Friday, September 05, 2014

Taste and Evolution

Anna's hummingbird
Most of us get in line at the ice cream shop or tear into a piece of chocolate cake without giving much thought to why we like what we do. Humans appreciate a wide variety of tastes because of our omnivorous evolutionary history and the genes we carry that allow us to sense sweet, salty, sour, bitter, and umami (i.e., savory) flavors. But the same isn't true of all animals. Most cats, for example, dubiously sniff at sweets. This is because, over the course of its evolutionary history, the feline lineage lost a functional gene to detect sweet flavors. Birds also lack this gene and, usually, the sweet tooth that comes with it — but there are a few notable exceptions. Hummingbirds, for example, make a proverbial beeline for honey-sweet liquids. Why are hummingbirds sugar junkies, while robins stick with worms? New research reveals at a genetic level the evolutionary changes that account for such diverse tastes./.../

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