How gliding animals fine-tuned the rules of evolution

SEPTEMBER 23, 2019

by Lachlan Gilbert, University of New South Wales

A study of gliding animals has challenged the idea that evolutionary innovations—adaptations that bring new abilities and advantages—spur the origin of other new body types and other characteristics in descendant species.

The research, undertaken by evolutionary biologists at UNSW Sydney and universities in the US and Spain, examined the key innovation of gliding in two types of gliding animals: 'flying' dragons (family Agamidae) and 'flying' squirrels (family Sciuridae), both common to forests in South East Asia.

The study confirms previous assumptions that gliding animals originated from arboreal ancestors and likely arose as a means of escaping predators some 25-30 million years ago.

Lead author Dr. Terry Ord, an evolutionary ecologist with UNSW's Evolution & Ecology Research Centre, says another advantage that gliding brought was the ability to exploit a new three dimensional environment and explore more of the forest than just one tree.

"From an evolutionary biologist's perspective, these types of innovation that open up new opportunities are assumed to drive even more adapted diversification," Dr. Ord says.

"Suddenly there's all these new microhabitats available offering up new resources and you have new species moving into those particular microhabitats where you would expect them to adapt even more."

Winging it

The evolution of flight in birds, insects and bats is an example where the changes brought about by 'taking to the wing' caused an explosion in diversity. Millions of species of insects, tens of thousands of birds and more than a thousand species of bats developed greatly different shapes, sizes, behaviours and habitats since their ancestors first evolved to fly.

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