Ecological Niches

An ecological niche is the role of a species within its ecosystem

--> includes what it eats, the abiotic and biotic factors acting on a species

No two species can fill the same niche within a habitat

Food is obtained through different modes and competition is minimised

Organisms have to adapt their behaviour and physicality to carry out their role

Resource partitioning: species occupying an ecological niche will show adaptions to avoid competition

Obligate aerobes require continuous oxygen supply

• Live in oxic environments

• Rely on aerobic respiration

E.g all animals and plants

Obligate anaerobes are killed by oxygen

• Live in anoxic environments

• Only carry out anaerobic respiration

E.g. clostridium tetani

Facultative anaerobes grow better with oxygen but can live without it

• Live in both oxic or anoxic environments

• Mainly respire aerobically but can switch fully to anaerobic respiration

• Yeast

This species has certain physiological tolerances in temperature, salinity that determine where the species can exist

Each of the abiotic factors has an optimum range

Outside the optimum range are zones of stress, where the species can survive, but experiences physiological stress

Beyond the zones of stress, are zones of intolerance, which represent conditions the species cannot tolerate and won't be found

The tolerance ranges for all relevant abiotic conditions represent species fundamental niche

Species interactions (predation, mutualisms) may result in this species not being found throughout its entire fundamental niche