Page 703 - Environment: The Science Behind the Stories

Chapter 10 be susceptible to elevated tree mortality (an edge effect Fig. 16.6 Released off the southeast coast of Japan, the
that extends 300 m in) and increased wind disturbance buoy would be carried northeast by the Kuroshio Cur-
Fig. 10.2 Overall growth of the human population pro-
vides the answer. Since the period 2007–2009, our global (which extends 400 m in). rent and then eastward across the ocean on the North
population has increased by several hundred million peo- Pacific Current. Upon reaching North America, it could
ple, with the vast majority of this growth occurring in Chapter 13 turn southward on the California Current and float by the
developing nations. Thus, although the absolute number western coast of the United States, passing Washington,
of undernourished people in the developing world has Fig. 13.1 The dashed red line (which projects the urban Oregon, and California. Alternatively, the buoy might fol-
remained the same (852 million), many people have been population) in less-developed regions surpasses the low the Alaska Current northward upon reaching North
added to the total population, so the percentage of people dashed blue line (which projects the rural population) America and pass Alaska, then return to Japan. So al-
who are undernourished has fallen. in less-developed regions between the year 2010 and the though Japan is closer to Australia, ocean currents would
year 2020. carry the buoy to the United States first.
Fig. 10.10 Beef requires 17.5 times more land to pro-
2
2
duce than chicken (245.0 m /14.0 m = 17.5). Beef also Fig. 13.11b Roadway costs and parking costs are created
requires 15 times more water to produce than chicken by automobile traffic but not by rail traffic. Note that the Chapter 17
(750 kg/50 kg = 15). bars for automobile traffic in part (b) of the figure contain Fig. 17.14b Population has increased by 52% since
yellow and orange portions, as well as the red portions 1970. Emissions have decreased by 68%. Thus, emis-
Fig. 10.25 In the last 5 years, GM crops have been grow- shared by rail traffic. These roadway costs and parking
ing faster in developing nations, as indicated by the fact costs make automobile traffic more costly overall than sions per person have decreased by nearly five times.
that the developing nations’ curve rises upward more rail traffic. (Imagine a population rising from 100 to 152, and emis-
steeply than the curve for industrialized nations. In 2012, sions dropping from 100 to 32. 32/152 = 0.21, or one-
developing nations for the first time produced more GM Fig. 2 (SBS) Among the four data points for years for fifth of the original 1-unit-per-person rate.)
crops than industrialized nations. If current trends con- areas labeled “urban” (with 40% impervious surface), Fig.17.19 Answers will vary. But for example, a per-
tinue, developing nations should be growing more GM three of them lie above the level at which there is chronic son living in Los Angeles would face a risk of 50–75 in
crops than industrialized nations in 2015. To estimate toxicity to freshwater life. 1 million of developing cancer due to toxic air pollution.
how much more GM crops they might be growing in
2015, we can extend the two trend lines forward 3 years, Fig.17.23 According to the data in the graph, in the
keeping their slopes the same as in the previous several Chapter 14 1970s ozone levels averaged a bit above 0.30 ppm. In
years. Doing this leads approximately to values of 110 Fig. 2 (SBS1) Begin by connecting the data points in the the most recent years, ozone levels have been about 0.14
million hectares for developing nations and 90 million figure to form a dose-response curve like that shown in ppm. This represents about a 55% reduction.
ha for industrialized nations. The spread between these Figure 14.16c. Mark the spot on the curve directly above
two values might be even greater if, as the data suggest, 70 ng/g on the X-axis. Then reference the Y-axis at the site Fig. 17.31 Answers will vary, but in virtually all loca-
developing nations are speeding up their rate of adoption of your mark, which indicates that an estimated 9% of the tions, precipitation has become less acidic. For example,
and industrialized nations are slowing down theirs. in many parts of the northeastern United States, pH has
mice would likely suffer chromosomal effects at that dose. increased from about 4.3 to about 4.9.
Fig. 14.4 Consulting the figure, note that about 28% of
Chapter 11 Americans were obese and 17% were smokers in 2011. Chapter 18
Fig. 11.4 The right portion of the figure shows that there For the calculations in part (a), multiply 0.28 (28%) by
are 4680 species of mammals. The left portion of the 312 million people and find that roughly 87,360,000 Fig. 18.2 Since 1750 the atmospheric carbon dioxide
figure shows that there are about 1,750,000 known and Americans were obese in 2011. Similarly, for part (b), concentration has increased from about 280 ppm to about
described species of organisms in total. Because 4680 is multiply 0.17 (17%) by 312 million people, and find that 396 ppm—a 41% increase.
