 Lorenz’s analysis can readily be expressed in information-theoretic terms, with the environment as the signal source and the organism as the receiver. Organisms need to reduce their uncertainty about what demands the environment will place on them and to develop in a way that meets those demands. There are two ways to do this. The first way is to gather information about the environment during development. The water flea Daphnia pulex monitors chemical traces of predators as it develops. If an individual flea detects evidence that predators are present, then that flea grows defensive armor. Thus, a flea’s possession or lack of defensive armour reflects environmental information. The alternative is to inherit information from your ancestors. The human sickle cell allele has harmful effects in homozygotes and survives in a population only because it confers resistance to malaria in heterozygotes. Hence the fact that an individual carries the allele provides information about the prevalence of malaria in the ancestral environment and thus, probably, in the environment of the organism which inherits the allele. The sickle cell allele can thus be seen as passing on information about the environment which was ‘learnt’ by ancestors through natural selection. To the extent that the functional adjustment of a trait to its environment is explained by ‘inherited information’ of this kind, Lorenz argued, the trait is innate. Hence, albeit in a very different way from Tinbergen, Lorenz also came to see whether a behavior is an adaptation as the key issue.