laboratory projects. As William E.
Odum put it in 1959, “the ecological
niche of an organism depends not
only on where it lives, but also on
what it does.”From field to lab
Laboratory experiments and field
observations are the main methods
of providing data for the study
of ecological processes, but field
experiments—in which a local
environment is manipulated to test
a hypothesis—were not conducted
with scientific rigor until Joe
Connell’s work with barnacles
in Scotland. His experiments—the
results of which were published
in 1961—were meticulously planned
and observed, and were repeatable.
Connell set the “gold standard”
for fieldwork, but experiments in
laboratories still have a vital roleto play, too—as Earl Werner
demonstrated 30 years later. His
work revealed the non-consumptive
impact of predatory dragonfly larvae
on the behavior and physical
development of their tadpole prey.
Since the mid-20th century,
many new ideas on ecological
processes have emerged. Work by
Robert MacArthur and others on
competition between species led to
the development of optimal foraging
theory, which seeks to explain why
animals choose to eat some food
items and not others. Mutualistic
relationships became better
understood through the research
of biologists such as Daniel Janzen.
Robert Paine’s work with starfish
and mussels also highlighted the
concept of keystone species—
those that have a disproportionate
influence on their ecosystems.New technology
Technological advances—including
sophisticated chemical sampling
techniques, satellites with remote
sensing equipment, and computers
capable of rapidly processing huge
quantities of data—have opened
up new areas of study.
Ecological stoichiometry, for
example, studies the flow of energy
and chemical elements throughout
food webs and ecosystems, from the
molecular level up. Like so many
ideas in ecology, its origins can be
traced back many years, but only
took hold with Robert Sterner and
James Elser’s 2003 book Ecological
stoichiometry: The biology of
elements from molecules to the
biosphere. New techniques such
as this will undoubtedly continue
to deepen our understanding of
processes in ecology. ■ECOLOGICAL PROCESSES
1977
Research published by
Ronald Pulliam, Eric Charnov,
and Graham Pyke expands on
the optimal foraging theory that
animals try to gather resources
while wasting as little
energy as possible.1970 s
Roy Anderson and Robert
May demonstrate how
epidemics affect animal
population growth rates.2002
Robert Sterner and James Elser
pioneer the study of ecological
stoichiometry—how ratios of
different chemicals within
living organisms change
with certain reactions.1972
Knut Schmidt-Nielsen
publishes How Animals
Work. The book hugely
influences the field
of ecophysiology.1991
Earl Werner publishes
his findings about
nonconsumptive
effects of predators
on prey.43
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