Unit 3 Symbiosis

Question 1

Define symbiosis

Answer 1

Symbiosis is a co-evolved intimate relationship between members of two different species

Question 2

Define co-evolution

Answer 2

Is when species evolving based on the selection pressures they both impose

Question 3

Why can parasites not survive without their host

Answer 3

As they have limited metabolisms more common that parasites that live inside the body can’t live without their host

Question 4

List three ways parasites can be transmitted to their host

Answer 4

1) Direct contact (e.g lice)
2) Release of resistant stages (e.g larva)
3) vectors (e.g mosquitoes)

Question 5

two types of parasites life cycles

Answer 5

Direct

Indirect

Question 6

What is a direct life cycle

Answer 6

They have one host and eggs are shed and passed on to the next member of the host species

Question 7

What is an indirect life cycle

Answer 7

Involve a primary and secondary host. Primary host is usually the site of sexual reproduction. Where secondary host is where the parasite completes their life cycles

Question 8

3 types of symbiosis

Answer 8

Mutualism
Commensalism
Paratism

Question 9

What is mutualism

Answer 9

Where both organism benefit

Question 10

What is commensalism

Answer 10

One benefits one remains neutral

Question 11

What is paratism

Answer 11

One is benefited one is harmed