Class #12 - INTERspecific Interactions

Neutral

0,0

mutualism

+,+

commensalism

+, 0

competition

-,-

Amensalism

-, 0

predation

parasitism

parasatodism

+,-

species interactions can be agents of

natural selection

coevolution

occurs when two or more species reciprocally affect each other's evolution through the process of natural selection.

diffuses species interacations

most interactions between species are not exclusive nor only involve 2 species

GROUPS OF A SPECIES INTERACT WITH OTHER GROUPS OF SPECIES!!

Niche

Fundamental Niche

It is the range of physical and chemical conditions under which that a species can survive and reproduce

n-dimensional

a species niche is an n-dimensional hypervolume, representing multiple environmental fractos

Realized niche

portion of the fundamental niche that is greater than the fundamental niche

3 types of species interactions that influence a realized niche

• predation

• pathogens

• mutualism/commensalism

(True/False) A realized niche is bigger than a fundamental niche

True

How does the Lotka Volterra Model differ than logistic growth model?

The LV competition model incorporates the effect of the competition from another species

Four outcomes predicted with LV Model:

• competitive exlusion

• stable coexistance

• unsatable coexistance

• coesxisting species below k

alpha (a)

competition coefficent

character displacement

an evolutionary process that occurs when similar species compete for resources or mates in the same area. This competition leads to the development of different traits in the species, which can help them coexist

ecological release

when a species' population increases due to a reduction in limiting factors. Causes INCREASE IN NICHE EXPANSION

‘Ghost of Competition Past’

an ecological hypothesis that past competition affects the traits and distributions of current populations. This hypothesis can explain why species have different niches, even when direct competition is no longer occurring.

competitive Exclusion principle

complete competitors cannot coexist

• assumptions:

  • competitors require the same resources

  • environment is stable

4 factors that can lead to coexistence

• non-resource variability

• resource variabillity

• resource can be a variety (ex: water)

• ]disturbance

Paradox of the Plankton

the ecological phenomenon where a large number of different plankton species can coexist in seemingly similar environments with limited resources, despite the expectation that in such conditions, one species should outcompete the others and dominate the ecosystem, contradicting the principle of competitive exclusion

G.E. HUTCHINSON

what kind of factor is Non-resource variability?

environmental factors

what kind of factor is resource variability?

availability of resources

Resource Partitioning

when species share resources to avoid direct competition and coexist in the same ecosystem. It's an evolutionary adaptation that helps species with similar needs coexist

How does disturbance lead to species coexistence?

• prevents competitive exclusion

• environmental variation allows for coexistence