A branch cannot exist at the exact same time as the base of the stem it grows from. There had to be a period of time where LUCA’s population began to drift apart genetically until one group became “True Bacteria” and the other became “True Archaea.”

Evolution

First True Bacteria

~3.8 Billion years ago

Prokaryotic Life

3.55 Billion Years Ago (+/- 100 million)

Membrane and metabolic diversity.

Bacteria Photosynthesis begins

~3 Billion years ago

Photosynthetic experiments

Cyanobacteria: Sun Energy as Food!

top view of woman holding paper cut sun and planet with renewable energy sources on turquoise

2.7 Billion Years Ago

2.7 to 2.6 BYA

Bacteria cyanobacteria & oxygenic photosynthesis

~2.5 Billion years ago (+/- 100 million)

Photosynthetic Specialization Emerges

Bacteria Aerobic metabolism expands

~2.2 Billion years ago (+/- 200 million)

Oxygen-respiring bacteria diversify

Bacteria Endosymbiosis event

~2 Billion years ago (+/- 100 million)

Bacteria are added to cells

Bacteria Diversify: Major modern phyla

~1.3 Billion years ago (+/- 200 million)