1. One of the biggest questions: Where did we come from? Why life?
Origin of Life Ch & 14.2 (p )
One of the biggest questions:
Where did we come from?
Why life?
The early debate was:
Biogenesis vs. Spontaneous Generation
What do these words mean?
Bio
Genesis
Spontaneous
generate

2. Biogenesis = all living things come from other living things
Origin of Life Ch & 14.2 (p )
Biogenesis = all living things come from other living things
Ok but what was the first living thing? Was there a first?...
What came first the chicken or the egg?
Spontaneous generation = living things can arise from non-living things

3. Redi’s Experiment: Control: meat in open jar
Origin of Life Ch & 14.2 (p )
Redi’s Experiment:
Control: meat in open jar
Experimental: meat in open jar covered by gauze
Results: No maggots formed on meat covered by gauze.
Point Biogenesis

4. Spallanzani’s experiment:
Origin of Life Ch & 14.2 (p )
Spallanzani’s experiment:
Control: boil broth, leave open
Experimental: boil broth, seal
Results: no bacteria in sealed flask
Point biogenesis

5. Pasteur’s experiment:
Origin of Life Ch & 14.2 (p )
Pasteur’s experiment:
Same as Spallazani’s but he came up with a way to leave it open.
Control: boil and leave open
Experimental: boil and leave open but neck is curved
Results: no bacteria in curved-neck flask
Biogenesis wins.
But we still don’t
know how started.

6. Radioactive isotope dating = very accurate measurement for age
Origin of Life Ch & 14.2 (p )
14.2 The Earth is old.
Radioactive isotope dating = very accurate measurement for age
Measures half-life decay = the time it takes half of the radioactivity to decay
Useful for things that aren’t changing: rocks, dead things

8. Put chemicals in flask that were present in early earth
Origin of Life Ch & 14.2 (p )
14.2 Miller’s Experiment:
Put chemicals in flask that were present in early earth
Simulated conditions: water, lightning….
Results: amino acids formed by themselves
What do amino acids form?