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LIFE ATLAS 3DALL LIFE. CONNECTED.
See it in the 3D treeAll groups

Three truths

Timed
Began about 4.2 billion years ago · the last 100% of life's story
Named
≈1.7 million named living species · 100% of all named
Weighed
At least ≈541 Gt C · 98% or more of all life's carbon
Some members are not measured (no figure in Bar-On et al. 2018).

Shared ancestry · group

First common ancestor (LUCA)

Last universal common ancestor (LUCA)

Living · roughly 1.7 million described species

The date or placement of this group is still debated.

No licensed image yet. Images will be added only with clear licences and credit.

LUCA is the most recent population that all living things descend from. It was not the first life: other early lineages existed but left no living descendants. One 2024 study puts it at about 4.2 billion years ago; estimates vary widely.

Not the first life, but the last ancestor all life shares. It probably lived around deep-sea vents.

Key characteristics

  • Inferred from genes shared by bacteria and archaea, not from fossils
  • Probably already had DNA, RNA, proteins and ribosomes
  • Likely lived without oxygen
Habitat
Inferred: possibly warm, mineral-rich water such as hydrothermal settings

Child lineages

Classification

  1. First common ancestor (LUCA)

Sources