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Charles Darwin1809-1882
The Father of Evolution
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Charles Darwin Born in 1809, Shrewsbury,
England Naturalist Studied Medicine Degree in
Theology Buried in Westminster Abbey
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After Cambridge, Charles was recommended for a
surveying trip on the HMS Beagle.
The mission of the voyage was to chart stretches
of the South American coast.
Darwin sailed aboard the Beagle for 5 years,
working as a naturalist.
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Row, row, row your boat!

• Voyage of H.M.S. Beagle
• 5 year unpaid voyage
• Darwin studied plants, animals, collected fossils
• Found fossils of extinct animals that were
  similar to modern species. On the Galapagos
  Islands in the Pacific Ocean he noticed many
  variations among plants and animals of the same
  general type as those in South America.

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This voyage lasted from 1831 to 1836.
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Many of Darwins conclusions were based on
observations of wildlife in the Galapagos Islands.
The Galapagos Islands lie 500 miles west of
Ecuador in the Pacific Ocean, directly on the
equator.
Galapagos means turtle.
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Darwin was influenced by

• Geologist
• Contribution
• Earth is very old (much older than thought)
• Earth has changed over time (constantly changing)

Sir Charles Lyell 1797 - 1875
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Another influential person

• Economist
• Contribution
• Populations have the potential to increase faster
  than the available food supply

Thomas Malthus 1766-1834
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Another influential scientist
Alfred Russel Wallace

• Botanist
• Contribution
• Essay described evolution by natural selection

Alfred Russel Wallace 1823 - 1913
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Galapagos finches
Darwin noticed there were several types of
finches on these islands.
In particular, Darwin observed something odd
about the finches they all looked like a bird he
had seen on the South American continent.
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In all, there were 13 types of finches, some
species being confined to only one island.
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The most distinct difference among finch species
is their beaks, which are adapted for the
specific diets available on the islands.
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Darwin wondered if the birds and other animals
had been created to match their environment, why
didnt these birds look like the birds of the
African continent, since the environments of both
the Galapagos and Africa were similar.
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Darwin guessed that some of the birds from South
America migrated to the Galapagos.
Once on the islands, the birds must have changed
over the years.
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large ground finch
woodpecker finch
cactus finch
This would explain the numerous species of birds
present.
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PHYLOGENIC TREE A diagram showing the
evolutionary history of a species of an animal.
This tree has how many major branches?
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TWO TYPES OF EVOLUTION

• Convergent Evolution process by which unrelated
  species become similar as they adapt to similar
  environments.
• Divergent Evolution formation of new species
  from an existing species adapting to new
  environments.
• What type of evolution is a phylogenic tree?

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After returning from the Galapagos and studying
all the different types of plants animals.
Darwin concluded new concepts of change.
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Darwin called this
evolution
which means (change in species over time)
Darwin extended these principles to biology,
which helped him form his theory of
Natural Selection
which means Survival of the Fittest.
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Five basic components of
Natural Selection
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1. All species have genetic variation.
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2. The environment presents challenges to
survival.
There is a constant struggle for survival.
Examples are Drought Fires Floods Snowstorms
Hurricanes Tornadoes Other natural disasters
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3. Organisms produce more offspring than can
survive. Competition exists WITHIN and AMONG
species.
Within a Species
Among Species
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4. Individuals that are fit to their environment
leave more offspring than those who arent.
Darwins definition of fitness
Organisms who possess favorable traits will leave
more offspring.
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5. Characteristics of fit individuals increase
in a population over time.
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Therefore Darwins contributions

• Provided evidence that species evolve
• In 1859, he proposed the Theory of Natural
  Selection to explain evolution (Survival of the
  fittest)
• Over time, change within species leads to the
  replacement of old species by new species as less
  successful species become extinct.
• Some evidence from fossils may prove that species
  on Earth have evolved from ancestral forms that
  are extinct. (species that have disappeared
  permanently.)

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What is a species?

• One or more populations of individuals that can
  interbreed, producing fertile offspring.
• Speciation is the process by which new species
  are formed over time.

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Equus, the modern horse, evolved from the
dog-sized Hyracotherium. Notice it evolved from
a four-toed front foot to the one-toed front foot
of the modern horse.
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Scientific Evidence of Evolution includes

• Fossil Record
• Comparative Anatomy
• Embryology
• DNA Proteins (Biochemical Evidence)

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Fossil Record

• In order for fossils to form
• Calcium must be replaced
• Burial must occur by sediment
• Usually occurs in swamps, mud, ocean floors, tar
  pits, etc.

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COMPARATIVE ANATOMY Homologous structures are
characteristics which are shared by related
species because they have been inherited in some
way from a common ancestor.
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• For example, the bones on the front fins of a
  whale are homologous to the bones in a human arm
  and both are homologous to the bones in a
  chimpanzee arm.

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Analogous Structures
similar in function but not in origin and
structure
In convergent evolution, organisms evolve similar
features independently, often because they live
in similar habitats.
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VESTIGIAL STRUCTURESstructures that serve no
useful purpose

• Examples include
• Tailbone Whales pelvis Canines
• Appendix muscles to move ears

EMBRYOLOGYstudy of organisms in their earliest
stage of development
BIOCHEM (DNA PROTEINS)comparing genes to show
relationships
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Because of Darwins discoveries we know that
Evolution is the change of species over time NOT
the origin of life! This is NOT a theory but a
possible hypothesis based on Natural Selection!