Important words and concepts
from Chapter 50, Campbell & Reece, 2002 (3/25/2005):
by Stephen T. Abedon (abedon.1@osu.edu)
for Biology 113 at the Ohio State University
|
|
Course-external links are
in brackets Click [index] to access site index Click here to access
text’s website Vocabulary
words
are found below |
|
(1) Chapter title: An Introduction to Ecology
(a)
[an introduction to ecology
(Google Search)]
[index]
(b)
Note that the lecture this material covers has become something of a
mosaic in response to personal preferences of this instructor combined with the
modifications associated with the new edition of Campbell & Reece (2002)
(c)
These notes consequently cover chapter 50 from Campbell & Reece
(2002) approximately from pp. 1092-1095, i.e., essentially the section titled
“The Scope of Ecology” (that is, it is this instructor’s preference to not
cover the rest of this chapter)
(d)
In addition, we will now also be covering material in chapter 44 that
previously had been covered in chapter 50; consequently, please read pp.
925-927 of your text, essentially the section titled, “An Overview of
Homeostasis”
(a)
A few quotes:
(i)
"The scientific study of the interactions between organisms and
their environments is called ecology."
(ii)
"The trouble with ecology is that you never know where to start
because everything affects everything else." Robert A. Heinlein (from Farmer
in the Sky)
(iii)
"As an area of scientific study, ecology incorporates the
hypothetico-deductive approach, using observations and experiments to test
hypothetical explanations of ecological phenomena. . . . ecologists often face
extraordinary challenges in their research because of the complexity of their
questions, the diversity of their subjects, and the large expanses of time and
space over which studies must often be conducted. Ecology is also challenging
because of its multidisciplinary nature; ecological questions form a continuum
with those from other areas of biology, including genetics, evolution,
physiology, and behavior, as well as those from other sciences, such as
chemistry, physics, geology, and meteorology." (p. 1061, Campbell, 1996)
(iv)
"Ecology concerns itself with the interrelationships of living
organisms, plant or animal, and their environments; these are studied with a
view to discovering the principles which govern the relationships. That such
principles exist is a basic assumption---and an act of faith---of the
ecologist. His field of inquiry is no less wide than the totality of the living
conditions of plants and animals under observation, their systematic position,
their reactions to the environment and to each other, and the physical and
chemical nature of their inanimate surroundings . . . It must be admitted that
the ecologist is something of a chartered libertine. He roams at will over the
legitimate preserves of the plant and animal biologist, the taxonomist, the
physiologist, [the microbiologist,] the behaviorist, the meteorologist, the
geologist, the physicist, the chemist and even the sociologist; he poaches from
all these and from other established and respected disciplines. It is indeed a
major problem for the ecologist, in his own interest, to set bounds to his
divagations." (p. 5, Kormondy, 1996 quoting Macfadyen, 1957)
(b)
In other words, understanding ecology requires understanding everything
else there is to know about biology, and then some
(c)
[ecology (Google Search)]
[index]
MAJOR COMPONENTS OF ECOLOGY
(a)
An organism's environment may be distinguished into an abiotic component and a biotic component
(b)
"Organisms are affected by their environment but, by their very
presence and activities, they also change it—often dramatically."
(c)
["natural
environment" ecology (Google Search)]
[index]
(a)
The abiotic component of an environment are all of the non-living
components of an organism's environment
(b)
These include such things as
(i)
Temperature
(ii)
Light
(iii)
Water
(iv)
Wind
(v)
Nutrients
(vi)
Substrate (e.g., rock and soil)
(vii)
Periodic disturbances
(c)
The abiotic component of an environment can and does have a dramatic
impact on the ability of organisms to survive and reproduce
(d)
Generally, a given organism is capable of surviving over only a limited
range of abiotic variables, and the environments in which one (or more) abiotic
component ranges outside of an organism's range of tolerance will not be able
to support stable populations of that organism
(e)
"The existence of a species in a particular place depends on two
factors: The species must reach that location, and it must be able to survive
and reproduce in that location once it is there."
