Community Ecology 1 - Resources and Competition Flashcards
Resource
a thing or factor that causes population growth and is reduced by use
- CONTEXT: O2 and sunlight can still be a resource depending on the context
Limiting Resource
resource that is reduced the most by use and thereby limits population growth first
Niche
full range or resources that a species can use combined with the range of conditions a species can tolerate
Fundamental Niche
the full set of all environmental conditions in which a species can survive and reproduce without any limiting factors
Realized Niche
set of conditions actually used by the given species, after interactions with other species (predation + competition) have been taken into account and limiting factors are present
Resource Partitioning
process by which different species within an ecosystem divide up resources to avoid interspecific competition
Competition in Ecosystems
Competition between resources is strongest where niches overlap - intense competition can lead to species using a realized niche smaller than its fundamental niche
Ecological Interactions + Selection
These ecological interactions (resource partitioning) can exert strong selection pressure, that the trait to use the resource can adapt to a distinctly new character state
- Character Displacement
OR
- Competitive Exclusion
WILL OCCUR
Character Displacement
- shift in trait value
- an evolutionary adaptation in a heritable trait caused by resource partitioning
Competitive Exclusion
if the trait in question lacks enough heritable variation for character displacement to occur then:
- the inevitable elimination from a habitat of one or two different species with identical needs for resources
Interspecific Competition
competition for resources that drives reductions in niche overlap
- has negative effects on both species in the interaction between it uses up ENERGY
- individuals from each species would have more success (less energy used) in the absence of the other species
LOSE-LOSE SITUATION
Predation
predator-prey interactions; one species consuming the other
WIN-LOSE SITUATION
Parasitism
parasite-host interactions; a species lives on or in another species that it harms over time, sometimes causing host death
WIN-LOSE SITUATION
Herbivory
a grazer eats a plant
WIN-LOSE SITUATION
Mutualism
both species benefit from the interaction
- EX: pollination
WIN-WIN SITUATION
