Darwin

1
Darwins Voyage

• 5 year trip around the world- 1831
• 22 year old Englishman-
• Charles Darwin
• Observed plants and animals
• Developed the theory of evolution
• by natural selection

2
1835 Galapagos Islands

• Diverse group of life forms
• Small Islands off the Coast of South America near
  Ecuador
• Differences between organism on island from same
  species on the mainland were noted

3
Differences on the Galapagos

• Cormorant- doesnt fly
• Larger claws- on the iguanas to grasp rocks
  and find food
• Finch beaks many different sizes adapt to food
  available

4
EVOLUTION..

• Define evolution as a gradual change in a species
  over time- a new scientific theory
• Theory- well-tested concept that explains a wide
  range of observations.
• Adaptation- a trait that helps an organism
  survive and reproduce

5
1858 Natural Selection- The Origin of Species

• Darwin noticed
• -natural variation (ex. No two zebras have the
  same stripes)
• -artificial selection (best crops, best
  livestock).
• He wondered Did this type of selection happen
  on its own in nature?
• Darwin came up with a possible explanation of how
  evolution occurs.
• He called it natural selection.

6
Natural Selection-

• the process by which individuals that are better
  adapted to their environment are more likely to
  survive and reproduce.

7
Natural Selection cont.

• Over a long time, natural selection can modify a
  population enough to produce a new species
• Helpful variations accumulate in a species while
  unfavorable ones disappear.
• Survival of the Sneakiest- http//evolution.berkel
  ey.edu/evolibrary/article/0_0_0/sneakermales_01

8
GENES in Evolution

• Only genes can pass on a trait from parent to
  offspring
• 1977 Finches beaks changed in ONE year due to a
  drought
• Peppered Moth- changed color because of
  Industrial Revolution

9
New Species form

• When a group of individuals remain separated from
  the rest of the species long enough to evolve
  different traits
• Pangaea /Continental Drift
• Landform isolation- river, mountain, water.
  (ex. Squirrels of N. Grand Canyon p.155)
• Australia