Ecology (8-10)
Terms
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- Limiting factor
- the factor changes the average or equilibrium density of a pop.
- "bottom up limitation"
- pop abundance limited by available resources
- "top down limitations"
- abundance determined by pop's consumer's
- Regulating factor
- keeps pop within a certain interval around the avrg or equilibrium abundance
- Keystone species
- species that consumes and limits the pop of another species that would otherwise dominate the system
- Disturbance
- event that frees up resources &/or habs by removing orgs
- Peterbation
- more general than a dist, species additions and deletions, gradual changes in factors as well as dists.
- Stress
- anything that lowers the efficiency of an org below optimal level
- Intensity
- strength of dist. force
- Severity
- residue biota left
- Frequency
- return time of dist
- Magnitude
- spatial extent of dist relative to pop distrib.
- Distrib over habitat
- concentrated or patchy
- Timing
- season
- Succesion
- sequential changes, following dist, in the dominant biota occupying and affecting a site
- degradative succesion
- habitat dissapears over time (rotten log)
- primary succ.
- on bare space>>abiotic (volcanic rock)
- secondary succ.
- space has been opened a depop'd but some residual biota has survived
- climax
- late succ. stage where dominant species can replace themselves, they can succesfully recruit. (redwood).
- Early succesional species:
-
-r-selected
-can tolerate harsh, abrasive conditions - Late Succ. species
- -k selected
- Species of life
- 10-30 mill, but only 1.8 identified