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Are there different species of human?


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This is a question asked in my science class today, as we watched a show on evolution. Asian, Caucasian, african, Mexican, Latino? And are mixed races hybrids. Like someone like me, where my mom is jamaican and my dad is Caucasian

You are living proof that they are not different species. :) It's not an all-encompassing definition but it's the largest group of organsims capable of having off-spring.

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We are more like these carrots. Actually pretty much exactly like them. The easiest example is snapdragon flowers which are pink,red or white. The red and white can be bred together to produce all pink flowers. The red can be bred with the red only producing red and the same for the white. However the pink can be bred with pink to produce either pink,white or red flowers etc

 

640px-Carrots_of_many_colors.jpg

Edited by fiveworlds
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Ok. That all makes sense. But different races of people are built differently. Caucasians are built for power, throwing and lifting things. East Africans are great at distance running, and west africans/carribeans are built for speed. It's all in their bodies. For example, East Africans tend to be taller, with slender frames, and large lungs. But west Africans are shorter, and naturally have more muscle, and a chemical in their blood that helps with the large burst of power which comes in the form of sprinting? Are we more like dogs? Different breeds, yet we can breed together to make mixes

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Ok. That all makes sense. But different races of people are built differently. Caucasians are built for power, throwing and lifting things. East Africans are great at distance running, and west africans/carribeans are built for speed. It's all in their bodies. For example, East Africans tend to be taller, with slender frames, and large lungs. But west Africans are shorter, and naturally have more muscle, and a chemical in their blood that helps with the large burst of power which comes in the form of sprinting?

 

 

Yes which are different genes I was really only talking about one specific gene aka color. There are loads of them and they each do different things. Tall or short, skinny or fat, being able to stay long in the sun or survive the snow etc We think there is upwards of 24000 of them each working together to make us who we are. Then again they keep on revising this number down so it could be less.

Edited by fiveworlds
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Ok. Makes sense, since Jamaicans produce top runners, and they usually marry other Jamaicans, which keeps the speed genes in the jamaican country

 

 

Yeah pretty much but jamaica is kinda small and just breeding withing jamaica would eventually lead to in-breeding which isn't good either because it reduces biodiversity. Problems with this are seen when new tribes are discovered who haven't seen people in ages they get the cold from us and die. Obviously the more a population disperses around the globe the more it learns to fight off new infections easier and faster than our more stagnant counterparts that stay in one place.

Edited by fiveworlds
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Homo sapiens is not very diverse genetically, Chimps or even Gorillas despite their low numbers are actually quite a bit more diverse than humans. There have been more than one species of humans, Neanderthals and Denisovans were arguably different species than Homo sapiens and several other species have been described from the genus Homo.

 

To say humans are biologically significantly different from each other due to superficial reasons like body shape and color fails due to the fact of gene flow, no group of humans have been genetically isolated for any extended period of time and we are all members of the same gene pool. All human beings are much closer related than it would seem and our lineage or pedigree suffers from pedigree collapse if you go back more than a few thousand years.

 

Everyone alive a mere few thousand years ago is the ancestor of everyone alive today or the ancestor of no one. As an example everyone alive today or very nearly everyone can trace their lineage back to a few notables in history. Confucius is one individual whose bloodline is reasonably well documented and can be said to be the ancestor of everyone alive today.

 

Gene flow is not a difficult concept if you stop thinking of individuals and think of gene flow like a river and it's tributaries, at some point a tiny trickle of water of water in the rocky mountains is evenly mixed nearly all the water on the NA continent at the mouth of the Mississippi river.

 

Pedigree collapse is the concept as you go back through generations we all begin to share the same ancestors, I can't remember specifically how many generations it is but the general consensus is that around 4000 years ago all the genes that were present then are present now in the way that we all are related if you go back that far due to gene flow. Everyone alive now is related in this fashion. This relationship is not as distant as it appears and your genes can be traced back to people who are "racially" very different from you not very many generations back. I may not be accurately portraying this due to my own lack of understanding of the matter but it is illustrated very well in this video if you care to look.

 

Edited by Moontanman
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Ok. That all makes sense. But different races of people are built differently. Caucasians are built for power, throwing and lifting things. East Africans are great at distance running, and west africans/carribeans are built for speed. It's all in their bodies. For example, East Africans tend to be taller, with slender frames, and large lungs. But west Africans are shorter, and naturally have more muscle, and a chemical in their blood that helps with the large burst of power which comes in the form of sprinting? Are we more like dogs? Different breeds, yet we can breed together to make mixes

 

 

I have heard that genetic studies and other research has disproved the idea that physical and behavioral qualities are a function of breeding populations. Here are some applicable quotes:

  • Keita, S O Y et al. 2004. "Conceptualizing human variation". Nature 36 (11s):

    "Modern human biological variation is not structured into phylogenetic subspecies ('races'), nor are the taxa of the standard anthropological 'racial' classifications breeding populations. The 'racial taxa' do not meet the phylogenetic criteria. 'Race' denotes socially constructed units as a function of the incorrect usage of the term."

