Ecological NicheEcological Niche

Ecological nicheEcological niche

The ecological niche describes The ecological niche describes the role an organism plays in the role an organism plays in its environment. It consists of:its environment. It consists of:The species habitat.The species habitat.The organisms activity, the The organisms activity, the period of time it is active.period of time it is active.The resources it obtains from The resources it obtains from the environment.the environment.Eg. A pukeko lives in marsh Eg. A pukeko lives in marsh areas. It feeds of small insects areas. It feeds of small insects and grasses. and grasses.

Fundamental niche and realised Fundamental niche and realised nicheniche

The The fundamental nichefundamental niche of of a species includes the a species includes the total range of total range of environmental conditions environmental conditions that are suitable for that are suitable for existence without the existence without the influence of influence of interspecificinterspecific competitioncompetition or or predationpredation from other from other species. The species. The realized realized nicheniche describes that part describes that part of the fundamental niche of the fundamental niche actually occupied by the actually occupied by the species. species.

Niche differencesNiche differences

Organisms can be identified as eitherOrganisms can be identified as either– GeneralistsGeneralists

Organisms with a Organisms with a broadbroad niche niche

Eat lots of types of foodEat lots of types of food

Live in many types of environmentsLive in many types of environments

Eg. house miceEg. house mice

– SpecialistsSpecialistsOrganisms with a Organisms with a narrownarrow niche niche

Eat a narrow range of food itemsEat a narrow range of food items

Live in few, specific types of habitatsLive in few, specific types of habitats

Eg. panda bearEg. panda bear

Law of toleranceLaw of tolerance

The law of tolerance The law of tolerance states that for every states that for every abiotic factor, an abiotic factor, an organism has a range organism has a range of tolerance within of tolerance within which it can survive.which it can survive.

HabitatHabitat

The habitat provides the The habitat provides the organism with the following organism with the following resources:resources:Mating sites Mating sites Food and waterFood and waterNesting sites Nesting sites Shelter from climate extremesShelter from climate extremesPredator avoidancePredator avoidance

Organisms may or may nit Organisms may or may nit have the adaptations to exploit have the adaptations to exploit all the available resources all the available resources successfully. successfully.

What determines where species can What determines where species can live?live?

All species have requirements for many All species have requirements for many factors/conditions. factors/conditions. – AbioticAbiotic factors – non-living factors; ex. factors – non-living factors; ex.

temperature, precipitation, pHtemperature, precipitation, pH– BioticBiotic factors – other species; ex. prey factors – other species; ex. prey

species, competing speciesspecies, competing species

For each of these factors, species exhibit For each of these factors, species exhibit a a range of tolerancerange of tolerance. . – For example, a fish species may only be For example, a fish species may only be

found within a pH range of 4.5 to 6 in lakes.found within a pH range of 4.5 to 6 in lakes.

CompetitionCompetition

When two species use the same resources, they When two species use the same resources, they are said to compete and their interaction = are said to compete and their interaction = competitioncompetition..– ex. lions and hyenas compete for food in Africaex. lions and hyenas compete for food in Africa

Competition does not necessarily involve Competition does not necessarily involve contact; interaction may be only by means of contact; interaction may be only by means of effects on the resources.effects on the resources.

No two organisms can occupy exactly the No two organisms can occupy exactly the same niche at the same timesame niche at the same time