Provide a brief account of the history of evolution.

(N/A) The first cellular forms of life appeared on Earth about $2000$ million years ago $(mya)$. How the non-cellular aggregates of giant macromolecules could evolve into cells with membranous envelopes is not known. Some of these cells had the ability to release $O_2$. The reaction could have been similar to the light reaction in photosynthesis where water is split with the help of solar energy and captured by light-harvesting pigments.
Slowly,single-celled organisms became multi-cellular life forms. By $500$ $mya$,invertebrates were formed and active. Jawless fish probably evolved around $350$ $mya$. Seaweeds and plants existed probably around $320$ $mya$. We can say that plants were the first organisms that invaded land. They were widespread on land when animals invaded land. Fish with stout and strong fins could move on land and go back to water.