Lesson Worksheet: Disruption to Ecosystems Science

Start Practising

In this worksheet, we will practice describing the impact of a change in a population on a food web, and explaining why toxins build up through a food chain.

Q1:

The figure shows some of the organisms that make up a food web in a pond.

How many omnivores are there in this food web?

How many links are there in the longest food chain in this web?

Which organism will decrease in numbers most rapidly if many of the pike are removed by fishing activities?

AWater boatman
BStickleback
CDiving beetle
DHeron

Which organism in the food web is most likely to be poisoned by insecticide that has been sprayed on farmland and then washed into the pond?

AHeron
BPond snail
CAlgae
DMicroscopic plants
EMayfly larva

Q2:

Which of the following substances is passed along the food chain and can poison the top predators?

AAmino acids
BInsecticides
CAcid rain
DCarbon dioxide

Q3:

The figure shows a food chain.

What would happen to the snake population if the eagle population suddenly decreased due to disease?

AIt would increase.
BIt would stay the same.
CIt would decrease.

What would happen to the mouse population if the eagle population suddenly decreased due to disease?

AIt would decrease.
BIt would increase.
CIt would stay the same.

Q4:

Complete the sentence: Individuals of the same species living in the same area at the same time is called .

Aan ecosystem
Ba community
Ca niche
Da population

Q5:

What would happen to the consumers if many of the producers in an ecosystem died?

AMany consumers would increase in numbers because there would be no producers to eat them.
BMany consumers would die because they would have nothing to eat.
CThe consumers would be unaffected by the number of producers.

Q6:

The figure shows an ocean food chain.

Which organism in the chain is most likely to be poisoned by small amounts of mercury that have been released into the water from a nearby factory?