3.5 Symbiosis

Question 1

Define ‘Symbiosis’

Answer 1

A co-evolved intimate relationship between two members of different species

Question 2

Give an example of a symbiotic relationship

Answer 2

Plants and Bees

Lichens(Green Algae and Fungus)

Question 3

What are the two types of symbiosis?

Answer 3

Parasitism and Mutualism

Question 4

Describe Mutualism

Answer 4

Mutualism is a symbiotic relationship where both organisms in the relationship benefit

Question 5

Give examples of mutualism

Answer 5

Mitochondria/Chloroplasts and eukaryotic cells

Algae and Fungus(to make Lichen)

Question 6

Define Parasitism

Answer 6

Parasitism is a symbiotic relationship where one partner benefits whilst the other is harmed

Question 7

Give an example of a parasitic relationship

Answer 7

Plasmodium(Malaria) and Humans

Question 8

What are the two types of parasites?

Answer 8

Obligate and Facultative

Question 9

What is the difference between <strong>obligate</strong> and <strong>facultative</strong> parasites?

Answer 9

Obligate parasites - cannot survive without a host

Facultative parasites - able to survive without a host

Question 10

What are the three ways a parasite can be transmitted?

Answer 10

<ul>
<li>Direct Contact</li>
<li>Resistant Stage</li>
<li>Vector</li>
</ul>

Question 11

What is a ‘resistant stage’ in a parasitic life cycle?

Answer 11

A resistant stage is a part of parasitic life cycle where the parasite is able to survive adverse environmental change

Question 12

Describe the evolution of eukaryotic cells with mitochondria and chloroplast

Answer 12

An ancestral eukaryotic cell engulfed a mitochondria(originally an independent prokaryotic cell) and later a (in certain photosynthetic organisms) a chloroplast was engulfed and they both entered an interdependent relationship with the eukaryotic cell

Question 13

What evidence suggests the symbiotic prokaryotic origin of mitochondria/chloroplasts?

Answer 13

• Chloroplasts/Mitochondria contain circular DNA

- Chloroplasts/Mitochondria are similar in size and structure to Prokaryotes

Question 14

What is coevolution?

Answer 14

Coevolution is the influence of closely associated species on the other species evolution

Question 15

Describe the relationship between algae and fungus in Lichen

Answer 15

It is a MUTUALISTIC relationship
Algae benefits by receiving nutrients from fungus
Fungus benefits by receiving glucose from algae

Question 16

Parasitism is one form of symbiosis. Name another form.

Answer 16

Mutualism

Question 17

Define <em>‘Interdependence’</em>

Answer 17

The dependance of two(or more) things on each other

Question 18

What is the name for a parasite that can survive without its host?

Answer 18

Facultative

Question 19

What is the name for a parasite that cannot survive without its host?

Answer 19

Obligate

Question 20

What is a primary host?

Answer 20

A host where the adult parasite lives and reproduces sexually

Question 21

What is the secondary host?

Answer 21

A host where immature versions of the parasite lives