Ecology Flashcards
Ecology
The study of the distribution and abundance of organisms
What determines where a species is located (i.e. distribution)?
The species that are present depend on past and current conditions
- dispersal (can a species get there?)
- once there, can it survive and reproduce?
- ecological time scale: hours = years
Why is species X absent from an area?
Does dispersal limit its distribution?
- yes = area inaccessible or there is insufficient time
- no = does behavior limit its distribution?
- yes = habitat selection
- no = do biotic factors (interactions with other species; i.e. predation and competition) limit its distribution?
- yes = predation, parasitism; competition, disease
- no = do abiotic (interactions with non-living factors) limit its distribution?
- chemical factors = water, oxygen, salinity, pH, soil nutrients, etc.
- physical factors = temperature, light, soil structure, fire, moisture, etc.
Biogeography
Study of species distribution, often with an emphasis on historical events and differences between past and present patterns of distribution
- results of evolution apparent over time and also over space
- historical events in Earth’s history had strong effects on distribution of species (plate tectonics)
Continental drift
Earth’s crust is dynamic in geologic time and is evidence of “super continent” pangea
Dispersal
Movement of individuals away from centers of high population density or from their area of origin
- can happen due to human activity
- can happen due to natural movement of organism
- scale of natural dispersal is highly variable among taxa and groups
Abiotic factors
Important effects on organism distribution
Biotic factors
Affects the distribution of organisms
Climate
Long term, prevailing weather patterns in an area
- key abiotic factor
- creates distinct biomes
Biome
Characteristic type of ecological community within a particular climate
