Exam 27: Community Interactions

Most bacteria can reproduce very quickly, so their population sizes increase rapidly. Describe the evolutionary process that prevents most human disease-causing bacterial parasites from causing the human population to become extinct.

A species that is a mimic may:

A caterpillar develops toxic spikes to deter the bird that preys on it. Over time the bird develops a digestive enzyme that neutralizes the toxin. This is an example of:

The first organisms to colonize a disturbed ecosystem are the climax species. True or False?

Harmless king snakes mimic the color patterns of venomous coral snakes, which serve as models. If avoidance were based solely on prior predator experience with the model, what do you predict would happen in areas where coral snakes were never present?

In a stable ecosystem, there are more predators than prey. True or False?

In his 1961 paper, "The Paradox of the Plankton," ecologist G. E. Hutchinson noted that several species of algae coexist, sharing the same few mineral nutrient resources in homogeneous open-water systems. Because there is little chance of resource partitioning and niche differentiation in such a situation, the paradox of their coexistence is an apparent violation of:

What factor most determines the intensity of interspecific competition?

Bison are a ________ in the prairie, helping to maintain the grasses, opening water holes and wallows, and creating the ecological framework for the prairie ecosystem.

Ornithologists visiting an island find two species of bird that appear nearly identical except for bill size. Which of the following is the most likely explanation for their discovery?

Two species that have a high degree of niche overlap will:

The roles that a species plays in its community are known as its ________.

The ________ principle states that two species cannot occupy the same niche in the same habitat at the same time.

Two species of buttercup are found in a field in North Dakota, and they tend to flower at approximately the same time in early spring. When some ecology students decide to conduct an experiment in community dynamics, they selectively remove one species from the field by hand-picking all emergent plants. When the one species is removed, the other species shows a significant increase in its population size the next season. This study demonstrates:

Fire is increasingly used as a management tool in both forest and grassland ecosystems to increase species diversity. How might fire influence the occurrence of a climax community and species diversity?

The tiny wasp Ooencyrtus kuvanae lays its eggs inside the egg masses of gypsy moths. When the wasp larvae hatch, they burrow into the gypsy moth caterpillars and eat them from the inside. After they have completed their development, the adult wasps emerge from the bodies of the moth caterpillars, killing them in the process. Although this relationship has several of the characteristics of parasitism, it is more properly classified as:

What evidence did Gause and MacArthur find for the competitive exclusion principle?

Mosquitoes are:

Why is the African elephant considered a keystone species?

Birds follow animal herds to catch insects that are disturbed as the large herbivores like water buffalo walk through the grass. The birds fly into the air and make warning calls when large predators like lions are near. What is the ecological relationship between the birds and the herbivores called?