Ecology
Scientific study of interactions that determine the distribution and abundance of organisms (Krebs, 1972)
Environment
Factors and phenomena outside the organism that influence it
- Abiotic
- Biotic
Abiotic
Physical and chemical
Biotic
Other organisms
Population
Individuals of the same species
-Trends, fluctuations
Community
A greater or lesser number of species populations
-Composition and organisation
Interactions include…
Energy and matter transformations
2 Broad approaches to Ecology
Building from properties at level below
Dealing directly with properties of the level of interest
Building from properties at level below
Physiology
Population- survival probabilities, clutch sizes
Food consumption rates- predator prey interactions
Dealing directly with properties of the level of interest
Niche breadth
Importance of density-dependant processes
Species diversity- community
Rate of biomass production
5 Main Categories of Species Interaction
Competition Predation Parasitism Mutualism Detritivory
Competition
Interaction where one organism consumes a resource that would have been available to another
- Deprives i.e. grows more slowly
- Within or between species
Predation
Consumption of one organism by another, prey is alive and the predator first attacks it
-Herbivory or Carnivory
Parasitism
Relationship between species, parasite lives on or in another organism (host) causing it some harm
-More than 50% species are parasites
Mutualism
Cases of reciprocal exploitation where each partner is a net beneficiary (Herre and West, 1997)
-Conflict lies at heart of these interactions
Detritivory
Organisms that feed on dead organic material
