Ecology Unit Pre-assessment (Grade 7)

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2. Rate, on a scale of 1 – 4, 1 being the lowest and 4 being the highest, how interested you are in ecology?

The given question asks the respondent to rate their level of interest in ecology on a scale of 1 to 4, with 1 being the lowest and 4 being the highest. The answer provided includes all four options (1, 2, 3, and 4), indicating that the respondent is equally open to any level of interest in ecology.

Explanation

The given question asks the respondent to rate their level of interest in ecology on a scale of 1 to 4, with 1 being the lowest and 4 being the highest. The answer provided includes all four options (1, 2, 3, and 4), indicating that the respondent is equally open to any level of interest in ecology.

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3. In the food web depicted below, which organism is the autotroph (Standards 1.1a, 1.1b, 1.1c, 6.1a)?

Owl

Hawk

Tree

Grasshopper

Rabbit

The correct answer is "Tree" because autotrophs are organisms that can produce their own food through photosynthesis or chemosynthesis. Trees are autotrophs because they can produce their own food through photosynthesis, using sunlight, water, and carbon dioxide to create glucose and oxygen.

Explanation

The correct answer is "Tree" because autotrophs are organisms that can produce their own food through photosynthesis or chemosynthesis. Trees are autotrophs because they can produce their own food through photosynthesis, using sunlight, water, and carbon dioxide to create glucose and oxygen.

4. Which of the following organisms could fit in the space labeled x in this food chain? (Standards 1.1a, 1.1b, 1.1c) Grass → X → Snake → Puma

Raptors or Eagles

Mice

Leaves

Coyote

Algae

Mice could fit in the space labeled x in this food chain because they are herbivores that eat grass. They are the primary consumers in this food chain, feeding on the grass. The snake is the secondary consumer, feeding on the mice, and the puma is the tertiary consumer, feeding on the snake. Therefore, mice are the most suitable organism to fit in the space labeled x.

Explanation

Mice could fit in the space labeled x in this food chain because they are herbivores that eat grass. They are the primary consumers in this food chain, feeding on the grass. The snake is the secondary consumer, feeding on the mice, and the puma is the tertiary consumer, feeding on the snake. Therefore, mice are the most suitable organism to fit in the space labeled x.

5. What are the two major life processes that involve carbon and oxygen (Standards 6.1d, 6.1e)?

Coal formation and photosynthesis

Photosynthesis and respiration

Fuel combustion and open burning

Death and decay

Nitrogen fixation and denitrification

Photosynthesis and respiration are the two major life processes that involve carbon and oxygen. Photosynthesis is the process by which plants, algae, and some bacteria convert carbon dioxide and sunlight into glucose and oxygen. Respiration, on the other hand, is the process by which organisms break down glucose and other organic molecules to release energy, using oxygen and producing carbon dioxide as a byproduct. Both processes are essential for the exchange of carbon and oxygen in living organisms and play a crucial role in the carbon cycle.

Explanation

Photosynthesis and respiration are the two major life processes that involve carbon and oxygen. Photosynthesis is the process by which plants, algae, and some bacteria convert carbon dioxide and sunlight into glucose and oxygen. Respiration, on the other hand, is the process by which organisms break down glucose and other organic molecules to release energy, using oxygen and producing carbon dioxide as a byproduct. Both processes are essential for the exchange of carbon and oxygen in living organisms and play a crucial role in the carbon cycle.

6. The process is best described as:

Ecological Succession

An Energy Cycle

Negative Feedback

A Food Web

Commensalism

Ecological succession refers to the process of change in the structure and composition of an ecosystem over time. It involves the gradual replacement of one community by another, as different species colonize and modify the environment. This process is driven by interactions between organisms and their environment, such as competition for resources and the ability of certain species to tolerate or adapt to specific conditions. Ecological succession is a dynamic process that allows ecosystems to recover and adapt to disturbances, making it the best description for the given process.

Explanation

Ecological succession refers to the process of change in the structure and composition of an ecosystem over time. It involves the gradual replacement of one community by another, as different species colonize and modify the environment. This process is driven by interactions between organisms and their environment, such as competition for resources and the ability of certain species to tolerate or adapt to specific conditions. Ecological succession is a dynamic process that allows ecosystems to recover and adapt to disturbances, making it the best description for the given process.

7. Which term represents an indirect economic value of biodiversity?

Food

Clothing

Flood Protection

Medicines

Fuel

Flood protection represents an indirect economic value of biodiversity because it helps to mitigate the impact of floods and reduce the damage caused by them. Biodiversity plays a crucial role in maintaining healthy ecosystems, including wetlands and forests, which act as natural buffers against floods. These ecosystems absorb and store water, regulate water flow, and prevent soil erosion, thereby providing flood protection services. This indirectly benefits the economy by reducing the costs associated with flood damage, such as property damage, infrastructure repair, and loss of livelihoods.

Explanation

Flood protection represents an indirect economic value of biodiversity because it helps to mitigate the impact of floods and reduce the damage caused by them. Biodiversity plays a crucial role in maintaining healthy ecosystems, including wetlands and forests, which act as natural buffers against floods. These ecosystems absorb and store water, regulate water flow, and prevent soil erosion, thereby providing flood protection services. This indirectly benefits the economy by reducing the costs associated with flood damage, such as property damage, infrastructure repair, and loss of livelihoods.

