In the footsteps of Charles Darwin

							Galapagos Islands - an inspiration for
      the Theory of Evolution

                  by
           Jerzy Barchanski
Location of the Galapagos Islands




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Galapagos Islands




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            Galapagos Islands
• The Galapagos Islands are located in the
  eastern Pacific Ocean approximately 600 miles
  (1000 km) off the west coast of South
  America. The closest land mass is the
  mainland of Ecuador to the east (the country
  to which they belong), to the North are the
  Cocos Islands 432 miles (720 km) and to the
  South is Easter Island and San Felix Island at
  1920 miles (3200 km).
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Charles Darwin
 1809 - 1882




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          Darwin’s Journeys
In 1831 Darwin accepted the offer of
 Commander Robert FitzRoy of travelling on a
 survey ship, HMS Beagle, as a "scientific
 person" or naturalist. The round-the-world
 journey lasted five years




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         Darwin’s Journeys
Darwin spent most of these years
investigating the geology and zoology of the
lands he visited, especially South America,
Pacific Oceanic islands and the Galapagos
islands .
Darwin was exploring the Galapagos
archipelago from 16 September to 20 October
of 1835.

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HMS Beagle




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        Most important works
• In 1859 On the Origin of Species by means of
  Natural Selection, or the Preservation of
  Favoured Races in the Struggle for Life was
  published in London on 24 November by John
  Murray.

• 1871 The Descent of Man, and Selection in
  relation to Sex.

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Charles Darwin

       • Darwin's most famous
         book, was published in
         1859. Within 20 years it
         convinced most of the
         international scientific
         community that
         evolution was a fact




                                10
Richard Dawkins
        • Ethologist and
          Evolutionary Biologist
        • Emeritus fellow of New
          College, Oxford
          University
        • Oxford University
          Professor for Public
          Understanding of
          Science from 1995 until
          2008
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          Richard Dawkins Books
•   The Selfish Gene, 1976 and 2006
•   The Extended Phenotype. 1982
•   The Blind Watchmaker 1986
•   The God Delusion, 2006
•   The Greatest Show on Earth:
    The Evidence for Evolution, 2009
     ……and many more

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Odyssey




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Panga boat




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In front of the Charles Darwin research station,
Santa Cruz, Galapagos




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Posters at the CDS




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    History of evolutionary thought
•   Aristotle - 4th century BC- Natural History
•   Pliny the Elder- 1st century AD – Natural History
•   Linnaeus- 18th century – Classification
•   Erasmus Darwin – 18th century – common ancestors
•   Lamarck – 19th century - common ancestors
•   Cuvier – 19th century - fossils
•   Charles Darwin - 1859 - natural selection
•   Alfred Russell Wallace – 1859 – similar ideas as
    Darwin

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    Age of the Earth Controversy
• According to literary Bible interpretation
  - 4600 years
• Using modern scientific methods (accepted by
  most scientists) - 4.5 bln years




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The basic timeline is a 4.5 billion year old Earth,
with (very approximate) dates:
3.8 billion years of simple cells (prokaryotes),
3 billion years of photosynthesis,
2 billion years of complex cells (eukaryotes),
1 billion years of multicellular life,
600 million years of simple animals,
570 million years of arthropods (ancestors of
insects, arachnids and crustaceans),
550 million years of complex animals,
500 million years of fish and proto-amphibians,
475 million years of land plants,
400 million years of insects and seeds,
360 million years of amphibians,
300 million years of reptiles,
200 million years of mammals,
150 million years of birds,
130 million years of flowers,
65 million years since the non-avian dinosaurs
died out,
2.5 million years since the appearance of the
genus Homo,
200,000 years since humans started looking like
they do today,
25,000 years since Neanderthals died out.
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  Darwin vs modern Evolutionists
• Much of the Darwin’s theory of evolution was
  an inspired guesswork
• Darwin’s greatest idea was that of natural
  selection
• Darwin was wrong on the mechanism of
  inheritance
• Modern evolutionists need not to guess - they
  can consult genetic scripture – DNA code

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Summary of modern theory of evolution

Life on Earth evolved gradually beginning with
one primitive species – perhaps a self
replicating molecule – that lived more than
3.5 billion years ago; it then branched out
over time, throwing off many new and diverse
species; and the mechanism for most (but not
all) of evolutionary change is natural selection.



