Species Interactions and Competition

Question 1

competition

Answer 1

-/-

Question 2

predation

Answer 2

+/-

Question 3

mutualism

Answer 3

+/+

Question 4

commensalism

Answer 4

+/0

Question 5

amensalism

Answer 5

-/0

Question 6

neutralism

Answer 6

0/0

Question 7

intraspecific competiiton

Answer 7

between individuals of the same species

Question 8

interspecific competition

Answer 8

between species

Question 9

interference competition (schoener’s mechanisms)

Answer 9

direct interactions between individuals

- chemical (toxins), territorial (defence of space), encounter (short term interactions for space)

Question 10

resource competition (schoener’s mechanisms)

Answer 10

compete through dependence on the same limiting resources

- consumptive/exploitative, pre-emptive (dominating space), overgrowth (blocking access to light and resources)

Question 11

intraspecific competition examples

Answer 11

plant competition increases with density = self-thinning eg. smaller potatoes
leaf hoppers get reduced survivorship, smaller size and increased developmental time
even when there is no resource shortage, this competition can be high

Question 12

competitive exclusion and niches

Answer 12

the competitive exclusion principle proposes that two species with identical niches cannot coexist indefinitely, which leads to the prediction that coexisting species will have different niches
- functional vs realised

Question 13

mathematical and lab models

Answer 13

models provide a theoretical foundation for studying interspecific competition in nature

• expansion on logistic model of population growth
• intraspecific: rate of population growth reduces as numbers reach k therefore as competition increases, pop growth decreases (density dependent)
• lab evidence: numbers of prey and predators fluctuate together

Question 14

who wins competition?

Answer 14

depends on context

- climate, habitat heterogeneity, community composition

Question 15

competition can have a significant ecological and evolutionary influence on niche of species…

Answer 15

niches may be narrower than they would have otherwise have been - checker board pattern with islands

Question 16

niche partitioning

Answer 16

divergence in use of resources between species that would have competed

• process of natural selection
• character displacement: diverge from average character when with other species to reduce competition

Question 17

mutualisms can be

Answer 17

facultative - can live without mutualistic partners

obligate - cannot live without partner