Origin of Life

1
Origin of Life

• K. Sathasivan

2
Are we alone?

1. Yes
2. No

3
How do you think life originated on earth?

1. Extraterrestrial aliens brought it
2. Came with meteors from other planets
3. Some superhuman powers created it
4. Chemical from primordial soup combined to make
   life
5. None of the above

4
History of Life
5
Stromatolites
6
Early prokaryotes
7
Cyanobacteria fossils
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Possible Sources of Lifes Origin
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Possible Steps in the Origin of Life

• Protobionts and Liposomes

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Which came first?

• DNA
• RNA
• Protein
• Carbohydrates
• Lipids

• DNA ? RNA ? PROTEIN
• (Genetic (Information (Catalytic and
  Information) and catalytic) Structural)

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Abiotic RNA Replication
12
Primitive RNA and Proteins
13
Which of the following is/are testable hypothesis
about origin of life on earth?

1. Extraterrestrial aliens brought it
2. Came with meteors from other planets
3. Some superhuman powers created it
4. Chemical from primordial soup combined to make
   life
5. None of the above

14
The Five Kingdom System
15
Domain Systems