3.5 Symbiosis

Question 1

What is symbiosis?

Answer 1

An intimate relationship between organisms of two different species that live in direct contact with one another

Question 2

What are they the result of?

Answer 2

These ecological relationships are the result of millions of years of co-evolution

Question 3

What is Parasitism?

Answer 3

One organisms, the parasite, benefits in terms of energy or nutrients whereas it’s host is harmed by the loss of these resources.

Question 4

Will the parasite kill the host?

Answer 4

It is not in the best interests of the parasite to do too much harm to the host because it needs the nutrients.

Question 5

In nutritional/energy terms, the parasitism relationship is..

Answer 5

Positive for the parasite and negative for the host

Question 6

Can parasites survive or of contact with a host?

Answer 6

Many parasites often have a limited metabolism and cannot survive out of contact with a host

Question 7

What are the ways that parasites can be transmitted to new hosts?

Answer 7

Direct contact
Release of resistant stages
Use of a vector

Question 8

What is Direct Contact?

Answer 8

Passed from organism to organisms by physical contact e.g. head lice

Question 9

What is the release of a resistant stage?

Answer 9

Stages when able to survive adverse environmental conditions until they come in contact with a new host

Question 10

What is the use of a vector?

Answer 10

A vector is an intermediate organism that transports the parasite from one host to another e.g. the anopheles mosquito.

Question 11

What are the two types of a parasitic life cycle?

Answer 11

Direct and Indirect

Question 12

What is a Direct Life Cycle?

Answer 12

Where eggs are shed and pass on to a new member of the host species. This cycle involves ONE SPECIES OF HOST and is common amongst parasites such as flea and louse which feed outside of their host.

Question 13

What is an Indirect Life Cycle?

Answer 13

In addition to using a primary host species as the sight for sexual reproduction, the parasite becomes adapted by evolution to involve an INTERMEDIATE (SECONDARY) HOST SPECIES in it’s life cycle.

Question 14

Why is a secondary host species required in indirect life cycles?

Answer 14

To allow the parasite to complete its life cycle.

Question 15

What is Mutualism?

Answer 15

In a mutualistic symbiotic relationship both species involved in the interdependent relationship benefits.

Question 16

Why are many mutualistic relationships described as interdependent?

Answer 16

Neither can survive without the other.

Question 17

What three ways can mutualism be seen?

Answer 17

1. Relationship where both organisms provide a service
2. Relationship where one organism provides a service and another receives a resource
3. Relationships where both organisms receive a source