Community ecology

Question 1

community ecology

Answer 1

community: populations of diff species living in a certain area.
- community ecologists ask: about the types of interactions between species, what happens if a top predator is removed, etc

Question 2

5 types of species interactions

Answer 2

1. Amensalism (-/0)
2. Commensalism (+/0)
3. Mutualism (+/+)
4. Consumption(+/-)
5. Competition (-/-)

(+) = increased fitness
(-) = decreased fitness

Question 3

Amensalism

Answer 3

-/0

when an organism inflicts harm to another without any fitness cost/ benefit to itself

Question 4

Commensalism

Answer 4

(+/0)

when one species benefits from an interaction but the other is unaffected

Question 5

mutualism

Answer 5

+/+

when two species act in a way that confers fitness benefits to both

Question 6

consumption

Answer 6

(+/-)
when one organism eats (or absorbs thee nutrients) from another.( +) effect for the consumer,( - )for the prey
predation
herbivory
parasitism

Question 7

Competition

Answer 7

(-/-)
when individuals use the same limited resources. negative fitness consequences for both because neither species has access to the full range of resources

• can be intraspecific or ointerspecific

Question 8

3 themes of species interactions

Answer 8

1. species interaction can affect the distribution + abundance of a particular species.
   - predator effects
2. species act as agents of natural selection when they interact.
   ie: speedy and agile deers promote natural selection that favours wolves and cougars (predators) that are fast and have superior eyesight, sense of smell and hunting strategies
3. the outcome of interactions among species is dynamic and conditional. interactions between species may change over time

Question 9

biomass

Answer 9

the total mass of an organism in a given volume or area

Question 10

2 ecological outcomes of interspecific competition

Answer 10

1. stable co-existence through niche differentiation (resource/partition)
   - species specialize in their use of resources. ie using different resources, different locations, at different times.
   - realized niche < fundamental
   - the more ecologically similar two species after the less likely their are to coexist
2. competitive exclusion
   1 of 2 competing species is eliminated from the site/habitat.
   the more ecologically similar two species after the less likely their are to coexist

*****outcome (1 or 2) depends on the level of ecological (niche) overlap

Question 11

niche

Answer 11

• the habitat in which a species is found
• all the resources a species uses
  the function or role a species players in an ecosystem

“a combo of biotic and abiotic factors that create an environment in which the organism is able to thrive”

Question 12

fundamental niche

Answer 12

full range of resources (conditions) a species is able to use (or tolerate) in the absence of competition (or other negative interactions)

Question 13

realized niche

Answer 13

range of resources a species is able to use in the presence of competitors

Question 14

character displacement

Answer 14

the change in a species trait that allows competing individuals to exploit different resources

Question 15

succession

Answer 15

changes in the species composition of a community over time after a disturbance