ABSTRACT
The most obvious trait of any biological organism is its functionality. It is so universal that its presence was almost unnoticed until the early 19th century. Charles Darwin’s (1859) fundamental contribution to biology was to propose natural selection and adaptation as the explanation for the great variety of seemingly intelligent design in Nature. In biology, the most common use of the word
adaptation
is the modiÞcation of a trait by natural selection during evolution. For example the white camoußage color of hares in winter and their gray-brown fur in summer can be referred to as adaptations. Here we refer to adaptation in a wider sense: as any process that allows adjustments to the environment. The high importance of adaptation for biological units can be seen from the fact that there are three separate ways
that adaptation takes place in biology (Figure 33.1). All three types of adaptation may partly determine individual behavior; whichever is dominant may depend on the current circumstances. We refer to them as different levels of adaptation, which reßects the different timescales that they work on. Although most models of populations and organisms do not specify any process of adaptation, or assume the dominance of a particular kind of adaptation, the idea of adaptation underlies most, if not all, theories and models in ecology. If not for genetic adaptation, one could not assume that a parameter value measured for some individuals also would apply to other members of the population. If not for phenotypic plasticity, one could not assume life history adjustment resulting from climate changes. And if not for learning and memory, one could not assume group dynamics and territoriality.
