Another day, another meeting report: this time a lecture I attended by Cambridge palaeobiologist Simon Conway Morris on ‘Nine evolutionary myths: the closing of the Darwinian mind?’. In fact this meeting took place a couple of weeks ago, but I’ve only now got around to writing about it. Conway Morris is always stimulating because of his willingness to think outside the box, even though he gets accused of being a creationist (which he most definitely is not) for doing so. In short, his nine myths were:
1) The myth of randomness. Evolution is constrained and its biological products seem to express a “self organising principle”. The evidence of widespread evolutionary convergence suggests “navigation towards an attractor”, but what is the attractor?
2) The myth of deep homology. Predependence on certain widely distributed regulatory genes does not explain, for example, the homology of eyes in creatures as different as cephalopods and vertebrates quite as tidily as some have imagined.
3) The myth of simplicity. However far back you go in evolutionary history, things are complicated. While eschewing the notion of irreducible complexity, the bacterial flagellum and its homologues illustrate the complexity of even the simplest organisms.
4) The myth of “Well, it will do”. Organisms are not cobbled together as a series of adequate compromises but are close to optimality. Examples of supposedly “poor design” often turn out to be “very well engineered indeed”.
5) The myth of a good fossil record. The overall history of life may be well known (Conway Morris would be horrified to find an Ordovician human!) but many pieces of the jigsaw puzzle are still missing.
6) The myth of “missing links”. Convergence in fossil lineages is ubiquitous, such that, for example, theropods must have evolved flight independently multiple times. The evolution of birds (and theropods and tetrapods, etc) was, in some sense, inevitable.
7) The myth of mass extinctions. Mass extinctions made much less difference to the history of life than many have suggested. Bivalves would probably have come to dominate with or without the end-Permian event and likewise with the dominance of mammals after the end-Cretaceous event.
8) The myth of mentality. Sentience goes back much further than we tend to imagine and the molecular equipment for nervous systems evolved long before nervous systems themselves.
9) The myth of extraterrestrials. Although there are probably billions of habitable planets in our galaxy, the ETs are still elusive. The best explanation is that we really are alone.
Some interesting things to ponder…