(f)
[abiotic component (Google Search)]
[index]
(a)
The biotic component of an environment are all of the other organisms
found in an environment with which an organism makes contact, directly or
indirectly
(b)
These organisms may be competing, preying upon, being preyed upon,
providing shelter, or in some other way impact on the environment
(c)
Generally, organisms, en total, make a significant impact on other
organisms within an environment
(d)
[biotic component (Google Search)]
[index]
(a)
The complexity associated with ecology explains in part why the study
of evolution is so intensely difficult: Evolution happens within a context of
ecology, i.e., in real ecosystems, one organism at a time
(b)
Part of the complexity associated with ecology, however, is a
consequence of the impact of evolution on ecosystems: Ecosystems are not only
the products of evolution, they also contain populations that are actively
evolving, all of the time
(c)
In other words, ecology is essentially evolution running in real time,
while evolution is essentially the product of enormous numbers of ecological
interactions between organisms and their biotic and abiotic environments
(d)
[(Google Search)]
[index]
(a)
One way to understand ecology is in terms of flows of energy; organisms
take in energy and then use that energy to survive and to reproduce
(b)
All adaptations are compromises, no organism is perfectly adapted to
everything, and everything costs energy
(c)
An organism must balance out its allocation of energy to survival and
its need to allocate energy to reproduction
(d)
Genotypes that strike a good balance between allocation to survival and
to reproduction, such that net reproduction is large compared with other
genotypes, are said to have higher relative fitnesses
(e)
These ideas form the basis of the principle of allocation
(f)
"Each organism has a limited amount of energy that can be
allocated for obtaining nutrients, escaping from predators, coping with
environmental fluctuations, growth and reproduction."
(g)
Energy allocated to survival is not available for reproduction.
(h)
“Complex life like animals and plants needs a lot of energy.” Gretchen
Vogel (1999. Expanding the habitable zone. Science 286:70-71)
(i)
Relatively simple organisms have lower energy needs, but tend also to
be more limited in where they live or how much energy they can obtain per unit
time
(j)
(note that for Campbell & Reece, 2002, the “Principle of
Allocation” has all but been eliminated, though it is still found defined in
the glossary; I find this concept so useful for understanding ecology, however,
that I am retaining it as part of the required material for this chapter)
(k)
[principle of allocation
(Google Search)]
[index]
(a)
"Organisms
can respond to variations in the environment with a variety of adaptations [is this the correct quote?]
(i)
Behavioral adaptations are almost instantaneous
in their effects and easily reversed, whereas
(ii)
Physiological adaptations may be implemented and changed over time
scales ranging from seconds to weeks.
(iii)
Morphological adaptations may develop over the lifetimes of individual
organisms or between generations.
(iv)
Adaptive genetic changes in populations are slower still, usually
evolving over several generations.
(b)
The appropriate response to environmental change depends on the
duration of that change."
(c)
"The distinction between short-term adjustments on the scale of ecological
time and adaptation on the scale of evolutionary time begins to blur when we
consider that the range of responses of an individual to changes in the
environment is itself the product of evolutionary history."
(d)
That is, “phenotypic plasticity” is itself a product of evolution
(e)
"In general, plants are more morphologically plastic than animals;
this response helps them compensate for their inability to move from one
environmental patch to another."
(f)
[adaptation, phenotypic plasticity
(Google Search)]
[index]
MAJOR AREAS OF ECOLOGICAL
STUDY
(9) Hierarchical study of ecology
(a)
The study of ecology is often achieved by concentrating on a certain
level of a hierarchy of ecological study, just as more reductionist forms of
biology focus on certain levels of organisms ranging from the molecular,
through the cellular, through the organismal
(b)
"Ecology ultimately deals with the highest levels in the hierarchy
of biological organization. The web of interactions at the heart of ecological
phenomena is what makes this branch of biology so engaging."
