English naturalist. Born 1809. While studying theology h

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Evolution
Definition All organisms are descended (with
modification) from pre-existing organisms
overtime, the process by which this occurs is
called evolution
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Charles Darwin

• English naturalist
• Born 1809
• While studying theology he became interested in
  natural history
• 1831 - invited to join an expedition to map
  coastline of South America

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Captain Robert FitzRoy

• Ship HMS Beagle
• Captain a young aristocrat called Robert
  FitzRoy.
• Sailed 27th December 1831
• He was to be away five years

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• Fourth great grandson of Charles II(1600s)
• This king replaced Cromwell!
• His consuming passion was the weather

• 1826 given the command of a ship
• after the captain commited suicide.
• . In 1831 his request for a second surveying
  mission was granted and his companion was Charles
  Darwin
• . In 1854 he was appointed to head a department
  that became known as the British Meteorological
  Office

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Darwin

• Not an experienced scientist
• Undistinguished candidate for Holy Orders
• Courage
• Horse sence

• Hardest headed biologist of the century
• He learned to apply critical judgement
• Upon his return to England, he worked for 20
  years before he began to write about evolution in
  1856
• 5494

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HMS Beagle
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Model of the HMS Beagle
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HMS Beagle

• The compass used by Charles Darwin on HMS Beagle
• 27m-long
• Crew 73 men
• 22 chronometers instruments for accurately
  measuring longitude

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The Voyage

• In Brazil he saw his first tropical forest

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The Voyage (Cape Verde Is.)

• The Fogo volcano, a major tourist attraction
  today, reaches a height of 2829m.
• Varied colour tones contrasting lava landscapes
  with the agricultural and vineyard plantations
  that produce Fogo wine.

• The Cape Verde Islands provided him with his
  first object lesson of a volcano.

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The Cape Verde Islands
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The Voyage (Argentina)

• In Argentina he found his first fossils sloths,
  mastodons, and horses.

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The Voyage( Tierra del Fuego)

• In Tierra del Fuego he saw a race of men so
  savage, so devoid of any beliefs ( and
  occasionally cannibalistic) that they hardly
  seemed human. Three of them had been taken to
  England three years previously by Fitzroy to
  teach them the elements of Christianity and the
  use of tools, and they were now being
  repatriated. Darwin was astonished that three
  years had been sufficient to change savages into
  as far as habits go complete and voluntary
  Europeans. But they soon reverted to savagery.

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Tierra del Fuego
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The Voyage (Chile)

• In Chile, Darwin witnessed an earthquake and
  observed both its effects in raising the level of
  the land and its connection with volcanic
  eruption. Repeatedly when ashore he went on
  long, arduous, and dangerous expeditions on
  horseback, collecting and shooting, which showed
  that his addiction to sport had not been useless.

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The Voyage

• On one journey from Chile to Argentina over high
  passes of the Andes, he was bitten
  massively by bugs. From the Galapagos Islands
  the Beagle sailed to Tahiti, New Zealand,
  Australia, Cocos Keeling Island, Brazil again (
  to check chronometers), and then home. Darwin
  landed at Falmouth on Oct. 2, 1836.

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The Galapagos Islands

• The Galapagos Islands are located 650 miles west
  of Ecuador in the Pacific Ocean.

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Species on the islands

• Dozens of unique species of both plants and
  animals found nowhere else in the world
• Giant tortoises
• A comorant that has lost its ability to fly
• The only lizard that feeds in the sea
• The only equatorial penguin in the world

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The Penguins
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Giant Tortoises
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Harriet she didnt look a day over 154

• Harriet was one of three tortoisis Darwin brought
  back from the Galapagos Islands to England.
• Subsequently, he gave Harriet to a friend heading
  for Australia.
• Harriet was mistakenly considered a male for over
  100 years. Ouch!
• She died in June, 2006 at an Australian Zoo where
  shes been a key attraction for years.

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A unique form of giant cactus
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• Darwins visit to the Galapagos for 5 weeks in
  1835 provided the starting
• point for his theory of natural selection.
• He did not understand a great deal of what he was
  seeing when he was there.
• It wasnt until he got back to England and had
  ornithologist John Gould and other experts look
  at the finches that he realized he had discovered
  something big.

