[Paleopsych] Sigma Xi: Lynn Margulis: Ernst Mayr, Biologist Extraordinaire
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Mon Apr 11 21:56:07 UTC 2005
Lynn Margulis: Ernst Mayr, Biologist Extraordinaire
An appreciation of Harvard's visionary of modern evolutionary synthesis
Ernst Mayr, Harvard University professor emeritus and biologist
extraordinaire, died peacefully in Bedford, Massachusetts, on February
3. He was 100 years old and had been associated with the biology
department at Harvard since he joined its faculty in 1953. An era in
evolutionary thought, called variously the New Synthesis,
neo-Darwinism or the Modern Synthesis, came to an end with his
The death of the last of the great evolutionary biologists of the 20th
century concluded an intellectual movement in the study of
evolution--a point of view whose most striking aspect was the extent
to which all of the evolutionary history of life on Earth was
perceived as a subdiscipline of biology. Whereas Thomas Kuhn, author
of The Structure of Scientific Revolutions, might have called it a
paradigm, Ludwik Fleck (author of Genesis and Development of a
Scientific Fact, 1935) would have recognized the correlated demise of
neo-Darwinism and the death of Professor Mayr as a paradigm lost.
An accomplished naturalist, Ernst Mayr began his work in 1923 at the
age of 19. The last of his 25 books, a collection of essays called
What Makes Biology Unique? Considerations on the Autonomy of a
Scientific Discipline, was published by Cambridge University Press in
the summer of 2004, one month after his 100th birthday! This fact
attests to Mayr's intellectual talents and unwavering interest in
science, its history and philosophy.
And last May, shortly before Mayr's centenary birthday in July, an
open celebration of his work and life was held in the auditorium of
the Mineralogical and Geological Museum at Harvard. The place was
crowded with admirers, spectators, students from universities and
colleges from all over the Boston area and beyond. Several famous
evolutionary biologists, colleagues, many of whom were among his
former students and are now professional leaders, came to pay tribute.
What struck me at this well-attended, enthusiastic gathering was that,
among the marvelous lecturers in an all-day session about the
evolutionary panorama of life on Earth, the most moving and
informative of the talks, in my opinion, was the final statement by
Ernst Mayr himself!
Mayr was born in Kempten, Germany (Bavaria), to an educated family,
many of whom were physicians. His father, Otto Mayr, was a judge and a
bird-watching enthusiast. During his school holidays Ernst worked at
the Berlin Zoological Museum at the invitation of Erwin Stresemann,
the best ornithologist in the country at that time. Following his two
years of study at the University of Greifswald, oriented toward
medicine as urged by his family, he completed his doctoral program in
16 months at the University of Berlin. Why did he opt to study at
Greifswald? Why did he go north to a relatively unknown academic
institution? Because his real interests were in the study of natural
history, especially watching birds.
Nature Not Books
Like Darwin, Mayr was always fascinated by live animals in nature. He
was particularly compelled by the question: How do species originate?
Some three years before he died, he told me about his delight when the
University of Berlin called him back to celebrate the 75th anniversary
of receipt of his doctorate degree. I asked him if I might accompany
him to attend the scientific program. "Oh, you don't want to do that,"
he remarked. "There will be no science, just endless and boring talks
We had been discussing modes of speciation, and I had shown him our
10-minute film on Mixotricha paradoxa, an Australian termite protist,
in his daughter Susanne Harrison's kitchen in Bedford. I had explained
"symbiogenesis" as a mode of speciation. "I get it, I get it," he
said, first pensively, then excitedly as he watched the five or more
integrated microbial symbionts that comprise a single Mixotricha
protist swim away as a single individual.
I tried to distinguish "symbiosis" from "symbiogenesis" for him. "Oh,
you don't have to tell me what 'symbiosis' is!" he exclaimed, a little
impatiently. "I studied symbiosis with Paul Buchner in Greifswald, who
was a young instructor there" for a very short time before he moved
on, eventually to Italy. Buchner, author of the seminal work
Endosymbiose der Tiere mit pflanzlichen Mikroorganismen (1953), was
the founder of modern symbiosis research.
Mayr took seriously Louis Agassiz's admonition. He studied "Nature not
Books" between 1928 and 1930 when he collected more than 3,000 birds
in the South Pacific, mainly the Solomon Islands and New Guinea. He
learned to live off the land. After removal of the skin and feathers
in the preparation of "study skins" and taxidermic samples for species
identification, morphological analysis and shipment to museum
collections, nothing would be wasted: The innards went to pot for
dinner. That Ernst Mayr ate more birds of paradise than any other
modern ornithologist is a well-known anecdote.
