A growing human population demands increased food production. Farmers try to meet that demand by intensive farming, using fertilisers and pesticides that are impacting on the environment.
Which term describes the loss of fertiliser chemicals as water moves through soil?
What effect can leached fertiliser have on fresh water?
Increased nutrient concentration
Increased oxygen concentration
What can cause algal blooms?
A decrease in the populations of consumers in a lake
An increase in the concentration of dissolved nutrients in a lake
A reduction in the oxygen concentration of a lake
Weeds compete with crop plants for nutrients, water and light. How can farmers reduce this competition for resources?
By using pesticides
By using indicator species
By using fertilisers
A pesticide accumulates in the bodies of organisms in the food chain shown below.
In which organism will the highest concentration of the pesticide be found?
Great blue heron
What happens to the toxicity of a pesticide in the bodies of organisms at higher levels in a food chain?
Stays the same
What do plants use nitrate for?
To produce fats
To produce proteins
To produce sugars
Which term describes an organism of one species that can be used to reduce the population size of another species?
Biological control agent
Which chemical must be inserted into a crop plant to genetically modify it?
Which of the following characteristics of a genetically modified crop plant would reduce the need to give it large quantities of fertiliser?
Increased ability to take up carbon dioxide from the air
Increased ability to take up nitrates from the soil
Increased ability to take up water from the soil