How did life develop?

Question 1

4 billion years ago

Answer 1

Earth’s atmosphere was mainly carbon dioxide, methane, water vapour, nitrogen and ammonia.

Question 2

OCEANS

Answer 2

Formed when water vapour condensed due to warmer temperatures.

Question 3

3-4 billion years ago

Answer 3

In oceans (primordial soup), bacteria developed, which used underwater volcanoes as a source of food.
Then photosynthetic cyanobacteria developed.

Question 4

2-5 billion years ago

Answer 4

Algae evolved which used photosynthesis to make its food from gases in the atmosphere.
CO2 levels decrease and is locked up in fossil fuels and dissolved into oceans.
THIS RELEASED OXYGEN WHICH BUILT UP OVER A LONG PERIOD OF TIME, EVENTUALLY RESULTING IN GREAT OXYGENATION EVENT.

Question 5

After GOE

Answer 5

Oxygen released in GOE reacted with the methane and ammonia in the atmosphere, contributing to the greenhouse effect.
(Oxygen+Ammonia= Nitrogen)
(Oxygen+Methane= CO2+H2O)

Question 6

600 million years ago

Answer 6

Animals evolved which could use oxygen for respiration.