Mayr's work in the field, especially with avian diversity, led him to
his most familiar contribution to science, documented in his two dozen
single-authored or edited books and more than 600 scientific
publications. He framed the animal species concept. Members of the
same species can mate and breed to produce fertile offspring. Even
plants and animals that greatly resemble each other are not to be
assigned to the same species if they are not interfertile. On the
other hand, animals that look very different from each other (such as
Great Danes and Yorkshire terriers) if they produce fertile offspring
do belong to the same species.
He told me about the wood duck and the green-headed mallards
illustrated on his conservation-society shower curtain--that they were
perfectly fertile, and a mating between these birds resulted in normal
numbers of healthy chicks. He said that nevertheless he agreed that
the two very different-looking ducks must be assigned, as they are, to
two different species. Why? Because, he insisted, even when they live
on the same pond, such as the duck pond here in Amherst, they only
mate with their own kind. His definition of species, he insisted, is
"organisms are members of the same species that, in nature, mate to
produce fertile offspring."
He always emphasized the importance of the environment. Speciation
could almost always be associated with geographical isolation. When
members of the same species are separated for long times by
environmental barriers (such as newly formed volcanic mountains,
islands, rivers or climatic change), the barriers lead to impeded
mating. It is these isolated populations that tend to form new
species. The importance of geographical details in the origin and
evolution of species was always emphasized. "I don't need to measure
the pH and see that it is lower than six in that soil," he would say.
"When sphagnum and cranberries grow in the bog there, we know what the
pH must be." A proud naturalist, Mayr was a superb writer who
communicated primarily by handwritten notes. He was the last of the
neo-Darwinians to revere nature, work inside her and with her. His
life always extended beyond the computer and mathematical models.
What Evolution Is
We celebrated the publication of our books, both brought out by Basic
Books, in the summer of 2002. At his lovely retirement village, with
the help of many friends as well as family (including Mayr's daughters
Susanne and biologist Christa Menzel of Simsbury, Connecticut), we had
a wonderful bibliophilic party. For our book (Lynn Margulis and Dorion
Sagan, Acquiring Genomes: A Theory of the Origins of Species), Mayr
had written the fascinating, not uncritical, foreword. But Mayr's book
was what we all came to celebrate. For readers unfamiliar with his
comprehensive opus spanning more than 75 years of scientific
productivity on a panoply of evolutionary themes, I recommend that you
begin with this one, his 24th: What Evolution Is. Designed for the
curious, nonspecialist reader, it is a fine read for those interested
in the achievements of importance in 20th-century evolutionary
Not immodestly, Mayr considered his 2002 trade book to be the single
best summary of uncontested, documented evolutionary thought.
"Evolution" refers to the results of experimental, observational and
theoretical science that support the common ancestry of all life on
Earth. Yes, of course, people are primates directly related to other
great apes such as gorillas, chimps and bonobos. Yes, of course,
humans were not made by an all-seeing, all-knowing white-man deity.
Indeed, evidence points to the possibility that several species of
nonhumans became extinct because of our aggressive, even murderous,
greedy ancestors. These early Homo sapiens, related to us, displayed
traits that still abound!
The questions and answers, at the end of the book especially, help any
reader, even one naive with respect to science, to understand the
basic concepts of this most important area of study. Mayr's
reasonableness is especially pertinent today in the face of ignorance,
prejudice and religious fundamentalism. For those who try to deny the
validity of science that uses carefully collected evidence from
investigators worldwide, this book is a responsible antidote.
Some three weeks before his death, I called him at home in Bedford and
asked, "Ernst, how are you? How do you feel?" He responded cheerily,
"I feel fine. That is, I feel exceptionally well given the diagnosis."
"What diagnosis?" I asked. "Didn't I tell you? The doctors tell me I
have cancer. It has already metastasized, but I don't feel sick at
all." "Oh, Ernst, I'm so sorry," I responded. "Well, Lynn," he said
cheerfully, "I will have to die of something."
Of Possible Interest
Book Review: A More Modern Synthesis
Column: 1798: Darwin and Malthus
Book Review: Triumphalism in Science
Book Review: Demythologizing McClintock
Book Review: Planters vs. Weeders
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