Unit 3 - Key Area 4 - Energy in Ecosystems

Question 1

What does a food chain show?

Answer 1

A food chain shows the feeding relationships between organisms in an ecosystem.

Question 2

What is a food web?

Answer 2

Many food chains interconnect to form a food web.

Question 3

What do the arrows in a food web represent?

Answer 3

Arrows represent the flow of energy from one organism to another.

The feeding relationships between organisms are balanced.

Question 4

What would happen to the an organism if one of its food sources was removed and why?

Answer 4

The population would decrease as one of their food sources is gone.

The population would stay the same as they have other food sources.

Question 5

What would happen to a prey if one of their predators food sources was removed and why?

Answer 5

The preys population would decrease as it loses one of their food sources (the other prey).

The preys population would stay the same as it has other food sources.

Question 6

How is energy lost from one level to the next in a food chain?

Answer 6

In transfers from one level to the next in a food chain, the majority of the energy is lost as:
• Undigested waste
• Movement
• Heat

Question 7

How much energy is passed onto the next level and what is it used for?

Answer 7

Only a very small quantity is used for growth and is available at next level of the food chain.

Question 8

What does the pyramid of numbers represent?

Answer 8

A pyramid of numbers shows the number of organisms at each stage in the food chain.

Question 9

Why are some pyramid of numbers irregular shapes?

Answer 9

The size of organisms can make some pyramid of numbers irregular shapes.

Large producers (like a tree) or food chains ending in parasites (fleas etc) can cause irregularities in shape.

Question 10

What does the pyramid of energy show?

Answer 10

A pyramid of energy shows the total quantity of available energy stored in organisms at each level in the food chain of an ecosystem per year.

Question 11

Why is the pyramid of energy a true representation of a food chain?

Answer 11

Pyramids of energy are true representations of a food chain and show that the producers store the highest quantity of energy.

The energy stored then decreases at each level in the food chain of the ecosystem.