Giant Steps – Dr. Lynn Margulis on Science and Evolution

Are accidental genome shifts the engine of change in evolution? Is species evolution a process of tiny steps?

“No,” says Dr. Lynn Margulis (Distinguished University Professor in the Department of Geosciences at the University of Massachusetts, Amherst), in her stellar book Acquiring Genomes (written with Dorian Sagan), from their catalog of excellent work, which includes Microcosmos and her remarkable Five Kingdoms (a personal favorite, because it so satisfies the naturalist in me).

And so, what has led us in the wrong direction? What limits scientific practice and thought?

Politics, fragmentation and self-isolation.

From Chapter 7, History of the Heritable p 95-96″:

Acquiring Genomes by Dr. Lynn Margulis and Dorian Sagan

The stories of how microbes tend to physically join each other, and of their multiple interactions among themselves and with larger associates, have been told many times in the specialized language of the sciences.

Inevitably these stories are poorly known, in part because the sciences themselves are so fragmented.

Even those of us who understand how much already is known about the origin of species are limited to work on our own tiny discoveries, usually one species at a time.

Academic biology departments once joined the zoologists with the botanists. Plants and animals were studied together.

Falling through the cracks at liberal arts institutions, the study of microbes was largely shunted to its own departments, called microbiology, all of which resided in medical or agricultural schools. The main concern with understanding microbes – as disease agents or food contaminants – was in order to kill them.

Since the 1980s many biological science departments have splintered further into molecular versus organismal biology, a move that exacerbates misunderstanding. The relevant information on species origins is scattered across more than a dozen fields, each with its own esoteric language or languages.

Identical organisms are sometimes partitioned into distinct disciplines. Cyanobacteria, for instance, are studied under phycology (or algology, a branch of botany) rather than bacteriology because they were once misnamed “blue-green algae.”

Biochemistry, cell biology, geology, and virology are all relevant to deciphering the origins of species. Most of these fields, black boxes to the public as well as to graduate students, remain mysterious even to many scientists who practice evolutionary biology today.

Many of Darwin’s fashionable but misguided followers habitually misinterpret even the parts of science they know well. The revelation of much science beyond his century, extended by molecular biology and paleontology, is entirely inconsistent with Darwin’s great insight.

But that revelation shows that the luxuriant living diversity surrounding us did not evolve gradually, as the students of the fossil record so vociferously tell us.

Precious little evidence in the sedimentary rocks exists for small steps that connect one species gradually to its descendants.

The “traces of bygone biospheres,” in Vladimir Vernadsky’s immortal phrase, proclaim the opposite. Punctuated equilibrium is there for all who take the time to see it.

The discontinuous record of past life shows clearly that the transition from one species to another occurs in discrete jumps. In trilobites, snails, seed ferns, horses, lungfish, sharks, and clams, evidence abounds for punctuated change.

In spite of Darwin’s own protest of an incomplete record and his claim of a “passage” of one form to another, for example in pigeons, barnacles, and dogs, animal and plant life has evolved in microbe genome-sized steps.”

Liam

One Comment

  1. A terrific interview with Lynn Margulis in Smithsonian Magazine from 1989:

    Here

    Some excerpts:

    Consider one species of desert termite. Living in its hindgut are millions of single-celled, lemon-shaped organisms called Trichonympha ampla. Attached to the surface of one T. ampla live thousands of whiplike bacteria known as spirochetes. Inside live still other kinds of bacteria. If not for these microbial symbionts (in some wood-eating insects, the symbionts are too numerous to count), the termite, unable to digest wood, would starve.

    But, the termite itself is only one element in a planetary set of interlocking, mutual interactions which Lovelock’s neighbor, novelist William Golding, dubbed Gaia, for the Greek goddess of the Earth. After digesting wood, the termite expels the gas methane into the air. (In fact, the world’s species of termites. cows, elephants and other animals harboring methane-producing bacteria account for a significant portion of Earth’s atmospheric methane.)

    Methane performs the vital task of regulating the amount of oxygen in Earth’s atmosphere. If there were too much oxygen, fires would burn continuously; too little and animals plants and many other live beings would suffocate. Earth s atmospheric oxygen is maintained, altered and regulated by the breathing activities of living creatures. such as those of the methane-makers in the microcosmos. Life does not passively “adapt.” Rather, it actively. though “unknowingly,” modifies its own environment

    When NASA sponsored a search for life on Mars in the early 1970s, Lovelock looked for ways that life might have modified the Martian atmosphere. Finding no particular modification attributable to microbes or any other form of life, he and Margulis predicted that the Viking probe would find a dead Mars. They turned out to be right. “Gaia is more a point of view than a theory.” says Margulis. “It is a manifestation of the organization of the planet.’

    That organization resembles those hollow Russian dolls that nest one inside another. “For example, some bacteria in the hindgut of a termite cannot survive outside that microbial community,” explains Gail Fleischaker, Boston University philosopher of science and a former graduate student of Margulis’. “The community of termites, in turn, requires a larger ecological nest. And so it expands. You will never find life in isolation. Life, if it exists at all, is globe covering.”

    Although Margulis provided the “biological ammunition” for Gaia and remains its staunch advocate, she does little work on it directly. “I’ve concentrated all my life on the cell,” she says. The ideas that she has championed were once “too fantastic for mention in polite biological society,” as one scientific observer described them in the l920s. As recently as 20 years ago, these ideas were so much at odds with the established point of view that, according to another observer, they “could not be discussed at respectable scientific meetings.”

    Although aspects of the symbiotic theory of cell evolution still provoke hostility, the theory is now taught to high school students. “This quiet revolution in microbiological thought is primarily due to the insight and enthusiasm of Lynn Margulis,” states Yale ecologist G. Evelyn Hutchinson. “Hers is one of the most constructively speculative minds, immensely learned, highly imaginative and occasionally a little naughty.”

    more

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