Tinbergen's Four Questions - Causal Relationships

Causal Relationships

The figure shows the causal relationships among the categories of explanations. The left-hand side represents the evolutionary explanations at the species level; the right-hand side represents the proximate explanations at the individual level. In the middle are those processes’ end products—genes (i.e., genome) and behavior, both of which can be analyzed at both levels.

Evolution, which is determined by both function and phylogeny, results in the genes of a population. The genes of an individual interact with its developmental environment, resulting in mechanisms, such as a nervous system. A mechanism (which is also an end-product in its own right) interacts with the individual’s immediate environment, resulting in its behavior. Here we return to the population level. Over many generations, the success of the species’ behavior in its ancestral environment (or more technically, the environment of evolutionary adaptedness ) may result in evolution as measured by a change in its genes.

In sum, there are two processes—one at the population level and one at the individual level—which are influenced by environments in three time periods.