LUCA was neither bacteria nor archaea and this group does not have a nucleus (prokaryotes). Over time, LUCA’s population drifted apart genetically until one lineage became true bacteria and the other became true archaea. This group predates the branch that ultimately leads to eukaryotes then plants, fungi, and animals.

LUCA lived about 3.75 bya
Bacteria Evolution Starts 3.7 bya

Prokaryotic Life

Archaea look like bacteria at first glance — small, simple, and lacking a nucleus. But they are fundamentally different.

3.73 Billion Years Ago (after LUCA)

Membrane and metabolic diversity.

Touch: Life Learns to Feel Force

About 3.72 billion years ago, right after LUCA, when cells emerged, touch became the most ancient form of biological sensing: required to physically navigate reality.

~3.72 Billion Years Ago (after prokaryotes)

Mechanical sensitivity to pressure and membrane stretch

First True Bacteria

Bacteria and archaea are both prokaryotes, but archaea’s membrane chemistry and genetic machinery are fundamentally different — and archaeal ancestry gave rise to eukaryotic cells.

~3.7 Billion years ago (shortly after LUCA)

Peptidoglycan cell wall and Ester-linked lipids

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

Blue-Green Bacteria (Not Algae)

Long before plants covered the land, cyanobacteria were already harvesting sunlight. In doing so, they slowly helped change Earth’s oceans and atmosphere, preparing the way for more complex life.

2.65 Billion years ago (+/- 50 million years)

Bacteria cyanobacteria & oxygenic photosynthesis

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

Photosynthetic Specialization Emerges

Bacterial Endosymbiosis: Origin of Eukaryotes

About 2 billion years ago, bacteria are added to cells and that group leads to eukaryotes. You are a walking chimera ecosystem made of an Archaea host and trillions of Bacterial power-plants.

~2.4 Billion years ago (+/- 100 million)

Bacteria are added to eukaryote ancestor cells

Bacteria Aerobic metabolism expands

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

Oxygen-respiring bacteria diversify

Bacteria Diversify: Major modern phyla

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