Final Flashcards
Successional Theory
Ecological communities go through predictable stages of teleological development, reaching a final “climax” state determined by climate and soils (Frederick Clements)
Disturbance theory
Disturbance is the norm in most ecosystems, and can result in unpredictable, unidirectional shifts at certain tipping points (Henry Gleason)
Punctuated equilibrium
Little change occurs over long periods of time, but major shifts sometimes occur, leading to the formation of new species (Stephen J. Gould)
Chaos theory
Future weather is extremely sensitive to conditions today; climate systems are prone to radical changes and unpredictable outcomes (Edward Lorenz)
Cyclical change
Patterns of change over time that operate on cycles, such as the days, seasons, and El Nino patterns
Directional change
Changes that do not repeat. These may be long-term shifts or random one-time events. For example, many wildlife populations rise and fall over time (cyclical) but species extinctions can happen only once
The environment
A complex system of systems
Balance of nature
the assumption that the Earth is in a kind of timeless, divinely-ordered balance
Great Chain of Being
Hierarchy with God at the top, then angels, humans, and the rest of the animal kingdom. Created by Didacus Valdes in 1579
Carl Linnaeus
Argued that “There are only as many species as the Infinite Being produced diverse forms in the beginning
The Peaceable Kingdom
Painting by Edward Hicks about the balance of Nature
Uniformitarianism
The same gradual processes that currently shape life on earth have always been underway (Charles Lyell)
Catastrophism
Earth history is shaped by occasional, unpredictable, transformative events (Georges Cuvier). example could be Meteor impact
Phyletic gradualism
Small variations over time produce larger changes in plant and animal species, as populations respond to natural selection (Charles Darwin)
Gaia Hypothesis
Earth is a self-regulating system with built-in mechanisms that discourage changes and maintain equilibrium (James Lovelock)
Direct sources
Measurements were taken of the thing or process itself. Ex: counting the number of fish in a pond, then repeating that count a year later
Indirect/Proxy sources
Measurements taken of one thing that are used to study another. EX: Tree rings to measure past precipitation levels
Indicator species
They can serve as representatives of ecosystem health because they are sensitive to changes in their environments
Correlation
An apparent relationship between two variables. Does not imply a meaningful relationship
Causation
An actual relationship between two variables, such that changes in the value of one affect the value of another.
Type 1 error
A false positive. Thinking you see a pattern, change, or relationship when no such thing exists (“crying wolf”
Type 2 error
A false negative. Thinking there is no pattern, change, or relationship even though one does exist (“sticking your head in the sand”
Driving forces
Large-scale processes that create the conditions for patterns of change. EX: the influence of climate cycles on the distribution of wildlife species
