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There’s a cool new Web site—and iPhone app—that could ____1____ in a wide variety of circumstances. It’s called Time Tree. And it tells you how closely related any two organisms are over time. In other words, it’ll tell you what the available data say is the time since any two organisms shared a common ancestor. Time Tree is ____2____ run by Penn State’s Blair Hedges and Arizona State’s Sudhir Kumar.
So let’s say you’re out for a walk in the woods, with your iPhone handy, and you ____3____ a grizzly bear. You quickly load the app and ____4____ the two organisms you’re interested in. Those would be you, a human, and grizzly bear, the thing that’s approaching you alarmingly fast. In just a couple of seconds, you are informed that you and the grizzly bear shared a common ancestor just 98.2 million years ago.
If you have a computer and are just curious about the grizzly bear, go to . The results average the findings of published papers ____5____ your search and include links to the papers.