Simanaitis Says

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HOW COME tree-of-life diagrams always have humans at the top?

A heady thought, this.

There are subtleties galore in today’s evolutionary theory. Indeed, profound changes are taking place in how we fit into the greater picture. Today’s SimanaitisSays might well invoke humility on our part. Tomorrow’s item is even more daunting: How is the concept of evolution itself evolving?

Steven Rose discusses these aspects in “Coloured Spots v. Iridescence,” his review of Jonathan B. Losos’ book Improbable Destinies: Fate, Chance, and the Future of Evolution, in the March 22 2018, issue of London Review of Books.

A Traditional Tree of Life. LRB reviewer Rose observes, “As humans, we tend to regard large brains and intelligent behavior as the high point of evolution, an apogee toward which life has been striving ever since the appearance of the first single-celled organism.”

Haeckel’s Tree of Life, 1879.

Like many early evolutionists, German Ernst Haeckel, 1834-1919, considered humans to be the pinnacle of evolution. By contrast, Charles Darwin, 1809–1882, was rather more cautious in assigning levels of evolution. Modern thought offers nuances of evolutionary success.

Other Measures of Success. As Rose notes, “intelligence isn’t the only measure of success, and anyway, even on brain size and complexity, dolphins beat us.”

In fact, in terms of neural complexity, so do octopuses. As discussed here at SimanaitisSays, octopus neurons are distributed throughout its body. It has been described as an “independent experiment in evolution of large brains and complex behavior.”

“Choose other criteria,” Rose says, “and we fail miserably. On the basis of biomass or numbers of individual organisms, ants match and bacteria outnumber us. If it’s longevity you want, better to be a giant redwood.”

The “Sentinel Tree,’ a giant redwood, Sequioadendron giganteum, in Giant Forest Grove, Sequoia National Park, California.

On the other hand, I’m also reminded of Winston Churchill’s comment: “History will be kind to me, for I intend to write it.”

Tomorrow at SimanaitisSays, LRB reviewer Rose asks, “What if evolution were rewound and rerun? Would we even be here?” ds

© Dennis Simanaitis,, 2018

One comment on “THE TREE(S) OF LIFE

  1. MikeB
    May 8, 2018

    History (and the family tree) is defined by the victor (or at least by the one doing the drawing).

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