Getting your teeth into evolution
Development of jaws in vertebrates is considered one of the key changes in the history of animal evolution and forms the basis of the whole of vertebrate biodiversity. Researchers from an EU-funded project tested the hypothesis that the tooth-like structures in jawless vertebrates predated the origin of jaws. Scientists also studied whether teeth were present in placoderms, fish-like vertebrate with bony plates on the head and upper body and considered the earliest vertebrates to possess jaws. The ‘Jaws emerge: Insight from placoderms to resolve the evolutionary emergence of gnathostomes (JAWS Emerge) project used state-of-the-art microscope technologies to study tooth-like structures in the gill area of a primitive jawless vertebrate known as Loganellia scotica. Findings revealed that the structures were internal scales and different from the teeth of jawed vertebrates. Examination of the relationship between these internal scales and teeth indicated convergent evolution. This is a process whereby organisms not closely related independently develop common traits when adapting to a similar environment, for example teeth in jawed vertebrates. Thanks to the work of the JAWS Emerge consortium in testing the hypothesis regarding the development of jaws and teeth, scientists now have a fuller understanding of vertebrate evolution. The project has therefore had a significant influence on palaeobiology, evolutionary biology and developmental genetics.
