Week 11 Flashcards
Niche
combination of a species’ physical habitat and its ecological role in that habitat
Grinnell
niche is sum of the habitat requirements needed for a species’ survival and reproduction
Elton
niche is the role a species plays in a community, switching emphasis from the habitat to the species itself
Hutchinson
niche as a multidimensional habitat that allows a species to practice its way of life
abiotic factors
non living, physical
climate
soil chemistry
biotic factors
living, biological
interactions with other species
fundamental niche
full range of climate conditions and food resources that permits the individual in a species to live
realised niche
actual range of habitats occupied by a pecies
phylogenetic niche conservatism
usually some aspect of the niches of closely related species is similar and so are evolutionarily conserved
competition
interaction in which the use of a mutually needed resource by one individual or group of individuals lowers the availability of the resource for another individual or group
intraspecific competition
caused by tension between intrinsic growth rate and environmental carrying capacity; competition between individuals of a single species
Main reason why population growth slows as the species’ environment approaches its carrying capacity
interspecific competition
competition occurs between individuals of different species
Darwin
‘struggle for existence’ is a primary driver for natural selection
Competitive exclusion
competition between two species prevents one from occupying a particular niche
resource partitioning
species whose niches overlap diverge and become different subspecies or species
caused by competitive exclusion
predation
one organism consumes another, its prey
Predator benefits at expense of prey
gause
a simple system with one predator and one prey population is inherently unstable; predator overexploits the prey, driving it to extinction and then becomes extinct itself
huffaker
if the prey had refuges where some individuals could escape from predators, they could persist while predator populations declined
Predators and prey cycle repeatedly through periods of increasing and then decreasing density, as predators track their prey and some prey escape predation
A long term, stable oscillation pattern can be achieved
parasites
live in close association with another species, gaining nutrition by consuming their hosts’ tissues
Do not kill their host but can reduce host fitness by tapping its resources
Limit the population size of their host, keeping numbers well below the carrying capacity of the environment
herbivory
consumption of plant parts, benefits herbivorous plants by providing some nutrients, and harms plants by direct affecting the products of photosynthesis
Most plants are well defended with chemical or physical deterrents to herbivory
facilitation
indirect attraction between two attacking species that benefits them both
mutualism
interaction when the benefits for each participant outweighs their costs
Each side is acting in its own self interest and bears costs that are weighed against benefits in terms of growth and reproduction
symbioses
close interactions between species that have evolved over long periods of time
obligate mutualism
when one or both sides of a mutualism cannot survive without the other
facultative mutualism
one or both participants can survive without the other
commensalism
one partner benefits with no apparent effect on the other
ammensalism
one partner is harmed with no apparent effect on the other
