>
> At first I thought I understood what you were saying. Since mammals are a
> tiny part of the biosphere, the complexity of the biosphere hasn't
> increased since the advent of multi-celled organisms.
>
That's not what I said at all. You had said that mammals were becoming more
complex as they evolved. I said that in fact they were not becoming more
complex because the mammalian level of complexity was simply being reshuffled
and rearranged. I said nothing about comparing mammals with the biosphere.
>
> But you seem to be saying a
> human brain is no more complex than that of a cow--only differently
> organized. (I'd sure like to hear the views of a neuro-biologist.)
>
A neurobiologist told me that.
>
> In any
> case, how about a reptile. Is a human brain (or central nervous system)
> more complex?
>
Brain? Yes, but only in the sense that the human brain has a larger
structure. CNS? No, at least not from an anatomical, physiological or
biochemical standpoint.
>
> Or a fish--the varieties present billions of year ago, not octopus.
>
Same answer as above. "Not octopus" what?
>
> Or a worm?
>
Same answer as above, except that worms do not have brains.
>
> If there was any increase in complexity since the appearance of
> worms, when would you consider it occurred?
>
This is a different question. Complexity has been increasing continuously
since worms first appeared, at different rates for different systems, but
only in certain ways. Biochemically and physiologically there has been
almost no change, but some systems have undergone a great deal of anatomical
change. Again, however, any increase in complexity simply represents an
increase in structure.
Kevin L. O'Brien