In evolution, convergence refers to different groups of organisms developing a similar body structure independently. Birds and bats are a common example: They both have wings, but those wings evolved independently. This concept is very useful for comparative biology, since convergence in the shape is usually related to convergence in the function — different organisms with similar structures usually show similar behavior involving that body structure. Thanks to the phenomenon of convergence, we learn a lot about how extinct species lived by looking at their body structures in the fossil record.
However, this can sometimes be misleading.
In , researchers explore convergence in the skulls of sabre-toothed carnivores. Sabre-tooth skulls, often showing remarkably elongated canine teeth, evolved independently in unrelated groups of animals over more than 200 millions of years. Until now, scientists interpreted that skull shape as an adaptation for eating large animals, assuming each of these carnivores had a similar hunting behavior.
The researchers, however, found evidence against this assumption. They performed a series of biomechanical analyses, studying jaw shape and bite force. These analyses led them to conclude that animals with sabre-tooth skulls prey on animals of a variety of sizes — not just large prey. They also use their skulls to kill in many ways, including a ‘killing bite’ and a ‘canine-shear bite’.
This study shows a disconnect between morphological convergence and functional convergence. Most importantly, it is an example of one essential characteristic of science: the ability of revising long-standing assumptions and assessing their prevalence when new methodologies and ideas are developed.