Top 10 Mysteries of the First Humans

I found this list from livescience and found it really interesting. In a time when, we as a species, believe we know more than we actually do, it's always good to get a proper dose of things that we don't know. Of course, this list does not take into consideration theories by those such as Sitchin, who believes that humans were genetically altered by extraterrestrials, as it is a highly debated theory, but even still, the questions still remain. With that said:

The Top 10 Mysteries of the First Humans

10
Where do modern humans come from?

The most bitterly debated question in the discipline of human evolution is likely over where modern humans evolved. The out-of-Africa hypothesis maintains that modern humans evolved relatively recently in Africa and then spread around the world, replacing existing populations of archaic humans. The multiregional hypothesis contends that modern humans evolved over a broad area from archaic humans, with populations in different regions mating with their neighbors to share traits, resulting in the evolution of modern humans. The out-of-Africa hypothesis currently holds the lead, but proponents of the multiregional hypothesis remain strong in their views.

9
Who was the first hominid?

Scientists are uncovering more and more ancient hominids all the time -- here meaning bipeds including humans, our direct ancestors and closest relatives. They strive to find the earliest one, to help answer that most fundamental question in human evolution -- what adaptations made us human, and in what order did they happen?

8
Did we have sex with Neanderthals?

Did we interbreed? Does our species possess any genes leftover from our extinct cousins? Scientists have suggested that perhaps the Neanderthals did not die out, but instead were absorbed were absorbed into modern humanity.

7
Why did modern humanity expand past Africa about 50,000 years ago?

Roughly 50,000 years ago, modern humans expanded out of Africa, spreading rapidly across most of the world's lands to colonize all continents except Antarctica, reaching even the most remote Pacific islands. A number of scientists conjecture this migration was linked with a mutation that transformed our brains, leading to our modern, complex use of language and enabling more sophisticated tools, art and societies. The more popular view suggests hints of such modern behavior existed long before this exodus, and that humanity instead had crossed a threshold in terms of population size in Africa that made such a revolution possible.

6
What is the hobbit?

Is the 'hobbit' -- the nickname given to diminutive skeletons found on the Indonesian isle of Flores in 2003 -- in fact an extinct human species, enough to be called Homo floresiensis? Are these skeletons just examples of deformed Homo sapiens? Are they a different species than us, but perhaps not an extinct human species and instead as separate as chimpanzees are? Solving this mystery could help shed light on the radical paths human evolution may have taken.

5
Is human evolution accelerating?

Recent evidence suggests that humanity is not only still evolving, but that human evolution is actually accelerating, speeding up to 100 times historical levels after agriculture spread. A number of scientists challenge the strength of this evidence, saying that it remains difficult to ascertain whether or not certain genes really have recently grown in prominence because they offer some adaptive benefit. Still, if human evolution is accelerating, the question becomes why? Diet and diseases may be some of the pressures that caused humans to change.

4
Why did our closest relatives go extinct?

Roughly 24,000 years ago, our species, Homo sapiens, was not alone in the world -- our closest relatives, the Neanderthals, (Homo neanderthalensis) were still alive. The so-called 'hobbit' found in Indonesia might also have been a member of the genus Homo, and it apparently survived until as recently as 12,000 years ago. So why did they die and we survive? Did infections or radical shifts in their environments kill them off? Or did our species do away with them? Some evidence exists for both scenarios, but no conclusion is agreed upon.

3
What happened to our hair?

Humans are unique for looking naked compared to our hairier ape cousins. So why did this nakedness evolve? One suggestion is that our ancestors shed hairiness to keep cool when venturing across the hot savannahs of Africa. Another is that losing our fur coats helped free us parasite infestations and the diseases they can spread. One unorthodox idea even suggests human nakedness developed after our ancestors briefly adapted for a streamlined life in the water, although most aquatic mammals of roughly human size actually possess dense fur.

2
Why do humans walk on two legs?

Our ancestors evolved an upright posture well before our large brains or stone tools even appeared. The question, then: Why stand and walk on two legs when our ape cousins get by on four limbs? Walking as bipeds might actually use less energy than movement on all fours does. Freeing up the arms might also have enabled our ancestors to carry more food. Standing upright might even have helped them control their temperature better by reducing the amount of skin directly exposed to the sun.

1
Why did we grow large brains?

There is no question that our large brains have provided humans an extraordinary advantage in the world. Still, the human brain is an incredibly expensive organ, taking up only about 2 percent of the body's mass yet using more than a fifth of the body's energy, and until about 2 million years ago none of our ancestors had a brain larger than an ape's when compared to body size. So what kicked off the push for a larger brain? One possibility is that increased smarts helped our ancestors make better tools. Another is that larger brains helped us interact better with each other. Perhaps radical changes in the environment also demanded that our ancestors deal with a shifting world.

[edit on 13-11-2009 by xEphon]

Nice thread..those are some thought provoking questions.

reply to post by xEphon


Interesting post!

I actually watched the NOVA special on human evolution and they measured the energy expenditure of a chimp walking vs. a human, and I believe they said a human uses 25% of the energy a chimp does while walking.

It makes sense, that if we were kicked out of the forest and forced to walk our bodies would adapt to the travelling using the least amount of energy.

Also, the lack of abundant edible vegetation on savannas might have had something to do with forcing us upright to save energy.

Personally, I think human evolution is accelerating. We rely on our brains moreso now than ever before, so it only makes sense that as a species we adapt by relying on that organ more than others.

