Human Invasion and Neanderthal Extinction

Study Notes

Modern humans' spread into Europe/Asia likely played a role in Neanderthal extinction.
This presents a new framework for understanding human history, suggesting humans are an invasive species.
Evidence suggests that humans arrived approximately 40,000 years ago
Humans and Neanderthals exchanged genes (1-4%).
Wolf-dogs interacted with humans.
Neanderthal extinction is studied through aDNA studies.

Invasive species move into new geographic regions.
Examples include zebra mussels, lionfish, and kudzu.
Invasive species are typically transported by humans, either intentionally (e.g., seafaring voyages) or unintentionally (e.g., bilge water).
A species needs a minimum viable population size to persist.
Australia provides an example. Human arrival, 45,000 years ago, was followed by a population of 1 million aborigines in 1788. Growth rate was from 1,000-3,000 initial population members.
Invasive species initially spread along coastlines.
Eventually, they move inland as maritime technology is developed.
Population increases from 1-3,000 people to 1 million over 45,000 years.

Humans are considered the "Sixth Extinction" due to their impact on biodiversity.
Humans have colonized almost all habitats.
Apex predators have become extinct.
Biodiversity is collapsing.
Culprits may include both humans and climate change.

Neanderthals were a different type of hominin.
They are similar to modern humans (Homo sapiens), but are a distinct species.
Neanderthals developed tools, used fire and may have had signs of language.
They are closely related to Homo Sapiens, contributing to the Homo Sapiens genome.
Neanderthals used the Mousterian stone tool technique. Their tools were made using the Levallois technique, which involved preparing cores to strike flakes from their edges, resulting in tools shaped like turtle shells.
Levallois replaced the Acheulian technique in Europe.

Neanderthal extinction coincides with the arrival of modern humans in Europe.
Possible symbiotic relationships existed between humans and semi-domesticated wolves.

Neanderthal mitochondrial DNA (mtDNA) diverged from Homo sapiens 700,000 years ago.
Neanderthal nuclear DNA overlapped (1-4%) with Homo sapiens DNA.
Interbreeding with modern humans is likely, but the process's details are unclear.
Neanderthals bred and produced offspring, indicating they weren't separate species.

Neanderthal DNA influences modern human traits like keratin.
Keratin helps determine skin, hair and nail characteristics.
It could have been adapted to cold Eurasion climates, helping wound healing.
This is also tied to diseases that may have become more prevalent in modern humans (e.g. lupus, Crohn's, diabetes).
Homo Sapiens and Neanderthals were close enough to interbreed to some extent.

Archaeology can inform about past human and hominin behaviors.
Future research will investigate how environmental pressures shape species development.
The fate of Neanderthals provides useful lessons to modern humans.