I, Asteroid
A new study by the Audubon Society has found that bird populations are in a precipitous decline. The "state of the birds" report, entitled Common birds in Decline, is based on survey data compiled in the US over the past 40 years and the results are profoundly troubling to anyone with knowledge of population dynamics and trophic webs. For example, the populations of 8 formerly common species has declined by more than 70%, and 20 have declined by more than 50%. Because the starting populations of these species was initially very large in most cases they don't qualify for endangered status (yet), but that should not be construed as indicating that this isn't a major warning sign of what looks very much like the initial stages of a mass extinction.
Taken together with the massive die-offs of amphibians, primates and plants, and the fact that much of what's happening has been caused by human alteration of environments, it adds up to a very sad portrait of the state of life on earth in the face of mankind's ever-expanding niche. We seem to be the equivalent of the causes of the massive die-offs that occurred at the end of the Cretaceous. A fellow named Aleister Crowley once said that "every man and woman is a star." I think he was as wrong; we're more like asteroids.
It's hard to find a bright spot in any of this, but there is one if looked at from the right angle. It's not good news for our own species, nor for most of the others, but it's very good news for a few hardy little generalist organisms. When we look back through the history of life, one thing that becomes immediately apparent is that periodic mass extinctions are always followed by rapid evolutionary radiation of the survivors. The mass extinction that marks the end of the Cretaceous, for example, was followed by the rise of mammalian dominance without which we ourselves would not be here. Similar events triggered the profound shifts in group dominance at several other points in evolutionary history: the end of the Cambrian, Ordovician, Permian, etc. All of these together add up to what we see now. Life will find a way, and the end of one age always turns out to be the beginning of another. We just won't be here to see it.
There are some likely survivors, though, and we don't have to look too hard to find them. We can be rather certain that many insect taxa will survive. There is almost certainly going to be some form of ant around, and cockroaches are famous for their adaptability and overall toughness. Rats, raccoons, sea gulls and squirrels will undoubtedly have descendants that will survive whatever we do to the planet, so long as there's still free oxygen and liquid water. The earth will never be rid of dandelions, crab grass and kudzu, no matter how hard we try to wipe them out. Life will go on; it will have a different composition than it does now (which is already arguably different from what it was just a few thousand years ago).
Since it's currently impossible to predict what that new make-up will be, it's fun to speculate on whether something resembling human intelligence might arise once again. One can imagine a world tens of millions of years from now in which rat-descended paleontologists discover a layer of debris and fossils and conclude about it the same things that present scientists think about when looking at the K-T boundary. Perhaps they will someday have their own version of the Discovery Channel on which grave-voiced narrators will warn viewers that it's happening again, that they must change their ways or face their own extinction. Perhaps they will have web pages that solemnly document the disappearance of entire branches of the "tree of life," just as the frogs and herons disappeared from the earth in those dim days of the latter Holocene.
On the other hand, one might also consider that maybe this whole intelligence thing will turn out not to have been such a good survival strategy after all. There may be a whole new solution to the problems of living long enough to pass on genes. It's a fascinatingly wide-open area for any kind of speculation in which one cares to indulge. Life not only finds a way, after all; it finds many ways.
As a self-interested mammal, though, I wouldn't mind not being part of the cause of a mass extinction that might well include my own descendants. Moreover, I like the birds and salamanders and hoverflies and all. I'd like them to continue their existence on earth out of, if nothing else, my own personal aesthetics. I enjoy the songs of the birds in the daytime and the tree frogs at night. I derive great pleasure from staring into the eye of an alligator and the knowledge that there are lions roaming the African savanna. I'm a biophile; the thought that I might be part of the cause of an extinction event is a tremendously unhappy one. I never intended to be an asteroid.
