A digression into the History of Evolution and the Adaptive Landscape

1
A digression into the History of Evolution and
the Adaptive Landscape
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Carl Linnaeus (1707-1778)

• Father of Taxonomy
• He was born on May 23, 1707, at Stenbrohult, in
  the province of Småland in southern Sweden.
• His father, Nils Ingemarsson Linnaeus, was both
  an avid gardener and a Lutheran pastor,
• Linnaeus went to the Netherlands in 1735,
  promptly finished his medical degree at the
  University of Harderwijk, and then enrolled in
  the University of Leiden for further studies.
  That same year, he published the first edition of
  his classification of living things, the Systema
  Naturae.

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Was Linnaeus an evolutionist?

• It is true that he abandoned his earlier belief
  in the fixity of species, and it is true that
  hybridization has produced new species of plants,
  and in some cases of animals. Yet to Linnaeus,
  the process of generating new species was not
  open-ended and unlimited. Whatever new species
  might have arisen from the primae speciei, the
  original species in the Garden of Eden, were
  still part of God's plan for creation, for they
  had always potentially been present.

4
Erasmus Darwin (1731-1802)

• As a naturalist, he formulated one of the first
  formal theories on evolution in Zoonomia, or, The
  Laws of Organic Life (1794-1796).
• He also presented his evolutionary ideas in
  verse, in particular in the posthumously
  published poem The Temple of Nature.
• Although he did not come up with natural
  selection, he did discuss ideas that his grandson
  elaborated on sixty years later, such as how life
  evolved from a single common ancestor, forming
  "one living filament". Although some of his ideas
  on how evolution might occur are quite close to
  those of Lamarck, Erasmus Darwin also talked
  about how competition and sexual selection could
  cause changes in species "The final course of
  this contest among males seems to be, that the
  strongest and most active animal should propogate
  the species which should thus be improved".

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Jean-Baptiste Lamarck (1744-1829)

• Lamarck's scientific theories were largely
  ignored or attacked during his lifetime Lamarck
  never won the acceptance and esteem of his
  colleagues Buffon and Cuvier, and he died in
  poverty and obscurity.
• Today, the name of Lamarck is associated merely
  with a discredited theory of heredity, the
  "inheritance of acquired traits."
• Charles Darwin wrote in 1861
• Lamarck was the first man whose conclusions on
  the subject excited much attention. This justly
  celebrated naturalist first published his views
  in 1801. . . he first did the eminent service of
  arousing attention to the probability of all
  changes in the organic, as well as in the
  inorganic world, being the result of law, and not
  of miraculous interposition.

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Jean-Baptiste Lamarck (1744-1829) part deu

• Lamarck published a series of books on
  invertebrate zoology and paleontology. Of these,
  Philosophie zoologique, published in 1809, most
  clearly states Lamarck's theories of evolution
• Lamarck's contributions to evolutionary theory,
  his works on invertebrates represent a great
  advance over existing classifications he was the
  first to separate the Crustacea, Arachnida, and
  Annelida from the "Insecta." His classification
  of the mollusks was far in advance of anything
  proposed previously Lamarck broke with tradition
  in removing the tunicates and the barnacles from
  the Mollusca. He also anticipated the work of
  Schleiden Schwann in cell theory in stating
  that
• . . . no body can have life if its constituent
  parts are not cellular tissue or are not formed
  by cellular tissue.

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Georges-Louis Leclerc, Comte de Buffon
(1707-1788)

• It is not the average person who questions two
  thousand years of dogma, but that is what Buffon
  did 100 years before Darwin, Buffon, in his
  Historie Naturelle, a 44 volume encyclopedia
  describing everything known about the natural
  world, wrestled with the similarities of humans
  and apes and even talked about common ancestry of
  Man and apes.
• Although Buffon believed in organic change, he
  did not provide a coherent mechanism for such
  changes. He thought that the environment acted
  directly on organisms through what he called
  "organic particles".

