1. An Introduction to Ecology and the Biosphere
Chapter 52
An Introduction to Ecology and the Biosphere
Questions prepared by
Eric Ribbens Western Illinois University
John Zarnetske Hoosick Falls Central Schools

2. Ecology is often called an integrative science
Ecology is often called an integrative science. This means that ecologists
need to be able to calculate integrals.
often combine skills and information from other scientific disciplines.
build theories that integrate ideas from many different biomes.
study life at very large spatial scales.
don’t separate the ecosystems they study into their different components.
Answer: b

3. The figure below shows the distribution of red kangaroos in Australia
The figure below shows the distribution of red kangaroos in Australia. From this figure, we can predict that kangaroos
are herbivorous.
are best adapted to climatic conditions in southeast Australia.
utilize seasonal migratory routes.
prefer to live in areas of low human population.
are more abundant in some years than in other years.
Answer: b
(Figure in the textbook)

4. Study the following graph
Study the following graph. Seaweed was much more abundant when limpets and sea urchins were removed. However, removing limpets alone had no effect, but removing sea urchins alone had a substantial effect. From this, you can conclude that
limpets don’t eat seaweed.
limpets eat sea urchins.
limpets don’t matter.
sea urchins can eat more seaweed than limpets can.
limpets can eat more seaweed than sea urchins can.
Answer: d
(Figure in the textbook).

5. One reason that deserts tend to be found at 20ºN and S latitude is that
deserts are dry.
it’s warmer near the equator.
global wind and pressure patterns affect where rain falls.
desert soils are different from tropical rain forest soils.
mountains change rainfall patterns.
Answer: c

6. From this graph, we can conclude that
each biome has distinct temperature and mean annual precipitation.
precipitation and temperature determine biomes.
precipitation determines temperature.
tundra and tropical forest are climatically different.
biomes determine precipitation.
Answer: b
(Figure 52.10)

7. Biomes are affected by disturbance and climate
Biomes are affected by disturbance and climate. However, disturbances usually don’t change a biome from one type of biome to another. Which of the following is an exception?
Temperate forests can be changed to grassland by frequent fires.
Grasslands can be changed to estuaries by frequent floods.
Deserts can be changed to chaparral by frequent acid overgrazing.
Boreal forests can be changed to tundra by excessive snowfall amounts.
Tropical rain forest can be changed to savanna by frequent hurricanes.
Answer: a

8. The tundra biome is situated as a gray band in the Northern Hemisphere, especially along the Arctic Ocean and the edges of Greenland. There is no comparable band in the Southern Hemisphere. This is probably because
the tundra plants and animals can’t migrate that far away.
it’s warmer in the Southern Hemisphere.
Global wind and pressure areas differ in the northern and Southern Hemispheres.
it has all been destroyed by global warming.
there isn’t land at that latitude in the Southern Hemisphere.
Answer: e

9. Even though the tundra biome is shown as a gray band in the north, there is tundra in the tropics. This is probably because
the climate is suitable for tundra at high-elevation equatorial locations.
global warming is making all of the biomes move toward the tropics.
birds that nest for the summer in the arctic tundra disperse tundra seeds when they migrate south.
tundra evolved more than once.
the global air pattern is generally for air to move from the poles toward the equator.
Answer: a

10. Identify three specific biome boundaries that would have to be redrawn if global temperature were to increase 4oC and explain why the change in distribution would likely occur.
Answers may vary, but some correct responses would be: shrinking and northward movement of tundra; expansion of deserts; high mountain areas would shrink; taiga would become shrink, being replaced by grassland or temperate broadleaf forest, etc.

11. Describe the seasonal turnover in deep temperate lakes in terms of the physical properties of water. Discuss the importance of this seasonal turnover to the organisms in a lake ecosystem.
Seasonal turnover is centered around water’s density change due to temperature. Water is most dense in its liquid state and when it is 4o C. This means that when heated by the Sun in the summer, water warms near the surface and a distinct thermocline forms which separates the warmer less dense water from the cooler more dense water. In the fall as ambient temperatures cool, the surface water becomes cooler (4oC), sinks, and pushes water that has been at the bottom all summer to rise. As winter temperatures continue to fall, the surface will turn into the solid form of water which is less dense than liquid water, so it floats on the surface of liquid water that ranges from below freezing C to 4o C. In the spring, as temperatures rise, the ice melts, mixes with the surface waters, and heats to 4o C, causing it to sink forcing a spring upwelling of water that has been on the bottom all winter.
The importance of the biannual overturns is to exchange oxygen and nutrients between the zones of the lake seasonally. Specifically, dissolved oxygen that accumulates in the surface layers in the spring needs to sink to the bottom to replenish the low oxygen levels of the organisms living there throughout the year. Likewise, in the fall, nutrients that tend to accumulate at the bottom and be used up by organisms at the surface during the summer are replenished during the fall overturn.

12. Plants carry on photosynthesis several different ways
Plants carry on photosynthesis several different ways. In particular, we classify plants as C3 or C4 plants (in reference to the carbon compound they manufacture at first). C3 plants do better in cooler environments, C4 plants in warmer environments. Therefore, we would expect
tropical forests to be dominated by C4 plants.
temperate grasslands to be dominated by C3 plants.
temperate broadleaf forests to be dominated by C4 plants.
tundra regions to be dominated by C3 plants.
that C3 and C4 plants should be present in every biome.
Answer: d

13. The figure from the textbook shows the distribution of cattle egrets
The figure from the textbook shows the distribution of cattle egrets. One conclusion that can be drawn from this graph is that cattle egrets
are generally moving away from South America and into North America.
emigrated from South Africa because the Americas are a better habitat.
cause environmental damage because they are not native.
don’t prefer tropical rain forest habitat because they haven’t yet moved into Brazil.
didn’t live in the United States during the 1800s.
Answer: e
(Figure 52.19)