Year 9 Ecology

Decomposer

An organism, such as a fungus or bacterium, that breaks down dead organisms and waste and returns matter to the environment.

Omnivore

A consumer that eats both producers and other consumers.

First-order consumer

Another name for a primary consumer; an organism that eats a producer.

Top-order consumer

A consumer at the top of a food chain that is not usually eaten by another organism in that food web.

What is the role of a decomposer?

To break down dead matter and waste so nutrients and matter can be recycled through the ecosystem.

Which way should arrows point in a food chain?

From the organism being eaten to the organism that eats it.

How can you identify a predator in a food web?

Follow an arrow from its prey towards the predator.

How can you identify organisms that compete for food?

Find two organisms that eat the same food source.

How can you identify a herbivore in a food web?

It receives energy directly from a producer and eats plants or algae.

How can you identify an omnivore in a food web?

It eats both a producer and another consumer.

What happens to prey if one of its predators decreases?

The prey population will usually increase.

What may happen to a predator if its prey decreases?

The predator population may decrease because less food is available.

Why can changing one population affect an entire food web?

Organisms are connected through feeding relationships, so a change can affect their predators, prey and competitors.

What matter can producers take from the abiotic environment?

Carbon dioxide from the air or water and water from the environment.

Give an example of matter moving from a biotic factor to an abiotic factor.

An animal releases carbon dioxide into the air during cellular respiration.

Give an example of matter moving from an abiotic factor to a biotic factor.

A plant absorbs carbon dioxide and water for photosynthesis.

Why is sunlight energy but not matter?

Sunlight provides energy but does not have mass or take up space as biological matter does.

When can photosynthesis occur?

When light is available, usually during daylight.

When does cellular respiration occur?

Continuously in living cells, during both day and night.

What portion of an organism’s energy can pass to the next consumer?

Only the energy stored in its body tissues.

Why can energy stored as heat not pass up a food chain?

Heat is released into the non-living environment and cannot be eaten by the next consumer.

How do you construct a food web?

Place the producer first, add consumers and draw arrows from each food source towards the organism that eats it.

How do you identify a producer in a food web?

It makes its own food and has arrows leading from it towards consumers.

How do you identify a top-order consumer?

Arrows lead towards it from its prey, but no arrows lead from it towards another predator.

What is the difference between a predator–prey relationship and symbiosis?

A predator kills and eats its prey, while symbiosis is a close relationship where at least one organism benefits.

Explain why only some energy from prey reaches a predator.

The prey uses energy for cellular respiration and life processes, and much is released as heat and waste. Only energy stored in its tissues is available to the predator.

How are the photosynthesis and respiration equations connected?

The glucose and oxygen made in photosynthesis are used in respiration, while the carbon dioxide and water made in respiration are used in photosynthesis.

Decomposer

An organism, such as a fungus or bacterium, that breaks down dead organisms and waste and returns matter to the environment.

Omnivore

A consumer that eats both producers and other consumers.

First-order consumer

Another name for a primary consumer; an organism that eats a producer.

Top-order consumer

A consumer at the top of a food chain that is not usually eaten by another organism in that food web.

What is the role of a decomposer?

To break down dead matter and waste so nutrients and matter can be recycled through the ecosystem.

Which way should arrows point in a food chain?

From the organism being eaten to the organism that eats it.

How can you identify a predator in a food web?

Follow an arrow from its prey towards the predator.

How can you identify organisms that compete for food?

Find two organisms that eat the same food source.

How can you identify a herbivore in a food web?

It receives energy directly from a producer and eats plants or algae.

How can you identify an omnivore in a food web?

It eats both a producer and another consumer.

What happens to prey if one of its predators decreases?

The prey population will usually increase.

What may happen to a predator if its prey decreases?

The predator population may decrease because less food is available.

Why can changing one population affect an entire food web?

Organisms are connected through feeding relationships, so a change can affect their predators, prey and competitors.

What matter can producers take from the abiotic environment?

Carbon dioxide from the air or water and water from the environment.

Give an example of matter moving from a biotic factor to an abiotic factor.

An animal releases carbon dioxide into the air during cellular respiration.

Give an example of matter moving from an abiotic factor to a biotic factor.

A plant absorbs carbon dioxide and water for photosynthesis.

Why is sunlight energy but not matter?

Sunlight provides energy but does not have mass or take up space as biological matter does.

When can photosynthesis occur?

When light is available, usually during daylight.

When does cellular respiration occur?

Continuously in living cells, during both day and night.

What portion of an organism’s energy can pass to the next consumer?

Only the energy stored in its body tissues.

Why can energy stored as heat not pass up a food chain?

Heat is released into the non-living environment and cannot be eaten by the next consumer.

How do you construct a food web?

Place the producer first, add consumers and draw arrows from each food source towards the organism that eats it.

How do you identify a producer in a food web?

It makes its own food and has arrows leading from it towards consumers.

How do you identify a top-order consumer?

Arrows lead towards it from its prey, but no arrows lead from it towards another predator.

What is the difference between a predator–prey relationship and symbiosis?

A predator kills and eats its prey, while symbiosis is a close relationship where at least one organism benefits.

Explain why only some energy from prey reaches a predator.

The prey uses energy for cellular respiration and life processes, and much is released as heat and waste. Only energy stored in its tissues is available to the predator.

How are the photosynthesis and respiration equations connected?

The glucose and oxygen made in photosynthesis are used in respiration, while the carbon dioxide and water made in respiration are used in photosynthesis.