Studying adaptation at the invisible scale

In order to understand adaptation by natural selection, it is necessary to observe organisms in their natural habitat. For this reason, the field of behavioral ecology, which specializes in testing adaptive explanations for biological observations, is dominated by research on larger multicellular animals such as insects, mammals, fish, and birds. The vast majority of modern life sciences, however, is concerned with the study of cells, genes, and molecules, which are often impossible to observe directly in nature. This severely compromises our ability to complement mechanistic understand of traits of interest with adaptive understanding. This matters because only the theory of adaptation can provide an explanation for <i>why</i> biology operates in the way that it does, why it varies across individuals and species, a formal tool for making predictions about the future. The good news is that technological advances are creating new opportunities for understanding cellular and subcellular traits as the products of natural selection.