paleoanthropology3: When and where did humans first appear and how are Neanderthals related to us? (v1.0)

Key Reference are Wikipedia, and prof John Hawks of university of Wisconsin, Madison. 

Homo Sapiens first evolved and emerged in Africa some 300,000 years ago. As indicated in a previous essay, their ancestors were the species Homo Erectus (oldest fossil is 2 million years old in Kenya) and later, in Africa, Homo Heidelbergensis. Homo Erectus were the first to venture out of Africa and spread throughout Eurasia with a continental range extending from the Iberian Peninsula to Java. Homo Sapiens migrating out of Africa gradually replaced and interbred with local populations of Homo genus. Around 200,000 years ago Neanderthals (Homo Neanderthalensis) existed in Europe and parts of Asia, so they coexisted with humans. Denisovans who are close to Neanderthals populated Asia also.  Human and Neanderthal populations mixed with each other. Today using modern technology, we have the genetic material from Neanderthals to definitively establish this. About 2% of human genome stretching from Europe through Asia comes from Neanderthals. Though humans vary in many traits (such as genetic predispositions and physical features), any two humans are at least 99% genetically similar. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. For most of their history, humans were nomadic hunter-gatherers. 

The line of Neanderthals split, but when that occurred is not clear; studies have produced various times ranging from 315,000 to more than 800,000 years ago and they existed until 30,000 years ago. That period was a time of a lot of changes – both in climate terms and human biological terms. The date of divergence of Neanderthals from their likely ancestor H Heidenbergensis is also unclear. The oldest potential Neanderthal bones date to 430,000 years ago, but the classification remains uncertain. Neanderthals are known from numerous fossils, especially from after 130,000 years ago. The origins of H Heidenbergensis are unclear, but it is a descendent of Homo Erectus. It is debated if some of their specimens could be split off into their own species or a subspecies of H. erectus. Because the classification is so disputed, the Middle Pleistocene (the Pleistocene stretch from 2.58 million years ago to 11,700 years ago) is often called the "muddle in the middle".

For much of the early 20th century, European researchers depicted Neanderthals as primitive, unintelligent, and brutish. Although knowledge and perception of them has markedly changed since then in the scientific community, the image of the unevolved caveman archetype remains prevalent in popular culture. However, Neanderthal technology was quite sophisticated. It includes the Mousterian stone-tool industry as well as the abilities to create fire, build cave hearths make adhesive birch bark tar, craft at least simple clothes similar to blankets and ponchos, weave, go seafaring through the Mediterranean, make use of medicinal plants, treat severe injuries, store food, and use various cooking techniques such as roasting, boiling, and smoking. Neanderthals consumed a wide array of food, mainly hoofed animals, megafauna plants, small mammals, birds, and aquatic and marine resources.

Why did Neanderthals become extinct? The causes of their extinction are not fully known but some possible factors include:

• Violence and disease transmission from modern humans.
• Competitive replacement by modern humans. 
• Extinction by interbreeding with modern humans. 
• Natural catastrophe and climate change that affected their habitat and prey.
• Inbreeding depression and genetic drift. 

Atapuerca in Spain today is a very dominant and very important site to archaeologists and paleoanthropologists. There are a very large number of homo fossils and artifacts in the hill here, especially in the gran dolina cavern and also Sima de los Huesos (pit of bones). Bone fragments from 800,000 years ago found here are the earliest examples of hominid settlements and cannibalism in western Europe. Ninety percent of the known Homo heidelbergensis (likely ancestors of Neanderthals) fossil record have been obtained at the site. The other major site is Krapina in Croatia for Neanderthals. Neanderthals did something that early humans did not. They buried their dead. There are many neanderthal pretty complete fossils there.

In summary, Neanderthals are a separate line in evolution from humans, a common ancestor is Homo Heidenbergensis. But there are neanderthal contributions to the human genome because the two intermixed.