I loaded a bunch of TED Talks on my IPod for a recent trip. One of them was by Elaine Morgan. She's a proponent of the Aquatic Ape Hypothesis. I hadn't ever heard of this. The basic premise is that if we had evolved in the water for some part of our evolution, it would explain a few issues such as the difficulties in beginning to walk bipedally, what happened to our hair, our hooded noses, narrow shoulders, subcutaneous fat, etc. It's really an interesting talk. She's a strong advocate and borderline indignant about science's wide rejection of the hypothesis.
Since I hadn't heard of this, I'm curious as to solid refutations of the idea. Anyone discussed it at length in a class? Read a great paper on it? Off hand, my brain is trying to wrap itself around the timeline of Ardi and Lucy being bi-pedal, Any chance they fit any part of Aquatic Ape Hypothesis? Any chance of cross breeding and keeping us as one species while some of these changes happened? I'd like to get a better understanding of this if someone feels like they have a grasp on it.
Here is the vid and the Wiki-link which includes criticism of it.
As I understand it the suspect in the near extinction was the Lake Toba supervolcano erupting (if memory serves it's in Sumatra). Which just makes Yellowstone's being about due for a KaBoom! all the more worrisome.
This whole idea of near extinction and the Lake Toba volcano event has failed to pass the reality check. It only works if you are old and still stick with a much slower and later leaving Africa date than the current data supports. Humans were in Australia when Toba blew. Additionally our ancestry is a bush not a tree. Every new discovery has made it bushier.
How did they get there? It was an ice age. From Africa to about 60 miles short of Australia was all dry land because the ocean was lower. They walked from Africa to Australia. Arabia was savannah with some forests not desert. The South China Sea was dry land. Even with the most recent date for the evolution of humans at 100,000 years ago that was 40,000 years to get from south Africa to Australia. All of that had roughly the same climate and same food animals and vegetation.
When I go look at the commonly accepted dates for Toba and the Australian aborigines genetic divergence and actual arrival in Australia, at least part of it doesn't refute the Toba hypothesis as you seem to think it does.
Australian humans branched off genetically from other extant humans 62-75 thousand years ago (having left Africa about 70K years ago), and apparently arrived in Australia 50,000 years ago. Toba blew its top 69-77K years ago. these together appear to contradict your assertion that "Humans were in Australia when Toba blew"
There is some overlap between these ranges but the strong suggestion is the indigenous Australians diverged genetically, while still in Africa, right around the time of the blowup (possibly as a result of it wiping out all neighbors of a small population, isolating them genetically).
RE: "Australian humans branched off genetically from other extant humans 62-75 thousand years ago (having left Africa about 70K years ago), and apparently arrived in Australia 50,000 years ago."
Thanks to technological advances in transportation, that journey has been shortened considerably since then.
I found this extremely informative.
That looks like something worth seeking out in DVD--especially since I collect BBC blurays--(but it's a bit long to stream on a data allowance). Thanks!
Poking around some more, there was apparently never (during the last couple of hundred thousand years) a land bridge all the way from indochina to Australia. There was always a break that left "Sahul" (Australia and New Guinea) separate from Asia. Humans were the ONLY large mammal to cross that; presumably the ancestors of the indigenous Australians (is "aborigine" now considered derogatory?) had boats.
It took people about 1500 years to make their way from Alaska to Tierra del Fuego (I understand), through greatly varying ecological zones, so Africa to what is now Indonesia, where things were a lot more similar, was probably at least as fast; the final jump to Sahul could have been quick or slow depending on the boat hi tech of the time.
Actually, it's the fourth of a series of five, hour-long BBC specials, in which Dr. Roberts traces the migration of Humanity throughout the world.
Except for sex, I can't think of a better way to spend five hours.
Not the same as "Human Planet" then, which is in shrink wrap still on the coffee table, and second in the queue.
RE: "'aborigine' - derogatory?" - my good friend, Suzanne Olson-Hyde, of Sydney, is a devotee of indigenous Australian art, customs and people, and she uses it regularly, so I must presume she wouldn't, if it were.
You never do know though what will turn out to set someone's teeth on edge. Christians seem upset when I call them wafermunchers.
Also I am indebted to Sagacious Hawk who found these two links
which generally support what I said; though pushing the arrival of humans in Oz to 60K years ago, that's still not before the Toba blow.
Yeah, Saggy's a cool frood!
Yes an incredibly sloppy statement on my part. My point is not the extinction but the idea of down to only 500 people. The ash of Toba is found mainly in India. And there is a genetic break between east and west of India indicating people in India were likely eliminated.
However to have people from Africa to east of India one has to have had many, many more than 500 people.
As to suggesting a general extinction of humans from the event outside of the ash fall region humans are the most adaptable of all species. I would not accept such a human extinction unless every species in the human range also underwent a near extinction. I have never read of such a thing.
As to Australia that should have been an entirely different digression. I find the time to get to Australia from Africa almost impossibly slow. It was essentially dry land all the way from Africa to about 80 miles from Australia because of the ice age. The mouth of the Red Sea may have been a mile or two wide. It was coast line all the way with whatever forays inland after whatever might have tasted good.