Am I correct in saying that nowhere within academically recognized evolutionary theory do experts think that this “missing link” issue is serious enough to posit that proto-humans mated with some species from another planet in order to produce the current species of humans?
If so, can anyone point me in the direction of a fairly simple, concise refutation of a) the notion that there is some mysterious “missing” link that confounds our theory of evolution, and b) the notion that there was some alien intervention.
Perhaps the latter is such a wildly radical idea that no serious scientist would even take the time to provide evidence against it, but this is a topic I’m fairly ignorant about, and I’d like to have some good information to give to a friend who, for some reason, believes in this alien story.
There is just way too much wrong with the premis presented to deal with it in a single post.
There ain’t no evidence of aliens. There ain’t no evidence of alien DNA in humans. There ain’t no evidence of any attempt of such “theories” as this one being examined by any sort of rigorous scientific method.
I’ll take a quick swipe at the missing link regarding human evolution.
We have quite a few fossils showing a gradual progression from apes to humans. Between each one of these fossils is a gap, and we would like to find fossils to link that gap. But of course, each time we find a fossil showing a creature in between two others, we now have two gaps instead of one. We will always have gaps, which some refer to as missing links, but the gaps themselves are getting narrower with every find.
There is no single large step that could possibly cast doubt on the model of human evolution. There will likely be tweaks to it, minor changes, but our current fossil record shows a nice gradual progression already.
The whole notion of a “missing link” dates back to the 19th century when people were first coming to grips with the possibility - as it was oversimplistically and wrongly posed - that humans were descended from the apes. If this were true, as the scientists claimed, then logically there must be some intervening step, half-ape and half-human, which was dubbed the missing link.
As already noted, this is entirely incorrect. Humans and apes are both descendants of some earlier non-human, non-ape (a lemur-like creature is most likely) and went through a huge number of small changes to arrive at their present forms.
The fossil record is not complete and has some large gaps in it, but it is fairly well known back some 15-20 million years. There is not the slightest possibility that aliens came out of the sky and changed everything in one mating.
I also have to re-emphasize the point that all life on earth from one-celled creatures on up share commonalities in their DNA that make it even more impossible that alien DNA was suddenly introduced to earth at any recent point.
You don’t need to be a serious scientist to knock this idea for a loop. It’s on a par with saying that aliens introduced the number “3” in between “2” and “4”.
You didn’t say humans and chimps, but you did say humns and apes. The only living apes are humans, chimps, gorillas, orang-utans and, i think, gibbons. The common ancestor of all of these was was still an ape. So while humans aren’t descanded from the apes - meaning the still living, non-human apes - they are descanded from apes, namely this common ancestor.
It says modern humans can trace themselves back to a female living 150,000 years ago. So a single mating can be significant. Not with an alien, of course.
It is possible an alien came here and maybe did a little genetic tweaking, but probably not by inserting some of its DNA. If you know what you’re doing, you can probably do whatever you want with the genetic building blocks all earth creatures already possess.
Even more far-fetched but fun to think about, maybe life on Earth was seeded by the same planet these aliens come from. So that, even after all these millions of years, we’re still made of the same basic proteins that they are made of. They still couldn’t mate with us any more than a modern human could mate with algae, but they’d at least be familiar enough with our proteins to do some rearranging.
I think this just means that she would be the most recent common ancestor of all presently living humans, and not that her DNA or that of her children brought any remarkable changes.
Note that “modern humans” — as in the kind you could might feasibly have a conversation with, lose a game of chess to, teach how to drive a stick-shift, and the like — didn’t arrive until something like 30 to 50 thousand years ago.
All of which leaves the question: How did that alien DNA arise in the first place? If life could spring from non-life on some other planet, why couldn’t it just as easily have done the same thing here, where we already know conditions are favorable for it?
Seems to me that the aliens are a complicating and unnecessary hypothesis.
I think that an analysis for “means, motive, and opportunity” for some hypothetical interstellar being to come to Earth ten or twelve times over the 6 million year period during which genus Homo has been in existence would be an interesting first step in providing evidence for this theory.
And yet, somehow I don’t expect to see that. Go figure.
That’s unclear. Some anthropologist hypothesize that there was a significant change in H. sapiens that happened as recently as 50k years ago that makes us different from those that lived, say, 100k yrs ago. Most of this is based more on “absence of evidence”, than anything else-- absence of cave painting, other types of art, and certain tools in the fossil record earlier than 50k yrs ago. But that’s far from proof, and there is no consensus among anthropolists as to whether this hypothesis is valid or not.
What seems to have happened is that humans went thru an evolutionary bottleneck sometime around 75k yrs ago (+/-). Right after that, we left Africa and populated the rest of the continents. What those African ancestors were like previous to 75k yrs ago is not very well known. Were they different from us in culture only, or was there some significant mental capacity that we have and which they didn’t?
Well, since the Ape family include humans, then humans ARE apes. Or rather, there is no consistent definition of the word “ape” that includes chimps, gorillas and orangutans but not humans. Since humans ARE apes, our common ancestor with the other apes would be classified as an ape.
We understand the idea that Chimps are our closest relative. But it is harder to grasp the idea that humans are the chimpanzee’s closest relative. Chimps are more closely related to humans than they are to gorillas. So any category (say, “ape”) that includes both chimps and gorillas must also include humans.
But back to the fossil record. Every hominid fossil found is a “missing link”. The only way to avoid a missing link would be to have every human ancestor since we first crawled out of the ocean lie down in a row and get fossilized. Since very few human ancestors got fossilized, of course we are missing 99.99999% of all possible “missing links”.
She’s probably not even the most recent common ancestor. If you take your mother, and then your mother’s mother, and then your mother’s mother’s mother, and so on, then eventually you’ll get back to “Mitochondrial Eve”. Likewise, if you take your father, and then his father, and so on, you’ll eventually get back to “Y Chromosone Adam”, another common ancestor of all modern humans (not contemporary with Mit Eve, mind you). These two common ancestors are easy to trace, since we get our mitochondria exclusively from the mother’s side, and males get the Y chromosone exclusively from the father’s side. But there’s almost certainly a common ancestor to all modern humans much more recent than Mitochondrial Eve. It’s just that you have to use both maternal and paternal lines to trace back to her, and there’s no known way to do so.
It’s actually even easier than that to find a more recent ancestor. Just like the mtDNA-Eve, there is a Y-chromosome-Adam. And the data indicates that “Adam” lived more recently than “Eve” did. From a review of The Journey of Man: