The recording of this program from 5 Dec 2023 is now available online

On the job chasing feathered dinosaurs (photo courtesy of Ashley Heers)

The program starts 40 seconds in.

Evolution of Avian Flight with Dr. Ashley Heers

Birds are the Olympic athletes of the animal world. Flight is the most physically demanding mode of locomotion and birds take even that to an extreme, during behaviors like hovering, long distance migration, high altitude flight, or even “flying” underwater at great depths. Birds are able to accomplish these feats due to a suite of specialized anatomical features, including large wings, hypertrophied muscles, and robust skeletons. But birds did not start out with these specializations — the developmental and evolutionary beginnings of birds look very different. Most hatchlings are not capable of flight and have very rudimentary anatomies: small or nonexistent wings, underdeveloped muscles, less specialized skeletons. This transition from flight-incapable hatchling to flight-capable adult is extremely dramatic, both in terms of anatomical change and corresponding improvements in locomotion. The evolutionary beginning of birds was equally dramatic. Birds evolved from a subset of theropod dinosaurs over millions of years, during one of Earth’s great evolutionary transformations. How do birds function during these major developmental or evolutionary transitions? In other words, what do birds with rudimentary or transitional anatomies do? Here, Dr. Ashley Heers will explore the functional relevance of rudimentary wings in baby birds and their extinct dinosaur ancestors.

Dr. Ashley Heers is Assistant Professor of Biology at California State University, Los Angeles, where she teaches Anatomy and Physiology and Comparative Vertebrate Anatomy. Her post-doc was at Stanford University; she also worked at the American Museum of Natural History in New York City. She has been fascinated by birds since high school when she discovered that the birds in her back yard were actually living dinosaurs.

A baby feathered dinosaur before they get large, mean and hungry. (photo courtesy of Ashley Heers)