Humans Into Existence · Science Nerd

Humans Into Existence

# Recursive Humanity: How We Became Ourselves Through Crossroads, Flows, and Encoded Memory

Kenneth Parrott

## Abstract

Humanity did not emerge through a single origin, but through recursive flows of migration, hybridization, and adaptation across continents. Genetic and archaeological evidence demonstrates that *Homo sapiens* is a braided lineage, carrying signatures from Neanderthals, Denisovans, and other archaic populations. These crossroads of contact and exchange—especially in the Levant, South Asia, and later the Americas—created today’s genetic and cognitive diversity. This paper argues that human identity is the product of recursion: repeated movements, encounters, and integrations that encoded survival traits and cognitive variety into our species. Understanding humanity’s hybrid, fractal past clarifies our present diversity and opens new ways of interpreting the flow of civilizations.

## 1. Introduction

The traditional view of human origins describes *Homo sapiens* emerging in Africa ~300,000 years ago and expanding outward, replacing archaic relatives (Stringer, 2012). New evidence paints a richer story. We are not a single-origin species, but the product of repeated flows of movement and blending across deep time.

Ancient DNA reveals that Neanderthals, Denisovans, and “ghost” lineages contributed directly to the modern human genome (Green et al., 2010; Reich et al., 2010; Sankararaman et al., 2016). Archaeology shows multiple waves of expansion out of Africa and across Eurasia, culminating in the push into the Americas (Goebel et al., 2008). These flows did not create barriers, but crossroads—zones where populations encountered each other, exchanged genes, and transmitted cultural knowledge.

## 2. Foundational Lineages

### Homo erectus (~2 million – 100,000 years ago)

- The first great explorer, spreading from Africa to Europe and Asia (Antón, 2003).

- Survived nearly 2 million years, laying down the pathways later humans would follow.

- Mastered fire, cooperative hunting, and Acheulean tools.

### Homo heidelbergensis (~600,000 – 200,000 years ago)

- Likely descended from *erectus*, Heidelbergensis was highly adaptable (Rightmire, 1998).

- In Africa, their populations gave rise to *Homo sapiens* (Hublin, 2017).

- In Europe, their populations diverged into Neanderthals.

- In Asia, they gave rise to Denisovans.

- Fossils show a wide range of body forms, tool-making skills, and hunting strategies—evidence of diversity across regions.

- Heidelbergensis is therefore the seed stock of modern humanity: a species whose internal diversity created the branches that still echo in our DNA.

## 3. Hybridization: We Are Many

Genomics confirms modern humans are hybrids of at least six lineages:

- Neanderthals: 1–2% of DNA in all non-Africans. Contributed immunity, hair/skin adaptations, and fat metabolism traits (Green et al., 2010).

- Denisovans: 2–5% in Melanesians, Aboriginal Australians, and Tibetans. Contributed altitude adaptation (EPAS1 gene) (Huerta-Sánchez et al., 2014).

- Ghost archaic Africans: Traces in West African populations from unknown hominins (Durvasula & Sankararaman, 2020).

- Homo erectus (possible introgression): Hints of ancient admixture in Asian genomes (Pääbo, 2022).

- Homo heidelbergensis: Present as the common ancestral base.

- Other SE Asian hominins (Flores, Luzon): Possible faint signals in island populations (Reich, 2018).

This braided ancestry makes every human alive today a living archive of encounters.

## 4. Crossroads of Humanity

### The Levant (Israel/Palestine)

- Archaeological finds in caves like Skhul and Qafzeh (~120k years ago) show early *sapiens* alongside Neanderthals (Vandermeersch & Bar-Yosef, 1993).

- This region was a constant meeting point of Africa, Europe, and Asia.

- Genetic exchanges here seeded later hybrid populations.

- The Levant remains symbolically important: a literal and figurative crossroads of peoples, faiths, and ideas.

### India and South Asia

- India absorbed waves of humans moving east from Africa and west from Asia (Narasimhan et al., 2019).

- Genetic studies show deep continuity, with traces of Denisovan admixture stronger here than in Europe.

- India acted as a filter and mixing bowl—sending populations further east into Southeast Asia and Oceania.

- Today’s incredible linguistic and genetic diversity in South Asia reflects this deep-time crossroads.

