Males in a population differ in the time they spend displaying to females. A researcher hypothesizes that predators are responsible for these differences. Males display for longer durations when there are no predators in the vicinity and for shorter durations when there is a predator nearby. Which of the following study designs is the most appropriate test of this hypothesis?

#Question id: 12674

#Unit 10. Ecological Principles

#Question id: 12578

#Unit 10. Ecological Principles

Refer to the following experiment, which is designed to test the co evolutionary relationships among an unpalatable butterfly (the  monarch),  a  palatable  butterfly  (the  viceroy),  and  a  butterfly  predator  (the  jay).  Monarch butterflies are reared on three diets: milkweed (their natural food), cabbage, and cabbage treated with an extract from milkweed leaves. Viceroy butterflies, mimics of monarchs, also are reared on three diets: willows (their natural food), cabbage, and cabbage treated with an extract from milkweed leaves. In trial 1 of the first experiment, adult butterflies reared on a particular diet are presented one at a  time  at  1-hour  intervals  to  jays  and  the  jays  are  allowed  to  feed.  Each jay is  fed  until  it refuses to eat the butterfly presented, but no more than 12 butterflies are presented to a jay during a particular test. Five birds are used for each test; therefore, up to 60 butterflies can be consumed for each diet test. The observer records the actual number of butterflies  eaten. In trial 2, the experiment is repeated 2 weeks later. In the second experiment, the butterflies are reared on the same diets as in experiment 1. However, when they are offered to jays, some jays receive a monarch  reared  on  milkweed  before  being  offered  the  butterflies  reared  on  the  experimental  diets;  the  other  group  of jays is  first given a viceroy reared on willow before being  offered the butterflies reared on the experimental diets. The initial butterfly offered is included in the total number eaten, but no more than 12 butterflies are presented to each jay

Which of the following supports the hypothesis that viceroys receive protection from predation because they resemble monarchs?

#Question id: 11330

#Unit 10. Ecological Principles

Bio geographers have noted that the tropics have more terrestrial species than temperate regions. Which of the following is NOT a plausible explanation for this pattern?

#Question id: 11331

#Unit 10. Ecological Principles

Based on the intermediate disturbance hypothesis, a community’s species diversity is increased by

#Question id: 11332

#Unit 10. Ecological Principles

The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that

 A) tropical communities are older.

 B) tropical regions generally have more available water and higher levels of solar radiation.

 C) higher temperatures cause more rapid speciation.

 D) diversity increases as evapotranspiration decreases.

#Question id: 11333

#Unit 10. Ecological Principles

Small geographic areas with high concentrations of endemic species and a large number of endangered and threatened species are known as