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Humans Evolved From a Single Origin In Africa
Invisible Pink Unicorn writes "Researchers at the University of Cambridge have combined studies of global human genetic variations with skull measurements worldwide to show conclusively the validity of the single origin hypothesis. The alternative hypothesis contended that different populations independently evolved from Homo erectus to Home sapiens in different areas. The lead researcher explains, 'The origin of anatomically modern humans has been the focus of much heated debate. Our genetic research shows the further modern humans have migrated from Africa, the more genetic diversity has been lost within a population. However, some have used skull data to argue that modern humans originated in multiple spots around the world. We have combined our genetic data with new measurements of a large sample of skulls to show definitively that modern humans originated from a single area in Sub-saharan Africa.' The article abstract is available from Nature."
It looks like this research is already being torn to pieces:
"John Hawks of the University of Wisconsin-Madison says the paper is mistaken. A major flaw is that the current research is largely based on skull variability. "You can't find the origin of people by measuring the variability of their skulls," Hawks said.
"Differences in skull features are related to genetics, and genetic variation depends on how much mixing occurs with other populations. "The main problem with the paper is that it takes some assumptions from genetics papers of 10 to 15 years ago that we now know are wrong," Hawks said.
"Other scenarios, besides the single-origin theory, could account for the link between distance and skull variability. "Africa is ecologically diverse, and cranial variation is a function of environments," he said. In environments supporting hardy foods such as roots, people would need bigger jaw muscles, and thus larger areas for muscle attachments.
"Also, correcting for climate is not a good idea, according to Hawks. "The most important feature that is related to climate is skull size. So by correcting for climate, they are subtracting a major component of variability," he said.
"In his own research, Hawks is finding that natural selection has led to changes in thousands of genes during only the past few thousand years.
"I'm really thinking just the opposite of this paper," Hawks said. "There are differences in the skull between populations, including their variability, but it is mostly due to very recent effects and not the origin of modern humans."
"At the end of the day, a resolution to the "Out of Africa" debate may be impossible, he said. Most of the evidence can be interpreted as supporting both human-origins theories. "It's really hard to find observations that distinguish the two," Hawks said.
"The multiregional idea is identical to the recent African origin idea, except for its prediction that Europeans and Asians were part of the single population of origin and didn't become extinct."
I am wondering if this information may or may not discount the theory the Homosapians and Neanderthalls in Europe may have cross breaded?
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
There, fixed it for you.
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A bit off-topic, I know, but what often puzzles me is that all living things basically work with the same chemistry. All have DNA, and there are many proteins that are physically very similar between different species, even between animals and plants. This leads me to conclude that all life must have come form one ancestor that materialized somewhere on the planet. But the earth is a big place. To me it seems very unlikely that life hasn't occurred in more than one place and more than one time. So how is it possible that all life, on a chemical level, is more or less the same?
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This evidence proves conclusively without a doubt that there is a 100% chance that humans either evolved from primates, were created by God, or both. Case closed!
I'm pretty sure these sort of ideas are thought up just to piss off creationists: "Hey guess what, we've found scientific evidence that the human race actually could have started from a single couple like Adam and Eve, but guess what? They were black".
None of those posts appeared yet. Why invoke them? For karma?
The sooner they are relegated to obscurity, the better -- then most people will consider them the crackpots that they are. Giving them attention before they even appear doesn't help.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
I am not a scientist, nor do I play one on TV. But my understanding of the way evolution worked is that you need a breeding population sharing common mutations and traits in order to lock in evolutionary traits. The old textbook example for regular speciation within a main population a fertile jungle valley split in two by a great river. Species A was once on both sides of the river and populations could interbreed if presented the opportunity. But given enough isolation, and especially if any environmental factors differ on one side or the other, a Species B can emerge. When the changes are minor, one could refer to the changed one as a sub-species. If the changes become very pronounced, such that interbreeding is difficult or rarely results in viable offspring, then you could say that second population constitutes a new species.
