Mutualism and Parasitism

Question 1

define mutualism

Answer 1

a mutually beneficial interaction between individuals of two or more species

Question 2

define commensalism

Answer 2

an interaction in which individuals of one species benefit while individuals of the other species do not benefit nor are harmed (i.e., neutral)

Question 3

define symbiosis

Answer 3

a relationship where individuals live in close physical contact
- close physical, interdependent association between > 2 organisms

Question 4

Examples of non-symbiotic mutualisms

Answer 4

• pollination
• birds cleaning ungulates
• cleaner fish

Question 5

Example of commensalism

Answer 5

barnacles: benefit form substate and dispersal provided by whales (+), whales benefit and no harm by barnacles

Question 6

Define parasitism

Answer 6

ecological interaction that is beneficial for one organism but detrimental to the other
- another form of exploitation

Question 7

example of parasitism

Answer 7

tick: benefit by feeding blood in animals (+), host animal is harmed through blood removal and disease risk

Question 8

Facultative mutualisms

Answer 8

• occurring optionally
• no dependence on specific partners (low risk of extinction if a partner goes extinct)

Question 9

obligate mutualisms

Answer 9

• occurring by necessity
• dependance on specific partners (high risk of extinction if a partner goes extinct)

Question 10

Example of Service-Service Relationship

Answer 10

• rarest kind of relationship
• anemones and clown fish
• anemones provide fish with protection from predators
• clownfish defends anemones from butterfly fish

Question 11

Example of Resource-Resource relationships

Answer 11

mycorrhiza: a symbiotic relationship between fungi and plant root
- fungi increase the surface area for the plant to take up water and nutrients
- plants supply fungi with carbohydrates

Question 12

Example of Service-Resource relationships

Answer 12

• most common type
• pollination
• cleaning symbiosis
• zoochory

Question 13

Define Pollination

Answer 13

the transfer of pollen grains for reproduction by wind, water, animals or within the same flower (selfing)

Question 14

Can animals be pollen dispersal vectors?

Answer 14

yes
- plant species that rely on animals for pollen dispersal often have very specific pollinators that they can co-evolved with

Question 15

Example of Sexually deceptive pollinator

Answer 15

ophrys apifera
- a flower that resembles a female bee
- also emits chemicals that mimic female bees
- males attracted and attempt to copulate with it

Question 16

Ways that plants attract pollinators?

Answer 16

through colour and scent
- butterflies: attracted to bright colours (yellow, orange, red)
- bees: red-blind, attracted to yellow or blue
- nocturnal moths: attracted by heavy scent released during the night

Question 17

What are zooxanthellae? and what is their function?

Answer 17

• they are single-celled dinoflagellate/ algae that photosynthesize inside of coral tissue
• they provide glucose, glycerol and amino acid to the coral in exchange for protection
• help remove coral’s waste
• they also give coral their coloration

Question 18

What are lichens? what is their function?

Answer 18

• the body of a lichen consists of fungal filaments (hyphae) surrounding cells of green algae and/or blue-green cyanobacteria
• fungus receive nutrients obtained via photosynthesis
• algae recieve food/protection/stability from fungus