From Darwin to the Modern Synthesis

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Organic Evolution

• From Darwin to the Modern Synthesis

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Predecessors

• The idea of evolution had been around since the
  times of the ancient Greeks
• The problem was the explanatory mechanism, in
  other words, how evolution works?

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The Lunar Society

• Met every Monday nearest the full moon (when
  there was the most light to travel home by) from
  1765 until 1813
• Interested in science and its applications to
  manufacturing, mining, transportation, education,
  medicine
• They believed that the good life is more than
  material decency, but the good life must be based
  on material decency
• They believed that by raising productive capacity
  they would be able to deliver material decency
  for all

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Members

• Matthew Boulton made James Watt's condensing
  steam engine and invented a fraud resistant
  coinage
• Richard Lovell Edgeworth A pioneer of telegraphy
  
• James Keir made advances in the manufacture of
  glass and was a pioneer of the chemical industry
• Joseph Priestley discovered oxygen, the
  indiarubber eraser and invented carbonated water
• William Murdock inventor of gas lighting
• William Small doctor of medicine who had taught
  mathematics to the young Thomas Jefferson

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• James Watt inventor of the condensing and rotary
  steam engines, an early copying process maker of
  musical and scientific instruments, canal
  surveyor
• Josiah Wedgwood celebrated potter, canal
  promoter and Charles Darwins grandfather
• John Whitehurst maker of clocks and scientific
  instruments, and a pioneering geologist who did
  work on how the earth had been formed
• William Withering medical doctor, botanist with
  interests in metallurgy and chemistry. He
  discovered the medicinal properties of the
  foxglove in treating heart disease

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• Jonathan Stokes botanist
• Benjamin Franklin a corresponding member
• Erasmus Darwin

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Erasmus Darwin (1731-1802)

• One of the leading intellectuals of eighteenth
  century England
• Remarkable array of interests and pursuits
• A respected physician, a well known poet,
  philosopher, botanist, and naturalist

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• As a naturalist, he formulated one of the first
  formal theories on evolution in Zoonomia, or, The
  Laws of Organic Life (1794-1796)
• This was a very popular book translated into
  several languages, published 4 years before
  Malthus' Essay on Population and 9 years before
  Lamarck's published explanation on the theory of
  use and disuse

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• He also presented his evolutionary ideas in
  verse, in particular in the posthumously
  published poem The Temple of Nature (1802)
• Organic life beneath the shoreless waves
• Was born and nurs'd in ocean's pearly caves
• First forms minute, unseen by spheric glass,
• Move on the mud, or pierce the watery mass
• These, as successive generations bloom,
• New powers acquire and larger limbs assume
• Whence countless groups of vegetation spring,
• And breathing realms of fin and feet and wing

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• Believed the Earth was millions of years old
• Rejected the theory of special creation
• Discussed how life evolved from a single common
  ancestor, forming one living filament
• Believed in the inheritance of acquired
  characters
• Differences among animals were driven by three
  different forces lust, hunger, and security

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• These forces, when interacting among themselves
  and acting upon the Natural Variation of
  individual in species improving, thus, the
  different races (natural selection?)
• Believed in spontaneous generation
• Some of his ideas on how evolution might occur
  sound like Lamarckian, but actually it is the
  other way around
• Erasmus Darwin also wrote 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 propagate the species which
  should thus be improved

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• He used his observations of domesticated animals,
  the behavior of wildlife, and he integrated his
  vast knowledge of many different fields, such as
  paleontology, biogeography, systematics,
  embryology, and comparative anatomy

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• Did he anticipate the erroneous ideas of Lamarck?
• Did Erasmus Influence Charles Darwin? CD said no!
  
