Chapter 13: Species Interactions and Competitions

Ecology (UTEP / Biol 3316)

Denno and Roderick proposed that the effects of the increased competition between planthoppers were the result of blank​.

reduced food quality

In what type of symbiotic relationship do both members benefit?

mutualism

Grosholz, based on experimental results, proposed that the effects of competition between isopods were the result of blank​.

increased cannibalism

When an organism such as a tick benefits by sucking blood from a deer who is harmed, this is a symbiotic relationship called

parasitism

The competitive exclusion principle states that two species with blank​ niches cannot coexist indefinitely.

identical

In a symbiotc relationship called ______________, one member is benefited and the other member is neither benefited nor harmed.

commensalism

Interference competition involves blank​ interaction between individuals.

direct

In the results of their experiments with planthoppers about intraspecific competition, Denno and Roderick found that insects grown in the highest density cages were characterized by which of the following?

increased development time

reduced survivorship

decreased body length

Grosholz, in his competition experiments, found that isopods grown at higher density had reduced blank​ compared to those grown at lower densities.

survivorship

True or False:

Under the principle of competitive exclusion, beak size in Darwin's finches should be linked to differences in feeding niches.

True

Remember competition harms both members so evolution favors avoiding it where possible.

From the perspective of interspecific competition, we would expect that under the competitive exclusion principle, species living together will generally have blank​ niches.

high

In what symbiotic relationship does one member benefit while the other is neither benefited nor harmed?

commensalism

Flies and wasps appear to have reduced competition with one another by evolving to prefer different hosts. This process is called __________ partioning

niche

The type of competition that involves the direct interaction between individuals is ____________ competition

interference

The results of mathematical models in ecology can be used to generate blank​ for experimental research.

predictions

Denno and Roderick proposed that the effects of the increased competition between planthoppers were the result of blank​.

reduced food quality

In the Lotka-Volterra model of competition, which term is added to the logistic equation for a population to reflect the effects of the competitor?

αN

The beak sizes of Darwin's finches are related to differences in blank​ and those differences result in changes in fitness as some birds were able to out-compete others.  

diet

In the Lotka-Volterra equations, the term α₂₁N ₁ can be thought of as the number of species blank​ that is equivalent to the number of species blank​ in depleting resources.

1; 2

Niche partitioning between species results in blank​.

reduced competition between the species 

In the Lotka-Volterra equations, when the value of the competition coefficient (α) is greater than 1, then we can think of intraspecific competition being blank​ interspecific competition.

less than

Which of the following are considered to be characteristics of models used in ecological research?

abstraction

insightful

man-made construct

The priority effect in competition occurs when the species that establishes itself in greater numbers first, wins.

True

Reason:

Priority indicates the first one to establish in significant numbers will win out.

The Lotka-Volterra model assumes that blank​ will diminish as a result of both intra- and interspecific competition.

resources

Under the principle of competitive exclusion, beak size in Darwin's finches should be linked to differences in feeding niches.

True

Reason:

Remember competition harms both members so evolution favors avoiding it where possible.

Balanus barnacles crowd out Chthamalus barnacles in intertidal zones. This is an example of the blank​ exclusion principle.

competitive

In the Lotka-Volterra equations, the competition coefficient α₁₂ measures the effects of an individual of species blank​ on species blank​.

2; 1

In his experiments on competition between several species of desert rodents, Brown grouped the species based upon blank​ and blank​.

size; feeding habits

In the Lotka-Volterra equations, coexistence will occur when blank​ competition is greater than blank​ competition for both species.

intraspecific; interspecific

By changing the size of holes in the fencing of the desert rodent he was studying, Brown was able to make the study plots "semipermeable" with respect to what characteristic of the rodents?

size

The priority effect in competition occurs when the species that blank​ wins.

starts with greater numbers

In the Lotka-Volterra model of competition, which term is added to the logistic equation for a population to reflect the effects of the competitor?

αN

In the barnacle plots where Balanus was allowed to settle, Chthamalus populations declined due to blank​ by the Balanus.

crowding

Granivores are organisms that feed on blank​ and were divided by Brown into two groups based on their size.

seeds

How did Brown restrict the movement of rodents into and out of the study plots?

fencing