Chapter 3.5 Human Impact on the environment

Question 1

The increasing human popualtion requires an

Answer 1

increased food supply

Question 2

Methods of increasing food supply have included the use of;

Answer 2

fertilizers, pesticides, biological control and genetically modified (GM) crops.

Question 3

Fertilizers can leach from fields into freshwater increasing the effects of

Answer 3

algal blooms

Question 4

When algal blooms dies they are decomposed by aerobic bacteria which

Answer 4

multiply and reduce the oxygen concentration in the water

Question 5

Pesticides can accumulate in the bodies of

Answer 5

organisms and so build up along the food chain

Question 6

Toxicity levels of pesticides in the bodies of carnivores to the extent that the animal

Answer 6

or its reproduction is damaged

Question 7

The presence, abundance or absence of

Answer 7

indicator species can reveal information about the environment and level of pollution present.

Question 8

Biological control relies on natural solutions to

Answer 8

pest problems such as making use of natural predators or parasites

Question 9

Crop species can be genetically modified to increase their yields without the need for

Answer 9

fertilizers or pesticides

Question 10

Biological control and GM crops are alternatives to

Answer 10

intensive farming methods

Question 11

Using biological control and GM crops rather than intensive farming methods could result in

Answer 11

less damage to the environment