Last universal common ancestor (LUCA)

Definition

The Last Universal Common Ancestor (LUCA) is the most recent common ancestor of all current life on Earth, estimated to have lived around 3.5 to 3.8 billion years ago. It represents a key node in the tree of life from which all prokaryotic and eukaryotic organisms diverged.

5 Must Know Facts For Your Next Test

1. LUCA is not a single organism but a population of organisms sharing genetic characteristics.
2. It possessed basic cellular structures like ribosomes and was likely capable of DNA replication, transcription, and translation.
3. LUCA's environment was anaerobic, meaning it thrived in an oxygen-free environment.
4. Genomic analyses suggest that LUCA had features common to both bacteria and archaea.
5. Studying LUCA helps scientists understand the early evolution and diversification of life forms.

Review Questions

• What are some basic cellular structures that LUCA likely had?
• Why is LUCA considered crucial for understanding the tree of life?
• In what type of environment did LUCA most likely thrive?

Related terms

Prokaryote: A single-celled organism without a distinct nucleus or specialized organelles.

Phylogeny: The evolutionary history and relationship among species or groups of species.

Archaea: A domain of single-celled microorganisms that are similar to bacteria but have distinct molecular characteristics.