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     Components of the evolution theory

•   Evolution
•   Gradualism
•   Speciation
•   Common ancestry
•   Natural selection
•   Nonselective mechanisms of evolutionary
    change

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        THE EVIDENCE FOR EVOLUTION:
                Biogeography
• Biogeography is the science that seeks to
  explain the distribution of living things
  through space and time on Earth.
  Biogeography looks at current species of
  animals and plants as well as the evidence of
  past life (fossils) in order to determine how
  species arose.



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         THE EVIDENCE FOR EVOLUTION:
                 Biogeography
• If species were created as perfectly adapted to their
  environment, we might assume similar environments
  to have similar plant and animal life. This is NOT the
  case. Instead, the animals and plants of a region are
  most closely related to those of nearby regions and
  reflect the history of the region. Biogeography states
  that the range and dispersal (basically, where an
  organisms lives) is dependent upon the barriers in
  moving from one area to another.


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Galapagos Mockingbird




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           Galapagos Mockingbird

• The Galapagos Mockingbirds descended from
  the Ecuadorian Long-tailed Mockingbird. They
  were the first that were found in Darwin’s trip
  to the islands in 1835. They had a greater
  influence than any other animal on Darwin’s
  theory of evolution when he arrived there
  because it was the first species that Darwin
  noticed distinct differences among when he
  looked from island to island.
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                  Galapagos finches

• The Galapagos Archipelago is home to 13 species of finch,
  belonging to 4 genera. These finches all evolved from a single
  species similar to the blue-black grassquit finch (volatina
  jacarina) commonly found along the Pacific Coast of South
  America. Once in the Galapagos Islands the finches adapted
  to their habitat and the size and shape of their bills reflect
  their specializations. Vegetarian finch and ground finch all
  have crushing bills while tree finch have a grasping bill and
  cactus finch, warbler finch and woodpecker finch have
  probing bills.



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Evolution of bird’s beaks as tools




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Galapagos finches




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Galapagos finches




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          GALAPAGOS TORTOISES

Naturalists believe tortoises arrived in the islands
clinging to a piece of driftwood from a river mouth
along the Pacific Coast. A relatively large tortoise,
related to the Galapagos tortoise lives on the South
American mainland. The tortoises arrived in San
Cristobal then spread throughout the archipelago.
Those on individual islands or in isolated parts of the
larger islands developed into its own sub-species.



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            GALAPAGOS TORTOISES

• The Galapagos was once home to 15 sub-species of
  which 11 sub-species still exists. The smallest
  tortoises like those on Española and Pinta have
  "saddle backs”.
• The largest of the tortoises, those on Santa Cruz and
  from the Alcedo Volcano on Isabela have "dome
  backs". In this isolated habitat these giant tortoises
  fill the niche occupied by larger vegetarian mammals
  in continental regions.


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Giant tortoise




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Tortoise at the CDS




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              GALAPAGOS IGUANAS

• The Galapagos Islands are home to Marine Iguanas, Land
  Iguanas, and a hybrid mix whose father's are marine iguanas
  and mother's are land iguanas as well as the newly discovered
  pink iguanas.
• Land iguanas grow to a bulky girth and 3 ft (1 m) in length.
  Their yellowish-orange belly and brownish red back make
  them more colorfull then their cousins, the marine iguana.
  The land iguana lives in the arid portion of the islands.
• The cactus provides both food and water for the land iguana,
  who can go without fresh water for a year. Part of the
  adaptation to the drier environment includes a conservation
  of energy by slow movement

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Land iguana




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Land iguana on Santa Cruz




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                    Marine iguanas

• Marine iguanas exist only in the Galapagos Islands. Living on
  the black lava shore rocks they have developed into efficient
  swimmers feeding off shore mostly on marine algae and
  seaweed.
• The cold waters of the Galapagos provide both the necessary
  food for the marine iguanas and its most deadly threats. Until
  the arrival of man, marine iguanas only threats were that of
  larger fish and sharks encountered while swimming.




