the idea of the extended phenotype has been developed by richard dawkins to mean all the effects a gene has on the outside world that may influence its chances of being inherited. these can be effects on the organism carrying the trait, the environment, or other organisms. for instance, a beaver dam might be considered a phenotype of beaver genes, the same way beavers' powerful incisor teeth are phenotype expressions of their genes. dawkins also cites the effect of an organism on the behaviour of another organism (such as the devoted nurturing of a cuckoo by a parent clearly of a different species) as an example of the extended phenotype.