SL Biology - Option C: Ecology (copy)

limiting factor

a component of an ecosystem which limits the contribution or number of a population

biotic factors

interactions between organisms (intraspecific) and between species (interspecific)

abiotic factors

environmental conditions such as light, pH, rainfall and salinity

law of tolerance

proposes that populations have optimal survival conditions that fall within critical maximum and minimum thresholds as a population is exposed to the extremes of a particular limiting factor

optimal zone

the central portion of the law of tolerance curve which has conditions that favor maximal reproductive success and survivability

zones of stress

regions on the law of tolerance curve which flank the optimal zone where organisms can survive but with reduced reproductive success

zones of intolerance

the outermost regions on the law of tolerance curve in which organisms cannot survive

ecological niche

describes the functional position and role of an organism within it’s environment

competitive exclusion

one species uses the resources more efficiently, driving other species to local extinction

resource partitioning

both species alter their use of the habitat to divide resources between them

fundamental niche

the entire theoretical set of conditions under which an organism can survive and reproduce

realized niche

a set of conditions used by an organism after including interactions with other species

mutualism

a type of symbiosis where both species benefit from the interaction

commensalism

a type of symbiosis where one species benefits and the other is unaffected

parasitism

a type of symbiosis where one species benefits to the detriment of the other

biomass

the total dry weight of organic matter in organisms or ecosystems

primary productions

the production of chemical energy in organic compounds by producers

Gross Primary Production (GPP)

the amount of chemical energy as biomass that a producer creates in a given length of time

Net Primary Production (NPP)

the amount of chemical energy that is not consumed by respiration

secondary production

the generation of biomass by heterotrophic organisms driven by the transfer of organic compounds

closed ecosystem

ecosystem which exchanges energy but not matter

open ecosystem

an ecosystem which exchanges both energy and matter with it’s surrounding environment

primary succession

occurs when communities develop on entirely new land without any established soil

endemic species

species which are native to a defined geographic region

alien species

species which have been transferred from their natural habitat to a new environment

invasive species

if an introduced alien species has a detrimental effect upon the pre-existing food chains

cane toads

an invasive species introduced into Australia in 1935 to control the the spread of the sugar cane beetle which was damaging crops which now endangers native wildlife

physical control

controlling the population of an invasive species through manual or mechanical removal or restriction

biological control

controlling the population of an invasive species using a living organism (or virus)

chemical control

controlling the population of an invasive species through the use of chemical agents

biomagnification

the process in which chemical substances become more concentrated at each trophic level

bioaccumulation

the build up of a chemical substance in the tissues of a single organism

indicator species

species which are sensitive to specific environmental conditions whose growth or reduction indicates changes to the environment

biotic index

compares the relative frequency of indicator species and provide an overall assessment of environmental health

biodiversity

the variety and variability of all living organisms within a given ecological area

Simpson’s reciprocal index

a measure of the relative biodiversity of a given community