In “The species that evaded extinction,” (New Scientist, 13 September 2011), Colin Barras reports
Life has notched up something like 3.8 billion years on Earth, and it has been a rough ride. The average mammalian species, for instance, rarely makes it much beyond its millionth birthday before evolution ushers it out of existence by churning out a replacement species that’s an even better fit to its particular environment. Even species who survive this never-ending competition are likely to be snuffed out during a rare mass extinction event.
But the fossil record suggests that every so often evolution hits the jackpot: an organism so impeccably and robustly suited to its environment that further modification is apparently unnecessary. These ancient survivors count their time on Earth in the tens or hundreds of millions of years, and seem able to endure the bleakest of mass extinctions. Darwin had a name for them: living fossils. That peculiarly oxymoronic moniker, too, has survived – for around 150 years.
“Living fossil”: Another Darwin term that, along with missing link, now that New Scientist mentions it.” Both terms reliably turn one’s thoughts into falling dominos, falling on a set path, wiping out useful thinking.
If it’s living, it’s not a fossil, or anyway, we don’t know it as one. We know it as a living organism. How about “durable species”?
Perhaps it is because the most durable of survivors are so unimpressive in appearance that Fortey buries them in the middle of the book.
Okay, so looks don’t matter. What does?
We begin and end with far more charismatic – and younger – survivors, including lungfish similar to those found in 220-million-year-old rocks, and horseshoe crabs that have changed barely a jot in 450 million years. The latter appear on the front cover (perhaps inevitably, given that they are the closest living relatives to the trilobites Fortey spent many years studying). Horseshoe crabs are noteworthy for their blue blood – which seems only appropriate for an organism whose ancient looks make it as deserving of regal status as any in the animal kingdom.
Why do we always retreat to romanticism when we are on the risk of asking key questions like; Why durability?
Maybe “static species”is better. That’s what we are talking about. Thoughts?
See also: For daddy long legs, evolution never happened, it seems
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