## 5. Encoded in Us

The flows of hybridization left functional legacies:

- Neanderthal genes: boosted immunity, skin and hair adaptation to colder climates (Dannemann & Kelso, 2017).

- Denisovan genes: allowed survival in hypoxic environments (Tibetans) (Huerta-Sánchez et al., 2014).

- Archaic African admixture: increased immune system diversity (Durvasula & Sankararaman, 2020).

Modern humans carry percentages of these archaic lineages as biological echoes: 1–5% is small per gene, but profound at the level of survival. These fragments are proof that identity is recursive—stacked from many lives.

## 6. The Push Into the Americas

The final great expansion brought humans into the Americas.

- Genetic evidence shows a migration across the Bering land bridge from Siberia into Alaska ~15–20k years ago (Goebel et al., 2008).

- These groups carried the braided legacy of Africa, Europe, Asia, and Denisovan/Neanderthal ancestry with them.

- Archaeology (e.g., Monte Verde in Chile, Clovis traditions in North America) shows rapid southward movement, adapted to landscapes from tundra to rainforest (Dillehay, 1997).

- By this migration, humanity completed its global spread: all continents inhabited, all traits interwoven.

The Americas are therefore the capstone of human expansion: a synthesis of all prior flows.

## 7. Sensory Awareness and the Human Condition

Before complex language, early humans relied on sensory awareness and instincts. Attraction across groups would not have been linguistic but sensory: physical difference, unique features, pheromones, and presence. Encounters at crossroads were charged with both survival need and instinctive desire.

This explains hybridization as not just pragmatic but deeply human. We are animals; attraction across difference was natural. The result was genetic diversity that ensured resilience.

Neurodiverse cognition—hyperfocus, sensory tuning, lateral thinking—should be seen as primal, not deviant. Different minds were survival tools, encoded and carried forward recursively into modern populations.

## 8. The Flow as Pattern

Humanity is not a straight tree but a braided river:

- Branches split (*erectus, heidelbergensis*).

- Streams rejoined (*sapiens* with Neanderthals and Denisovans).

- Tributaries carried genetic and cultural knowledge east and south, then finally into the Americas.

This recursive flow is fractal: small encounters mirror large migrations, each echoing across scales. Today, modern humans still carry these flows in their genomes, their cultures, and their ways of thinking.

## 9. Conclusion

We became human not through isolation but through recursion: repeated cycles of movement, meeting, and merging. Heidelbergensis provided the diverse foundation; Neanderthals and Denisovans added adaptive strength; crossroads in the Levant and India braided the lineages together; and the final push into the Americas spread the fully hybrid human worldwide.

To understand humanity’s future, we must honor its recursive past. We are hybrids of many lineages, united not by purity but by pattern. The story of humanity is the story of flows—streams of people, genes, and ideas converging into one river.

## References

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- Dannemann, M., & Kelso, J. (2017). The contribution of Neanderthals to phenotypic variation in modern humans. *American Journal of Human Genetics*, 101(4), 578–589.

- Dillehay, T. D. (1997). *Monte Verde: A Late Pleistocene Settlement in Chile*. Smithsonian Institution Press.

- Durvasula, A., & Sankararaman, S. (2020). Recovering signals of ghost archaic introgression in African populations. *Science Advances*, 6(7), eaax5097.

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- Huerta-Sánchez, E., et al. (2014). Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA. *Nature*, 512(7513), 194–197.

- Narasimhan, V. M., et al. (2019). The formation of human populations in South and Central Asia. *Science*, 365(6457), eaat7487.

- Pääbo, S. (2022). *Neanderthal Man: In Search of Lost Genomes*. Basic Books.

- Reich, D. (2018). *Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past*. Pantheon.

- Reich, D., et al. (2010). Genetic history of an archaic hominin group from Denisova Cave. *Nature*, 468, 1053–1060.

- Rightmire, G. P. (1998). Human evolution in the Middle Pleistocene: The role of *Homo heidelbergensis*. *Evolutionary Anthropology*, 6(6), 218–227.

- Sankararaman, S., et al. (2016). The combined landscape of Denisovan and Neanderthal ancestry in present-day humans. *Current Biology*, 26(9), 1241–1247.

- Stringer, C. (2012). *The Origin of Our Species*. Penguin Books.

- Vandermeersch, B., & Bar-Yosef, O. (1993). *The Qafzeh Cave and Skhul: Early Modern Humans in the Levant*. Academic Press.

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