K, you might find this interesting.

RIP

Carl Sagan's wife Lynn Margulis died just the other day, very close to the anniversary of her Husband's death.

"Lynn Margulis, who has died aged 73, was a microbiologist whose work on the origin of cells transformed the study of evolution; with James Lovelock, she also developed the "Gaia theory" of Earth as a vast self-regulating system.

It was Lynn Margulis’s expertise in microbes that led her, in the mid-Seventies, to the British atmospheric chemist James Lovelock, who had come to suspect that living organisms had a greater effect on the atmosphere than was commonly recognised. Together they proposed a theory that Earth itself — its atmosphere, the geology and the organisms that inhabit it — is a self-regulating system in which living organisms help to regulate the terrestrial and atmospheric conditions that make the planet habitable.

In particular they suggested that plankton act as a living thermostat, helping to regulate global temperature; that bogs and peat lands affect glaciers as the organisms within them release and absorb greenhouse gases; and that colonies of bacteria and other microbes in tidal mud flats process enough salt to help keep ocean salinity fairly constant. It was Lovelock who suggested they call their hypothesis Gaia, after the ancient Greek goddess of the Earth.

Though advancing such theories exposed her to enormous hostility from within the scientific community, she came to be regarded as one of the most creative and respected researchers of her generation.

In the 1960s Lynn Margulis became convinced that, while Darwin had successfully proved that all species of living things are descended from earlier ones, neither he nor his followers had ever satisfactorily explained the source of the variation that gives rise to new species.

She began focusing on the evolution of eukaryotic cells — cells containing a nucleus (a membraned envelope enclosing chromosomes), and organelles (which are distinct structures that perform such functions as photosynthesis). While it was well known that a nucleus contains DNA, Lynn Margulis focused on the genes which exist outside the nucleus, to find a clue to how the earliest bacteria-like cells could have evolved into more complex organisms.

She resurrected a long-ignored idea that the organelles within eukaryotes were once free-living bacteria that had once invaded other bacterial forms. First these were parasites; then they became “symbionts”, providing services for their hosts in return for a protective environment; finally they were fully integrated into their hosts’ biological make-up as organelles.

Lynn Margulis’s theory of “symbiogenesis” challenged the Neo-Darwinist consensus by suggesting that inherited variation does not come, or does not come exclusively, from random genetic mutation but from long-lasting interaction between organisms.

At first the idea met with scorn: her findings were rejected by 15 academic journals and grant applications were brusquely rebuffed. The response to one application was: “Your research is crap. Don’t ever bother to apply again.”

[link to www.telegraph.co.uk]


Well, I for one thank her for her contributions.