Parasites can take many forms. Just this week, I’ve written about a giant virusthat reproduces inside amoebae (and has survived being frozen 30,000 years in permafrost), along with a wasp that performs brain surgery to zombify hosts for its young. Viruses and wasps are radically different organisms–some would say that viruses don’t even deserve the label of organism. And they make use of their hosts in different ways. The virus sits inside a cell, manipulates its biochemistry to build virus proteins and DNA. The wasp, on the other hand, sips fluids inside a still-living roach, and builds its own proteins and DNA–and then becomes a free-living creature that can climb out of its host and fly away.

So why are they both parasites? The answer lies beyond the details of anatomy and molecules. It’s all about relationships. Continue reading “The Information Parasites” →

My late winter is revving up into a state of rolling semi-controlled chaos, and so I’ve let a few items slip here at the Loom. Consider this a catch-up post.

1. On Thursday, I wrote my “Matter” column for the New York Times about an intriguing experiment on the evolution of learning. As I’ve written before, animals pay a price to become better learners, and so scientists have been investigating what the benefits are for different species. It turns out that competition for sex can drive the evolution of better learning, at least in flies. Randomly pairing flies into monogamous couples for a hundred generations leads to worse learning. Continue reading “Catching Up: Resurrected Viruses, Sex-Driven Smarts, And Some Upcoming Talks” →

About 4.567 billion years ago, a quivering bead of magma 93 million miles from the Sun cooled down until it grew a skin of rock. Eventually, it would be named Earth. We don’t know a lot about what the planet was like back then, because that primordial crust is almost entirely recycled–eroded away, pushed back down into the molten depths of the planet, or smashed to bits by the huge impacts that blasted Earth for its first few hundred million years.

Geologists have wandered the planet to find scraps of the infant Earth. One mineral that is particularly precious to them is known as a zircon. Tiny zircon crystals can withstand billions of years of abuse–getting ripped out of their original rock, incorporated into new rocks, heated up, and squeezed at tremendous pressures–and yet still retain their original chemistry. Zircons have the added attraction of holding onto radioactive isotopes such as uranium. Over billions of years, the uranium decays at a steady rate into lead. By measuring the atoms of uranium and lead in a zircon, scientists can get a tight estimate of the zircon’s age. Continue reading “Searching For the Oldest Pieces of Earth” →