Tag Archives: Evolution of Diet

Evolution of Birds: New Evidence for Foraging Behavior

Birds evolved during the Mesozoic, during the various “Ages” of the dinosaurs, as a subset of those dinosaurs. Many researchers believe that these early birds were different from their then very close dinosaur cousins because of their flight adaptations, and some have linked this idea to flight-based or tree- based foraging.Today, most birds fly (counting by species) and their flight is linked to their primary dietary adaptation. Some birds actually feed on the wing, while others fly to food sites and once there do not locomote very much. Other birds forage on the ground habitually. The difference between these two kinds of birds should be evident in the morphology of their feet.If you examine bird feet today and can successfully characterize these feet in a way that links reliably to mode of foraging, then you should be able to look at Mesozoic bird (and dinosaur) feet and say something about how they foraged. In this way, you can test the hypothesis that early birds were flight- and tree-foragers rather than foot-foragers. A paper in Current Biology does this. Continue reading Evolution of Birds: New Evidence for Foraging Behavior

Roots Coming Home to Roost

Many years ago a couple of researchers (Hatley and Kappleman) suggested omnivory, including eating of roots, to be a common theme in the adaptations we see in bears, humans, and pigs. Some years later, Richard Wrangham and I independently and for different reasons came to the idea that roots are potentially important in human evolution, so we collaborated on a paper suggesting this. Subsequently, bits and pieces of data have been accumulating to support this hypothesis (the “root hypothesis”). And here, Jim Moore of San Diego, is reporting on living chimps eating roots in a relatively savanna like environment. As we predicted.

Chimps dig up clues to human past? from PhysOrg.com
One of the keys enabling the earliest human ancestors to trade a forest home for more open country may have been the ability to gather underground foods. Now a team of scientists reports for the first time that in Tanzania our closest living relatives, chimpanzees, are using sticks and pieces of bark to dig for edible roots, tubers and bulbs.[]

Plants can help you. They can kill you. And they can get you stoned.

I find it absolutely fascinating that scientists often bother to estimate the effects of diet by feeding controlled quantities of food, especially plant food, to rats to see what happens.For example, there is a common substance in cooked food that, if fed in even modest quantity to rats, causes the rats to get cancer and die in no time. This raises concerns for humans because, well, the rats died. So the substance must be “bad for you.”But this approach to nutritional science, and the reasoning that goes with it, is deeply flawed. Continue reading Plants can help you. They can kill you. And they can get you stoned.