LE 10: Competition Flashcards
What is competition?
when the presence of one species negatively affects the other species; there is reciprocated interaction
What is Intraspeceific vs Interspecific competition?
Intraspecific competition: between individuals of the same species
Interspecific competition: between individuals of different species
What are the two types of competition?
Exploitative competition: individuals consume and drive down the abundance of a resource that results in other individuals not having them
- occurs when competing for similar resources
Interference competition: when competitors do not immediately consume resources, and defend them instead
- occurs when species directly interfere with access to a resource
What are some examples of interference competition?
Long-legged ants plug nests harvester ants with soil and rocks, allowing for them to forage without interference from harvester ants.
Allelopathy: when organisms use chemicals to harm their competitors
- eucalyptus trees secrete chemicals so nothing can grow on the ground near them; they ≠ have to compete for nutrients in the soil
Kleptoparasitism: when organisms takes food from others
- seagulls
- can be exploitative depending on the supply of a resource
What is the competitive exclusion principle and how do you interpret the graph?
If two species with the same niche coexisted in the same ecosystem, then one of them will be excluded due to intense competition
Graph:
- narrower niche = worse competitor
- overlap in fundamental niche state = stronger competitor pushes weaker competitor into a narrow space allowing for coexistence
- complete overlap = they can not coexist; the species that is better at turning resources into offspring drives the weaker competition into extinction
What are the fundamental and realized dimensions of niches?
fundamental niche: range of conditions that an organism can survive and reproduce itself in
realized niche: the actual set of conditions used by an organism in the environment
What are some examples between the dimensions of niches?
Different species of coral can coexist with each other
- D.Hemiprichi catch phytoplankton better and D.sinaiensis filters algae better
- differences in food source allows for them to coexist
How do variable conditions modulate competition? Give examples:
Soil can affect which species will be more predominant when they are grown together.
- white bedstraw thrives in alkaline soil
- heath bedstraw thrives in acidic soils
Predation can affect some species more than others.
example: tadpoles
- when there are no predators, one species has more of an advantage
- when there are predators, there is more evenness leading to more biodiversity and coexistence
What are isoclines?
Combinations of species one and species two where the population growth will be 0 for either species
- each species has its own isocline