8
Georges Cuvier (1769-1832)

• Almost single-handedly, he founded vertebrate
  paleontology as a scientific
• comparative method of organismal biology
• extinction of past lifeforms
• Cuvier's insistence on the functional integration
  of organisms led him to classify animals into
  four "branches," or embranchements Vertebrata,
  Articulata (arthropods and segmented worms),
  Mollusca (which at the time meant all other soft,
  bilaterally symmetrical invertebrates), and
  Radiata (cnidarians and echinoderms). For Cuvier,
  these embranchements were fundamentally different
  from each other and could not be connected by any
  evolutionary transformation.

9
Thomas Malthus (1766-1834)

• Malthus was a political economist who was
  concerned about, what he saw as, the decline of
  living conditions in nineteenth century England.
• He blamed this decline on three elements The
  overproduction of young the inability of
  resources to keep up with the rising human
  population and the irresponsibility of the lower
  classes.
• What "struck" Darwin in Essay on the Principle of
  Population (1798) was Malthus's observation that
  in nature plants and animals produce far more
  offspring than can survive, and that Man too is
  capable of overproducing if left unchecked.

10
Charles Darwin, from his autobiography. (1876)

• "In October 1838, that is, fifteen months after I
  had begun my systematic inquiry, I happened to
  read for amusement Malthus on Population, and
  being well prepared to appreciate the struggle
  for existence which everywhere goes on from long-
  continued observation of the habits of animals
  and plants, it at once struck me that under these
  circumstances favourable variations would tend to
  be preserved, and unfavourable ones to be
  destroyed. The results of this would be the
  formation of a new species. Here, then I had at
  last got a theory by which to work".

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Alfred Russel Wallace 1823-1913

• Cofounder of Natural Selection
• 1st Biogeographer

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Étienne Geoffroy St. Hilaire (1772-1844)

• Geoffroy asked the question "Can the
  organization of vertebrated animals be referred
  to one uniform type?" The answer for Geoffroy was
  yes he saw all vertebrates as modifications of a
  single archetype, a single form.
• Vestigial organs and embryonic transformations
  might serve no functional purpose, but they
  indicated the common derivation of an animal from
  its archetype.
• Cuvier disagreed "If there are resemblances
  between the organs of fishes and those of the
  other vertebrate classes, it is only insofar as
  there are resemblances between their functions

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More on Geoffrey

• Geoffroy spent much time drawing up rules for
  deciding when structures in two different
  organisms were variants of the same type -- in
  modern terminology, when they were homologous.
  His criterion was connections between parts
  structures in different organisms were the same
  if their parts were connected to each other in
  the same pattern.
• It would be an error to call Geoffroy an
  evolutionary biologist in anything like the
  modern sense. Geoffroy's field was morphology --
  the study of form, pure and simple, not of the
  evolutionary history of forms. The archetypal
  forms of Geoffroy's "transcendental zoology" were
  abstractions, not once-living ancestors shared
  archetypal form did not necessarily indicate
  common ancestry.
• As Charles Darwin described his work in 1859, in
  The Origin of Species
• What can be more curious than that the hand of a
  man, formed for grasping, that of a mole for
  digging, the leg of the horse, the paddle of the
  porpoise, and the wing of the bat, should all be
  constructed on the same pattern, and should
  include the same bones, in the same relative
  positions? Geoffroy St. Hilaire has insisted
  strongly on the high importance of relative
  connexion in homologous organs the parts may
  change to almost any extent in form and size, and
  yet they always remain connected together in the
  same order.

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Richard Owen (1804-1892)

• Owen synthesized French anatomical work,
  especially from Cuvier and Geoffroy, with German
  transcendental anatomy. He gave us many of the
  terms still used today in anatomy and
  evolutionary biology, including "homology". Owen
  famously defined homology in 1843 as "the same
  organ in different animals under every variety of
  form and function." To take one example of
  homology Structures as different as a bat's
  wing, a seal flipper, a cat's paw and a human
  hand nonetheless display a common plan of
  structure, with identical or very similar
  arrangements of bones and muscles. Taking
  homology to its conclusion, Owen reasoned that
  there must exist a common structural plan for all
  vertebrates, as well as for each class of
  vertebrates. He called this plan the archetype
  his vertebrate archetype is illustrated below.

