Chapter 52: An Introduction to Ecology and the Biosphere

Which of the following examples of an ecological effect leading to an evolutionary effect is most correct?

A few individuals with denser fur survive the coldest days of an ice age, and the reproducing survivors of the ice age will likely have more dense fur.

The range of cattle egrets has expanded between 1937 and today. How would an ecologist likely explain the expansion of the cattle egret?

A habitat left unoccupied by native herons and egrets met the biotic and abiotic requirements of the cattle egret transplants and their descendants.

If you are interested in observing a relatively simple community structure in a clear water lake, you would do well to choose diving into _____.

An oligotrophic lake.

Which of the following types of organisms is likely to have the widest geographic distribution?

Bacteria.

Fire suppression by humans _____.

Can change the species composition within biological communities.

Two plant species live in the same biome but on different continents. Although the two species are not at all closely related, they may appear quite similar as a result of _____.

Convergent evolution.

If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced the sunlight reaching Earth's surface by 70 percent for one year, which of the following marine communities most likely would be least affected?

Deep-sea vent.

Generally speaking, deserts are located in places where air masses are usually _____.

Descending.

Studying species transplants is a way that ecologists _____.

Determine if dispersal is a key factor in limiting distribution of organisms.

Which of the following choices includes all of the others in creating global terrestrial climates?

Differential heating of Earth's surface.

Which statement describes how climate might change if Earth was 75 percent land and 25 percent water?

Earth's daytime temperatures would be higher and nighttime temperatures lower.

Which level of ecological study focuses the most on abiotic factors?

Ecosystem ecology.

As climate changes because of global warming, plant species' ranges in the northern hemisphere may move northward. The trees that are most likely to avoid extinction in such an environment are those that _____.

Have seeds that are easily dispersed by wind or animals.

When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes _____.

In biomes at different latitudes.

A certain species of pine tree survives only in scattered locations at elevations above 2800 meters in the western United States. To understand why this tree grows only in these specific places, an ecologist should _____.

Investigate the various biotic and abiotic factors that are unique to high altitude.

Imagine that a deep temperate zone lake did not turn over during the spring and fall seasons. Based on the physical and biological properties of limnetic ecosystems, what would be the difference from normal seasonal turnover?

Lakes would suffer a nutrient depletion in surface layers.

Which of the following investigations would shed the most light on the future distribution of organisms in temperate regions that are faced with climate change?

Look at the climatic changes that occurred since the last Ice Age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends.

Which of the following statements best describes the interaction between fire and ecosystems?

Many kinds of plants and plant communities have adapted to frequent fires.

Coral reefs can be found on the southeast coast of the United States but not at similar latitudes on the southwest coast. Differences in which of the following most likely account for this?

Ocean currents.

Which statements about dispersal are correct?

Only I and III. Dispersal is a common component of the life cycles of plants and animals. Colonization of devastated areas after floods or volcanic eruptions primarily depends upon climate.

The oceans affect the biosphere by _____.

Only I and III. Producing a substantial amount of the biosphere's oxygen. Being the source of most of Earth's rainfall.

A fish species known for its success in the aphotic zone may have which of the following characteristics?

Only II, III, and IV. Highly developed chemoreception. Adaptations for burrowing. Adaptations for sit-and-wait predation.

Why is the climate drier on the leeward (downwind) side of mountain ranges that are subjected to prevailing winds?

Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving drier air to descend the leeward side.

Generalized global air circulation and precipitation patterns are caused by _____.

Rising, warm, moist air masses that cool and release precipitation as they rise and then, at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics.

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 to 33.5degrees?

Summers and winters in the United States would likely become warmer and colder, respectively.

The main reason polar regions are cooler than the equator is that _____.

Sunlight strikes the poles at a lower angle.

In mountainous areas of western North America, north-facing slopes would be expected to _____.

Support biological communities similar to those found at higher elevations on similar south-facing slopes.

In areas of permafrost, stands of black spruce are frequently observed in the landscape, while other tree species are noticeably absent. Often these stands are referred to as "drunken forests" because many of the black spruce are displaced from their normal vertical alignment. What is the most likely explanation for the unusual growth of these forests in this marginal habitat?

Taproot formation is impossible, so trees developed shallow root beds.

If global warming continues at its present rate, which biomes will likely take the place of the coniferous forest (taiga)?

Temperate broadleaf forest and grassland.

Besides sunlight, which would be the next most important climatic factors for terrestrial plants?

Temperature and moisture.

Which of the following statements best describes the effect of climate on biome distribution?

The average climate and pattern of climate are important in determining biome distribution.

A fish swimming into an estuary from a river would have which of the following as its greatest physiological challenge?

The change in water solute content would challenge the osmotic balance of the fish.

Turnover of water in temperate lakes during the spring and fall is made possible by which of the following?

The changes in the density of water as seasonal temperatures change.

If carbon dioxide levels continue to increase and climate change continues over the next century, which of the following would best predict the directional migration of the North American ecosystems from the biomes shown in this climograph?

The ecosystems will shift to the north as temperatures warm.

Which of the following might be an investigation of microclimate?

The effect of sunlight intensity on species composition in a decaying rat carcass.

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 _____.

The elimination of seasonal variation.

In the development of terrestrial biomes, which factor is most dependent on all the others?

The species of colonizing animals.

Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they encounter extensive north-south mountain ranges, such as the Sierra Nevada and the Cascades. Which statement best describes the outcome of this encounter between a landform and an air mass?

The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range. This cool, now dry air mass heats up as it descends on the leeward side of the range.

The success of plants extending their range northward following glacial retreat is best determined by _____.

Their seed dispersal rate.

What would be the effect on climate in the temperate latitudes if Earth were to slow its rate of rotation from a 24-hour period of rotation to a 48-hour period of rotation?

There often would be a larger range between daytime high and nighttime low temperatures.

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?

Tropical rain forest.

Which of the following is an important feature of most terrestrial biomes?

Vegetation demonstrating vertical layering.

Subtropical plants are commonplace in Land's End, England, whose latitude is the equivalent of Labrador in coastal Canada, where the local flora is subarctic. Which statement best explains why this apparent anomaly exists between North America and Europe?

Warm ocean currents interact with England, whereas cold ocean currents interact with Labrador.

Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes?

Water is densest at 4°C.

Which of the following can be said about light in aquatic environments?

Water selectively reflects and absorbs certain wavelengths of light.

If the direction of Earth's rotation reversed, the most predictable effect would be _____.

Winds blowing from west to east along the equator.

What would happen to the seasons if the Earth were tilted 35 degrees off its orbital plane instead of the usual 23.5 degrees?

Winters and summers would be more severe.