by Miller & Levine
[complete Table of Contents]
the pull-down menu to jump to any of the Book's 40 Chapters:
An extraordinary site from the University
An exhibition about our planet and its oceans, sponsored by NASA
Parks and Wildlife
Extensive information about Texas wildlife and natural regions of the
chapter, students will will read about how the biologists called ecologists
study the relationships among organisms in the living part of the Earth's
environment, called the biosphere. You will also discover how energy and
nutrients flow through the biosphere The links below lead to additional
resources to help you with this chapter. These include Hot Links
to Web sites related to the topics in this chapter, the Take It to
the Net activities referred to in your textbook, a Self-Test
you can use to test your knowledge of this chapter, and Teaching Links
that instructors may find useful for their students.
Section 3-1: What
the various relationships within the biosphere, ecologists ask questions
about events and organisms that range in complexity from a single individual
to a population, community, ecosystem, or biome, or to the entire biosphere.
modern ecological research according to three basic approaches: observing,
experimenting, and modeling. All of these approaches rely on the application
of scientific methods to guide ecological inquiry.
Section 3-2: Energy Flow
Sunlight is the main energy source for
life on Earth. In a few ecosystems, some organisms rely on the energy
stored in inorganic chemical compounds.
Energy flows through an ecosystem in
one direction, from the sun or inorganic compounds to autotrophs (producers)
and then to various heterotrophs (consumers).
Only about 10 percent of the energy available
within one trophic level is transferred to organisms at the next trophic
Section 3-3: Cycles of Matter
Unlike the one-way flow of energy, matter
is recycled within and between ecosystems.
Every living organism needs nutrients
to build tissues and carry out essential life functions. Like water, nutrients
are passed between organisms and the environment through biogeochemical