Given that two identical populations can drift away from the ability to interbreed through nothing more than isolation, how likely would it be that one species, scattered across many environments, could independently evolve into a new species whose members could interbreed? That seems a bit off!
I do think that hybrid species are pretty cool, even though they don't occur too often in nature. We had the polar/kodiak hybrid shot a year or so back. Zoos also have many examples of lygers, tylons, etc. Wolves and domestic dogs can interbreed, the same goes with cyotes and jackals as well. It does make one wonder how far humans could drift apart if several populations were isolated for 20,000 years. I wonder if they'd all still look alike except for different bumpy foreheads?
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Adam and Eve were black? Next you'll be telling us that Jesus was Jewish!
Seriously, though, the creationists I respect go to the Bible/Koran/Talmud and say "God created the heavens and the earth" then go to a science textbook to figure out how he did it.
You are reading a copy of my copyrighted post.
Now my wife can tell everyone she's married to a black man!
... before you start bashing them, okay? I believe in intelligent design, but I don't see that this post has much to do with it. Those of us who believe in a literal interpretation of Genesis obviously don't believe that humans came from multiple sources, we believe all humans descended from one couple. However, even if you could conclusively prove that all humanity came from one population - that doesn't disprove evolution (which is probably why you didn't immediately get the ID crowd all posting "see! see! we were right!". In fact, I'd think that even from an evolutionists POV, the chance of a species evolving independently from multiple populations is low.
Now if someone said they'd proven that humans couldn't have evolved from one population, I might be inclined to look at their findings more closely.
Prov 9:8 Do not rebuke mockers or they will hate you; rebuke the wise and they will love you.
... we were in part genetically influenced by what we call alien life. Not in just one place on this planet.
Perhaps the real questions are regarding time lines and why evidence either exist or does not. Rate of deterioration under what conditions?
This whole Darwin vs. god vs. intelligent design is all rather silly.
Its like right to life vs. freedom of choice. Want to know the truth about that? Ask a starving child!
Likewise, the evolution of conscious beings is probably a mix of Darwin, god (the right conditions existing - father physics and mother nature) and intelligent design, even though intelligence can sometimes be stupid (selective breading and external intelligence influence)
Anyone who wants to divide what actually is, is looking to create a problem that doesn't really exist.
Yes, and because blue M&Ms were made after brown ones they taste better too. First, to support racism there would need to be, well, races. Lack of actual genetic races aside Homo sapiens that evolved in Africa were subjected to evolutionary forces the same way the ones who migrated out of Africa were. All Homo sapiens continue to be subjected to so some degree of evolutionary shaping (cancer anyone?). Just because some people left Africa does not mean that they progressed faster from an evolutionary standpoint, just that it was more noticeable (skin color, hair, size, etc). Finally, saying that Homo sapiens that left Africa are better than ones who stayed because of evolution is silly; by that measure Chimpanzees who remain in Africa are better than all of us because they are evolving faster genetically. Genetic evolution is a sign that the species is adapting to just survive... if you look at successful species like turtles they change very little over a very long time, so if you want to play racist then the ones who left are the weak ones... but that just shows the absurdity of your argument. Go take a biological anthropology class, it would do you some good.
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Yes, and that ancestor is a very simple RNA-based bacterium. And this evolved into DNA-based simple bacteria. Then bacteria which included other simple and ultra-specialized bacteria (cloroplasts and mitochondria). Which evolved into simple multi-celular life forms like sponges and extremely simple worms (hardly more than essentially an elongated torus whose surface was a bacterial film.) Which further evolved into more and more complex stuff.
And some figured out how to eat the others. E.g., fungi evolved to take another cell apart for food. And then some of those managed to, well, more or less do agriculture with other bacteria: the lichen are more or less a combination of a fungus and a bacteria, where the fungus traps the bacteria and helps fixate water and minerals for it, then scoop the food the bacteria produced. Or sometimes just destroy and eat those bacteria for food.