8. 1. Termites are small insects that eat wood causing so much damage that they can eventually cause a house to fall down. However, termites cannot make enzymes that digest cellulose, the main component in wood. A small protozoan called Trichonympha sphaerica lives inside the termite’s gut and excretes enzymes to break down cellulose. However, the protozoa itself cannot make the enzymes. Instead, a species of bacteria that lives inside the protozoa produces the enzyme. What type of relationships are described in this passage? (Standards 6.1f, 6.1g, 6.3a).

Predator/Prey

Consumer/Decomposer

Parasitism

Mutualism

Commensalism

The passage describes a mutualistic relationship between termites and the protozoan Trichonympha sphaerica. The termites provide a habitat for the protozoa, which in turn provides the termites with the necessary enzymes to break down cellulose in wood. Both species benefit from this relationship, making it a mutualistic interaction.

Explanation

The passage describes a mutualistic relationship between termites and the protozoan Trichonympha sphaerica. The termites provide a habitat for the protozoa, which in turn provides the termites with the necessary enzymes to break down cellulose in wood. Both species benefit from this relationship, making it a mutualistic interaction.

9. The main source of energy for a wetlands ecosystem is (Standard 1.1b, 1.1e, 1.1f)

Water

Soil

Plants

Fish

The Sun

The Sun is the main source of energy for a wetlands ecosystem. Sunlight provides the energy needed for photosynthesis, which is the process by which plants convert sunlight into food. This food is then consumed by other organisms in the ecosystem, creating a food chain. Without the Sun, there would be no energy input into the ecosystem, and the ecosystem would not be able to sustain life.

Explanation

The Sun is the main source of energy for a wetlands ecosystem. Sunlight provides the energy needed for photosynthesis, which is the process by which plants convert sunlight into food. This food is then consumed by other organisms in the ecosystem, creating a food chain. Without the Sun, there would be no energy input into the ecosystem, and the ecosystem would not be able to sustain life.

10. What important biotic factor is missing from the food web (Standards 1.1b, 1.1c, 6.1a, 6.1g)?

Water

Decomposers

Producers

Consumers

Sunlight

Decomposers are an important biotic factor that is missing from the food web. Decomposers play a crucial role in breaking down dead organisms and organic matter, recycling nutrients back into the ecosystem. Without decomposers, the food web would not be able to efficiently cycle nutrients, leading to a buildup of dead material and a decrease in the availability of essential nutrients for other organisms.

Explanation

Decomposers are an important biotic factor that is missing from the food web. Decomposers play a crucial role in breaking down dead organisms and organic matter, recycling nutrients back into the ecosystem. Without decomposers, the food web would not be able to efficiently cycle nutrients, leading to a buildup of dead material and a decrease in the availability of essential nutrients for other organisms.

11. Coyote, wolves, and other carnivores occasionally kill chickens, pigs, and cows that live on farms, although they mostly eat small mammals that live in the wild. Farmers will frequently kill these predators to protect their livestock. Which result is most likely to occur when the predator population decreases (Standard 6.1d, 6.1e)?

Herbivores will exceed carrying capacity and begin eating crops.

The amount of healthy livestock on the farm will double in size.

More grasses and seeds will be available for livestock to consume.

Decomposers will take the place of predators in the ecosystem.

The amount of parasites infecting the predators will increase.

When the predator population decreases, there will be fewer predators to control the herbivore population. As a result, the herbivores will have less competition for resources and their population will increase. Eventually, the herbivores may exceed the carrying capacity of their environment and start consuming crops as a source of food. This is the most likely result when the predator population decreases.

Explanation

When the predator population decreases, there will be fewer predators to control the herbivore population. As a result, the herbivores will have less competition for resources and their population will increase. Eventually, the herbivores may exceed the carrying capacity of their environment and start consuming crops as a source of food. This is the most likely result when the predator population decreases.

12. All life requires energy, carbon, oxygen, hydrogen, and nitrogen. Which statement best describes how they are used in the biosphere? (Standards 6.1a, 6.1b)

Energy is recycled but elements must be added from the outside.

Elements are recycled, but energy must be added from the outside.

Both energy and elements are recycled.

Neither energy nor elements are recycled.

The amount of elements and energy constantly increase.

All life requires energy, carbon, oxygen, hydrogen, and nitrogen. While elements such as carbon, oxygen, hydrogen, and nitrogen are recycled in the biosphere, energy cannot be recycled and must be constantly added from the outside. This is because energy is constantly being converted and used by organisms in various biological processes. Therefore, the statement "Elements are recycled, but energy must be added from the outside" best describes how energy and elements are used in the biosphere.

Explanation

All life requires energy, carbon, oxygen, hydrogen, and nitrogen. While elements such as carbon, oxygen, hydrogen, and nitrogen are recycled in the biosphere, energy cannot be recycled and must be constantly added from the outside. This is because energy is constantly being converted and used by organisms in various biological processes. Therefore, the statement "Elements are recycled, but energy must be added from the outside" best describes how energy and elements are used in the biosphere.