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Life
What is it?
Where did it come from?
Classify the following as livingnonliving thigs
What makes something a «living
thing» ?
A living organism is something that has the ability
to:
• Feed
• Move
• Breathe (Respiration)
• Get rid of waste (Excretion)
• Grow
• Be Sensitive
• Reproduce
What is life?
• Something´s ability to be born, grow,
reproduce, die, and, after several generations,
evolve.
Where did life originate?
- Creationism
Theories that attempt
to explain where life
originated
- Spontaneous generation
- Panspermia
- Chemical and cellular evolution
Creationism
Creationism
• The belief that Earth, Universe and life were
created by a supernatural being
Spontaneous generation
Spontaneous generation
• States that living organisms develop from nonliving matter
• Belief proposed by Aristotle. During 2000 years people
thought this was true
• Van Helmont: scientist that made an experiment proving
this theory to be true
• 1870: Thomas Huxley came up with the term abiogenesis
• Italian scientist Reidi: First to doubt this theory
• French scientist Pasteur proved the theory to be wrong
Pasteur´s experiment
Panspermia
Panspermia
• Life was created in outerspace and came into
the Earth via meteors etc.
• Anaxagoras- greek philosopher. First to
propose this theory
Chemical and cellular evolution
Chemical and cellular evolution
• States that life came from inert matter in
times when Earth´s environment was very
different from today´s
Alexander Oparin:
Energy from UV rays and
electric discharges from
thunderstorms
+
Gas molecules in the
atmosphere
=
Organic molecules
• Stanley Miller
Made an experiment recreating the Earth´s
atmosphere in order to prove Oparin´s
experiment
After a week he found organic compounds
Homework
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