interactions between species Flashcards
What are the three types of individual interactions in ecosystems?
- Trophic interactions
- Facilitative interactions
- Competition for common resources
What is competition in ecological terms?
Competition is an interaction between individuals brought about by a shared requirement for a resource in limited supply, leading to a reduction in survivorship, growth, or reproduction of the competing individuals.
How can competition be studied experimentally?
- Competitor density manipulations
- Resource availability manipulations
- Dominance manipulations
What is interference (contest) competition?
Interference competition occurs when one competitor directly harms or kills another, involving direct interactions between consumers that indirectly influence resource availability.
What is exploitative (scramble) competition?
Exploitative competition occurs when individuals use a resource, making it unavailable to others, with direct effects on resource availability.
What is asymmetrical competition?
Asymmetrical competition occurs when competitors are affected differently due to their differential ability to occupy higher positions in a competitive hierarchy.
What is the competitive exclusion principle?
The competitive exclusion principle states that species occupying the same niche cannot co-exist. The greater the niche overlap, the more likely one species will be excluded, leading to local extinction.
What is intraspecific competition?
Intraspecific competition is competition between individuals within the same species, often for resources like territory, habitat, mates, and food.
What is lottery competition?
Lottery competition involves positive frequency dependency, where many offspring compete for a small number of sites. One individual is randomly chosen to win the site, and once established, population growth occurs through a positive feedback loop.
What is interspecific competition?
Interspecific competition is competition between individuals from different species. Some species experience both intra- and interspecific competition, with interspecific competition usually having a larger effect.
What is the “context-dependent” nature of competition?
Competitive outcomes can change based on environmental context, such as predator cues or density manipulations. For example, the competitive result between fiddler crabs may be reversed when predator cues are present.
What environmental factors impact competition?
- Presence of predators
- Density
- Abiotic stress
- Availability of resources
What is the relative dominance model?
The relative dominance model predicts that the competitive outcome of benthic species is controlled by environmental factors, including:
- Bottom-up controls: e.g., nutrient levels
- Top-down controls: e.g., grazing
