Ashtar Command Book Blog : The braided stream

Wednesday, April 23, 2025

The braided stream

- Hmmm, I wonder how far back
this "braided stream" really goes?

My conversation with ChatGPT om human evolution continues...

How far back does the braided stream concept of evolution go? Homo heidelbergensis, Homo erectus...?

Awesome follow-up—and yes, the “braided stream” model can be extended well before Homo sapiens. In fact, many paleoanthropologists now believe that this reticulated, network-like evolution goes at least as far back as Homo erectus, and probably even earlier.

Let’s take a look at how far back this evolutionary “braiding” might go—and what that means for our ancestors.

🧬 What Is the Braided Stream Model?

Instead of imagining human evolution as a simple tree (with clean branches separating species), the braided stream model suggests:

Lineages diverge, but later interbreed or reconnect (like braided rivers),
There’s ongoing gene flow between populations,
Evolution is not strictly linear—it’s messy, regional, and dynamic,
“Species” and “subspecies” boundaries are blurred.

🏞️ How Far Back Does It Go?

🔹 Homo sapiens (300k–present):

Undeniably braided—multiple African populations, Neanderthal/Denisovan admixture, even “ghost” populations.

🔸 Homo heidelbergensis (roughly 600k–300k years ago):

Probably already a highly structured species.
Some populations gave rise to Neanderthals, others to modern humans, others to the Denisovans.
Fossils across Africa and Europe show both regional traits and shared features.

❗ Many now view Homo heidelbergensis as a "catch-all" category for diverse Middle Pleistocene humans who probably formed a braided, interconnected set of populations.

🔹 Homo erectus (~1.9 million to 100,000 years ago):

Spread across Africa, Asia, and Southeast Asia.
Clear regional variation: compare Java Man (Indonesia) with Dmanisi fossils (Georgia) or African forms.
Likely had interbreeding populations stretching from Africa to East Asia.
No clear boundary between early Homo erectus and later transitional forms.

🔄 There's evidence of long-distance migration and possibly gene flow across continents over long timescales. That’s braiding on a global scale!

🔸 Even earlier? Homo habilis / Homo rudolfensis / early Homo (~2.4–1.6 mya):

Highly diverse group of early humans in East and South Africa.
Likely coexisted and exchanged genes, possibly representing a cluster of closely related populations rather than distinct, neatly separated species.

📚 What This Means

The further back we go:

The less clear-cut the “species boundaries” become.
Evolution looks less like a ladder or even a tree, and more like a tangled bush, or—yes—a braided stream.
Our hominin ancestors were probably constantly migrating, mixing, adapting, and shaping each other’s evolution.

🧠 Analogy:

Instead of thinking of human evolution like a series of baton-passing runners in a relay race 🏃‍♂️➡️🏃‍♀️, Think of it like multiple rivers flowing, splitting, rejoining, and blending across a vast landscape 🌊🌍.

✅ Summary:

Time Period	Main Hominins	Braided Evolution?	Notes
0–300 kya	Homo sapiens, Neanderthals, Denisovans	✅ Yes	Gene flow across Africa and Eurasia
300–600 kya	Homo heidelbergensis	✅ Yes	Source population for multiple later humans
600–1.9 mya	Homo erectus	✅ Yes	Spread across continents, high variation
2.0–2.5 mya	Early Homo (habilis, rudolfensis)	✅ Likely	Coexisting diverse forms in Africa

Would you like a visual “braided timeline” showing how these populations connect and diverge over time? It makes this even easier to see.

Can you tell me something about the "ghost populations" within the genus Homo?

Absolutely—“ghost populations” are one of the coolest (and slightly eerie 😄) concepts in modern human evolutionary genetics. Let’s break it down:

👻 What Is a "Ghost Population"?

A ghost population refers to:

A group of ancient humans (or hominins) that interbred with other populations, leaving genetic traces in our DNA,
but whose fossils have never been found, or whose identity is still unknown.

So we know they existed—but we've never directly seen them in the fossil record.

🧬 How Do We Know They Were There?

Geneticists detect ghost populations when they find:

DNA segments in ancient or modern genomes that don’t match any known hominin (like Neanderthals or Denisovans),
But are too divergent to come from known populations,
Meaning: they must come from an unknown branch of the Homo family tree.

It's like finding a puzzle piece that fits, but doesn't match the picture on the box.

🧠 Major Examples of Ghost Populations:

1. "Ghost Archaic" in Sub-Saharan Africa

Modern African populations carry deeply divergent DNA from a previously unknown hominin.
Estimated to have split from other humans ~1–2 million years ago.
Possibly a relative of Homo erectus or another early African lineage.
No fossils matched to this lineage… yet.

2. Unknown Archaic Admixture in Denisovans

The Denisovans themselves show signs of admixture with an even older hominin.
Possibly Homo erectus or a close relative in Asia.
So Denisovans are a ghost-hybrid in part!

3. "Ghost" Population in Melanesians

Modern Melanesians and Papuans carry Denisovan-like DNA, but some of it doesn’t match the known Denisovan genome (from Denisova Cave).
Suggests there were multiple Denisovan groups, one of which we’ve never sampled.

🕵️ Why Are These Populations Still Ghosts?

Some lived in regions with poor fossil preservation (tropics, rainforests, etc.).
Some fossils may exist but are misidentified or too fragmentary.
Some may never fossilize at all—we’re talking hundreds of thousands or millions of years ago.

🌐 Big Picture

These ghost populations:

Show that human evolution was way messier than we once thought.
Suggest that many hominin species were coexisting and interbreeding over the last 2 million years.
Remind us that we’re only seeing a fragment of our true evolutionary past.

🤯 Bonus Thought:

The more ancient DNA we sequence, the more ghosts we seem to find. It’s very possible that many more unknown hominin lineages existed—and some of them live on in us, hidden in our genomes.

Let me know if you’d like a map of ghost populations and where they likely lived, or a chart showing how they fit into the Homo family tree. It's a fascinating web of ancestors!

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