How large was the group of humans that we've descended from?

[BlackDog]

A child would have problems with the Adam and Eve story, with the two brothers and two sisters, or whatever explanation there is in the Abrahamic tradition. There are just too few people involved. I think the species would die out pretty quick.

But how many people where there in the first Homo Sapiens group?

Is the Out of Africa theory a valid one? That explains how we spread, but what I'm interested is the first initial group and perhaps the evolution to the Homo Sapiens.

[Azathoth]

I would say an initial group would be hard to pin down as we would still have been interbreeding with our forerunners for a long time before we could have been classified as a separate species.

[goodboyCerberus]

As far as I know, there's no mention where Adam's son's wives came from in the Old Testament.



Its the first of six videos, please watch them all out when you have the time.

[BlackDog]

I would say an initial group would be hard to pin down as we would still have been interbreeding with our forerunners for a long time before we could have been classified as a separate species.

The reason I ask is because somebody asked me if this theory would mean the start would be incestuous. Which I doubt the numbers were so few. But I'm not sure tbh.

[BlackDog]

As far as I know, there's no mention where Adam's son's wives came from in the Old Testament.



Its the first of six videos, please watch them all out when you have the time.

I think it might be a muslim explanation. Not sure where the sisters came from? Maybe on earth, from Adam and Eve. I guess?

[ficklefiend]

AFAIK tens of thousands.

We have probably at times gone down to very low numbers indeed.

We are all seriously incestuous.

http://en.wikipedia.org/wiki/Toba_catastrophe_theory

[Xamonas Chegwé]

There would have been a fair sized population of hominids with varying traits. At some point, geographical isolation would have meant that one sub-group would have evolved into the ancestors of modern-day Homo sapiens.

Identifying the point at which a new species arises is impossible. There is a continuous gradation from the ancestor species to the descendant. It is the breeding isolation (usually geographical) of one group from other similar groups that causes speciation.

[Elessarina]

there would have been no "starting point" for Homo Sapiens anyway..

If you read Dawkins' latest book "The Greatest Show on Earth" (in Chapter 7) he explains why there is no missing link as such and how the transition from one species to another would be s seemless there would be no point where we could see it happen..

[Elessarina]

AFAIK tens of thousands.

We have probably at times gone down to very low numbers indeed.

We are all seriously incestuous.

http://en.wikipedia.org/wiki/Toba_catastrophe_theory

I think as well you only have to go back a few hundred years through your ancestors and you find, for example, everyone in Europe is related

[BlackDog]

there would have been no "starting point" for Homo Sapiens anyway..

If you read Dawkins' latest book "The Greatest Show on Earth" (in Chapter 7) he explains why there is no missing link as such and how the transition from one species to another would be s seemless there would be no point where we could see it happen..

Yeah I gotta re-read that chapter. Thanks.

[normal]

I seem to remember a number like 6000 or 60000. But I have no idea if that was part of a hypothesis or whatever.

[susu.exp]

The reason I ask is because somebody asked me if this theory would mean the start would be incestuous. Which I doubt the numbers were so few. But I'm not sure tbh.

Any population is incestrous to some degree. You´ve got two parents, 4 grandparents, 8 great-grandparents, etc. N generations back you had 2[sup]N[/sup] ancestors. You reach numbers where quite a few have to take multiple ancestor slots rather quickly.

I would say an initial group would be hard to pin down as we would still have been interbreeding with our forerunners for a long time before we could have been classified as a separate species.

There´s quite possibly a big species concept problem there. A species at any single point in time is defined as a set of populations where the probability that an allele present in some member ending up in a fertile descendent of another member that does not have that allele by common ancestry is higher than through convergence. A species in time is defined using common ancestry. Let´s assume that A and B are both species at some point in time using the above definition and WLOG that A is older than B. The two are the same species in time if
- B contains descendents of A
- No other species C exists at the same time as B that also contains descendents of A.
You can never interbreed with an ancestral species - just by the definition of species in time. At the time a descendent species exists, the ancestor doesn´t - there´s never any overlap.

[Gawdzilla Sama]

We had a "chokepoint", with the humans down to maybe 5,000. One of the lines in that population was very success, and this is where "Mitochondrial Eve" comes from, everybody seems to gotten some of her genes. However, I'm betting there are still some isolated populations out there that are untested and may not be related to her at all.

[enkidu]

We had a "chokepoint", with the humans down to maybe 5,000. One of the lines in that population was very success, and this is where "Mitochondrial Eve" comes from, everybody seems to gotten some of her genes. However, I'm betting there are still some isolated populations out there that are untested and may not be related to her at all.

From several recent sources I've seen: population <10 000, or something like a couple of thousand women of reproducing age. The BBC doc linked to in this thread is excellent. The clickable educational thing at Bradshaw Foundation is also very good:
http://www.bradshawfoundation.com/journey/

[Gawdzilla Sama]

We had a "chokepoint", with the humans down to maybe 5,000. One of the lines in that population was very success, and this is where "Mitochondrial Eve" comes from, everybody seems to gotten some of her genes. However, I'm betting there are still some isolated populations out there that are untested and may not be related to her at all.

From several recent sources I've seen: population <10 000, or something like a couple of thousand women of reproducing age. The BBC doc linked to in this thread is excellent. The clickable educational thing at Bradshaw Foundation is also very good:
http://www.bradshawfoundation.com/journey/

Population that size, trading people among various groups to keep the breed healthy (although they probably had their own reasons for doing it), and it's not surprising one woman shows up in the modern gene pool. 20 generations would do it, I think. Me no do maffs.