Chapter 52

Which of the following areas of study focuses on the exchange of energy, organisms, and materials between ecosystems? (A) organismal ecology (C) ecosystem ecology (B) landscape ecology (D) community ecology

Which lake zone would be absent in a very shallow lake? (A) benthic zone (C) pelagic zone (B) aphotic zone (D) littoral zone

Which of the following is characteristic of most terrestrial biomes? (A) a distribution predicted almost entirely by rock and soil patterns (B) clear boundaries between adjacent biomes (C) vegetation demonstrating vertical layering (D) cold winter months

The oceans affect the biosphere by (A) absorbing a substantial amount of the biosphere's oxygen. (B) regulating the pH of freshwater biomes and terrestrial groundwater. (C) decreasing winter temperatures of coastal ter restrial biomes. (D) removing carbon dioxide from the atmosphere.

Which statement about dispersal is true? (A) Dispersal is not a component of the life cycles of most plants and animals. (B) Dispersal occurs only on an evolutionary time scale. (C) Colonization of devastated areas after floods or volcanic eruptions depends on dispersal. (D) The ability to disperse does not affect the geographic distribution of a species.

Suppose that the number of bird species is determined mainly by the number of vertical strata found in the environment. If so, in which of the following biomes would you find the greatest number of bird species? (A) tropical rain forest (B) savanna (C) desert (D) temperate broadleaf forest

If the direction of Earth's rotation reversed, the most predictable effect would be (A) a big change in the length of the year. (B) winds blowing from west to east along the equator. (C) a loss of seasonal variation at high latitudes. (D) the elimination of ocean currents.

Discuss how the distribution of a species can be affected both by its evolutionary history and by ecological factors. Could ongoing evolutionary change alse affect its distribution? Explain.

Jens Clausen and colleagues, at the Carnegle Institution of Washington, studied how the size of yarrow plants (Achillea lanulosa) growing on the slopes of the Sierra Nevada varied with elevation. They found that plants from low elevations were generally taller than plants from high elevations, as shown in the diagram. Clausen and colleagues proposed two hypotheses to explain this variation within a species: (1) There are genetic differences between populations of plants found at different elevations. (2) The species has developmental flexibility and can assume tall or short growth forms, depending on local abiotic factors. If you had seeds from yarrow plants found at low and high elevations, how would you test these hypotheses?

Global warming is occurring rapidly in arctic marine and terrestrial ecosystems. The reflective white snow and ice cover are melting quickly and extensively, uncovering darker-colored ocean water, plants, and rocks. In a short essay (100-150 words), explain how this process might exemplify positive feedback.

If you were to hike up Mount Kilimanjaro in Tanzania, you would pass through several habitats, including savanna at the base, forest on the slopes, and alpine tundra near the top. Explain how such diverse habitats can be found at one location near the equator.