Week 3 : History of Life

ORIGIN OF LIFE

 

For this week reflective journal, I learn about the topic of history of life which is I learn how the life is formed 4.2 billion years ago from inorganic compound that has no oxygen.

4 requirements must have existed:

1.  Little/no free oxygen-earth's early atmosphere was strongly reducing.
2. Source of energy to form organic molecules-early earth was a place of high energy
3. Availability of chemical building blocks such as CO2, N2, H2, CO, water vapour. Some NH3, H2S and CH4,little or no O2.
4.  Sufficient time for molecule to accumulate and react

The first prokaryote that I learnt is chemoautotrophs that consume organic molecules for both energy and carbon and the first autotrophs that I have learnt is photoautotrophs. It used light electron from H2O to fix CO2 into sugar. It is happen when the organic compounds from the ocean become depleted, the prokaryotes who able to make their own food can grow (autotrophs) 


As for the topics for week 3-5, I already published a week 4 topic but I republished topic in week 4 or organize my blog so all 3 weeks topic share the same date.