6a Flashcards
community
the group of interacting species with an area
population
the total group of a specific species from a particular area
Ecosystem
the community and all the nonliving components of the area
Biosphere
the whole ecosystem that describes the entire planet. (lithosphere and atmosphere)
List the four major factors that determine population growth
birth, death, immigration and emigration;
Natural increases occur when the difference between birth and death is greater.
Define exponential growth
growth which as the point of recording has a growing offspring population than deaths this will produce a j shape on a graph. This often happens when there is an increase of food or invasive species have no natural predators.
logistic growth
S shaped population curve when new populations stabilise as a result from environmental resistance these resistance could either biotic (living like prey/predator population) or abiotic (environmental like weather, temperature)
boom-and-bust cycles
when a population size rapidly grows until the carrying capacity is reached, which then the population will rapidly decile, creates a curve on tha population graph.
carrying capacity
the capacity of which the ecosystem has to hold a population before stuffing damage. If the carrying capacity is exceeded this can risk perinatal decreasing the carrying capacity.
Define density-independent mortalitiy factor
limit population size regardless of the population density (weather)
define density-dependent mortality factor
control population as pressure increase as population increase (predation and interspecific and intraspecific competition)
Define the term ‘co-evolution’,
when two or more species reciprocally affect each other evolution as a ct as agents of natural selection. Consider predators killing the weaker population and the phenotype and genotypes become rarer for those species, the predator then adapts to hunt to more difficult species populations.
Define ‘ecological niche’
when the species occupies a specific habitat for reproduction and survival, these can be broad or narrow. The role refers to how the species engages with the community in the ecosystem.
Define ‘competition’
interaction between species in which both are harmed. Includes intraspecific (same specifics share the same resource) interspecies (multiple species share the same limited resources).
define interspecific
one of the species may be out-resourced and go extinct or develop an uneasy alliance with the competitor.