• CDs first edition of The Origin initially called
  Zoonomia

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• Others like William Lawrence (1783-1867), James
  C. Prichard (1786-1848), and William C. Wells
  (1857-1917) did not believe in the inheritance of
  acquired characters
• They were physicians and could not find support
  for it
• They believed in selection, mutation, segregation

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• Others Patrick Matthew (1790-1874), Edward
  Blythe (1810-1873), Charles Naudin (1815-1899),
  believed in natural selection

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Charles Darwin (1809-1882)

• Born in Shrewsbury, Shropshire, England, on 12
  February 1809
• Grandson of Erasmus Darwin
• His father was a physician, wealthy
• Family high intellectuality, professional
  ability, industriousness
• Mother died when he was eight years old

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Education

• Brought up by his sister
• Graduated from the elite school at Shrewsbury in
  1825 (Classics)
• Sent to Edinburgh to study medicine. Dropped out
  in 1827 (hated it)
• Sent to the University of Cambridge to study
  theology in preparation for becoming a clergyman
  of the Church of England
• Loved to collect plants, insects, and geological
  specimens

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• Guided by his cousin William Darwin Fox, an
  entomologist
• Scientific inclinations encouraged by his botany
  professor, John Stevens Henslow
• Henslow helped build Darwin's self-confidence
  taught him to be a meticulous and painstaking
  observer of natural phenomena and collector of
  specimens
• Also influenced by Adam Sedgwick, read Humboldt,
  graduated from Cambridge in 1831

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The Voyage of the Beagle

• Henslow was instrumental in securing a place for
  Darwin as an unpaid naturalist on the surveying
  expedition of HMS Beagle to Patagonia (1831-6)
• Heavy paternal opposition
• Under Captain Robert Fitzroy (an illegitimate
  descendent of King Charles II) visited Tenerife,
  the Cape Verde Is., Brazil, Montevideo, Tierra
  del Fuego, Buenos Aires, Valparaiso, Chile, the
  Galapagos, Tahiti, New Zealand, and Tasmania

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• Opportunity to observe the various geological
  formations found on different continents and
  islands along the way, as well as a huge variety
  of fossils and living organisms
• In the Keelings he devised his theory of coral
  reefs
• At the time, most geologists adhered to the
  catastrophist theory

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• The catastrophist viewpoint was challenged by Sir
  Charles Lyell in Principles of Geology (1830-33).
  Lyell maintained that the Earth's surface is
  undergoing constant change, the result of natural
  forces operating uniformly over long periods
• Read Charles Lyell
• Most impressed with the effect that natural
  forces had on shaping the Earth's surface
• Fossils in South America

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• Noted that certain fossils of supposedly extinct
  species closely resembled living species in the
  same geographical area
• The Galápagos
• Observed that each island supported its own form
  of tortoise, mockingbird, and finch closely
  related but differed in structure and eating
  habits from island to island (Observations
  reinforced by Goulds insights)

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Natural Selection

• Returned to England in 1836
• Began recording his ideas about changeability of
  species in his Notebooks on the Transmutation of
  Species
• In 1838 read An Essay on Population (1798), by
  the British economist Thomas Robert Malthus
• Explained how human populations remain in
  balance. Increase in the availability of food for
  basic human survival could not match the
  geometrical rate of population growth. The
  latter, therefore, had to be checked by natural
  limitations such as famine and disease, or by
  social actions such as war

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• Darwin applied Thomas Malthus's argument to
  animals and plants
• By 1838 he had arrived at a sketch of a theory of
  evolution through natural selection
• In 1842 he drew up his observations in some short
  notes
• Expanded in 1844 into a sketch of conclusions for
  his own use
• These embodied the idea of natural selection

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• Typically cautious, he delayed publication of his
  hypothesis
• For the next two decades he worked on his theory
  and other natural history projects
• In 1839 he married his first cousin,
  Emma Wedgwood (1808-96)
• In 1842 moved to a small estate,
  Down House, outside London
• They had ten children, three of whom died in
  infancy
• Independently wealthy and never had to earn an
  income

