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Remember the Linnaean system of classification that we all studied in High School biology – categorizing living things according to their common characteristics? Scientists are now delving deeper into how life forms are related to each other on a molecular level. As a result, it looks like we’re going to have to rethink the way we name the branches of the Tree of Life. I’m Jim Metzner, and this is the Pulse of the Planet.
Michael Donoghue is a Professor of Biology at Yale University.
“Many of us are familiar with animal groups — things like mammals and birds — those are major branches on the tree of life. Mammals and birds are included in a much larger branch of the tree of life called the amniotes, the things that have, eggs of type that we are used to. And those are included in an even larger branch of uh things that we call tetrapods, the vertebrates that live on land, and have four legs and so forth. Those are included in an even larger branch which is the branch of all the vertebrates that includes also the the bony fishes in the sea and so forth and we can get bigger and bigger and bigger. But many other standardly recognized things are are no longer single branches of the tree of life. A good example of that in the animal world is reptiles. Reptiles is not a single branch of the tree of life. Some of the so-called reptiles are more closely related to mammals and some of the so-called reptiles are more closely related to birds. And they’re not all directly related to one another in a single branch of the tree of life. So as we’ve gone about the business of reconstructing the whole tree we’ve discovered that some things are no longer single branches. And then we have to come up with new names that reflect that new knowledge.”
We’ll hear more about the Tree of Life in future programs.
To hear about our CD please visit pulseplanet.com. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.