  • AAA 1998:

    "Evidence from the analysis of genetics (e.g., DNA) indicates that most physical variation, about 94%, lies within so-called racial groups. Conventional geographic 'racial' groupings differ from one another only in about 6% of their genes. This means that there is greater variation within 'racial' groups than between them."

  • Lee et al. 2008:

    "We caution against making the naive leap to a genetic explanation for group differences in complex traits, especially for human behavioral traits such as IQ scores"

  • Harrison, Guy (2010). Race and Reality. Amherst, Prometheus Books:

    "Race is a poor empirical description of the patterns of difference that we encounter within our species. The billions of humans alive today simply do not fit into neat and tidy biological boxes called races. Science has proven this conclusively. The concept of race (...) is not scientific and goes against what is known about our ever-changing and complex biological diversity."

  • Roberts, Dorothy (2011). Fatal Invention. London, New York, The New Press:

    "The genetic differences that exist among populations are characterized by gradual changes across geographic regions, not sharp, categorical distinctions. Groups of people across the globe have varying frequencies of polymorphic genes, which are genes with any of several differing nucleotide sequences. There is no such thing as a set of genes that belongs exclusively to one group and not to another. The clinal, gradually changing nature of geographic genetic difference is complicated further by the migration and mixing that human groups have engaged in since prehistory. Human beings do not fit the zoological definition of race. A mountain of evidence assembled by historians, anthropologists, and biologists proves that race is not and cannot be a natural division of human beings."

Linking physical or behavioral standards to breeding groups or 'races' looks like something rather rejected by modern science.

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Theoretically this could be true. But in practice I'm pretty sure it can't since for most of the period there was little or no migration between Europe/Asia/Africa and the Americas/Australia/Tasmania.

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Theoretically this could be true. But in practice I'm pretty sure it can't since for most of the period there was little or no migration between Europe/Asia/Africa and the Americas/Australia/Tasmania.

 

 

If you had watched the video you would have noticed that your objection was addressed...

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If you had watched the video you would have noticed that your objection was addressed...

Where?

 

Also it seems to me to be faulty logic.

The video takes the view that an Inuit and I have ancestors in common because his ancestor tree and mine double at each generation so we run out of ancestors.

Well, so do the ancestors of my neighbour's dog.

Since dogs were only domesticated something like 15000 years ago and they breed faster than people they too run into a pedigree convergence.

Call it 3 years for a dog generation.

Even a hundred years gives about 33 generations

That's ten billion ancestral dogs- there can't have been that many dogs. there were only about 2 billion people

 

Why is there a difference between saying that we are all descended from Caesar and that we are all descended from his dog?

The obvious answer is that none of us is descended from his dog.

But that's begging the question.

Why are we all descended from JC?

What proof is there that my ancestors (in Scotland) were not all marrying within the village at the time the Romans invaded and have done so ever since?

The odds may be against it, but that's not proof.

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Where?

 

Also it seems to me to be faulty logic.

The video takes the view that an Inuit and I have ancestors in common because his ancestor tree and mine double at each generation so we run out of ancestors.

Well, so do the ancestors of my neighbour's dog.

Since dogs were only domesticated something like 15000 years ago and they breed faster than people they too run into a pedigree convergence.

Call it 3 years for a dog generation.

Even a hundred years gives about 33 generations

That's ten billion ancestral dogs- there can't have been that many dogs. there were only about 2 billion people

 

Why is there a difference between saying that we are all descended from Caesar and that we are all descended from his dog?

The obvious answer is that none of us is descended from his dog.

But that's begging the question.

Why are we all descended from JC?

What proof is there that my ancestors (in Scotland) were not all marrying within the village at the time the Romans invaded and have done so ever since?

The odds may be against it, but that's not proof.

 

 

Actually our genes show this as well...

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Actually our genes show this as well...

 

Perhaps you would like to answer my question and say where in the first video they actually address the issue of closed groups rather than posting a second one.

Don't get me wrong, I'm sure the human race is pretty thoroughly interbred, but there's nothing in that video that proves it.

Here's another idea for you to consider.

Imagine that the caste system in India had been up and running when JC was born.

Imagine that it was rigorously enforced and the people were only allowed to marry within their caste,.

That video talks about numbers of people and their ancestor.

