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1- Abiogenesis vs. Biogenesis

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1- Abiogenesis vs. Biogenesis Powered By Docstoc
					Living   Non-Living?
    Organize the following into your table..

•    Toenail            •   Fire
•    Sun                •   Tree bark
•    Hair               •   Water
•    Nerve Cell         •   Algae
•    Leaf               •   Bacteria
  What makes
something alive?

   Ideas?
7 Characteristics of Living
       Organisms
    1.   Feeding
    2.   Movement
    3.   Breathing/ Respiration
    4.   Excretion
    5.   Growth
    6.   Sensitivity
    7.   Reproduction
Where does it come from…?
   The Big
  Question:
    ????????

 Can Living things
    come from
Non-living things??
 What is Spontaneous Generation?
• The idea that organisms originate directly from
  non living matter
• “life from nonlife”
• ABIOGENESIS: the theory that states that non-living
  things can be transformed into living things.
• abiogenesis
   (a=not, bio= life, genesis= origin)
• It was common knowledge that simple
  organisms could come from dust, mud and food
  left out.
       How Did This Happen?
              • Every year the Nile River flooded
                leaving behind nutrient rich
                soil that enables people to
                grow that year’s crops.
              • However, along with the muddy
                soil, large numbers of frogs
                appeared that weren’t around in
Aristotle:      drier times.
Greek
philosopher
(384-322
BC)
      How Did This Happen?
• Conclusion:
  It was perfectly obvious to the people back
  then that muddy soil gave rise to the frogs.
      How Did This Happen?
• In many parts of Europe, medieval farmers
  stored grain in barns with thatched roofs.
  As a roof aged it started to leak. This could
  lead to spoiled or moldy grain, and of
  course, there were lots of mice around.
      How Did This Happen?
• Conclusion:
  It was obvious that the mice came from
  the moldy grain.
             van Helmont
• Even 300 years ago, a Belgian doctor, van
  Helmont concluded that mice could be created
  from grains of wheat and a dirty shirt.
• What was wrong with van Helmont’s
  experiment?
      Hello, Francesco Redi
• Italian Doctor most well-known for his
  experiment in 1668 which is regarded
  as a one of the first steps in refuting
  spontaneous generation.
   Up to this point, science was based on observation and
    analysis…now, experiments were needed to test the
                       hypothesis…

In 1668, An Italian
   physician,
   Dr. Redi,
   conducted an
   experiment to
   prove that flies
   did not come
   from rotting
   meat. Very
   controversial at
   the time…
1. What was the experimental variable?
2. What was the controlled variable?
3. What was the “active ingredient” that
   people believed was needed for
   spontaneous generation?
       The debate rages on…100 years later

• In 1748, John Needham performed an experiment
  similar to Redi’s except that he wanted to study the
  spontaneous generation of microorganisms instead of
  maggots.
  His experiment used 2 meat infusions which were both
  boiled to kill the microorganisms , then one was left
  open, the other was sealed with a cork. Micro-organisms
  grew in both flasks. Needham saw it as proof of
  spontaneous generation….

  What do you think? What was the problem with this
  experiment?
          Lazzaro Spallanzani
Lazzaro Spallanzani was an Italian naturalist who
also attempted to disprove the Theory of
Spontaneous Generation, almost one hundred
years after Francesco Redi.
With the invention of microscopes after Redi's
death, scientists were able to see tiny organisms
that they could not see with the naked eye.
In the late 1700's, Lazzaro Spallanzani tried to
disprove this by performing a controlled experiment
with broth.
Spallanzani…trying to disprove Needham
        Louis Pasteur

• Louis Pasteur was a French
  chemist who finally disproved the
  Theory of Spontaneous
  Generation in the mid 1800's.
• Louis Pasteur performed the
  same type of experiment as
  Spallanzani, except both of his
  flasks allowed air to enter
   And so, 2000 years after it
      started the debate of
 abiogenesis vs. biogenesis is
              settled:
 Life comes from life, not from
spontaneous generation of non-
          living things!!!
               Biogenesis
• Biogenesis is the process of life forms
  producing other life forms
LIVING                    LIVING

LIVING                    NON - LIVING

NON-LIVING                       LIVING
  (spontaneous generation doesn’t exist!!)
   Passport: In Your Own Words
• What is the difference between
  Abiogenesis and Biogenesis?

• Take a minute to write out the
  contributions of each scientist and how
  each affected the Abiogenesis vs.
  Biogenesis debate.

				
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posted:1/4/2013
language:English
pages:26