So there you already see the early split between plants and animals: one branch of the fork relied on photosynthesis to produce its own food and energy, using solar energy for it, and the other branch of the fork evolved to be basically parasites on the first one. Whether literally parasites eating the live plants (mostly plankton and algae at that point), or eating the corpses.
But before that fork, they evolved from the same ancestor, hence why they're still similar inside.
And from there it was often a race between species, driven by natural selection. E.g., the lignin based plants of the carboniferous era had a major temporary advantage, in that bacteria and fungi didn't yet exist which could digest this adaptation. However, that also applied to dead plants, which is why there's so much coal left from that age (and gave the age its name.) There simply was noone around which could eat a dead plant. But then bacteria evolved that could take apart lignin and celulosis. And then some animals evolved compartmented stomachs where they could store such bacteria so they could eat plants. (Don't think just literally animals. Some insects, e.g., termites, do exactly the same.)
And so on, an so forth, branching wildly ever since, and punctuated by some extinctions that trimmed the tree.
But, yes, once you trace all the branches back, it all leads to that first primitive bacterium. That's why it's all so similar at a chemistry level. Each step was a tweak of what already existed. Each step evolved more complex proteins, or just different proteins, and more specialized roles, but it was still based on the same reactions that worked before.
E.g., it still had enzymes which copied a strand of RNA, between a "START" and an "END" marker, to a protein. Even in DNA based cells, it's still not that horribly different: there's just an extra step of transcribing the DNA to RNA, so then you can transcribe the RNA to a protein. (As to why that more complicated mechanism evolved by natural selection: because breaking a single strand of DNA, for example by radiation or some chemicals, can still be fixed, while the same break in RNA means cell death. So the DNA based mutants were hideously more survivable than their RNA based ancestors.) Anyway, we essentially we still use the same mechanism of producing the proteins as that original proto-bacterium ancestor.
Where did that original bacterium come from? Well, probably from something even simpler. A bacterium is nothing more than a drop of sea water with a membrane. It makes it easier to keep the contents isolated from the rest of the world, much like a test tube does. But ultimately you just have some reactions in liquid water inside. So probably some chemica
A polar bear is a cartesian bear after a coordinate transform.
Eheheh, that reminds me a perl of anglo-saxon racial mythology:
"Which leads me to add one Remark: That the Number of purely white People in the World is proportionably very small. All Africa is black or tawny. Asia chiefly tawny. America (exclusive of the new Comers) wholly so. And in Europe, the Spaniards, Italians, French, Russians and Swedes, are generally of what we call a swarthy Complexion; as are the Germans also, the Saxons only excepted, who with the English, make the principal Body of White People on the Face of the Earth." Benjamim Franklin
So, to ol' Ben you're "tawny". I'm even in worse conditions, since I would probably be a hit-n-miss between tawny, swarthy, "hispanic" or "latino" (this last two by name alone).
That being said "white" is an historical construct onlyif you use the WASPish and/or nordicist redefinition of the term. It was already - and still is in most of the world - used to denote people of European descent. While there are grey areas the range itself (i.e. europoid people leaving outside of Europe) is more or less well defined in a racial sense. In general the discoverers you mention did view both africans and native americans as different in a racial perspective, going so far has having precise names for the resulting offspring according to the "mixture".
Scientists, as you point out, often have a 'religious' view of certain theories. We saw it back when the Big Bang theory was first proposed; the scientists of the day saw it as 'thinly veiled creationism'. What drives science forward, though, is when you have two groups of fanatics screaming at each other, the non-fanatics generally cluster to the side with the better arguments and better evidence. That's why the Big Bang theory is now taught in schools, and the various steady state theories are discarded, as are most of the 'Big Crunch' ideas.
Anyway, as far as your 4 theories go:
1. The Universe came into existence completely from nothing, by itself. There was nothing, then everything over time. Start with nothing & work forward.
