Interspecific Competition

Interspecific competition involves ___ or more species.

          Two

A relationship that _______ (- -) affects the population of two or more species is called interspecific competition.

Adversely

What are the two forms of interspecific competition?

Exploitation and interference

What are the six types of interactions that are sufficient to account for most instances of interspecific competition?

1. Consumption
2. Preemption
3. Overgrowth
4. Chemical interaction
5. Territorial
6. Encounter

Describe consumption competition.

Occurs when individuals of one species inhibit individuals of another by consuming a shared resource

Describe preemptive competition

Occurs primarily among sessile organisms, such as barnacles, in which the occupation by one individual precludes establishment (occupation) by others

Describe overgrowth.

When one organism literally grows over another inhibiting access to some essential resource

Describe chemical interactions.

When chemical growth inhibitors or toxins are released by an individual

Define allelopathy.

When plants produce chemicals that inhibit germination and establishment of other species

Describe territorial competition.

\`Behavioral exclusion of others from a space that is defended as a territory

Describe encounter competition.

When nonterritorial meetings between individuals negatively affects one of both participant species

What does alpha represent in the interspecific species competition equation?

It is the competition coefficient that quantifies the per capita effect of species 2 on species 1     

What does beta represent in the interspecific species competition equation?

It is the competition coefficient that quantifies the per capita effect of species 1 on species 2     

What is a competition coefficient?

Factors for converting an individual of one species into the equivalent number of individuals in the competing species based on their chares use of resources that define their carrying capacities

Assume species 1 and species 2 are both grazing herbivores that feed on the exact same food resources (grasses and other herbaceous plants). If individuals of species 2 have, on average, twice the body mass as individuals of species 1 and consume food resources at twice the rate, with respect to the food resources, an individual of species 2 is equivalent to ___ individuals of species 1 and a = ____

Two; two

Likewise, consuming food resources at only half the rate as species 2, an individual of species 1 is equivalent to ___ an individual of species 2 and b = ___

0\.5; 0.5

In the absence of interspecific competition b and a equal…

0

There are ___ possible outcomes of interspecific competition.

Four

Describe the competitive exclusion principle.

States that “complete” competitors cannot coexist

Define complete competitors.

Two species (non-breeding populations) that live in the same place and have the same ecological requirements

The competitive exclusion principle assumes…

1. Environmental conditions remain constant


2. Competitors have exactly the same resource requirements

True/False: Features other than resources within an environmental directly influence the outcome of competition between species.

True, could be things like pH of soil, humidity, salinity, temperature

True/False: As environmental conditions change, so does the relative competitive abilities of species.

True

True/False: Aggressive behavior as well as ability to survive determines the area of habitation for some organisms.

True

Define fundamental niche. 

Where a species can survive with no competition

Define realized niche.

An area where a species actually exploits resources (could be limited by competition)

Define competitive release.

When a specie’s niche expands because of the removal of a competitor

For species to coexist, ____ must be shared.

material

Define niche differentiation.

Differences in the range of resources used/environmental tolerances allow for species to coexist

How can species coexist when they compete with each other?

They partition available resources. Animals feed on different sized prey, forage in different areas, feed at different times

True/False: Because patterns of resource partitioning observed in nature are consistent with the hypothesis of phenotypic divergence arising from coevolution between competing species, it can be prove that competition functioned as the agent of natural selection that resulted in the observed differences in resource use

False, we cannot say because we have limited or no knowledge about resources and potential competitors that may have influenced natural selection

Describe “ghosts of competition past”

We cannot say that competition influenced natural selection due to not knowing about resources or competitive organism from the past