(c)
The hierarchies in ecological study include
(ii)
Population ecology
(iii)
Community ecology
(iv)
Ecosystem ecology
(d)
[ecology hierarchical
(Google Search)]
[index]
(a)
Organismal ecology is an attempt to understand how the characteristics
of individual organisms impact on the ability of those organisms to interact
with their environment
(b)
Thus, for example, inferring that giraffes use their long necks to
reach leaves found high in trees is an example of organismal ecology (though
often inferences are just a bit more subtle and difficult than this example)
(c)
Organismal microbial ecology is one description of what it is that I do
for a living [research interests
(MicroDude)]
(d)
From an ecological vantage, much of what we study in introductory
biology falls under the heading of organismal ecology, i.e., the adaptations
individual organisms possess and the impact those adaptations have on the
ability of organisms to survive and reproduce
(e)
“Organismal ecology is concerned with the morphological, physiological,
and behavioral ways in which individual organisms meet the challenges posed by
their biotic and abiotic environments. The geographic distribution of organisms
is often limited by the abiotic conditions they can tolerate.” (p. 1094,
Campbell & Reece, 2002)
(g)
[organismal ecology
(Google Search)]
[index]
(a)
Essentially a subset of organismal ecology, behavioral ecology studies
the non-physiological, non-mophological/anatomical adaptations organisms
possess, and the impact those adaptations have on the survival and reproduction
of organisms
(b)
Behavior, in other words, is how organisms act, and different behaviors
can have different impacts on the Darwinian fitness of organisms
(c)
Behavioral microbial ecology is another description of what it is that
I do for a living [research interests
(MicroDude)]
(d)
We will study behavioral ecology in Chapter 51
(e)
[behavioral ecology
(Google Search)]
[index]
(a)
Population ecology is the study of the size and composition of
populations of organisms
(b)
An example of population ecology would be the study of the factors
which influence the carrying capacity
of a given environment, i.e., the number of individuals an environment can
stably sustain
(c)
[This is a little taste of what we will be considering as we study
population ecology:
(d)
We will study population ecology in Chapter 52
(e)
[population ecology
(Google Search)]
[index]
(a)
A community is the assemblage of different species of organisms within
a given environment
(b)
Community ecology is the study of the interactions between these
organisms, e.g., predation, parasitism, competition, etc.
(c)
We will study community ecology in Chapter 53
(d)
[community ecology (Google Search)]
[index]
(a)
An ecosystem is the assemblage of the biotic and abiotic components of
a given environment
(b)
Often ecosystems are reasonably unambiguously defined (a lake, a
forest, etc.)
(c)
Understanding even an approximation of what goes on within an
ecosystem, any ecosystem, can be an overwhelming challenge
(d)
The everglades ecosystem as a function of altitude and other factors:
(e)
We will study ecosystem ecology in Chapter
54
(f)
[ecosystem ecology (Google Search)]
[index]
(a)
“Looking beyond the four basic levels of ecology, we come to landscape
ecology, which deals with arrays of ecosytems and how they are arranged in a
geographic region. A landscape or seascape consists of several different
ecosystems linked by exhanges of energy, materials, and organisms. The
landscape level of research focuses on the ways in which interactions among
populations, communities, and ecosystems are affected by the juxtaposition of
different ecosystems, such as streams, lakes, old-growth forests, and the
forest patches that have had their trees removed by clear-cut logging.” (pp.
1094-1095, Campbell & Reece, 2002)
(b)
[landscape ecology (Google Search)]
[index]
SEE CHAPTER 44, AN OVERVIEW
OF HOMEOSTASIS (PP. 925-927)
(a)
Part of the energy expended on survival goes toward maintaining the
internal environment of an organism
(b)
The active maintenance of the internal environment of an organism (by
the organism) is termed homeostasis
(c)
Some organisms spend considerably more energy on maintaining their
internal environment within relatively narrow constraints (regulators)
(d)
Other spend less energy on maintaining their internal environment
because they do not constrain it narrowly (conformers)
(e)
Any energy not spent on homeostasis is potentially available for other
needs such as reproduction (principle of allocation)
(f)
Note that this principle forms the basis of the conflicting strategies
of specialization (e.g., conformers) versus generalization (e.g., regulators)
(g)
Specialists potentially have more energy available to reproduce because
they very efficiently obtain energy necessary for maintaining homeostasis,
though this advantage is maintained only so long as the environment remains
amenable to the specialist’s needs (note: try to avoid equating the concept of
specialization with the concept of specialization with respect to foraging; the latter, specialization with regard to diet, is
essentially a subset of the former)
(h)
[homeostasis (Google Search)]
[index]
(a)
For organisms within relatively stable environments, energy can be made
available for other uses if internal environments are allowed to vary as
external environments vary
(b)
Such organisms may be termed conformers
(c)
See Figure 44.1, Regulators and Conformers
(d)
Note that a conformer may be very successful within its relatively
stable environment, but less able to survive outside of this environment
(e)
"Conformers that live in very stable environments . . . might be
able to channel more energy into growth and reproduction. However, the
intolerance of such specialists to environmental change severely restricts
their geographical distribution."