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• A country gentleman among his gardens,
  conservatories, pigeons, and fowls
• Practical knowledge in variation and
  interbreeding
• He developed a friendship with
  Sir Charles Lyell, became secretary
  of the Geological Society (1838-41)
• Continuous ill-health (suffered from
  Chagas's disease?, Panic disorder?)
• By 1846 he had published several works on the
  geological and zoological discoveries of his
  voyage

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• Placed him at once among the front rank of
  scientists
• Variability among barnacles
• Artificial selection
• Giraffe example
• Vestigial organs
• After five years of collecting the evidence, he
  began to speculate on the problem of the origin
  of species

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Alfred Russell Wallace (1823-1913)

• Natural history collector and explorer
• Also read Malthus. Wrote to Lyell
• Wrote to Darwin
• Wallace sent him a memoir on the
  Malay Archipelago
• Contained in essence the main ideas of theory of
  natural selection
• Lyell and Joseph Hooker persuaded Darwin to
  submit a paper of his own read simultaneously
  with Wallace's before the Linnean Society in 1858

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• Darwin then set to work to condense his vast mass
  of notes, and put into shape his great work, The
  Origin of Species by Means of Natural Selection,
  published in 1859. 6 editions
• Extremely readable book. First edition sold out
  the first day!
• Because of the food-supply the young born to any
  species intensely compete for survival
• The young that survive embody favorable natural
  variations the process of natural selection and
  these variations are passed on by heredity

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• Therefore, each generation will improve
  adaptively over the preceding generations, and
  this gradual and continuous process is the source
  of the evolution of species
• Also introduced the concept that all related
  organisms are descended from common ancestors
• Provided additional support for the older concept
  that the earth itself is not static but evolving

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Reaction

• Some biologists criticized Darwin's concept of
  variation, arguing that he could explain neither
  the origin of variations nor how they were passed
  to succeeding generations
• The most publicized attacks on Darwin's ideas
  came from religious opponents
• Seemed to place humanity on a plane with the
  animals
• Darwin spent the rest of his life expanding on
  different aspects of problems raised in the
  Origin
• 10 years after its publication most learned
  people had accepted it

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• Neither Darwin nor Wallace were present when the
  first public confrontation took place
• Soapy Sam Darwins Bulldog

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The exchange

• A man has no reason to be ashamed of having an
  ape for a grandfather. If there were an ancestor
  whom I should feel shame in recalling, it would
  rather be a man who plunges into scientific
  questions with which he had no real acquaintance,
  only to obscure them by an aimless rhetoric, and
  distract the attention of his hearers from the
  real point at issue by eloquent digressions and
  skilled appeals to religious prejudice."
• - Huxley

• Is the ape your ancestor from you grandmothers
  side or from your grandfathers side?
• Wilberforce

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Other Books by Charles Darwin

• The Fertilization of Orchids (1862)
• The Variation of Plants and Animals under
  Domestication (1867)
• The Descent of Man and Selection in Relation to
  Sex (1871)
• The Expression of Emotions in Man and Animals
  (1872)
• Insectivorous Plants (1875)
• The Effects of Cross and Self Fertilization in
  the Vegetable Kingdom (1876)
• Different Forms of Flowers in Plants of the Same
  Species (1877)
• The Formations of Vegetable Mould through the
  Action of Worms (1881)

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• Darwin was elected to the Royal Society (1839)
  and the French Academy of Sciences (1878)
• He was also honored by burial in Westminster
  Abbey after he died in Down, Kent, on 19 April
  1882

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• Raised the idea of evolution from a hypothesis to
  a verifiable theory
• Thus, after Darwin, the following major cultural
  revolutions had taken place in the human thought
• 1. The Expansion of the Time-Scale
• 2. The Concept of a Changing Universe
• 3. The Elimination of Design
• 4. The Elimination of Miracles
• 5. The Inclusion of Humans within Nature

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How Original was Charles Darwin?
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Was he assuming to be totally original?

• No educated person () could suppose I meant to
  arrogate to myself the origination of the
  doctrine that species had not been independently
  created.
• C.D. January 1860