I believe that Hawkings is actually espousing this idea. It seems highly unlikely to me, since it violates the First Law of Thermodynamics, without which all Chemistry, Physics, and Biology is meaningless.
2. The Universe always existed
Seems highly unlikely, given that a) the universe is expanding with no sign of collapsing and b) the Second Law of Thermodynamics.
3. The Universe is an illusion
Possible, but a pointless theory. Even if true, the universe behind the illusion still has to follow one of the other 3 possibilities (but #1 and #2 might be possible in a universe with different laws)
4. The Universe was created.
Almost certainly the case, the question is just by what. Perhaps another universe is unaffected by the Second and/or First law of Thermodynamics, and our universe was created there as an experiment/toy/prop. Perhaps our Universe was born from a black hole in another universe- and the black holes in our universe are also creating more universes. God creating this universe seems at least as likely as anything else, but that merely tells us he's insanely smart and/or powerful. He may care about our universe, but not care about us.
Our best science tells us that we can't know how the universe was created. Unless we get the opportunity to witness another Big Bang or talk to God, it seems likely we will never even have that good of an idea.
You are reading a copy of my copyrighted post.
I already said that life had to hit an incredibly improbable jackpot to appear, in the second half of the message, so I'm not sure who you're arguing with. Admittedly, it was a very long message, so I can't fault anyone for giving up.
That said,
1. While chlorophyll does match that spectrum well, the original photosynthesis was done by cyanobacteria, which _don't_ match that spectrum too well. So there you go, a less perfect solution was perfectly viable too, and the better solution appeared later.
So give me a break with the "too many things had to be just perfect" ID speech. Non-perfect partial solutions exist everywhere. Cyanobacteria themselves didn't disappear even after better tuned plants appeared, and are still around. They still exist and even specialized fungi exist which form lichen with the less efficient photosynthesizing bacteria. So you don't even have to guess or look at fossils there. The partial solution and intermediary step still exists.
2. I'm not sure if perfectly adapted to an atmosphere of oxygen, which is what we have now, is the same as perfectly adapted to an atmosphere of methane, which is what life started with. The argument that everything had to be designed just perfect isn't very believable, when you look at the fact that conditions were different in the first place, and changed _massively_ in the meantime.
3. "Astronomically small" chances happen eventually, if you have astronomically high populations and astronomically high time. When you have populations of trillions of trillions of bacteria, suffering mutations all the time, over a billion years, eventually one _will_ hit jackpot. Especially RNA based bacteria suffered a hideously high rate of mutations, and diverged very very fast in all directions.
As they say, "if you're one in a million, there are six thousand just like you". _That_ is how large populations and small chances work.
Let me give you an even more improbable example. Rolling 20 dice and rolling all sixes is incredibly improbable, in fact, 1 chance in 3,656,158,440,062,976. But if you had a billion people rolling dice once a second, it would only take on the average 3.6 million seconds or 1000 hours for that to happen. That's a little over a month. And when dealing with bacteria, a billion of them is actually an incredibly low population.
A polar bear is a cartesian bear after a coordinate transform.
A possible rebuttal:
I've read an account of the development of early civilisations which stresses almost the opposite explanation. The mediterranean basin is an easier place to grow food (if not hunt/gather), leading to more sedentary leisure time, thus more pondering, thus more technological developments, thus even more leisure time and so on. Consider: the Egyptians relied on a uniquely ideal environment around the Nile.
An analogy could be made with Britain and the industrial revolution. Success was not driven by hardship and necessity, but by ideal environmental conditions (rivers and coastline) for developing manufacturing and naval industries.
It is possible that the initial impetus to move from hunter-gatherer to arable farmer was driven by greater need in cooler climes, but then again how would one survive long enough to work out how to farm if the envrionment didn't provide enough food to live at least several years? (I suppose simply storing autumnal wild foods might do, actually).
Anyway, I don't think the 'forced to be inventive' thing can be a complete explanation, as even if it were briefly true, the necessity of invention ended the moment agrarian society was established, and that was thousands of years ago at least.