LUCA
Acronym

- the acronym for “Last Universal Common Ancestor” or "Last Universal Cellular Ancestor" used in evolutionary biology to describe the shared ancestral lineage of Bacteria, Archaea and Eukarya.

- the most recent ancestral cell population from which all living organisms on Earth descend.

- an organism hypothesised by molecular phylogenetics to represent the root of the tree of life.

CNRS, Nature, Wikipedia

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ORIGIN

The term LUCA was coined in the late 20th century (popularized in the 1990s) as scientists studying molecular evolution needed a precise term for the organism from which all current life on Earth descended. This organism is estimated to have lived approximately 3.5-4 billion years ago.

The acronym follows the scientific convention of creating memorable abbreviations for complex concepts, similar to DNA, RNA, or ATP.

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4 BILLION YEARS OF UNBROKEN SUCCESS

Every cell in our body carries instructions from an ancestor that lived when Earth had orange skies and no oxygen in the air. This ancestor is LUCA – the Last Universal Common Ancestor. Scientists believe this single organism existed around 3.8 billion years ago and gave rise to every living thing we see today.

LUCA wasn't the first life on Earth, just the one whose descendants survived while other early life forms died out. We know about LUCA by comparing the DNA of different species. The genes that bacteria, plants, mushrooms, and humans all share must have come from this ancient ancestor.

What was LUCA like? It probably lived near underwater volcanic vents where hot, mineral-rich water provided energy. It was simpler than even the most basic bacteria we know today. LUCA couldn't handle oxygen, which makes sense because there wasn't any oxygen in the atmosphere back then. It had a cell wall, could make proteins, and stored its genetic information in RNA.

Every person we meet, every tree we pass, every bird overhead – all of us trace back to this one organism. Our family tree doesn't just go back generations, it goes back billions of years. Understanding LUCA reminds us that life is persistent and that despite all our differences, humans and every other organism are connected by an unbroken chain of survival that has never failed, not once, in 4 billion years.

Helga & Paul Smith

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SYNONYMS

ancestral cell, ancestral lineage, common ancestor, earliest shared ancestor, life’s ultimate forebear, LUCA, original ancestor, our deep-time ancestor, primal forebear, primordial cell, progenitor of all life, root of the tree of life, universal progenitor

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SMUGGLE
 OWAD into a conversation today, say something like:

"The salutory story of LUCA reminds us that every human, whale and bacterium shares a connection that stretches back unbroken, billions of years.
"

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P L E A S E   S U P P O R T   O W A D