Topic 3 - Inter-relationships: Parasitism And Mutualism

Question 1

What is a parasitic relationship?

Answer 1

In a parasitic relationship, a parasite lives on or in a host. Parasites such as fleas take what they need to survive without giving anything back, and it often harms the host.

Question 2

What is mutualism?

Answer 2

It’s a relationship between two organisms where both benefit.

Question 3

Describe the relationship between nitrogen-fixing bacteria and legumes.

Answer 3

It’s a mutualistic relationship, so the survival of each depends on the other. Legumes carry the bacteria in their roots. The bacteria gets a constant supply of sugar from the plant, and the plant gets essential nitrates from the bacteria.

Question 4

Explain why fleas are parasites.

Answer 4

Fleas are insects that live in the fur and bedding of animals. They feed by sucking the blood of their hosts, but the hosts gain nothing from the relationship.

Question 5

Name four parasites.

Answer 5

E.g. head lice, tapeworms, mistletoe and fleas.