• Owen synthesized French anatomical work,
  especially from Cuvier and Geoffroy, with German
  transcendental anatomy. He gave us many of the
  terms still used today in anatomy and
  evolutionary biology, including "homology". Owen
  famously defined homology in 1843 as "the same
  organ in different animals under every variety of
  form and function." To take one example of
  homology Structures as different as a bat's
  wing, a seal flipper, a cat's paw and a human
  hand nonetheless display a common plan of
  structure, with identical or very similar
  arrangements of bones and muscles. Taking
  homology to its conclusion, Owen reasoned that
  there must exist a common structural plan for all
  vertebrates, as well as for each class of
  vertebrates. He called this plan the archetype
  his vertebrate archetype is illustrated below.

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Owens Vertebrate Archetype
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More Owen

• However, Owen did not believe that his archetype
  was anything like an ancestor to the vertebrates.
  Rather, the archetype represented an idea in the
  Divine mind, which also "foreknew all its
  modifications." Owen was not well disposed to
  Darwin's theory of evolution by natural selection
  when Darwin published Origin of Species in 1859.
  However, his pronouncements on the subject of
  evolution were puzzling and contradictory in
  later years he alternately denied its validity,
  professed ignorance on the matter, and claimed to
  have come up with the idea himself almost ten
  years before Darwin.
• Owen was also a taxonomist, naming and describing
  a vast number of living and fossil vertebrates.
  One of his positions was that of prosector for
  the London Zoo, which meant that he had to
  dissect and preserve any zoo animals that died in
  captivity. This gave him vast experience with the
  anatomy of exotic animals. (It also caused him
  some domestic difficulties, since he had to do
  this work at his own house. His wife Caroline
  recorded in her diary how, one summer day, "the
  presence of a portion of the defunct elephant on
  the premises" rendered the house so foul-smelling
  that she "got R. to smoke cigars all over the
  house.")

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Adam Sedgwick (1785-1873)

• Sedgwick was one of several great figures in what
  has been called the Heroic Age of geology
• Sedgwick's own geological views were generally
  catastrophic -- he believed that the history of
  the Earth had been marked by a series of
  cataclysmic events which had destroyed much of
  the Earth's life.
• Defined major geological era classified by
  different fossil compositions
• Sedgwick believed in the Divine creation of life
  over long periods of time, by "a power I cannot
  imitate or comprehend -- but in which I believe,
  by a legitimate conclusion of sound reason drawn
  from the laws of harmonies of nature." What
  Sedgwick objected to was the apparent amoral and
  materialist nature of Darwin's proposed
  mechanism, natural selection, which he thought
  degrading to humanity's spiritual aspirations.

18
Charles Lyell

• Father of modern geology

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Charles Darwin 1809-1882
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Louis Agassiz (1807-1873)

• One of the great scientists of his day, and one
  of the "founding fathers" of the modern American
  scientific tradition, Louis Agassiz remains
  something of a historical enigma. A great
  systematist and paleontologist, a renowned
  teacher and tireless promoter of science in
  America, he was also a lifelong opponent of
  Darwin's theory of evolution.
• The son of a minister, Jean Louis Rodolphe
  Agassiz was born on May 28, 1807 in the village
  of Montier, in the French-speaking part of
  Switzerland.
• he went to Paris in November 1831 to study
  comparative anatomy under Cuvier
• In 1846, Agassiz came to the United States in
  1848 he accepted a professorship at Harvard.