0.27% of 1,750,000, this means that mammals comprise about 53,040,000 Americans in 2011 were smokers. Fig. 18.3 Changing land use accounts for 6 metric tons
just 0.27% of all organisms (or about 1 out of 400). In of carbon dioxide emissions per year, and industry emits
reality, the percentage is actually much lower than this, 26 metric tons of carbon dioxide annually. Therefore,
because virtually all mammal species have already been Chapter 15 26/6 = 4.33. This means that for every 1 metric ton
discovered, yet most species of other types of organisms Fig. 15.2 Consulting the figure, note that 2.5% of the released by changing land use, 4.33 tons are released by
have not yet been discovered. water on Earth is fresh water and that 1% of all fresh industry.
water is surface water. Within this surface water, 52% is
Fig. 11.15b The bar for pollution stretches to a value found in lakes. To determine the percentage of Earth’s Fig. 18.9 Answers will vary. In most regions temperature
of nearly 1200 species, second only to habitat loss; this water found in freshwater lakes, multiply 2.5% (.025) by rose. In some areas of the Southeast it was stable or fell
indicates that pollution is the second greatest cause of 1% (0.01) and by 52% (0.52). Multiplying these three slightly.
amphibian declines overall. For threatened species alone, values (and then multiplying the answer by 100 to con-
we need to look at the red portions of the bars. Compar- vert it to a percentage) reveals that although freshwater
ing red portions of the bars, we can see that habitat loss lakes (such as the Great Lakes) seem massive, all of the Chapter 19
is the primary cause of declines for threatened species world’s freshwater lakes combined contain only 0.013%
of amphibians. Fig. 19.2 Answers will vary. One should take the value
of Earth’s water. at the far right end of the data line for oil (4.06 billion
Fig. 2 (SBS2) In the pie chart for the markets, note that Fig. 1b (SBS 2) To interpret figures with two y-axis tons in 2011) and divide it by the value of that line in the
the proportions of the genetic types are intermediate be- values, such as this one, carefully note which axis cor- year one was born. For a person born in 1995, when oil
tween those of each of the two geographic areas. The responds with which value on the graph. In this figure, consumption was about 3.25 billion tons per year, the
amounts of red, orange, pink, and yellow coloration in the left y-axis represents the area of the hypoxic zone (the percent change by 2011 would be 4.06 / 3.25 = 1.25, or
the market pie chart are midway between those of the bars on the figure), and the right axis represents nitrogen roughly a 25% increase.
other two pie charts. This indicates that the market pie flux (the line on the figure). To determine the year with
chart likely consists of a combination of individuals from the largest hypoxic zone, look for the highest bar (2002), Fig. 19.4 According to the data in the text boxes, the aver-
the other two areas. age U.S. citizen uses 7.28 tons per year, whereas the aver-
and then consult the left y-axis at its height. You’ll see age person in the world uses 1.76 tons per year. Dividing
that the hypoxic zone that year was around 22,000 km . 7.28 by 1.76, we see that the average U.S. citizen uses 4.14
2
To determine the year with the largest nitrogen flux, find times more energy than the average person in the world.
Chapter 12 the highest point on the line on the figure (1993), and
Fig. 12.19 According to the data in the graph, each year follow its value to the right y-axis. You’ll see that roughly Fig. 19.15 Answers will vary. One should take the value
a little more than 4 million hectares of primary forest 210,000 of metric tons of nitrogen entered the northern at the far right end of the black (“Total”) data line and
is lost, while about 5 million hectares in plantations is Gulf that year. divide it by the value of that line in the year one’s mother
gained. or father was born. For example, if one’s parent was born
in 1965, when emissions were about 3.0 billion tons per
Fig. 2 (SBS2) According to the data in the graph, the Chapter 16 year, then the percent change by 2011 would be about
forest plot held about 55 bird species in the 4 years it was 9.47 / 3.0 = 3.16, or roughly a 216% increase.
censused before its fragmentation in 1984. After the plot Fig. 16.4 Multiplying 1000 g by 3.5% (0.035) reveals
became a fragment, the average number of bird species that there are 35 g of salts in the 1000 g sample of seawa- Fig. 19.20 The United States produces 7.8 million bar-
dropped to about 20 species. ter in the beaker. To determine the grams of negatively- rels of oil per day and consumes 18.8 million barrels per
charged ions in the sample, sum the values for chloride day, as indicated by the graph’s orange and red bars, re-
A-2 Fig. 3 (SBS2) According to the data in the graph, a tree (1.9%), sulfate (0.3%), and bicarbonate (0.01%) and find spectively. Therefore, for every barrel that is produced,
18.8 / 7.8 = 2.4 barrels are consumed.
275 meters in from the edge of a forest fragment would
that 2.21% of the sample (or 22.1 g) is from such ions.

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