Unit 11 Essential Learning Packet: Ecosystems and Ecology

What is an ecosystem?

• A single organism

• A community of living organisms interacting with their non-living environment

• A non-living environment

• A type of plant.

Answer explanation

An ecosystem is defined as a community of living organisms interacting with their non-living environment. This includes plants, animals, and their physical surroundings, making the second choice the correct answer.

Biotic factors are the ______ components of an ecosystem.

• non-living

• living

• chemical

• artificial

Answer explanation

Biotic factors refer to the living components of an ecosystem, such as plants, animals, and microorganisms. Therefore, the correct answer is 'living', as it accurately describes these biological elements.

Which of the following is NOT an abiotic factor?

• Temperature

• Soil

• Animals

• Water

Answer explanation

Animals are biotic factors, as they are living organisms. In contrast, temperature, soil, and water are abiotic factors, which are non-living components of the environment.

In a commensalism relationship, one species benefits while the other is ______.

• Harmed

• Unaffected

• Benefited

• Destroyed

Answer explanation

In a commensalism relationship, one species benefits while the other is unaffected. This means the benefiting species gains advantages, while the other species does not experience harm or benefit.

Which of the following is an example of a producer in an ecosystem?

• Deer

• Algae

• Fox

• Eagle

Answer explanation

Algae are producers in an ecosystem because they perform photosynthesis, converting sunlight into energy. In contrast, deer, foxes, and eagles are consumers that rely on other organisms for food.

Fill in the blank: _______ consumers are top predators that eat secondary consumers.

• A) Primary

• B) Secondary

• C) Tertiary

Answer explanation

Tertiary consumers are the top predators in an ecosystem, feeding on secondary consumers. Primary consumers eat producers, while secondary consumers eat primary consumers, making tertiary consumers the correct choice.

Which of the following organisms is considered a decomposer?

• Deer

• Fungi

• Wolf

• Lion

Answer explanation

Fungi are decomposers that break down dead organic matter, recycling nutrients back into the ecosystem. In contrast, deer, wolves, and lions are consumers that obtain energy by eating other organisms.

In a food web, which of the following is a primary consumer?

• A) Trees

• B) Wolves

• C) Deer

• D) Fungi

Answer explanation

Deer are primary consumers as they eat plants (producers) for energy. Trees are producers, wolves are secondary consumers (predators), and fungi are decomposers, making C) Deer the correct choice.

What percentage of energy is passed from one trophic level to the next in a food chain?

• 5%

• 10%

• 15%

• 20%

Answer explanation

In a food chain, approximately 10% of the energy from one trophic level is transferred to the next. This is known as the 10% rule, which explains why energy decreases at higher trophic levels.

In a food chain, if 10,000 J of energy is available at the primary producer level, how much energy is available at the tertiary consumer level?

• 10 J

• 100 J

• 1,000 J

• 10,000 J

Answer explanation

In a food chain, energy decreases by about 90% at each trophic level. Starting with 10,000 J at the primary producers, only 10 J reaches the tertiary consumers, making 10 J the correct answer.