4 Thinking about adaptation
Section 3 identified a range of adaptations in insect eaters, most linked with their mode of feeding. Particular structures are identified as having particular functions. But there are problems with the concept of adaptation if it's taken too far. Not all features of an organism have to be functional in ways that perfectly suit that organism to its environment. In fact, the whole notion of the 'perfection' of animals and their workings is best avoided. The TV programme shows, for example, some of the shortcomings of the hearing mechanisms that long-eared bats use to locate their prey.
Remember too that a particular species is 'here and now' - it's at one point in its evolution. Species very often retain structures that are vestiges of their evolutionary past. For humans, the appendix (part of the large intestine) is one such organ you might be familiar with. If you study evolution in greater detail, you'll come across many other examples of such 'vestigial structures,' as well as numerous examples where we have little idea about why and how a particular behaviour or complex structure arose and its role in a mammal's natural habitat. Being enthusiastic about the wonders of mammalian life, as LoM and the TV programmes very properly are, is fine, but don't run away with the impression that mammals are perfect, either in the sense that they are the most efficient and complex systems imaginable or that they are ideally suited to every aspect of their environment. This notion is so important that we'll return to the idea of adaptation in the next course in this series, when we will use further mammalian examples to look critically at the meaning of the term.