The role of behaviour in evolution
Species behaviour has the potential to lead morphological evolution, by placing the organism under novel selection pressures. Many adaptations of living species could have originated in this way, although there are few documented examples.
Our research focuses on the fossil record, a potentially rich but under-exploited source of information on the role of behaviour in evolution.
The behaviour of fossilised species is traditionally deduced from their morphology. This prevents researchers from observing behavioural changes that may occur prior to morphological evolution. Examining behavioural proxies independent of adaptive morphology may help us to address this problem.
Examples of 'fossilised behaviour' include dietary information (wear traces on teeth and stable isotopes) and trace fossils indicating locomotor mode (footprints). The signature of a behavioural lead would be an observed shift in behaviour from one horizon (or species) to another, followed later by a morphological change relating to function.
Fossil case studies that suggest a behavioural role in evolution include:
- feeding shifts in finely resolved sequences of vertebrates, ranging from freshwater fish to terrestrial ungulates
- locomotion changes crucial to major evolutionary transitions in the origin of tetrapods, birds and humans
These examples suggest that behaviour is central to the process known as exaptation, in which structures acquire new functions.
Using fossil sequences to clarify behavioural roles is challenging. Problems include insufficient stratigraphic resolution and uncertainty over the adaptive function of observed traits. Researchers should consider these limitations in order to select promising research and formulate testable hypotheses about evolutionary modes.
Read more about behavioural leads in evolution in Dr Adrian Lister's paper in the Biological Journal of the Linnean Society.