The diagram below represents an energy pyramid constructed from data collected from an aquatic ecosystem. Which statement best describes this ecosystem?

Two food chains are represented below. Decomposers are important for supplying energy for