Evolution - small to big?

But, as Gould points out, that is a necessary consequence of life starting near the wall of lowest possible complexity. What Wright's article adds to the dunkard's walk analogy is the "rachet" caused by an environment that "holds onto" complexity once it is reached. However, he simply states that this is the case. I don't see any reference to evidence for it but it does have a certain intuitive appeal. This still leaves us with a drunkard walking randomly but now he is accompanied by others who like to lean on the wall and push him away from it. It is still for the most part a random walk.In addtion, a point that Gould makes is that the apparent complexity of life could be taken as simply an artifact of our position and where we view it from. A dispassionate observer would count species and number of individuals and conclude, as Gould suggests, that it was, is and always will be the age of bacteria. The apparent complexity is a tiny blip on the really big picture.

Emotionally I agree with you. And, in one sense, intellectually in that the human brain seems more interesting (more valuable in some way). However, "praiseworthy" isn't a survival trait. In the context that we are having this discussion it is exactly the filling of niches, the diversity that counts. Bacteria win that and are therefore more "praiseworthy".I don't see him (in "Full House" ) as saying anything more than we see this progression only because we have a very biased viewpoint. It isn't a big deal but it is a useful way to step back an look at things. When we are extinct will there be a follow on sentient species? I don't think that is assured at all. Given the time it took us to arise I don't see that there is a strong pressure to select for "smarts".The apparent increase in "aveage complexity" is only there because we don't take a real mathematical average. My guess is that Gould may well be right, the mathematical increase is very very tiny.The average living thing is still a bacteria. Or actuall that might be the median. The average is possibly much less complex. I recently read an article that says bacteriophages are 10 times more prevalent and based on that I suggst that they may represent the most common (and average ) form of life on the planet.

Could you explain this some more?If there are more available niches for large animals why do they go extinct more? If there are more niches for large animals why are the smaller animals more numerous and with more diversity?