R.I.P. Lynn Margulis, Biological Rebel

[TacticalPeek]

R.I.P. Lynn Margulis, Biological Rebel

By John Horgan | November 24, 2011


Lynn Margulis was among the most creative challengers of mainstream Darwinian thinking of the late 20th century. She challenged what she called “ultra-Darwinian orthodoxy” with several ideas. The first, and most successful, is the concept of symbiosis. Darwin and his heirs had always emphasized the role that competition between individuals and species played in evolution. In the 1960′s, however, Margulis began arguing that symbiosis had been an equally important factor–and perhaps more important–in the evolution of life. One of the greatest mysteries in evolution concerns the evolution of prokaryotes, cells that lack a nucleus and are the simplest of all organisms, into eukaryotes, cells that have nuclei. All multi-cellular organisms, including humans, consist of eukaryotic cells.

Margulis proposed that eukaryotes may have emerged when one prokaryote absorbed another, smaller one, which became the nucleus. She suggested that such cells be considered not as individual organisms but as “composites.” After Margulis provided examples of symbiotic relationships among living microorganisms, she gradually won support for her views on the role of symbiosis in early evolution. She did not stop there, however. Like Stephen Jay Gould and Niles Eldredge, authors of the punctuated equilibrium hypothesis, she argued that conventional Darwinian mechanisms could not account for the stops and starts observed in the fossil record. Symbiosis, she suggested, could explain why species appear so suddenly and why they persist so long without changing.

Margulis’s emphasis on symbiosis led naturally to a much more radical idea: Gaia. The concept and term (Gaia was the Greek goddess of the earth) were originally proposed in 1972 by James Lovelock, a British chemist and inventor. Gaia comes in many guises, but the basic idea is that the biota, the sum of all life on earth, is locked in a symbiotic relationship with the environment–the atmosphere, the seas and other aspects of the earth’s surface. In fact, the biota chemically regulates the environment in such a way as to promote its own survival. Margulis was immediately taken with Gaia, and she joined Lovelock in promulgating the idea.

I met Margulis in May 1994 in the first-class lounge of New York’s Pennsylvania Station, where she was waiting for a train. She resembled an aging tomboy: she had short hair and ruddy skin, and she wore a striped, short-sleeve shirt and khaki pants. She dutifully played the radical, at first. She ridiculed the suggestion of Ernst Mayr, Richard Dawkins and other ultra-Darwinians that evolutionary biology might be nearing completion, in terms of not requiring any major additions or revisions. “They’re finished,” Margulis declared, “but that’s just a small blip in the 20th century history of biology rather than a full-fledged and valid science.”

She emphasized that she had no problem with the basic premise of Darwinism. “Evolution no doubts occurs, and it’s been seen to occur, and it’s occurring now. Everyone who’s scientific-minded agrees with that. The question is, how does it occur? And that’s where everyone parts company.” Ultra-Darwinians, by focusing on the gene as the unit of selection, had failed to explain how speciation occurs. Only a much broader theory that incorporates symbiosis and higher-level selection could account for the diversity of the fossil record and of life today, according to Margulis.


http://blogs.scientificamerican.com/cross-check/2011/11/24/r-i-p-lynn-margulis-biological-rebel/

[Bonobo]

1. A hero of mine! Brilliant and original thinker. Rest well. nt