12 – Competition

If s21 > > s22 in a competition model, what does this indicate?

The intensity of interspecific competition exceeds that of intraspecific competition.

What is required for two species to successfully coexist in the same environment?

Niche overlap between the two species must be reduced.

In a scenario where hyenas and lions compete for the same prey, what ecological processes are occurring?

Interspecific competition is occurring, and exploitative competition results in limits on the growth of both populations.

What did Gause’s laboratory experiments with protozoans demonstrate?

Competitive exclusion.

Grasses grown at high density remain small, while those at low density grow larger. What is this evidence of?

Intraspecific competition.

What does the "self-thinning rule" in plants state?

When planted at high densities, the final plant density is lower and the average plant size is larger than at initial planting.

In Lotka-Volterra modeling, what do the s terms represent?

The effect or intensity of competition.

Why are Balanus barnacles found in the middle intertidal zone instead of Chthalamus, even though both larvae settle there?

Interspecific competition from Balanus excludes Chthalamus from the middle intertidal.

In Tilman's plant studies, why did increasing plant density reduce population growth?

It reflected stronger intraspecific competition.

In Park's flour beetle experiments, what did the outcome of competition depend on?

Environmental conditions, such as humidity and temperature.

What provides evidence for the evolutionary consequences of competition?

Character displacement.

As the density of grasshoppers in a lab experiment increases, what happens to body size and development time?

Body size decreases and development time increases.

Two individuals aggressively fighting over access to a habitat is an example of what?

Interference competition.