4. Interactions Flashcards
What is competition?
Two organisms use the same resource, to the detriment of both
What is predation?
One animal species eats all or part of a second animal species
What is herbivory?
One animal species eat all or part of a plant species
What is parasitism?
Two species live in a physically close obligatory association in which the parasite depends metabolically on the host
What is a disease?
An association between a pathogenic microorganism and a host species in which the host suffers physiologically
What is mutualism?
Two species live in close association with one another to the benefit of both
What is the niche?
An area in biological space that a species occupies
What is resource competition?
Scramble or exploitative competition, occurs when a number of organisms of the same or different species use common resources that are in short supply
What is interference competition?
Contest competition occurs when the organisms seeking a resource harm one another in the process even if the resources are not in short supply
What is Gause’s hypothesis?
As a result of competition two similar species scarcely occupy similar niches, but instead displace each other
What is Hardings 4 c’s principle?
Complete competitors cannot coexist
How did grinned describe the niche?
A subdivision of the habitat each niche is occupied by one species
Who created the n dimensional hypervolume?
Hutchinson 1958
What is the n dimensional hypervolume?
Fundamental niche, set by resources it can use in the absence of competition
What is the realised niche
The resource use of a species in the presence of competition
What does a normal
Bell shaped curve denote?
A unimodal symmetrical realised niche
When does competitive exclusion occur?
The environment is unstable
Resources are not limiting
The environment fluctuates such that the direction of competition reverses before extinction occurs
Why is competitive exclusion rate?
Species have adapted to avoid it, competition was always rare in nature, rescources are not always limiting
Who discovered rescource partintioning in dendroica species?
Bob MacArthur
What causes differences in rescource use among closely related species ?
Competition in the past
Speciation
What is resource utilisation and limiting similarity?
Species will evolve to exploit unused rescources, limited overlap enables both species to coexist, strong overlap drives one species to extinction or to exploit a different range of rescources
Which plant type has low stress tolerance but high disturbance tolerance?
Ruderals, weeds
What theory did Wilson and MacArthur come up with in 1967?
r and K selection
Define r animals?
Rabbits, mice, rats, Don’t suffer pressure from interspecific competition and establishment, no competitive mechanisms
Define K animals?
Suffer pressure from competition at or near the carrying capacity, resources must be used efficiently
What may happen in consequence of competition?
Species may diverge in some way
What did Darwin study in the Galapagos?
Finches, different sized beaks for different food
What are the 5 types of predator?
Carnivore, Herbivore, Insect parasite, parasite, cannibal
What is apparent competition?
Indirect effects without competition between predators, competition drives prey patterns
What was built in Australia to stop dingos killing red kangaroos?
A fat fence
What caused the decline of fish in the Great Lakes USA?
Lamprey
What characteristics of predators make then effective in controlling populations?
Numerical response,functional response, aggregative response, developmental response
What is numerical response?
One in which the density of predators in a given area increases by reproduction, e.g. Wolves
What is functional response?
One in which the number of prey eaten by individual predators changes?
What is a type 1 response?
The predation rate of wolves increases with moose density
What is developmental response?
One in which individual predators eat more or less prey as predators grow towards maturity
What is aggregative response?
One in which individual predators move into and concentrate in the study area
What is total response?
Gives the % of prey organisms eaten per unit times by the entire population
