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)Create simple organic compounds 2)Create complex chemical compounds 3)Enclose compounds in a “membrane” 4)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 non- living 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