Origins of Life | Genetics and Evolution - IB23

Miller-Urey Experiment

1. Water was heated into water vapor which was mixed with H₂, CO₂, CO, CH₄ and NH₃.

2. This mixture along with boiling water was paired with electricity to stimulate lightning.

3. The gases cooled down with circulating cold water to represent condensation which ran for a week.

4. Results showed a mixture that contained organic compounds and amino acids.

Problems w/ Miller-Urey Experiment

The Earth’s early atmosphere was mostly made of CO₂ and very little CH₄ and NH₃. This means the pre-biotic stage Miller-Urey showcased was inaccurate to the origins of life.

Miller-Urey Experiment Re-Done

This experiment was made with UV-light and CO₂. The results showed a production of all amino acids that can be found on Earth. Additionally, complex sugars and lipids were formed while the 5 chemical bases used in DNA and RNA also formed.

Life Formation on Earth

Everything started with the Big Bang, afterwards the Earth and sun was created. C-12 and C-13 suggests that the first signs of photosynthetic life came to be 4 billion years ago.

It is theorized that life first formed on Earth in deep ocean geothermal vents. Prokaryotic cells, namely photosynthetic cyanobacteria, increased the oxygen levels and eukaryotic cells were made.

Life on land came after land on water.

Timeline

1. 13,8 Billion Y.A - The Universe Formed

2. 4,6 Billion Y.A - The Sun and Earth Formed

3. 3,8-3,5~ Billion Y.A - Prokaryotic Cells Formed

4. 3,4-2,7 Billion Y.A - Cyanobacteria Formed

5. 2,2 Billion Y.A - Oxygen Increase —> Eukaryotic Cells Formed

6. 1,7 Billion Y.A - One-Celled Eukaryotic Organisms Formed

7. 1,2 Billion Y.A - Multicellular Organisms Formed

8. 500 Million Y.A - Moss, the First Plant Developed.

(Y.A = Years Ago)

Findings

Complex molecules can be made from chemical processes as proven by the Miller-Urey Experiment.

The first life on Earth could’ve been RNA-based since it’s less complicated than DNA, in addition, RNA can act as an enzyme and replicate.