"There has been much discussion whether recent forms are more highly developed than ancient. I will not here enter on this subject, for naturalists have not yet defined to each other's satisfaction what is meant by high and low forms" Charles Darwin, Origin of Species 1st edition (on Kindle)
Let me get straight to the issue: if higher and lower are based on phylogenetic position then there are higher and lower humans and that is most unacceptable. Higher and lower is unnecessary baggage from scala naturae when ancestral and derived work just fine but realizing this refers to the characters (not necessarily the organisms) that were analyzed. We still see higher and lower and we see it at my own institution.
"There has been much discussion whether recent forms are more highly developed than ancient. I will not here enter on this subject, for naturalists have not yet defined to each other's satisfaction what is meant by high and low forms" Charles Darwin, Origin of Species 1st edition (on Kindle)
Let me get straight to the issue: if higher and lower are based on phylogenetic position then there are higher and lower humans and that is most unacceptable. Higher and lower is unnecessary baggage from scala naturae when ancestral and derived work just fine but realizing this refers to the characters (not necessarily the organisms) that were analyzed. We still see higher and lower and we see it at my own institution.
It strikes me, though, that this issue framed in terms of complexity makes complete sense, in that the cells of Viridiplantae and Stramenophiles are more complex than those of other Eukaryotes, the cells of all of these are more complex than Bacteria and Archaea, and multicellular Eukaryotes (at least those with specialized tissue) are more complex than unicellular Eukaryotes.
ReplyDeleteAnd that might be true. But organisms can evolve to become simpler and less morphologically complex and yet they are more evolved. But organisms also have a metabolic element and how, if ever, does that fact in? Then I imagine there are probably many cases where these measures conflict. If we simply want to say taxon/clade/lineage X is more complex than Y by measure Z then I'm cool with that. But to imply that arbitrarily selected measure makes something higher or lower is less informative.
ReplyDeleteAyuh. My favorite example of the "simpler yet more evolved" is Trichoplax, which has lost most of the complexity of extant metazoans.
ReplyDeleteWhat is awesome about the amount of information available today is the amount of information available. This also makes difficult to find the natural history gems that I love. So I'm reading some natural history books that do some synthesizing. Where am I in this quest? in 1974 with The Medusa and the Snail by Lewis Thomas.
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