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Darwins Beagle Diary

• 22nd Sep., 1835 San Cristóbal Chatham Island,
  Galápagos We slept on the sand-beach, in the
  morning after having collected many new plants,
  birds, shells insects, we returned in the
  evening on board.
• October 1st 1835 Isabela Albemarle Island,
  Galápagos Albermale sic Is is as it were the
  mainland of the Archipelago ... From different
  accounts we had hoped to find water here. -- To
  our disappointment the little pits in the
  Sandstone contained scarcely a Gallon that not
  good. -- it was however sufficient to draw
  together all the little birds in the country. --
  Doves Finches swarmed around its margin.

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The different types of finch.

• The diversity of beak structure and feeding
  habits within the group of finches is remarkable.
• The different species are adapted to feed in a
  variety of ways.

• Some eat seeds
• Some eat insects
• Some remove ticks from tortoises
• Some eat leaves
• Some eat flowers,
• Some drink blood from seabirds
• Some use twigs to extract insect larve

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Back Home

• At first his interests were geological e.g. he
  discovered in the Andes at an altitude of 7000
  feet a fossil forest overlain by thousands of
  feet of sedimentary deposits laid down by the
  sea, thus proving the occurrence of earlier earth
  movements of the order of 10,000 feet vertical
  height.
• In 1856 Darwin started to put on paper his
  discoveries about evolution and natural
  selection.

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Back Home

• .
• In 1858 out of the blue, he received from Alfred
  Wallace, a naturalist then in the Malay
  Archipelago, a succinct but complete statement of
  his own conclusions on evolution and natural
  selection.
• A joint paper by both was read to the Linnean
  Society of London in 1858
• Darwin then made an abstract of the work on which
  he had been engaged for 20 years.
• This abstract was called the Origin of Species
  which was published on November 24, 1859, and
  sold out immediately.

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Origin of Species

• In the eyes of posterity, his publications on
  geology were so eclipsed by the bombshell on
  evolution that they have been neglected.
• With his book Darwin brought down on himself
  enemies of two kinds. Scientists (Adam Sedgwick
  and Richard Owen) and upholders of orthodox
  religious beliefs e.g. Samuel Wilberforce, bishop
  of Oxford.

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What was in the book?

• In it, Darwin makes one long argument with
  copious examples as support, for his theory that
  organisms gradually evolve not individually but
  in groups through the process of natural
  selection, a mechanism the book effectively
  introduced to the public.

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Summary statements 1 and 2

• S1 Organisms produce far more offspring than
  ever give rise to adult individuals.
• S2 The numbers of individuals of a species
  remain more or less the same (in a particular
  ecosystem).

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Deduction 1

• Therefore there must be a high death rate,
  resulting from the constant struggle taking place
  between all organisms for food, in avoiding
  predators and disease, and in coping with
  climatic conditions.

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Statement 3

• S3 The individuals in a species are not all
  identical, but show variations in their
  characteristics that have arisen, by chance,
  through sexual reproduction and mutations.

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Deduction 2

• In the competition for survival, variations allow
  some individuals to adapt, survive and reproduce
  better than others, so passing on these
  successful traits to their offspring. Over
  many generations, these small changes accumulate
  until two groupings within the population can no
  longer interbreed and a new species is formed.

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Evolution

• Evolution is the changing of one species into
  another that takes place through natural
  selection.

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Summary Revision

• More offspring..
• Numbers .. the same
• Death rate .. Struggle
• Variations
• Adapt, survive and reproduce .successful
  .new species

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Evidence for evolution

• Palaeontology The study of fossils
• Comparative Embryology
• Comparative Anatomy
• Comparative Biochemistry

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Palaentology

• Fossil Record ( Palaeontology)
• Fossil Remains of an organism or evidence that
  it once existed
• Fossils
• Actual remains e.g. Bones and Teeth
• Rock Fossils e.g. Casts or impressions of
  organisms and petrifaction of organisms
• Ice Fossils e.g. Woolly Mammoths in Siberia
• Amber Fossils e.g. flies trapped in resin which
  becomes amber.
• Sedimentary rocks are laid down in layers making
  it possible to date the fossils in each layer.
  The organisms in the lower layers being older
  than those in the top layers. The changes which
  occurred over time can clearly be seen in clear,
  simple and sequential fossil records e.g. the
  horse.

