Lesson Worksheet: Disruption to Ecosystems Science

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?

  • ATuna
  • BPlant plankton
  • CLarge fish
  • DAnimal plankton
  • ESmall fish

Q7:

The figure shows a marine food web.

In this food web, which organism is an omnivore?

  • AMussels
  • BFish
  • CSeagulls
  • DOctopus
  • EStarfish

An increase in sea temperature results in a growth in algae and plant plankton.

What other organisms in the food web will also increase as a result? Why?

  • AAll consumers in the food web, because they will have more food to eat
  • BOnly the herbivores in the food web, because they will have more food to eat
  • COnly the producers in the food web, because they will photosynthesize more
  • DOnly the carnivores in the food web, because they will have more food to eat

Which of the organisms below are most likely to be poisoned by the bioaccumulation of an insecticide that washes into the sea?

  • ASharks
  • BAnimal plankton
  • CMussels
  • DPlant plankton
  • EAlgae

This lesson includes 1 additional question for subscribers.

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