These events of the story of early life are not in order…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
These events of the story of early life are not in order.
- Some cells release oxygen.
- The Earth forms with no atmosphere.
- Amino acids form from simple gases.
- Rain fills the hollows and forms the oceans.
- Non-cellular forms of life appear.
- Single-celled organisms appear.
- Write the events in the right order.
- Which of them is the kind of event that Miller copied in his flask?
Need a reminder? The key ideaShow
The Earth is about billion years old. Chemical evolution came first, then non-cellular life, then cells. Pasteur showed that life comes from life. Miller made amino acids from methane, hydrogen, ammonia and water vapour with an electric discharge. A scale of a clock: billion years.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) The order is .
- The Earth forms with no atmosphere (2).
- Rain falls and the oceans form (4).
- Chemical evolution makes amino acids from simple gases (3).
- Non-cellular forms of life, giant molecules in capsules (5).
- Single-celled organisms (6).
- Some of the cells release oxygen (1).
Step 2. (b) Event 3. Miller used a spark for lightning, and he found amino acids.
Answer: 2, 4, 3, 5, 6, 1; the formation of amino acids from simple gases.
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