Transcript The Origin of Life

Early Earth & Life
How was the Earth formed?
????
Evidence we have:
1) Earth is 4 – 5 billion years old (using
radioactive dating and core sampling)
2) collisions among debris and gases in
space contributed to the formation of Earth
So what was Early Earth like?
Oparin’s Theory – early Earth was:
1) hot, volcanic, electrical storms
2) lots of gases (deadly gases like
ammonia, hydrogen, carbon dioxide &
carbon monoxide, methane, etc…)
3) water vapor, no liquid water
4) no “free” oxygen
5) eventually the Earth cooled, liquid
water condensed forming seas/oceans
Miller & Urey experiments
Miller & Urey conducted an experiment of
Oparin’s Theory.
Produced amino acids (organic compounds)
Miller & Urey experiment
Steps to life…
1)
2)
3)
4)
Create simple organic compounds
Create complex chemical compounds
Enclose compounds in a “membrane”
Perform chemical reactions that allow the
“cell” to do metabolism, reproduction &
other functions of life
The Origin of Life
Different Theories on the Origin of
Life
1) Spontaneous generation life from nonliving things
2) Biogenesis  life from living things
Experiments on Spontaneous
Generation
1) Redi – 2 jars of meat, one covered one
not covered. The uncovered jar had
maggots, the covered jar didn’t have
maggots.
Conclusion: life can’t come from non-living
things.
Redi’s experiment
2) Spallanzani – boiled broth in 2 flasks, one
was sealed, the other was not sealed. The
unsealed flask became cloudy with
bacteria.
Conclusion: disproved microorganisms
come from “vital force” in the air
3) Pasteur – boiled broth in an unsealed
flask with a curved neck. The broth never
became contaminated.
Conclusion: supported biogenesis.
Pasteur’s experiment