Download Concepts in contemporary ecological theory Ecology is the study of

Concepts in contemporary ecological theory































Ecology is the study of relationship between a species and its environment.
Environment consists of all those objects and forces external to the organism with which it interacts or by
which it is affected.
Most organisms exist in units known as populations, groups of individuals of the same species who occupy the
same given area and interbreed with one another.
Specific area where a population lives is its habitat.
The niche of a population in environment is its place, or how it makes a living (its “profession”).
Habitat is a concrete idea whereas niche is more abstract concept; since it includes how the population interacts
with both natural resources and other populations.
Adaptation is the process by which organisms or populations make biological or behavioral adjustments that
facilitate their survival and reproductive success in their environment.
Ecosystem -- cycle of matter, information and energy that includes all organic things and links them to the
inorganic.
Exchanges of energy, matter, and information can go on through a number of trophic levels, or levels of feeding
relationships, i.e., producers, herbivores, and consumers.
Sequence of exchange is also known as the food chain.
Every environment is limited in ability to support life.
Limiting factors (food, water, temperature, rainfall, presence of disease causing organisms, etc.) help determine
the carrying capacity of an environment the point at or below which a population tends to stabilize or,
alternatively, the limit to which a population can grow and still be supported by the environment.
Really the maximum number of individuals of a population that a given ecosystem can support without.
Carrying capacity determined not just by the total amount of food available (i.e., calories) but also by quality of
food in form of proteins, vitamins, minerals.
For human populations, carrying capacity can vary with technology.
Two important properties of ecosystems: stability and resilience.
Resilience is a measure of the degree of change a system can undergo while still maintaining its basic elements
or relationships.
Stability is a measure of the speed with which a system returns to equilibrium after absorbing disturbances.
Ecosystems may be highly resilient, yet have low stability, taking longer to return to equilibrium. But despite the
long period necessary to return to stability they continue to persist as systems since their parts do not change.
On the other hand, ecosystems may be highly stable, that is they return to equilibrium quickly, but have low
resilience because they are likely to collapse.
How/why are humans different?
Human interaction with environment differs from all other animal species in two ways:
o 1. While niche of most animal species is relatively narrow ... Humans occupy an exceptionally broad
ecological niche and can be found in an extremely wide range of habitats.
o 2. Once humans enter an ecosystem they tend to become the dominant species and affect thesurvival
and adaptiveness of other species.
Ability to modify environment (through technology) means that we can create artificial environments (farms &
cities) that must be sustained with enormous inputs of energy, matter and information.
Draws not just from local ecosystem but often from very far away.
Tremendous ability to modify environment means that human dominated ecosystems are often considerably less
resilient than other ecosystems.
They can be maintained only by constant expenditure of human energy and ingenuity.
Evolutionary ecology -- study of living organisms within context of their total environment, with the aim of
discovering how their evolved characteristics and strategies for survival contribute to their success in that
environment.
Combines synchronic (present) research from ecology with diachronic (change over time) perspective of
evolution.
Dual inheritance of humans -- cultural transmission and change working simultaneously with a parallel process
of natural selection.
In the process of adapting, humans are active decision makers and innovations lead to change.
Flexibility is key.
o "The organism with the best chance of reproductive success is not necessarily the one most
perfectly adjusted to its environment at any particular point, but rather the one that maintains
its ability to respond to the environment in a flexible variety of ways" (Bates page 32)