NEW UNIT: EVOLUTION Chap 15'1The Puzzle of Lifes Diversity

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NEW UNIT EVOLUTIONChap 15.1-The Puzzle of
Lifes Diversity

• Definitions
• THEORY
• -An explanation of how nature works that is
  (very) well-supported by many other scientists.
  It can still be tested for accuracy (or
  disproved) via experiments and observations.
• No theory is based on one scientists opinion
  but on multiple pieces of collected evidence by
  many scientists over time. The longer a theory
  has been accepted, the more accurate (valid) its
  considered to be.

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Defintions (continued)

• 2. EVOLUTION
• (means change over time) is the process by
  which modern organisms have descended
  (genetically) from ancient organisms.
• -Charles Darwin is the founder of the theory of
  evolution.

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The Theory of Evolution asks

• -How did life on earth come to exist? (no one was
  there to witness it!)
• -How has life changed (evolved) since then?
• -HOW and WHY did so many different forms of life
  (DIVERSITY) come to exist? (includes those still
  living and millions of species that have become
  extinct)
• -

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EVOLUTION ASKS Why is there no (undiscovered)
life here yet

PHOTOS OF MARS FROM RECENT MISSIONS
The red planet
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yet
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there is a multitude of life forms here on
Earth? (at least 1.5 million and still counting!)
Another good question WHY SO MANY??????!
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Evolution asks Are some of these different
species more closely (genetically) related than
others?

• Giant Sequoia Trees of Sequoia National Forest
  and Coastal Redwoods (California)

(Sequoia-known for width)
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Both Are Different But Very Closely related
Redwood-known for height
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Are these 2 species related?What do you think?
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Humans and Chimpanzees 95 of base pairs are
exactly the same
(This is what we mean we say.. 95 genetically
similar)
American Indian mom and baby 100 years ago
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Evolution asks What about those forms of life
that seem to be completely unrelated? (are they
related somehow?)
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EVOLUTION ASKS IS ALL LIFE RELATED SOMEHOW??
(YES!)
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CHARLES DARWIN (1809-1882)
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When Darwin was

• 22 years old (1831) he sailed around world for 5
  yrs. collecting and analyzing different species
• He sailed on a ship called the HMS Beagle
• He was most influenced by visiting the GALAPAGOS
  ISLANDS (600 miles off coast of South America)
  because of the unique animals he found there.

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Based on his observationsDarwin proposed that

• The great diversity of life (on earth) we see
  could only be possible if the earth was millions
  of years old.
• (Most in Darwins time thought the world to be
  only 6000 years old-too young for species to
  develop and change so much)

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It took about 1 billion years of erosion to carve
out this Canyon
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Darwin also noticed that

• 2) Animals seem to perfectly fit or be adapted
  to their own particular environment... How did
  this occur?

HOW IS THIS POLAR BEAR WELL- ADAPTEDTO ITS
ENVIRONMENT?? DO IS IT GIVE IT A SURVIVAL
ADVANTAGE??
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Darwin wondered..

• 3. Why had so many species become extinct (he
  found fossils)? Are some related to species
  living now?
• saber-toothed tiger tiger (still
  living)
• (extinct)

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Darwin observed that.

• -that animals and plants differed from each other
  in obvious ways on the different islands of the
  Galapagos
• HE WONDERED
• -if all the animals living on the Galapagos
  (though different now) had once all been members
  of the same species (family)??
• (they originally descended from their South
  American ancestors and then were isolated from
  each other on different islands)
• IF TRUE, WHY NOW WERE THEY SO DIFFERENT???

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BLUE-FOOTED BOOBIES (ONLY FOUND ON GALAPAGOS
ISLAND)
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Darwin based his theory on

• 4 OTHER FAMOUS SCIENTISTS
• James Hutton
• Charles Lyell
• Jean-Baptiste Lamarck
• Thomas Malthus

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James Hutton/Charles Lyell

• In 1785-1809, proposed that Earth was shaped by
  geological forces that took place over extremely
  long periods of timemillions of years not
  thousands of years as people commonly thought.

A u-shaped Valley Carved by Glacier-this Took a
lot of Time!
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A U-shaped glacial river valley