Who's Special?

Posted Thu, August 6, 2009 - 3:33 AM
philosophy, science, ecology

Recently I've been thinking about ideas that push the boundaries of what we - modern, 21st century Western-culture latte-drinking cell-phone-carrying TV-gossiping fashion-obsessed bipedal hairless apes - are willing to think of as "normal". I think there are some gaps between the world we think we live in, and the world we could actually be living in, even assuming it's still subject to constraints about what we believe to be historically, and physically, possible.

Here's an example - one day I started to ponder the following question: Could a species with intelligence comparable (or better) than humans have evolved at another point in earth's long history? That doesn't fit into the world view I'm talking about, but it certainly isn't a scentifically untenable hypothesis.

So imagine if you will, that nature experimented with an intelligent species of diapsid during the Carboniferous period, 150 million years ago. Say this species lived for oh... 3 million years, and then eventually died out.

Question: How could we learn such a thing?

Here are some random thoughts about indicators that could, or could not, give us some evidence.

• Fossils, with a suggestively large brain/body ratio. This probably would be the "smoking gun", if there were one. Nevertheless, fossils are always a hit-and-miss situation. And I could point to the cephalopods as a great example of highly intelligent animals that leave very little in the way of fossils. But we're talking about diapsids. Very well, they have bones, and a large braincase would be indicative.

Fossils have been the primary way we've learned about the history of life on this planet. But in this case, there might be other kinds of evidence - based on things we're observing now, as a side effect of our own existence. Of course, it's debatable how detectable such changes would be if they occurred that long ago.

• Writing - even if we assumed this intelligent species to be all about promoting themselves, and chiseled all their histories and boasts and conquests and culture into the rocks themselves, it surely would have weathered away in the intervening time. It's quite an assumption that writing existed at all, considering that, as far as we know (not enough surviving documents...) it has only been around for 0.2% of the time that H. sapiens has existed, and we got along fine as an fully "intelligent", social species before then.
• Artificial creations - shaped rocks, sticks, tools, wood, metal, glass, buildings, large-scale organized construction. Perhaps eventually, artificial chemicals, synthetics, plastics. But the question presents itself: could anything, no matter how complex or chemically inert, have lasted in recognizable amounts for timescales on the order of 10⁸ years? Natural building materials – stone, wood, corrodable or reactive metals, etc. – most certainly not. And humans still use these as the predominant component of every large-scale structure we build. Which leads to...
• Plastics? Or generally, synthetic chemicals. Currently, we're terribly worried about the nonbiodegradability of plastics and petroleum products. But what is the degradation time for plastics, even? Could a significant quantity of plastic (say, HDPE, or PFCs) be degraded in 10⁶ years? 10⁷ years? What about 10⁸ years? Could a niche evolve (likely microbial) to use it as food, even after the makers disappeared, then die out themselves when the food was gone? We've already observed bacteria capable of metabolizing hydrocarbons. With this example, there's a further concern about the availability of the raw materials; most of the petroleum on the earth was in fact produced during the Carboniferous Period.
• Engineering - at what scale? Cities? Dams? Taking steps to build Coruscant? In the intervening time, it be dwarfed by natural growth, then weathering, and eventually tectonics and orogeny. Human engineering certainly would. Just look at what has happened to Tikal in only a few hundred years. If we were gone, what would it take to burst Hoover Dam, or topple Taipei 101? What little earthquake could wipe out a hundred square miles of coastline, and how quickly would the leaves and vines ascend when there's no one to rebuild?

Another possibility, rather than actual artifacts, could be secondary effects. See the definition of the Anthropocene epoch for what I'm referring to.

• Extreme and rapid environmental changes - this could be a possible marker as well, if the species was capable of systemically modifying their ecosystem, for example, by widespread deforestation, or geologically rapid changes in atmospheric or oceanic parameters. This would produce secondary effects across the rest of the world's ecosystems that would be observable in the fossil record. Certainly the same effects can be produced by "natural" causes such as volcanism or the famous extraterrestial impacts, but it's not completely implausible that a single species, under the right conditions, could produce a worldwide ecological shift that has a similar signature.

One thing that strikes me, is how we're so damn worried about what's going to happen in the next ten years, or the next hundred, or the next thousand. Our exponents don't go above 3. A human lifetime is only 2 - and at least the Long Now Foundation is thinking of 4 - but complex life is all the way up at 8, and the earth's is more than 9. The history of terrestrial life is literally longer than we can comprehend.

Another question to ask is, how could a species that, by many metrics, was successful, only survive for three million years, rather than some other order of magnitude?

For a possible answer, consider the Toba event of approximately 75,000 years ago. Climactic indicators have shown an intense period of biomass restriction due to the eruption of the Toba supercaldera in modern-day Indonesia. It's likely that plant growth worldwide was stunted for several years by the tremendous amount of ash released, causing an unavoidable (and inescapable crash) in the food chain. Studies have shown that the worldwide population of humans encountered a genetic bottleneck at that time, and that all modern humans may be descended from as little as 2,000 survivors. One can only imagine the hardships those early humans must have faced; weeks of dim sunlight, bitter cold, snow even in the tropics, anemic to nonexistent growth on trees and shrubs, a sudden decrease in game, and eventually, widespread death by starvation just like every other animal on the planet. Is there any reason to believe this imaginary diapsid species would be any less vulnerable to sudden and drastic restrictions in the food supply than our ancestors were?

Another way to phrase this: intelligence may be able to help a species survive better against disease, predators, environmental changes, and other threats, but it cannot help with lack of suitable food sources!

I should give a H/T to a couple of books that have supported my thoughts on these topics. Both are well worth the price, if only for the ideas they conjure up.

Galapagos, a novel by Kurt Vonnegut.

The Story of B, a novel by Daniel Quinn.