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More Agassiz

• Agassiz continued Cuvier's catastrophism theory
  -- the Earth had been periodically wracked by
  global catastrophes, after each of which new
  species of animals and plants had appeared.
  Followers of Cuvier had suggested that the
  Biblical Flood was the last catastrophe. Agassiz
  replaced the Flood with his glaciers
• He believed glaciers had been formed
  instantaneously all over the world he called
  glaciers "God's great plough," and tried
  unsucessfully to find evidence of glaciation in
  Brazil.
• Agassiz's works on living and fossil fish and on
  glaciers have remained classics. His work on
  glaciers revolutionized geology, and drove
  another nail in the coffin of the Biblical Flood
  as a serious scientific hypothesis. He trained
  and influenced a generation of American
  zoologists and paleontologists, including Alpheus
  Hyatt, William Healey Dall, David Starr Jordan,
  Nathaniel Shaler, and Edward S. Morse. He left a
  mark on the development and the practice of
  American science, and brought science to "the man
  in the street" as no one else had before. People
  from all over the world read his books, sent him
  specimens, and asked his advice. By the time of
  his death, on December 14, 1873, he was publicly
  recognized as America's leading scientist.

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Thomas Henry Huxley (1825-1895)

• Thomas Henry Huxley was one of the first
  adherents to Darwin's theory of evolution by
  natural selection, and did more than anyone else
  to advance its acceptance among scientists and
  the public alike.
• Huxley was a passionate defender of Darwin's
  theory -- so passionate that he has been called
  "Darwin's Bulldog".

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Huxley

• I finished your book yesterday. . . Since I read
  Von Baer's Essays nine years ago no work on
  Natural History Science I have met with has made
  so great an impression on me I do most heartily
  thank you for the great store of new views you
  have given me. . .As for your doctrines I am
  prepared to go to the Stake if requisite. . .I
  trust you will not allow yourself to be in any
  way disgusted or annoyed by the considerable
  abuse misrepresentation which unless I greatly
  mistake is in store for you. . . And as to the
  curs which will bark and yelp -- you must
  recollect that some of your friends at any rate
  are endowed with an amount of combativeness which
  (though you have often justly rebuked it) may
  stand you in good stead -- I am sharpening up my
  claws and beak in readiness
• Letter of T. H. Huxley to Charles Darwin,
  November 23, 1859, regarding the Origin of
  Species

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Even More Huxley

• However, Huxley did not blindly follow Darwin's
  theory, and critiqued it even as he was defending
  it. In particular, where Darwin had seen
  evolution and a slow, gradual, continuous
  process, Huxley thought that an evolving lineage
  might make rapid jumps, or saltations.
• Huxley explicitly presented evidence for human
  evolution.
• He is best known for his famous debate in June
  1860, at the British Association meeting at
  Oxford. His opponent, Archbishop Samuel
  Wilberforce, was not-so-affectionately known as
  "Soapy Sam" for his renowned slipperiness in
  debate. Wilberforce was coached against Huxley by
  Richard Owen. During the debate, Archbishop
  Wilberforce ridiculed evolution and asked Huxley
  whether he was descended from an ape on his
  grandmother's side or his grandfather's. Accounts
  vary as to exactly what happened next, but
  according to one telling of the story, Huxley
  muttered "The Lord hath delivered him into my
  hands," and then rose to give a brilliant defense
  of Darwin's theory, concluding with the
  rejoinder, "I would rather be the offspring of
  two apes than be a man and afraid to face the
  truth."

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Ernst Haeckel (1834-1919)

• Haeckel is one of many thinkers who believed that
  all species were historical entities (lineages)
  but did not share Darwin's enthusiasm for natural
  selection as the main mechanism for generating
  the diversity of the biological world. Haeckel
  instead believed that the environment acted
  directly on organisms, producing new races (a
  version of Lamarckism).
• Although best known for the famous statement
  "ontogeny recapitulates phylogeny", he also
  coined many words commonly used by biologists
  today, such as phylum, phylogeny, and ecology. On
  the other hand, Haeckel also stated that
  "politics is applied biology", a quote used by
  Nazi propagandists. The Nazi party, rather
  unfortunately, used not only Haeckel's quotes,
  but also Haeckel's justifications for racism,
  nationalism and social darwinism.

