Website for Rost et al/Plant Biology 2e, ISBN: 0534495958
Objectives Chapter #26
Chapter 26 Ecology, Ecosystems, and Plant Populations
OBJECTIVES
After reading this chapter, you should be able to:
■ Define the term “ecology” and describe the goal of plant ecologists. Know the important
questions that must be answered to achieve this goal. Examine the methods used by plant
ecologists for finding answers.
■ Give examples of the biotic and the abiotic elements that compose an ecosystem. Describe the
trophic categories into which living organisms are placed, and the ways of summarizing each
trophic category. Explain why efficiency of energy transfer between trophic levels is limited
to 10% and therefore the relationship between trophic levels is expressed as a pyramid.
■ Define the term “population” and explain why the population, and not the individual, is the
basic ecological unit. Distinguish between population ecology and community (or ecosystem)
ecology. Show why plants must budget time and energy to maximize reproduction, and
describe the basic kinds of life cycle budgets. Explain how a life cycle budget can be expressed
as a life history pattern and describe the major components of life history patterns.
■ Compare differences in types of life spans, growth forms, timing of reproduction, and
sexuality. Distinguish between the following pairs of terms: “broadleaf” versus “needle-leaf,”
“hardwood” versus “softwood,” and “evergreen” versus “deciduous.” Describe the
advantages and disadvantages of semelparous and iteroparous reproduction, and of being
dioecious or monoecious. Explain how sexuality is determined in plants. Distinguish between
r and K life history patterns. Define plant demography and describe how the changes that
occur in population age structure over time are expressed.
■ Describe the differences between the microenvironment and the macroenvironment. Explain
the importance of water and soil, solar radiation, and fire in the distribution of plant
populations. Distinguish between xerophytes, mesophytes, halophytes, and hydrophytes.
Describe the traits these possess that adapt them to particular habitats.
■ Explain why the solar energy budget equals zero for the earth itself and for every organism or
part of an organism. Explain how the solar radiation that reaches a leaf is either reflected or
expended in transpiration, convection, reradiation, and photosynthesis. Describe the effect of
solar radiation on temperature, a limiting factor for plant life. Explain why each population
within a species is probably unique.
■ Define and give an example of the following kinds of species interactions: competition,
amensalism, mutualism, and commensalism. Explain why competition may be the most
important biotic factor affecting plant distribution. Know which of these are negative and
which are positive interactions.
■ Define all boldface terms.
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