Ecology Chapter 1
Terms
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- ecology
- the scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance
- proximate causation
- the present distribution and abundance of a species based on the "here and now," the environment and what it eats
- ultimate causation
- the present distibution and abundance of a species based on the ecological experience of its ancestors (evolutionary history)
- levels of organization
- the biological hierarchy that deals with individual organisms, populations, communities, and ecosystems
- individual organisms
- at this level, ecology deals with how individuals are affected (and how they affect) their environments
- populations
- at this level, ecology deals with the presence or absence of particular species, with abundance or rarity, and with trends and fluctuations in their numbers
- communities
- at this level, ecology deals with the composition or structure of ecological communities (different species in the same habitat)
- ecosystem
- comprises the community together with its physical environment (biotic + abiotic)
- natural field experiment
- experiments that are made without altering the natural environment of a species, in order to make observations
- manipulative field experiment
- unnatural acts in which some aspect of the environment is altered
- scale
- relative magnitude: time scales, spatial scales, and biological scales
- trophic cascade
- the patterns and effects at the ecosystem level caused by different trophic level interactions
- watershed
- the land surface that catches precipitation
- biodiversity
- the variability in number and species within ecosystems
- species richness
- a measure of biodiversity, the number of species in an ecosystem