Walking Back in Time
In December, Rob and I joined 30 or so other folks on a week-long trip to the Galapagos Islands. We went to several of the “younger islands,” bits of rock whose ages range from 0.7 million years old to 1.5 million. Those dates reflect the length of time the island’s surface has been above the water line. Most of the islands were formed by volcanoes, although at least one, Baltra, came to be due to geologic lift.
I came curious as to whether Darwin’s dangerous idea would be obvious still–whether one could get a sense of the forces that shape evolution, sense the power of environmental and ecological pressures to drive natural selection. And you know what? I think you can. Granted, maybe not in a way that stands up to scientifically rigorous review–but you can definitely grok it.
Part of what I saw clearly was the way in which systems become more complex over time. Or, to put it in the converse, how simple those systems are at the outset.
Here’re a few pictures from Bartolome, one of the youngest of the islands:
If you google Bartolome Island, this is the kind of image you’ll see. It’s taken from a viewing station pretty high up, and looks out onto a place where there’s vegetation at the edge of an old caldera. If you come expecting more bursts of green scattered here and there, then the other 99% of the island will come as something of a shock. Most of it looks like this:
That silvery scrub in the middle picture was the prevailing visible life on the island. I think we saw one lava lizard. No birds, no tortoises, no iguana, no feral anything.
Our tour guides said that the astronaut Buzz Aldrin had visited and described this landscape as the closest thing on earth that he’d seen to the moon.
For me, it’s the furthest back that I’ve walked in time. It became so amazingly clear that this place, except at the water line, lacked a soil rich enough to support many sorts of plants, and therefore also many sorts of critters. As you can see, there’s very little in the way of an ecosystem here. And that’s not the case on all the islands. Some are wildly diverse, as Darwin discovered. For him, moving from one island to another allowed him to develop ideas about speciation. For me, it became a chance to wander back and forth through time.