Can someone help answer these questions and discussion? Also cite any sources us

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Can someone help answer these questions and discussion? Also cite any sources used.

Week 2 Discussion Forum 21 days ago The first living organisms evolved in a reducing environment which had little free oxygen. Then, photosyntheitic prokaryotes arose and began "poisoning" Earth with free oxygen. This event is written in the geology of this planet, and had a profound effect on the evolution of living things 1 How did this chemical revolution affect early life? 2. What innovations were made possible? 3 What happened to those first, anaerobic organisms? Where are they found today? What does that say about the primordial earth? Reply 0 replies

Explanation / Answer

1. The great oxygenation event drastically altered the evolution of life. Many intermediate forms were eliminated and only stable forms are preserved due to the presence of oxygen. It is also referred to as oxygen holocaust which destroyed most of the then abundant obligate anaerobic organisms. It occurred during the Siderian period (2.45 billion years ago).
2. The presence of oxygen in the environment ushered the evolution of organisms which can utilize oxygen. This led to the evolution of more efficient aerobic respiration pathway.
3. Most of the primitive obligate anaerobes were diminished by the effect of oxygen. A few species are now present in thermal vents (Methanogens). This shows that the primordial earth was hot with reducing environment.

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