What does LUCA tell us about our origins?

~ < 1 of audio

Speed: 1.00

Author note.

Explore voice = Exploratory style. Very punchy. Personal, and lively using “me,” “you,” “us,” and “I” freely.

I want you to feel me right there with you. We use “I” and “me” and “us” without apology. If the Explain voice is a bridge, the Explore voice is the hike we take across it. It is lively, reflective, and sometimes a bit raw. It is the sound of a shared exploration where I lead you by the hand, but we both discover the view at the same time.

This is where I get to think out loud. Not with definitions, we aren’t just looking at the facts; we are looking at how they feel and what they mean for our lives. I’m talking to you about what I’ve found and what I’m still figuring out. It is engaging because it is real, and it is reflective because it is honest.

The goal is real advice and enjoyable reading. I want to land on something you can actually use. It’s about being direct, being punchy, and making sure that by the time we reach the end of the page, we’ve both found something worth keeping.

And now the piece.

What does LUCA tell us about our origins?

LUCA, or the Last Universal Common Ancestor, represents the point in history where all life on Earth converges. From humans to bacteria, every living organism shares this ancient ancestor. LUCA was a simple, single-celled organism that lived about 3.6 billion years ago, likely thriving in extreme environments like deep-sea vents. Though we don’t know much about what LUCA looked like, we know that the genes it passed down still exist in every living being today.

The discovery of LUCA tells us something profound: all life is interconnected. Every plant, animal, and microbe can trace its evolutionary roots back to this one ancestor. This shared lineage shows that the diversity of life on Earth—despite its many forms and complexities—springs from a common origin. We are all part of the same family tree.

Beyond the science, LUCA speaks to our place in the natural world. Understanding that we are connected to all living things reshapes how we see ourselves. It challenges the idea that humans are separate or special in the grand scheme of life and instead reminds us that we are just one branch on the vast tree of life.

Here's the key idea. LUCA shows that all life on Earth shares a single, ancient origin—making life fundamentally connected, not divided.

Finally, the core takeaway. LUCA quietly dissolves the illusion of separation. Long before culture, belief, or identity, there was chemistry learning to survive. Understanding our shared origin doesn’t diminish humanity—it grounds it. The deeper we trace our roots, the clearer it becomes: life is one story, endlessly branching, never starting over.

That Science FAQ,

was first published on TST 2 years ago.

The flashcard inspired by it is this.

Front: Was LUCA a prokaryote?

Back: No. We started as pre-prokaryotic cellular life.

All this is part of the broader TST project.

In this project, claims are never just asserted—they are attached to evidence, context, and traceable sources.

Each weekly edition of the TST Weekly Column consists of a central column supported by a research layer of stories, quotes, timelines, and FAQs.

The end!