But there's no way for JC's descendants to end up within any of those groups?

 

And that's before we address the idea that it's perfectly possible that JC was sterile- he left no legitimate heirs- perhaps he left none at all.

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I have not seen that videos but assuming he had no children it means that line ends there and no current descendants can be traced to him. That is, a whole line gets eliminated and today's population will have to come from a different line. The longer the time scale (i.e. the earlier we set the starting point) the lower the likelihood that a line extends to modern times and remains separated from other lines.

 

Under the theoretical caste systems lines would be separated but before that there are chances of converging lines, and the likelihood increases with each generation we go back (and we do not even need to stop at the species level, we could well go back to the common ancestors of modern humans and neanderthals, for example.

 

Genetic evidence (such as mitochondrial eve) traces back to about 200k years ago. However, modeling approaches suggest that actual common ancestors of all modern human may be found as early as ~4k years back (Douglas et al, 2004 Nature 431: 562-566).

 

edit: crossposted.

Edited by CharonY
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I think C0c0rdance made it pretty clear he was not literally saying JC as everyones ancestor, he was using him as an example of how pedigree collapse occurs before you go back very far in time.

Who is "C0c0rdance"

Assuming he's the narrator of the video then it's your turn to be told to listen to it.

In particular, listen to what he says starting from about 20 seconds in.

the narrator makes it explicitly clear that he's not talking of "a cousin of a cousin..." but a direct descendent, not just of Caesar but of almost all historical figures.

He makes the claim and he draws pretty diagrams.

But he doesn't prove his claim.

As far as I can see, if nothing else, you owe Delboy an apology.

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Ok. That all makes sense. But different races of people are built differently. Caucasians are built for power, throwing and lifting things. East Africans are great at distance running, and west africans/carribeans are built for speed. It's all in their bodies. For example, East Africans tend to be taller, with slender frames, and large lungs. But west Africans are shorter, and naturally have more muscle, and a chemical in their blood that helps with the large burst of power which comes in the form of sprinting? Are we more like dogs? Different breeds, yet we can breed together to make mixes

Environment matters. If you took a group from the Carribeans and moved them to Eastern Africa with in a couple generations they would be leaner and all that too. East Africans generally live at high altitude and get less fat and protien in their diets. The differences between various groups of people at not absolutes. Environment and culture play the biggest role as we all basically have the same DNA. I provided an environmental example above here is a cultural one; The United States fails to produce a top Soccer/Futball team while countries of different races like Holland and Brazil repeatedly are able too. Does this mean people in those countries have a genetic predisposition for Soccer/Futball? Of course not. It just means those countries care more about it culturally and more of their people are inclined to commit themselves to it. Jamacia could produce a top long distance running team within a couple generations if culturally the Island became as galvanized around that as they are sprinting.

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If you had watched the video you would have noticed that your objection was addressed...

Perhaps you would like to answer my question and say where in the first video they actually address the issue of closed groups rather than posting a second one.

Don't get me wrong, I'm sure the human race is pretty thoroughly interbred, but there's nothing in that video that proves it.

Here's another idea for you to consider.

Imagine that the caste system in India had been up and running when JC was born.

Imagine that it was rigorously enforced and the people were only allowed to marry within their caste,.

That video talks about numbers of people and their ancestor.

But there's no way for JC's descendants to end up within any of those groups?

 

And that's before we address the idea that it's perfectly possible that JC was sterile- he left no legitimate heirs- perhaps he left none at all.

Theoretically this could be true. But in practice I'm pretty sure it can't since for most of the period there was little or no migration between Europe/Asia/Africa and the Americas/Australia/Tasmania.

Here is where what you asked about was described, I apologize for not being as forthcoming as i should have been...

 

 

The video and the video #2 in this series did indeed explain in great detail how such migration did indeed occur. My apologies for the 2nd video i thought it made the stance clearer from a racial point of view. C0nc0rdance is a well know youtube personality and research scientist, yes he does indeed do research for a living. It becomes obvious that the 2nd video adresses delboy's questions.

 

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I trust you also accept that this was essentially completely wrong.

Concordance was, indeed, saying that JC was everyone's ancestor.

I think C0c0rdance made it pretty clear he was not literally saying JC as everyones ancestor, he was using him as an example of how pedigree collapse occurs before you go back very far in time.

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@Ten Oz all true, but would body type determine why some countries are good. I read an article, the same I have mentioned, earlier, I think. The author asked a professional distance runner from east Africa. He loved soccer, but East Africans don't have the body for it, being tall and gangly. At least that was the claim. And Jamaicans come from west african descent, which in turn shows they have a sprinting body, which leads to it being a cultural thing.

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