WHY do living things die? Obviously, things kill each other – that’s part of the natural order. But what causes “natural” death? It is a question that splits biologists. It has become like a game of ping pong – over the years, theories have been batted back and forth as new evidence comes to light.
One answer is that death is simply necessary – to avoid overcrowding, for instance. But evolution doesn’t – can’t – select for a “death switch” because evolution is supposed to be all about the individual. And yet there does seem to be a death switch – researchers have managed to locate genetic switches that massively extend the lifespan of some nematode worms.
That might seem a long way removed from where we’re at, but there are vertebrates that live a very, very long time. Blandings Turtles, just don’t seem to get old and decrepit, for example. Teasing out why that might be is a tricky job – but potentially worth it.