21. Community ecology: mutualism and symbiosis

Question 1

Symbiosis

Answer 1

living together

Question 2

Nutritional Mutualisms

Answer 2

• Legumes & rhizobia: exchange fixed C for fixed N
• Plants & mycorrhizal fungi: exchange C for P

Question 3

Defensive Mutualisms

Answer 3

• Cleaner fish & client fish: exchange parasite removal for food

Question 4

Dispersal Mutualisms

Answer 4

• Plants & animal seed dispersers: exchange seed dispersal for food
• Plants & animal pollinators: exchange gamete dispersal for food

Question 5

Invasional meltdown

Answer 5

2 non native species facilitate one another’s spread (2 invasive species that interact as mutualists) (invasive ants spreading with invasive plants)

Question 6

What limits the population growth of mutualists?

Answer 6

1) Strong intra-specific competition

2) A third species such as a predator or a competitor

3) Diminishing habitat the population grows

Question 7

vertically transmitted

Answer 7

they are passed in aphid eggs from mothers to offspring

Question 8

Horizontally transmitted

Answer 8

host requires trait form environment in every generation (most mutualisms are horizontally transmitted)

Question 9

Microbiomes

Answer 9

this term refers to either all the microorganisms living together in a community (often, a host) or their collective genomes