At any rate, thanks for the list.

reply to post by Avenginggecko


Yeah, I definitely think evolution is accelerating. Why? Who knows. There are so many theories out there that there try and explain this why this is happening that it would deserve its own thread. At any rate, here is a bit more from livescience regarding that.

Humans Still Evolving as Our Brains Shrink

Evolution in humans is commonly thought to have essentially stopped in recent times. But there are plenty of examples that the human race is still evolving, including our brains, and there are even signs that our evolution may be accelerating.

Shrinking brains

Comprehensive scans of the human genome reveal that hundreds of our genes show evidence of changes during the past 10,000 years of human evolution.

"We know the brain has been evolving in human populations quite recently," said paleoanthropologist John Hawks at the University of Wisconsin at Madison.

Surprisingly, based on skull measurements, the human brain appears to have been shrinking over the last 5,000 or so years.

So, not only are we evolving and getting smarter, but our brains are getting smaller. Good deal.

I don't believe that any skeletons of humanoids have ever been found on the Savannah.
Only in forested areas, or areas that were forests at the time the found creature lived.
And still they misuse the word "mutation" showing that they have no idea of what they are talking about. Or it is that they think you/we don't know what it means and they are doing a snow job to make themselves look good.
Somehow they find it impossible to just say, "We don't know".

reply to post by OhZone


Man you are so right, there has never been any proof that any species turned into another species.

The scientists just do not know, and they try to find someone who is good at guessing, and go with them, thats all they do.

Today mankind has the science to make evolution jumps, but that would not be natural evolution would it. There are probably endless ways the human race can go from here, and its upto who ever runs this world.



[edit on 11/13/2009 by andy1033]

Originally posted by OhZone
I don't believe that any skeletons of humanoids have ever been found on the Savannah.
Only in forested areas, or areas that were forests at the time the found creature lived.
And still they misuse the word "mutation" showing that they have no idea of what they are talking about. Or it is that they think you/we don't know what it means and they are doing a snow job to make themselves look good.
Somehow they find it impossible to just say, "We don't know".

That's not true. They've found fossil remains in places that were once savannah areas for many of the ancestors of homo sapiens. Homo Ergaster is the first evidence of our ancestors leaving the forests and living primarily in the plains. That was 2 million years ago. There's plenty of evidence that hominids walked the plains since then.

Source

Man you are so right, there has never been any proof that any species turned into another species.

Somehow they find it impossible to just say, "We don't know".

Are you kidding? Do you know what science is? Science is about taking a topic that you don't know, forming a hypothesis, testing the hypothesis, and forming a conclusion. Questioning is the very foundation of the entire field! Why do you think there are so very few scientific laws?

The scientists just do not know, and they try to find someone who is good at guessing, and go with them, thats all they do.

Today mankind has the science to make evolution jumps, but that would not be natural evolution would it. There are probably endless ways the human race can go from here, and its upto who ever runs this world.

There's plenty of preliminary evidence that we've found that species are possibly diverging. It's incredibly arrogant to state that there's no evidence of speciation and then not mention the fact that speciation isn't a "one day it's one, the next it's two" situation. Speciation is an incredibly slow, drawn out process, so unless you become an immortal time traveler we'll never be able to go back in time to know for sure.

You're right, scientists don't know for sure. But unlike your incredibly simplistic and incorrect generalization of paleontologists, evolutionary biologists, anthropologists, etc. they don't just find someone who's good at guessing. They go to school and spend often more than a decade in post secondary education learning about their field, and then they spend their lives studying it in the pursuit of truth. They are happy about uncovering new discoveries that tell us more about who we are and the process of how we got to be here, and you would be hard pressed to find someone who was unwilling to entertain a plausible notion.

[edit on 13-11-2009 by Avenginggecko]

[edit on 13-11-2009 by Avenginggecko]

Originally posted by xEphon


So, not only are we evolving and getting smarter, but our brains are getting smaller. Good deal.

so much for the skinny bodies/huge brain alien evolution theory! sadly in the U.S. that means we are getting fatter but our heads are shrinking. bummer. And I dont know about the no hair thing. the older I get....

If only there was a way to make ourselves smarter, to jump start brain development

Let me toss into the mix a couple of thoughts...

I have always found the evolution of man of great interest, and especially the following two theories:

The first is the mitochondrial Eve and the Y-chromosomal Adam:
re: en.wikipedia.org...

Evolutionary biologist Richard Dawkins has postulated that human mitochondrial DNA (inherited only from one's mother) and Y chromosome DNA (from one's father) show coalescence at around 140,000 and 60,000 years ago respectively. In other words, all living humans' female line ancestry trace back to a single female (Mitochondrial Eve) at around 140,000 years ago. Via the male line, all humans can trace their ancestry back to a single male (Y-chromosomal Adam) at 60,000 to 90,000 years ago.

This theory, based on its estimated time table begs to answer, if all female lineages trace to a single female, Mito Eve approximately 140,000 years ago, and the Y-chromo Adam to 90,000 years ago, then there must have been a really helpful milkman on the block for some 50,000 years.

The fact that I have always believed there was an outside influence and or manipulation in the evolution of man, brings to me think, could these supposed bottlenecks in human population size have an effect appearing to be manipulation by an outside source, e.g. alien intervention and genetic manipulation?

Re: en.wikipedia.org...

Other authors such as Endicott et al. (2009) think that bottlenecks in the human prehistory were such a common feature that they interfere with TMRCA determinations and imply the possible effect of the OIS-6 on population size reduction with a TMRCA around the time of late pliestocene climate optimum, approximately 120,000 years ago.