Organisms and their Environment IGCSE

Which factors would cause region X on the graph to become steeper?

• A decrease in predation, decrease in food supply

• B increase in food supply, decrease in disease

• C increase in food supply, increase in predation

• D increase in predation, decrease in disease

The diagram shows a simple food chain.

green plant → herbivore → carnivore

If a disease causes the number of herbivores to decrease, what will be the effect on the numbers of green plants and carnivores?

• A

• B

• C

• D

3 In the food chain below, the population of snakes is halved owing to a viral disease.

grass → locusts → snakes → eagles

What effect does this have on the other members of the food chain?

• A

• B

• C

• D

4 Which is an example of a population?

• A all the animals and plants living in a pond

• B all the mahogany trees growing in a forest

• C all the people born in a country over a period of 100 years

• D all the species of animals in Africa

Which process is represented by arrow X?

• A combustion

• B Feeding

• C photosynthesis

• D respiration

Which is the correct pyramid of numbers for this food chain?

• A

• B

• C

• D

Which organisms remove carbon dioxide from the atmosphere?

• A carnivores

• B decomposers

• C herbivores

• D producers

What stage in the sigmoid population growth curve is represented by region P?

• A death phase

• B exponential (log) phase

• C lag phase

• D stationary phase

The role of an organism in its natural environment; the way in which it interacts with other organisms and with the non-living parts of the environment

An organism that gets its energy from dead or waste organic material