The gang discusses two papers that use morphometrics to investigate patterns of selection on bird morphology. The first paper looks at the morphology of feathers, while the second paper looks more broadly at various parts of the avian body. Meanwhile, James breathes new life into a classic, Amanda is passionate about formatting, and Curt exposes "the truth".

Up-Goer Five (Curt Edition):

The friends talk about two papers that look at animals that move in the air. Both of these papers look at how these animals look and try to find out why these animals look the way they do. The first paper looks at the different types of soft things that these animals use to fly and also to stay warm. They look at how these soft things look and how that look has changed over time and between groups. Some of these animals that don't fly have soft things that are different from the ones that do fly, but they way they are different is different with each group that does not fly.

The second paper looks at parts of these animals like their mouths to see how they change between groups. They find that there are lots of things these animals could be doing that most of them are not doing. This makes them say that maybe there is something keeping the animals looking like that because if they change too much in one way it might be really really bad for them.

References:

Sayol, Ferran, et al. "Biophysical constraints on avian adaptation and diversification." BioRxiv (2023): 2023-10.

Saitta, Evan T., et al. "Feather evolution following flight loss in crown group birds: relaxed selection and developmental constraints." Evolution (2025): qpaf020.