Environmental Engineering Reference
In-Depth Information
Importance of Baseline Ecological Data
We need baseline data on the world's ecosystems so we
can see how they are changing and develop effective
strategies for preventing or slowing their degradation.
Before we can understand what is happening in nature
and how best to prevent harmful environmental
changes, we need to know about current conditions. In
other words, we need
baseline data
about the condition
of the earth's ecosystems.
By analogy, your doctor would like to have base-
line data on your blood pressure, weight, and func-
tioning of your organs and other systems as revealed
by blood and other basic tests. If something happens
to your health, the doctor can run new tests and com-
pare the results with the baseline data to determine
what has changed in an effort to come up with an ef-
fective treatment.
Bad news.
According to a 2002 ecological study pub-
lished by the Heinz Foundation and a 2005 Millennium
Ecosystem Assessment, scientists have less than half of
the basic ecological data they need to evaluate the sta-
tus of ecosystems in the United States. Even fewer data
are available for most other parts of the world.
2. a.
How would you set up a self-sustaining aquarium
for tropical fish?
b.
Suppose you have a balanced aquarium sealed with
a clear glass top. Can life continue in the aquarium
indefinitely as long as the sun shines regularly on it?
c.
A friend cleans out your aquarium and removes all
the soil and plants, leaving only the fish and water.
What will happen? Explain.
3.
Make a list of the food you ate for lunch or dinner to-
day. Trace each type of food back to a particular producer
species.
4.
Use the second law of thermodynamics (p. 31) to ex-
plain why a sharp decrease in usable energy occurs as en-
ergy flows through a food chain or web. Does an energy
loss at each step violate the first law of thermodynamics
(p. 31)? Explain.
5.
Use the second law of thermodynamics to explain
why many poor people in developing countries live on a
mostly vegetarian diet.
6.
Why do farmers not need to apply carbon to grow
their crops but often need to add fertilizer containing
nitrogen and phosphorus?
7.
Why are CO
2
levels in the atmosphere higher during
the day than at night?
8.
What would happen to an ecosystem if all its decom-
posers and detritus feeders were eliminated? If all its
producers were eliminated?
Two Principles of Sustainability
Ecosystems have sustained themselves for several
billion years by using solar energy and recycling the
chemical nutrients their organisms need.
As described in this chapter, almost all natural ecosys-
tems and the biosphere itself achieve
long-term
sustain-
ability in two ways.
First
, they use
renewable solar en-
ergy
as their energy source.
Second
, they
recycle the
chemical nutrients
their organisms need for survival,
growth, and reproduction.
These two sustainability principles arise from the
structure and function of natural ecosystems (Figures
3-6 and 3-13), the law of conservation of matter (p. 26),
and the two laws of thermodynamics (p. 31). Thus the
results of basic research in both the physical and
biological sciences provide the same guidelines or
lessons from nature on how we can live more sustain-
ably on the earth, as summarized in Figure 2-13 (p. 33).
9.
Visit a nearby aquatic life zone or terrestrial ecosystem
and try to identify its major producers, consumers, detri-
tivores, and decomposers.
LEARNING ONLINE
The website for this topic includes review questions for
the entire chapter, flash cards for key terms and concepts,
a multiple-choice practice quiz, interesting Internet sites,
references, and a guide for accessing thousands of
InfoTrac
®
College Edition articles.
Visit
http://biology.brookscole.com/miller11
Then choose Chapter 3, and select a learning resource. For
access to animations, additional quizzes, chapter outlines
and summaries, register and log in to
All things come from earth, and to earth they all return.
M
ENANDER
(342-290
B
.
C
.)
at
esnow.brookscole.com/miller11
using the access code
card in the front of your topic.
CRITICAL THINKING
1. a.
A bumper sticker asks, “Have you thanked a green
plant today?” Give two reasons for appreciating a
green plant.
b.
Trace the sources of the materials that make up the
bumper sticker, and decide whether the sticker it-
self is a sound application of the slogan.
c.
Explain how decomposers help keep you alive.
Active Graphing
Visit
http://esnow.brookscole.com/miller11
to
explore the graphing exercise for this chapter.
