Ecology in Further Detail ❮ 235
Rapid Review
The following terms are important in this chapter:
Population:collection of individuals of the same species living in the same geographic area.
Community:collection of populations of species in a geographic area.
Ecosystem:community+environment.
Biosphere:communities+ecosystems of planet.
Biotic components:living organisms of ecosystem.
Abiotic components:nonliving players in ecosystem.
Dispersion patterns:clumped dispersion(animals live in packs spaced from each other—cattle),
uniform distribution(species are evenly spaced out across an area, e.g., birds on a wire),
random distribution(species are randomly distributed across an area, e.g., trees in a forest).
Biotic potential:maximum growth rate for a population.
Carrying capacity:maximum number of individuals that a population can sustain in a given
environment.
Limiting factors:factors that keep population size in check: density-dependent(food,
waste, disease), density-independent(weather, natural disasters).
Population growth: exponential growth( J-shaped curve, unlimited growth), logistic
growth(S-shaped curve, limited growth).
Life history strategies:K-selected populations(constant size, low reproductive rate, exten-
sive postnatal care—humans); R-selected populations(rapid growth, J-curve style, little
postnatal care, reproduce quickly, die quickly—bacteria).
Survivorship curves:show survival rates for different-aged members of a population:
- Type I:live long life, until age is reached where death rate increases rapidly—humans,
large mammals.
- C—Two species that are aposematically colored
as an indicator of their chemical defense mech-
anism mimic each other’s color scheme in an
effort to increase the speed with which their
predators learn to avoid them. This, of course,
requires a predator that can learn based on
experience.
- A—This defense mechanism is warning coloration
adopted by animals that possess a chemical
defense mechanism. Ideally, predators will learn
to avoid the species, helping the prey survive
longer.
- D—K-selected populations tend to be popula-
tions of a roughly constant size, with low repro-
ductive rates and whose offspring require
extensive postnatal care until they have suffi-
ciently matured. R-selected populations tend to
produce many offspring per birth.
- B—Lizards follow a type II survivorship curve as
illustrated in the diagram in review question 12.
Humans (answer A) and whales (answer E)
follow a type I curve, while oysters and fish
(answers C and D) follow a type III survivorship
curve.
- D
- A
- C
- B
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