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Francis Galton 1822-1911

• Meanwhile, Galton had developed an interest in
  heredity, and the publication of the Origin of
  Species (1859) by Charles Darwin won Galton's
  immediate support. Impressed by evidence that
  distinction of any kind is apt to run in
  families, Galton made detailed studies of
  families conspicuous for inherited ability over
  several generations. He then advocated the
  application of scientific breeding to human
  populations. These studies laid the foundation
  for the science of eugenics (a term he invented),
  or race improvement, and led to the publication
  of Hereditary Genius (1869) and English Men of
  Science Their Nature and Nurture (1874).
• Biometriction and correlation
• Mendels Laws

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The Modern Synthesis
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Hugo de Vries (1848-1935)

• A Dutch botanist who proposed the mutation theory
  based on experiments with the evening primrose.
  However, most of the changes he observed were not
  gene mutations but a result of other phenomena
  such as chromosome changes and unusual
  combinations.
• Rediscovered Mendels laws independently

29
Ronald Fisher

• Sir Ronald Aylmer Fisher (1890 - 1962) was a
  British mathematician and geneticist whose book,
  The Genetical Theory of Natural Selection (1930)
  proved that Mendelian genetics is an essential
  underlying mechanism of Darwiniam evolution. His
  work laid the foundations for statistical
  analysis of all subsequent experiments in the
  life sciences.
• Fisher's legacy to evolutionary biology includes
  the following areas
• He described a process called runaway sexual
  selection to explain exaggerated characters of
  organisms such as the peacock's tail.
• He explained why sexual species maintain a sex
  ratio of roughly 5050.
• He developed a model of adaptive evolution
  which describes the relationship between the form
  of a character and its fitness.
• He proposed that accelerated evolution is an
  advantage of sexual reproduction that may
  outweigh the enormous costs of sex.

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John Burdon Sanderson Haldane (1892 - 1964

• John Burdon Sanderson Haldane (1892 - 1964) had a
  wide range of interests in biology. He began by
  studying the respiratory system, using himself as
  an experimental subject. He then turned to
  biochemistry, and finally to genetics.
• Here are some of his main contributions to
  evolutionary biology
• He produced mathematical models of natural
  selection which allow gene frequencies to be
  predicted.
• He described a cost of natural selection, and
  investigated what limits this might place on the
  rate of evolution.
• He suggested that selection can maintain a
  polymorphism when the heterozygote is fitter than
  either homozygote (see heterozygotic advantage).
• Haldane's work, together with that of R.A. Fisher
  and Sewall Wright, played a central part in the
  construction of the modern synthesis.

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Sewell Wright

• Sewall Wright (1889 - 1988) was an American
  geneticist who played a central part in the
  foundation of the modern synthesis, together with
  R.A. Fisher and J.B.S Haldane.
• Wright noticed that genes can disappear from a
  small population not because of selection, but
  because of chance - a phenomenon known as genetic
  drift.
• He invented the influencial concept of an
  adaptive topography - a graph of mean population
  fitness against gene frequency.
• Wright attempted a comprehensive, realistic model
  of evolution, including complex interactions
  between genes, random effects, selection between
  and within populations, and migration.
• He lived to a grand age, and published a
  four-volume treatise (1968 - 1978) at the end of
  his career.

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The Adaptive Landscape
Shifting Balance Theory
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Theodosius Dobzhansky 1900 - 1975

• Dobzhansky's studies in population genetics
  served as a basis for his explanation of how the
  evolution of races and species could have come
  about through adaptation. He discovered that
  successful species tend to have a wide variety
  of genes that, while they do not appear to be
  useful to the organism in its present
  environment, do provide a species as a whole with
  genetic diversity. This diversity enables the
  species to adapt effectively to changes in the
  surrounding environment.