Why did early humans arise from Africa?

Question

There is an absolutely dogmatic insistence in evolutionary texts that early humans simply had to arise from Africa. Why is that and who was the theorist that got this bandwagon rolling?

Okay, apologies for the early 5 with the flip (and do they seem angry?) answers for a cheap 2 points, check this first: http://www.modernhumanorigins.net/sapiens.html . Before significant finds were made in Africa, while European finds were plenteous, there was a seeming certainty in early evolutionary discussions that the first humans HAD to come from Africa. What was the reasoning, AND PERSON(s), behind the dogma?

If you've never heard of Mladec, Zlaty Kun, Cioclovina, Bacho Kiro, Velika Pecina, Miesslingtal, Vogelherd Cave, and the Hahnöfersand in Europe, Qafzeh or Skhul in the Middle East, Indonesian remains at Solo or Ngandong, or Chinese finds in Guizhou or Shaanxi Provinces, then say you're guessing, get your points and go. If you've got real answers, I'm all ears.

Answer 1

As David mentioned, it is not dogmatic insistence, it is simply that all of the actual evidence points to an African origin for early humans.

The earliest fossils of early humans (i.e. Australopithecus afarensis - or Lucy) are found in East Africa.

The earliest traces of early human activity (the Laetoli footprints) are found in East Africa.

The greatest degree of genetic variation between human populations is found on the African continent - indicating an African origin.

The greatest degree of mitochondrial DNA divergence is found within the African continent - also indicating an African origin.

The closest genetic relatives to humans - chimpanzees and gorillas are found only in Africa, giving another indication that Africa was likely the site of early human evolution.

The oldest stone tools are found in Africa, indicating that Africa is the most likely site of early human evolution and the development of stone tool technology.

None of these pieces of evidence came about because of a theoretical framework that insisted upon an African origin. The theoretical basis of early human African origin was formulated around the discovery of these myriad pieces of physical evidence.

When Raymond Dart found the first Australopithecine fossils in 1925, there were many European scholars who dismissed his findings because it did not fit their (evidence-free) belief that Europe must have been the source of all important developments in human evolution. This belief was one of the reasons that the Piltdown man hoax garnered any kind of scientific interest in Europe. It fit in with what many of the European archaeologists fervently hoped was true - that Europe was the site of human evolution. Workers from other countries almost universally dismissed Piltdown right from the beginning, but especially British scholars clung to it long after it was discredited, simply because it conformed to their dogmatic belief.

However, eventually, the physical evidence supporting the African center for human evolution became so overwhelming, that no scientist could reasonably argue against it. It would be like trying to argue that lions don't eat meat, or that the Earth is flat. This is why the African origin is presented without competing 'theories' in most modern textbooks, because there simply isn't any evidence to support any other explanation.

UPDATE: I'm not sure why you think that the first five answers are flip (or angry), or why you believe they are disingenuous attempts intended to garner two points. All of them addressed your question as stated (before the addenda) clearly and cogently.

As to your addenda, you are referring there to the so called "Out of Africa" hypothesis for the origin and dispersal of anatomicially modern humans (Homo sapiens sapiens). This is very, very different from the evidence for early humans (i.e. Australopithecines and early Homo) arising in Africa. Early humans refers to the earliest members of the group commonly referred to as the Family Hominidae - that is, the first upright-walking apes, as well as the beginnings of true sentience, tool-use, fire and the first migration out of the African continent (Homo erectus). The earliest humans evolved around 4-6 million years ago (possibly as long ago as 8 million years ago), while the earliest anatomically modern humans are known from the Klasies River Mouth site in South Africa, at about 100,000 years ago. These are very separate events in the evolutionary history of man, and the interpretation of the physical evidence and their import are totally separate topics.

The original question asked about early humans, not early anatomically modern humans. This may be the cause of your lack of satisifaction with the initial answers.

As for the dogmatic insistence on an African origin, as I alluded to above, this insistence simply did not exist in early discussions of human evolution. There were some camps that felt it likely that Africa would be the site of early human origins based on the modern geographical range of chimpanzees and gorillas, but it was far from being accepted dogma in evolutionary circles.

