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I learned about The Theory Of Evolution in middle school and our teachress told us that we evolved from African People. Is that true? How?

Hierarchist
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    Did your teacher say that we came from africa or african people? There's a difference there. – user40950 May 05 '19 at 18:08
  • Because you are young, you can see most simply from this list of images accompanied by the time in years, Ma means millions of years... https://en.wikipedia.org/wiki/List_of_human_evolution_fossils#Pleistocene Some of the people 's bones are at least 250,000 years old, if not older. If it takes 25 years for a generation of father to son, that means that we have skeletons from great-great-grandfather * 10,000 great. – bandybabboon May 06 '19 at 10:40

2 Answers2

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Welcome to Biology.SE!

Did we evolve from Africans?

Who is "we" in your sentence?

Although, it might not have been your intent, you seem to exclude Africans (and people of recent African descent) from the "we" (which would be rather insulting)!

I will rephrase your question. I will pick "caucasians" (thinking that you might be caucasians and by "we" you may have had "Caucasians" in mind) to rephrase your question but I could have picked Han Chineese, Polynesians, Micronesians, Mongolian or any other (big or small) extant human lineages that currently lives mainly outside of Africa. I will rephrase your question as Did [caucasians] evolve from Africans?

What does "evolve from" mean?

No extant lineage is the ancestor of another lineage. An extant species of lizard is not the ancestor of an extant species of mammal, just like an extant species of mammals is not the ancestor of an extant species of lizard. The same hold true for any two extant lineages. Extant lineages share common ancestors. Their Most Recent Common Ancestor (MRCA) may have lived a long time ago or only relatively recently. This answer might help you to understand these concepts.

If you mean to ask Did [Caucasians] evolve from current Africans? as in Is Nelson Mendela the ancestor of Kurt Cobain, then the answer is (obviously) "No".

So, when you ask Did [Caucasians] evolve from Africans?, I am assuming, you meant Did [Caucasians] have descendants who lived in Africa?

Did Caucasians have ancestors who lived in Africa?

Yes. All modern humans (aka Homo sapiens or Homo sapiens sapiens) are descendent from first humans that lived in Africa. The MRCA of all modern humans lived in Africa.

To reiterate the above, this in no way suggests that modern Africans are "ancestors of" or "more primitive than" or "less evolved than" any other human lineage. However, interestingly, because early split among human lineages happened in Africa, the majority of genetic diversity among humans is found in Africa still today.

I learned about The Theory Of Evolution in middle school [..]

If you want to learn a bit more, you might want to have a look at a simple and very introductory source of information such as evo101 by UC Berkeley

EDIT

Comments shows that the OP did not quite get it yet. Here are some more info...

First, please have a look at this answer (already indicated under the section What does "evolve from" mean? above). Make sure to read it fully. Did you read it?

H. sapiens is a monophyletic group (for simplicity, I will make abstraction of horizontal gene transfer here). The MRCA of this group used to live in Africa. Some of the sub clades of this group have moved elsewhere in Africa, and some have moved elsewhere outside of Africa (there has been a fair amount of back and forth too and a fair amount of secondary contacts as there is no reproductive isolation among H. sapiens). That's all!

Your confusion comes from the fact that you call "Africans" both the MRCA and the current lineages that live in Africa. It may make you feel that people currently living in Africa and the MRCA of all humans who lived in Africa are somehow more related just because they live on the same continent but that would be wrong. All human lineages have evolved from this MRCA (who lived in Africa), whether the lineage you want to consider is currently living in Africa or not.

Remi.b
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    Or to reduce it to one sentence: All humans, including modern Africans, evolved from ancestors who lived in Africa. – jamesqf May 05 '19 at 18:28
  • Hmmm, interesting. If I understand your theory correctly, we evolved from the MRCA African People and NOT the extant African People because there is a difference between extant African People and the MRCA African People? We're two different lineages? – Hierarchist May 05 '19 at 19:21
  • @Hierarchist I don't believe that's correct- properly speaking all the major lineages of humans are "African" lineages, which includes your "we". Some of these major lineages gave rise to people who left the African continent, but they still arose in the African continent. The MRCA of any group of people is different from the current people, was I believe what Remi.b was trying to communicate, so no one alive "evolved from" anyone else who's alive. More simply, the MRCA of "African people" is simply the MRCA of humans; all "non-African" humans are part of "African" lineages. – Maximilian Press May 05 '19 at 19:59
  • I'm trying to understand your theory: if the MRCA of us and African People is different from African People, then we're a different lineage from African People? Or are we the same lineage as African People because there's no difference between the MRCA of us and African People and African People? Moreover, you seemed to say that we split off from African People all the way back when we were Africans? I'd appreciate an explanation of your theory. – Hierarchist May 05 '19 at 20:27
  • @Hierarchist Please see the Edit section which will hopefully clear things up for you. – Remi.b May 05 '19 at 21:39
  • @Hierarchist Please stop saying "we" when you mean "caucasians" (or something else). 1) it is unclear who is included in the term "we". 2) You clearly exclude current Africans from the "we" (which sounds rude) and for all you know I might be Nigerian and hence it would make the conversation very confusing. – Remi.b May 05 '19 at 21:41
  • Also, it there any reason you repeated your theory three times? It make it sound like you have an incorrect view of the legitimacy of the modern evolutionary synthesis (which is the name of what you call the theory of evolution). See the post Is evolution a fact? for more info. – Remi.b May 05 '19 at 22:03
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    @Hierarchist I think the issue is that the idea of a coherent group of humans different from "Africans" is not scientifically well-supported. Talking about people by their continental birthplace and/or physical appearance is, at best, misleading. "Non-Africans" are still "Africans" in that they are part of one lineage among many lineages that arose in the African continent. "Non-Africans" are quite closely related to many "Africans". A "non-African" person is much more closely related to many "African" people than randomly selected people of "African" descent are, on average. – Maximilian Press May 05 '19 at 22:27
  • "Did Caucasians have descendants who lived in Africa?" Do you mean "Did Caucasians have ancestors who lived in Africa?" few caucasians have african descendants, they all have african ancestors. A parent is an ancestor of their offspring a child is a descendant of their parents. you confuse the two several times. – John May 05 '19 at 22:42
  • @John Thanks for the correction. I fixed the error. – Remi.b May 05 '19 at 22:55
  • @John: Though if you want to get into linguistic confusion, there are a good many (several million, at least) Caucasians who have descendants who were born & live in Africa :-) – jamesqf May 06 '19 at 04:58
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What you could do is to take a look at diagrams such as this one:enter image description here

