The Oldest Living Things On Earth

Carl Zimmer in his excellent blog, The Loom:

It is easy to feel sorry for the gastrotrich. This invertebrate animal, the size of a poppy seed and the shape of a bowling pin, swarms by the millions in rivers and lakes. After it hatches, it takes only three days to develop a complicated body, complete with a mouth, a gut, sensory organs, and a brain. Having reached maturity in just seventy-two hours, the gastrotrich starts laying eggs. And after a few more days, it becomes enfeebled and dies of old age.

To squeeze a whole life into a week seems like one of nature’s more cruel tricks. But that’s only because we are accustomed to measure our lives in decades. If the ancient animals and plants featured in this book could look upon us, they might feel sorry for us as well. We humans marvel at the longest-living human on record, Jean Calment, who lived from 1875 to 1997. But for a 13,000-year-old Palmer’s oak tree, Calment’s 122 years rushed by as quickly as a summer vacation.

Palmer’s oaks, gastrotrichs, and all the species in between are the products of evolution. The head-swimming diversity of life is joined in an evolutionary tree made up of tens of millions of branches. And one of the most spectacular of that diversity’s dimensions is longevity. If natural selection provides Palmer’s oaks with millennia, why does it only spare a gastrotrich a week of existence?

More here.