Dogmatic acceptance of the African origin of anatomically modern humans (Homo sapiens sapiens) also does not exist. Despite fairly strong evidence from fossils, archaeology, and genetics for an African origin, there are many, many scientists who are proponents of the multi-regional model, or even modified replacement regarding the origin and spread of anatomically modern humans (as covered in the site you linked to). This despite the fact that no one from the multi-regional camps has yet been able to propose a mechanism of evolution that would create selective pressure towards the exact same grouping of minor founder-effect style anatomical features (i.e. mental eminence, orbital bone morphology) in multiple, genetically isolated, unlinked populations of archaic Homo sapiens or Homo erectus.

Answer 2

Charles Darwin pointed out that because our closest known living relatives, gorillas and Chimps were from Africa, then our ancestors were probably from there. I believe this set up a bias that has existed since then. The truth is that once hominids left Africa (at least 2 million years) there is no way to say for certain where our ancestors evolved. Some of those ancestors may have moved back to Africa. Recent ape fossil evidence indicates that our Miocene (those from 20 to 5 million years ago) ancestors probably left Africa, evolved in Eurasia, and moved back to Africa. The Rift Valley in Africa is very favorable for finding fossils of relatively recent (less than 10,000,000 years old) and so an abundance of fossils in Africa might not necessary be indicative that our ancestors evolved in Africa only.

Answer 3

That's just what the fossil record has led scientists to believe. Also, I've read that the evolution of the genus Homo around 2.5 million years ago coincides with the beginning of a prolonged cooling climate trend in East Africa. Scientists believe it is likely that this significant environmental change was largely responsible for the rapid evolutionary changes among the hominids at that time.

Answer 4

First, early humans evolved durring an ice age. Although, neadrathals and other early homo species lived outside of africa, The Ice ages had alot to do with the early evolution and expansion of the human species. Humans evolved in the central eastern portion of africa. This area is mainly dense forests. These forests helped setup a geographical barrier to seperate humans from their ancestors.
The most compelling evidence for the evolution of humans in africa comes from genetic research. By studying mitochondrial DNA of different groups ("races", except this term is inaccurate and you should read my sources for more info), you can compare how similar one groups code is to another. The groups with the most different code from all other human groups must have most likely been seperated from all other humans first. For instance native americans could not breed with europeans and their for after migrating to america their mitochondrial dna would form unique mutations that would not be present in europeans. The data shows that earliest groups to seperate and stop mixing with the rest of the human gene pool were the pigmies and bushmen, both located in southern africa.
Other evidence supporting the human evolution in africa is research pointing to africa as being the place where other species of the genus homo evolved. Humans could not have evolved in the middle east, due to the terrible climate caused by the global temperatures.
I dont know who the theroist was, but this notion has existed since "The Origin of Species".

But anyways humans really evolved in the garden of eden and science is nonsense (thats why I vote republican).

Answer 5

It's dogmatic insitence because of a few different factors. The fossil record, genetic evidence, and linguistics.

Homo Habilis came from Africa and the earliest anatomically modern humans did too (that've been found)

Genetic evidence pointing to the Out of Africa model is CRAZY. There's more genetic diversity in one continent than anywhere else on Earth.

And well... I'm not a linguist but linguists have told me that there's linguistic evidence too, so I'll let you look that up on your own.

Answer 6

There is no reason why, other than the history of our evolution as a species.
There are indeed many proofs, including the oldest human and hominid fossil remains and the most diversified genetic markers (in terms of the DNA molecules, more diversification means that they had more time to diversify, thus are older).

Answer 7

As guy developed, the "hunter, gatherer" became the "customer, Explorer". i've got presently examine an academic commentary suggesting that Cromagnons and Neanderthals co-existed, as separate splinters from preform primates. Neanderthals have been extra feminised, and extra vulnerable to settle in a community and strengthen into extra advantageous tribes. Cromagnons have been vagabonds particularly early of their progression, and as they began to create migratory paths, the superior extra and extra over the years. innovations extra implied that Neanderthals stepped forward farming and social community, wereas CroMagnons stepped forward kit for searching and protection. someplace down the line there have been countless crossings of the two comparable species, ensuing in the beginnings of Homosapiens. the two found out and stepped forward from one yet another's traits. ultimately, the homosapien stepped forward a fashion of life of shuttle and settlement, ultimately advancing adequate for sea shuttle. i'm undecided if it relatively is a heavily conventional concept, notwithstanding it relatively is an relatively thrilling one.

Answer 8

They didn't.

Humans arose in the Garden of Eden.

Answer 9

To get out of there.