Mutualism and Commensalism

Question 1

positive interactions

Answer 1

those in which one or both species benefit and neither is harmed

Question 2

Mutualism

Answer 2

(+/+) relationship
Mutually beneficial interaction between individuals of two species

Question 3

Commensalism

Answer 3

(+/0)
Individuals of one species benefit; individuals of the other species do not benefit but are not harmed

Question 4

Symbiosis

Answer 4

two species live in close physical contact with each other

Question 5

What can symbioses include?

Answer 5

parasitism(+/-), mutualism (+/+), and commensalism (+/0)

Question 6

micorrhizae

Answer 6

symbiotic associations between the roots and various fungi

Question 7

What do micorrhizae do?

Answer 7

increase the surface area for the plant to take up water and soil nutrients

Question 8

What are positive interactions of fungi?

Answer 8

they protect plants from pathogens
they improve plant growth and survival in a wide range of habitats
they supply the fungi with carbohydrates

Question 9

Ectomicorrhizae

Answer 9

the fungus grows between root cells and forms a mantle around the root

Question 10

Arbuscular mycorrhizae

Answer 10

The fungus penetrates the cell walls of some root cells forming a branched network called an arbuscule

Question 11

obligate (def.)

Answer 11

not optional for either species

Question 12

In what scenerio would the outcomes of a mutualistic relationship change?

Answer 12

If the costs outweigh the benefits or if the environmental conditions change

Question 13

cheaters

Answer 13

individuals that increase offspring production by overexploiting their mutualistic partner