Our Environment Contents

1. Evolution

Approximately a billion years ago there was a giant leap forward in evolution from single celled organisms to the beginning of multi-cellular life. Much more DNA is required to create a multi-cellular organism as a large amount of genetic information is needed to build several different types of cell and place them accurately within the body.

There are three main theories about how multi-cellular life arose:

Symbiotic theory: Groups of different types of single-celled organisms became so dependent on each other that eventually they became one multi-cellular organism.

Cellularisation theory: A single-celled organism with multiple nuclei developed 'partitions' between its nuclei, with each one eventually becoming a separate cell.

Colonial theory: Symbiosis of many single-celled organisms of the same type developed to the point that they were one entity. This theory is currently considered the most likely explanation.

Colonial flagellate theory

What is the connection between DNA and multi-cellular life?