mineralogy

Any gardener can tell you that earthworms play a major role in soil ecology. But that information hasn’t always been common knowledge. Charles Darwin was one of the first to study earthworms, and in 1881, he discovered the curious fact that many species leave behind calcite crystals as they work their way through the soil. Now, new research might shed some light on the enduring mystery of how and why earthworms produce the crystals.

Taxonomy, the science of classification, connects creatures through genealogical relationships. But taxonomist Carl Linné (Linnaeus) didn't stop with living organisms; he applied his system to all natural objects — even minerals. And according to a new study, he may have been on to something: Iron may not pass genes to its rusted cousin iron oxide, but like living organisms, minerals have evolved considerably over the course of Earth’s history.