(f)
For contrast, see regulators
(g)
FAQ: I took another look at
the key for the last exam, and have a question:
#19 asks about the major disadvantage of being a conformer. Your answer:
limited range. My answer is "that one is more of a specialist so has a
narrower range of foods it will consume." Is my answer wrong because I say
range of foods, when "range" should be geographical? (the notes say
this). I guess my first question would be, why is a more-limited range of
foods a disadvantage? Plants, for example, are limited to sunlight and CO2
as their sources of energy and carbon, yet they don’t seem to be suffering for
that limitation. An animal that consumes a more limited range of foods has an
opportunity to increase the efficiency with which it obtains specific foods. We
actually might expect evolution to favor such specialization, at least over the
short term. But more important than that, why did you generalize a question
that specifically was about conformers (versus regulators) to one
instead that is about specialists (versus generalists). Yes, a conformer is a
kind of specialist, but the term is not synonymous with specialist. For many
specialists the cost is a narrowing in the range of foods they consume, and the
cost is that this limits their ability to survive given a loss of
specific food types or to expand their ranges into regions lacking those foods.
For a conformer the problem is instead one pertaining to the physical and
chemical environment. That is, their internal environment to a degree matches
that of their external environment. As a consequence conformers can only live
in environments with physical and chemical characteristics that match the
limits of what their internal environments can cope with. For a regulator this
is less of a problem because regulators are more adept at shielding their
internal environment from their external environment. The net result, as you
note, is that the conformer’s geographical range will be more limited than that
of the regulator.
(h)
[ecology conformer (Google Search)]
[index]
(a)
At the opposite end of the spectrum are the regulators (i.e., versus conformers)
(b)
These organisms expend a great deal of energy to keep their internal
environment constant regardless of the nature of their abiotic environment
(c)
Such organisms may be more adaptable, but at the cost of great
expenditures of energy that could otherwise be put toward such things as
reproduction
(d)
"Regulators that allocate a larger fraction of their energy to
coping with environmental changes may grow and propagate less efficiently, but
such organisms are able to survive and reproduce over a wider range of variable
environments."
(e)
See Figure 44.1, Regulators and Conformers
(f)
[(Google Search)]
[index]
SUPPLEMENTAL TOPIC
(19) Graininess (supplemental discussion, no need to memorize)
(a)
Another way of looking at ecology is in terms of environmental and
temporal grain
(b)
Environmental grain refers to the patchiness of an environment, and the
patchiness of an environment is perceived differently by different organisms
(c)
A coarsely grained environment has patches which are large enough that
they may be distinguished
(d)
A finely grained environment has patches which are so small that they
may not be readily distinguished, and an "organism may not even behave as
though patches exist," but what is fine-grained to one (typically larger)
organism may by coarse-grained to another (typically smaller) organism
(e)
Organisms tend to congregate within coarsely grained patches to which
they are best adapted
(f)
Temporal variation may also be finely or coarsely grained depending,
for example, on the life span of the experiencing organism, where short term
variations (finely grained) are those which occur over a short span of an
organism's life while long term variation (coarsely grained) occur over a
substantial fraction of an organism's life
(g)
[fine-grained environment,
coarse-grained environment
(Google Search)]
[index]
VOCABULARY
(b)
Adaptation
(d)
Biotic component
(f)
Conformers
(g)
Ecology
(i)
Environment
(k)
Graininess
(l)
Hierarchical study of ecology
(r)
Regulators