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Embryology

• Embryos of different species tend to pass through
  the same stages of development e.g. Human embryos
  have gill slits at an early stage.
• The similarities in the these stages of
  development can reflect the evolutionary
  relationships between organisms.
• The genes for basic embryo development e.g. Hox
  genes are shared by many complex animals.
• They express themselves similarly in the early
  stages of embryo development and then modify the
  structures produced, during the steps of
  development in order to make them suitable for
  the new organism

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Comparative Embryology
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Comparative anatomhy
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Comparative Anatomy
Homologus Structures Organs which have the
same basic structure but different functions.
e.g. pentadactyl limb Humerus Radius and Ulna
Carpals Phalanges
The same basic bone structure but different
functions indicate that the organisms have common
ancestors by evolution. Pandas Thumb Five
fingers and a thumb(modified wrist
bone) Exception which proves rule of common
ancestry. Evolution from a common ancestor to
varied descendants is also known as Divergent
Evolution or Adaptive Radiation.
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Biochemistry

• If you compare the chemicals e.g. DNA,
  Haemoglobin, ATP found in different animals and
  plants, the degree of similarity between these
  organisms can be measured
• There is a 1 difference between our DNA and that
  of Chimpanzees

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Famous debate at Oxford 1860

• Thomas Huxley Darwins bulldog vs Archbishop
  Samuel Wilberforce Soapy Sam
• Wilberforce was coached against Huxley by Richard
  Owen , a biologist.
• Wilberforce ridiculed evolution and asked Huxley
  whether he was descended from an ape on his
  grandmothers side or his grandfathers.
• One account has it that Huxley concluded his
  brilliant defence of Darwins theory, by saying
  I would rather be the offspring of two apes than
  be a man and afraid to face the truth

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Evolution

• Note there is no direction or plan to Evolution
  it is merely the rule book for the game of life.
• As Darwin concluded his book The Origin of
  Species by Natural Selection
• There is a grandeur in this view of life, with
  its several powers, having been originally
  breathed by the Creator in a few forms or into
  one and that, whilst this planet has gone
  cycling on according to the fixed law of gravity,
  from so simple a beginning endless forms most
  beautiful and most wondrous have been and are
  been evolved.

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• Other examples of Natural Selection in action
  include
• Evolution of pesticide resistance in beetles,
  incidence of sickle cell anaemia in areas which
  historically had malaria and the evolution of
  antibiotic resistance in bacteria.

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How Evolution Works - Natural Selection

• Biston Betularia, the Peppered Moth
• The peppered moth comes as two forms, a typical
  one which is peppered coloured to camouflage
  itself on the lichen covered barks of trees and a
  mutant black form which was first noticed in 1848
  in Manchester.
• Pollution from the Industrial Revolution in
  England killed the lichens on the trees and
  covered their barks with soot making them black.
• The environment had changed and now selected for
  the black form of the moth, so by 1898 in the
  polluted areas of England like Manchester the
  black form made up over 95 of the moths
  population and the peppered form less than 5.
• This process is known as Natural Selection.

Both unpolluted area
Both polluted area
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Religious problems

• The issues for religious believers were two fold
• If evolution was true, the account of the
  Creation in the Book of Genesis was false or, at
  least not literally true
• If evolution worked automatically by natural
  selection, there was no room for divine guidance
  and design in the production of living plants and
  animals, including man on earth.
• Darwins findings became well known but
  eventually gave Fitzroy great distress because he
  was a creationist

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Pope John Paul II 1996

• Today, almost half a century after the
  publication of Pius XIIs Encyclical, fresh
  knowledge has led to the recognition that
  evolution is more than a hypothesis. It is
  indeed remarkable that this theory has been
  progressively accepted by researchers, following
  a series of discoveries in various fields of
  knowledge. The convergence, neither sought nor
  fabricated, of the results of work that was
  conducted independently is in itself a
  significant argument in favour of this theory

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Web addresses

• www.whywework.com Blackbackground images
• http//members.virtualtourist.ccom/m/6987/f/8d3/
• http//oikos.villanova.edu/Nesomimus/darwinquote.h
  tmlcalandria diary
• http//www.abdn.ac.uk/zoohons/lecture5/sld011.htm
  slides onfinch http//www.nhc.ed.ac.uk/images/coll
  ections/invertebrates/fossils/16.jpg fossil

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Darwins Theory of Evolution

• Many are born
• Not all survive
• Individuals vary
• Variations are inherited
• Useful variations increase

Information on this slide is from lecture given
at the Annual Conference of the ISTA in UCC on
Saturday 24th March by Dr. Jeremy Pritchard,
University of Birmingham.