TLS Online TPP Program

#Question id: 12240


Two plant species co-occur in a prairie. Species X always occurs near species Y. However, species    often occurs in isolation from species X and produces more seeds when alone than when growing next to species X. Which of the following interactions between species X and Y could generate this pattern?

#Unit 10. Ecological Principles
  1. Competition, in which Y is superior to X in accumulating resources
  2. Mutualism, in which both X and Y benefit by exchanging resources
  3. Parasitism, in which X benefits from resources produced by Y and reduces the growth of Y by doing so
  4. Commensalism, in which X benefits from resources produced by Y but does not affect the growth of Y by doing so
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TLS Online TPP Program

#Question id: 13171

#Unit 10. Ecological Principles

Imagine some cosmic catastrophe jolts Earth so that its axis is perpendicular to the orbital plane between Earth and the sun. The most obvious effect of this change would be

TLS Online TPP Program

#Question id: 13170

#Unit 10. Ecological Principles

Which of the following events might you predict to occur if the tilt of Earth's axis relative to its plane of orbit was increased 33.5 degrees?

TLS Online TPP Program

#Question id: 13169

#Unit 10. Ecological Principles

Which of the following causes Earth's seasons?

TLS Online TPP Program

#Question id: 13168

#Unit 10. Ecological Principles

Use the following diagram from the text showing the spread of the cattle egret, Bulbulcus ibis, since its arrival in the New World, to answer the following question.


How would an ecologist likely explain the expansion of the cattle egret?

TLS Online TPP Program

#Question id: 13022

#Unit 10. Ecological Principles

A certain species of pine tree survives only in scattered locations at elevations above 2,800 m in the western United States. To understand why this tree grows only in these specific places an ecologist should

TLS Online TPP Program

#Question id: 13020

#Unit 10. Ecological Principles

Experts in deer ecology generally agree that population sizes of deer that live in temperate climates are limited by winter snow. The deer congregate in ?yarding? areas under evergreen trees because venturing out to feed in winter is energetically too expensive when snowfall depths accumulate to above 40 cm. Deer often stay yarded until the spring thaw. Snow depth over 40 inches for more than 60 days results in high mortality due to starvation.  This observation best illustrates which of the following principles about factors that limit distribution of organisms?