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5. Development
The response of an individual to a particular stress may be affected by the response of others within the same population or community.
Every plant has neighbours of the same or different species. These neighbours may interact, which could affect their survival in various ways. There may be no appreciable effect, a beneficial effect or an inhibitory effect. A beneficial effect is found in herd or shoal behaviour: fish and mammals will group together to improve their individual survival chances. Group behaviour is also seen in predators' hunting strategies, such as lions, which work in groups to isolate and bring down their prey. Perhaps the best examples of non-human social behaviour are those of the social insects: ants, bees and termites. These form complex colonies, with individuals specialised in form and function for particular tasks.
An inhibitory effect is different from simple competition for scarce resources, in that inhibitory mechanisms are seen as attributes that have evolved specifically to inhibit or deter competitors. 'Direct interference' is an expression used by ecologists to identify situations in which a species adds or removes a substance from the ecosystem although this substance is not required by the species itself, but has a negative effect on its competitors. It is this effect on competitors that influences the survival of the original species.
Can you distinguish between individual and group behaviour?