You can make a google image search for "Cavalli Sforza" and get a lot of similar diagrams. This diagram is using a concept known as genetic distance by fixation index. This is a way to measure how different different ethnic groups are genetically. From the diagram it is easy to see that there is a large genetic gap between the current sub-saharan Africans and the rest of humanity. The genetic distance between sub-saharan africans and any other ethnic group is almost twice as large as the distance between any two non-african ethnic groups. It is from measurements such as these that scientists are able to tell that humans first must have been living in Africa before we took off to the rest of the world.

The people who were living in Africa 50000-70000 years ago, before the "split", were probably on average very different from modern African people although they probably were adapted to the hot climate. I do not now if you are familiar with the so called "Bantu-Expansion" that occured in several waves in the last 4000 years? This is what wikipedia says about the populations in africa before the bantu-groups took over:

"Before the expansion of Bantu-speaking farmers, Central, Southern and Southeast Africa were populated by Pygmy foragers, Khoisan-speaking hunter-gatherers, Nilo-Saharan-speaking herders, and Cushitic-speaking pastoralists."

From very recent research we also know that all non-subsaharan groups are a result of interbreeding with Neanderthals/Denisovans. I think that current estimates says that people from western Eurasia has 2 percent of there genes from these groups, east asians has around 3 percent and people from Papua/New Guinea around 4 percent, but this is new research so those numbers might change.

Here are two other genetic distance by fixation index diagram, from this page, also based on the work of Cavalli-Sforza, more focused on how different ethnic groups in Africa are related:

genetic distance map 2

genetic distance map 3

There are also some more modern approaches that might not be so easy to comprehend, see for instance this article from Nature.

Agerhell
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    I find this figure somewhat misleading. Specifically, Cavalli-Sforza represents "Africans" as one clade, when in fact there are at least dozens if not hundreds of clades in that one leaf that are more distantly related than the other leaves are from each other. If you drew all those clades in, you'd see that all other clades are a rather tight group nested in the African clade. – Maximilian Press May 05 '19 at 22:31
  • You mean like this diagram on this page, which is also by Cavalli-Sforza, but I do not know if it is free of use, the other diagram was from wikipedia commons. – Agerhell May 05 '19 at 22:49
  • yes that one is better (URL is slightly broken)- it is still using the distance-based tree, which make it look like there are two clades, which we know isn't the case, but it is at least showing the huge diversity within the continent. From a cursory google, Figure 1 from this paper [https://www.nature.com/articles/srep29890] is much closer to the current scientific understanding. – Maximilian Press May 05 '19 at 22:56
  • On my current level of understanding the nature figure is a bit difficult to understand. The guy really just wanted to know why we think the "out of Africa" theory is true. Can you find some simple clues pointing in that direction in the Nature figure? – Agerhell May 05 '19 at 23:24
  • I think that OP had a somewhat different motivation for the question, though it's hard to be sure from his phrasing. We need to be very specific in this case because there is a lot of pseudoscience and bad stuff (racism, obviously) around human origins. The figure I linked is more accurate because it shows that "Africans" are not monophyletic. That is, there is not a common ancestor of "Africans" that is not also the common ancestor of "non-Africans", because "non-Africans" arose out of Africans. Cavalli-Sforza drew his figure to make the two groups look monophyletic, which is wrong. – Maximilian Press May 05 '19 at 23:30
  • @MaximilianPress, so we arose out of Africans? What's the difference between "around out of" and "evolved from"? – Hierarchist May 06 '19 at 01:49
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    A couple things: 1) The people currently living in the continent of Africa and the people who lived there 100,000+ years ago are not the same people. This is why the term "Africans" is pretty meaningless in your question. You need to be more specific or your question is unanswerable. It's like thinking that Moctezuma I and Pancho Villa are the same person because they both had political power in Mexico (except 200+ times less accurate). 2) not saying what you mean by "we" is starting to look like trolling. 3) I don't know what you mean by "evolved from". Humans are all the same species. – Maximilian Press May 07 '19 at 04:56