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Marine iguanas on Espanola




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Marine iguanas on Isabela




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       THE EVIDENCE FOR EVOLUTION
                     VESTIGES
• A vestigial organ is something that had an
  important function a long time ago, but over
  time has lost it
• The vestiges are important because they provide
  evidence for evolution
• They are little clues to what could have been
  billions of years ago
• Gives a stable foundation that some organisms
  share a common ancestor



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              Evolution of wings

• The appearance of wings on flightless birds is
  considered a strong proof for evolution
• Wings that are incapable of flight are now used for;
   – Absolutely nothing at all (cormorant, kakapo)
   – One time flight (queen ants)
   – Swimming (penguins)
   – Sexual displays
   – Insulation
   – Balance




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          WHY GIVE UP FLIGHT?

• Species families with shorter wings may be predisposed to
  flightlessness due to the higher cost associated with flight
• There is a trade off between stability and maneuverability
• Dominant pressures may keep wings short such as;
   – Predation
   – Foraging ( taking over for mammals)
   – Nesting
   – Habitat
• Many flightless birds are found on islands, like Galapagos




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              The Galapagos Penguin

• The only penguin living exclusively in equatorial region
• Second smallest of all penguins,
• Nest mainly inside lava tubes, underneath big boulders or in
  crevices offering a cool environment
• 95% occurs around Fernandina
• Lives in small colonies of 2 to 12 birds
• Feed mainly in inshore waters




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The Galapagos Pinguin




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The Galapagos Pinguin




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   THE GALAPAGOS CORMORANT

• The only flightless cormorant;
• Unique mating behaviour – female initiate and play
  more active role in courtship than male;
• Male choses from the competing females;
• Female deserts its mate and offspring and goes off to
  find a new mate, while the male alone raises the
  young until they attend full independence.




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THE FLIGHTLESS CORMORANT




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                  Sexual selection

• Supported by sexual dimorphism – traits that differ
  between males and females of a species (tails, color)
• Reduces chances of male survival by wasting a lot of
  energy and exposure to predators
• Exists in two forms – direct competition between
  males for access to females and female chooseness
  among possible males
• Support natural selection by increasing rate of
  reproduction of winning or chosen males

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Sea lions of Galapagos




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            Sea lions of Galapagos

Sea lions form colonies at their hauling-out areas. Adult males
known as bulls are the head of the colony, growing up to 7 ft
(2 m) long and weighing up to 800 lb (363 kg). As males grow
larger, they fight to win dominance of a harem of between 5
and 25 cows and the surrounding territory. Swimming from
border to border of his colony, the dominant bull jealously
defends his coastline against all other adult males. While
patrolling his area, he frequently rears his head out of the
water and barks, as an indication of his territorial ownership




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            Frigate Birds of Galapagos

• Frigate birds are large seabirds, about the size of a hen and
  have extremely long, slender wings.
• They are large (almost 6 feet/1.8 m. wingspan), lightweight
  and have a long, hooked beak to catch fish without getting
  wet.
• Male frigates have shiny green or purple plumage (depending
  on the species) and a resplendent scarlet pouch, which is
  displayed in courtship.
• There are two species of frigates in Galapagos: the
  Magnificent Frigate Bird and the Great Frigate Bird.


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Frigate Birds of Galapagos




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              Courtship of Frigate birds

• During courtship display, the male forces air into the pouch,
  causing it to inflate over a period of 20 minutes into a startling
  red balloon.
• As males tend to display in groups, the effect is magnified.
  Then the males sit quietly in the low shrubs watching for a
  female to fly overhead.
• At this, the males waggle their heads from side to side, shake
  their wings and call. If the display is attractive enough, then
  the female will land and sit beside her amour




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                  Conclusion

• The Galapagos Islands provided Charles
  Darwin an inspiration to creation of the
  theory of evolution.
• Many of Darwin’s ideas were just
   good guesses, he did not explain some
  aspects of evolution, like e.g. speciation.
   However the following research by others
  made the theory of evolution a proven fact.
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