Early Life

Question 1

What does an organism need to live on earth?

Answer 1

• Water
• Carbon dioxide (plants)
• Oxygen (aerobic organisms)
• Protection from UV
• Temperature in range of tolerance

Question 2

Why is water important?

Answer 2

• Biological temperature regulation (evaporation of sweat)
• Forms aquatic habitats
• Anomalous expansion of freezing (ice is less dense than water; floats)
• Solvent for biological reactions
• High specific heat capacity (reduced temp fluctuations
• Absorbs UV radiation (protected living organisms before ozone layer)
• Transport of essential nutrients