Chapter 50: An Introduction to Ecology and the Biosphere

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Chapter 50An Introduction toEcology and
theBiosphere
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Ecology

• "The scientific study of the interactions between
  organisms and their environments is called
  ecology.
• "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)

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Ecology

• "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)

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Hypothetico-Deductive
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Ecology

• "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 assumptionand an act of
  faithof 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 wanderings/digressions." (p. 5,
  Kormondy, 1996 quoting Macfadyen, 1957)
• Ecology is a pain in the butt (S.T.A., circa
  this past weekend) ?

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Chartered Libertine

• 962. Libertine. -- N. libertine voluptuary c.
  954 a rake, debauchee, loose fish, rip,
  rakehellobs3, fast man intrigantobs3,
  gallant, seducer, fornicator, lecher, satyr,
  goat, whoremonger, paillardobs3, adulterer, gay
  deceiver, Lothario, Don Juan, Bluebeardobs3
  chartered libertine.
• adulteress, advoutressobs3, courtesan,
  prostitute, strumpet, harlot, whore, punk, fille
  de joieFr woman, woman of the town
  streetwalker, Cyprian, miss, pieceFr frail
  sisterhood demirep, wench, trollop, trullobs3,
  baggage, hussy, drab, bitch, jade, skit, rig,
  queanobs3, mopsyobs3, slut, minx, harridan
  unfortunate, unfortunate female, unfortunate
  woman woman of easy virtue c. (unchaste) 961
  wanton, fornicatressobs3 Jezebel, Messalina,
  Delilah, Thais, Phryne, Aspasiaobs3, Lais,
  loretteobs3, cocotteobs3, petite dame,
  grisetteobs3 demimonde chippy obs3U.S.
  sapphistobs3 spiritual wife white slave.
• concubine, mistress, doxyobs3, chere amieFr,
  bona robaIt.
• pimp, procurer pander, pandarobs3 bawd,
  conciliatrixobs3, procuressobs3, mackerel,
  wittol
• http//poets.notredame.ac.jp/Roget/962.html

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Environment, etc.

• Environments consist of biotic and abiotic
  components
• Chemical (abiotic) aspects of environment
  nutrients (both organic and inorganic), substrate
  (what the organism lives in/on), poisons, etc.
• Physical (abiotic) aspects of environment
  temperature, light, chemical gradients, currents
  (e.g., wind or water), degree of moisture, etc.
• Biotic component of environment are other
  organisms
• Ecology is evolution running in real time
  Ecosystems are not only the product of evolution
  but populations are actively evolving, all the
  time
• Principle of allocation "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."

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Adaptation to Environment

• Organisms can respond to variations in the
  environment with a variety of adaptations
• Behavioral adaptations are almost instantaneous
  in their effects and easily reversed
• Physiological adaptations may be implemented and
  changed over time scales ranging from seconds to
  weeks
• Morphological adaptations may develop over the
  lifetimes of individual organisms or between
  generations
• Adaptive genetic changes in populations are
  slower still, usually evolving over several
  generations
• The appropriate response to environmental change
  depends on the duration of that change."

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Limits on Distribution
Dispersal is the movement of organisms away from
where they were born or from where their
population otherwise congregates
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Principle of Allocation

• All adaptations are compromises, no organism is
  perfectly adapted to everything, and everything
  costs energy
• An organism must balance out its allocation of
  energy to survival and its need to allocate
  energy to reproduction
• 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
• Conformers Organisms whose internal environment
  conforms physically or chemical to its external
  environment
• Regulators Organisms whose internal environment
  does not conform to its external environment (due
  to energetically costly regulatory mechanisms)
• Why regulate? Why conform?

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Reproduction vs. Survival
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Maintaining Homeostais

• Part of energy expended on survival goes toward
  maintaining an organisms internal environment
• Active maintenance of the internal environment of
  an organism (by the organism) is termed
  homeostasis
• Regulators spend considerably energy maintaining
  their internal environment within narrow
  constraints
• Conformers spend less energy maintaining their
  internal environment by not constraining it
  narrowly
• Specialists can have more energy available to
  reproduce because they very efficiently obtain
  energy necessary for maintaining homeostasis
• This advantage is maintained only so long as the
  environment remains amenable to the specialists
  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)

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Beavers, Camels, Nephrons
Less energy/anatomy devoted, e.g., to water
retention, the more that can be devoted to
reproduction
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Conformers / Regulators
But regulators usually are more adaptable
Conformers may be very successful within its
relatively stable environment, but less able to
survive outside of this environment
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Impact of Environment
Regulator
Conformer
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Conforming Limits Range
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Areas of Ecological Study

• Organismal ecology 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
• Behavioral ecology Essentially a subset of
  organismal ecology that deals specifically with
  behavior
• Population ecology The study of the size and
  composition of populations of organisms (one
  species)
• Community ecology The study of the interaction
  between different species of organisms
• Ecosystem ecology The study of biotic and
  abioitic assemblages, e.g., nutrient cycling
  through ecosystems
• Landscape ecology Ecology across assemblages of
  adjacent ecosystems, e.g., pond, marsh, and forest

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Organismal Ecology

• Organismal ecology is an attempt to understand
  how the characteristics of individual organisms
  impact on their ability to interact with their
  environment
• 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 a bit more subtle)
• 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.g., above)
• 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)

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Organismal Ecology
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Behavioral Ecology

• 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
• Behavior, in other words, is how organisms act,
  and different behaviors can have different
  impacts on the Darwinian fitness of organisms

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Population Ecology

• Population ecology is the study of the size and
  composition of populations of organisms
• 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

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Population Ecology
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Community Ecology

• A community is the assemblage of different
  species of organisms within a given environment
• Community ecology is the study of the
  interactions between these organisms, e.g.,
  predation, parasitism, competition, etc.

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Community Ecology
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Ecosystem Ecology

• An ecosystem is the assemblage of the biotic and
  abiotic components of a given environment
• Often ecosystems are reasonably unambiguously
  defined (a lake, a forest, etc.)
• Understanding even an approximation of what goes
  on within an ecosystem, any ecosystem, can be an
  overwhelming challenge
• The everglades ecosystem as a function of
  altitude and other factors

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Ecosystem Ecology
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Landscape Ecology
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The End