You’ve forgotten about everyones favorite flightless bird! [http://www.pbs.org/kratts/world/ant/penguin/images/penguin.jpg](Le penguin!)
In fact, all birds walk upright don’t they?
Fixed link: Le penguin!
This is a massive and v. interesting question, so I’ll just ramble…
Why is there such a gap between us and the nearest runner-up (the chimp I think)? At some point we must have been much closer, and something happened, some adaptation, which precipitated an explosion of abilities. Language - a common agreement to use arbitrary symbols to represent the world - is the obvious answer, but how did it start … to use language at all implies a prior belief that other people have similar minds and will understand you. To put it another way, you have know that communication is both possible and desirable. Animals do not appear to have this, at least beyond the basic level of ‘I want a share in that dead buffalo’.
Perhaps the way to tackle it is to identify what abilities we hold in common with chimps, so as to be more precise about what is different. I would go for some combination of imagination, language, and understanding of other minds.
Fuel:
Chimps are not monkeys. I hope you know that.
My “wondering” was a joke, but maybe you didn’t get it.
Wearia:
Birds walk on 2 legs, but I wouldn’t call it upright. Look at the slope of their spine.
Huh? Look at the penguin. Wearia posted a link to it. That’s pretty upright if you ask me.
So, do you believe that our ancestors changed from mammals that walked on all four limbs to Marine-straightbacked creatures overnight? This is unlikely.
The point someone was making is that when the limbs are free for purposes other than walking, they can be used for something else. This means the arms can do new things, such as carry food or wave sticks. This means that the creature has more potential abilities, and develops tools. This means that the creature can use intelligence more effectively, especially when combined with social instincts and language abilities.
But birds and dinosaurs had their limbs free (and even penguins who are upright) but haven’t developed human-like intelligence. This is the debate. Where do you weigh in on that?
bird primary source of transport = flying. Penguims primary source of transport = swimming. Besides, penguins don’t walk, they waddle…
Sigh, yes I know monkeys aren’t chimps. And i figured as much, but wanted to make a point.
Ponder this penguin skeleton. The spine may be vertical, but the legs (specifically, the femora) are not in line with it, as they are in humans.
**
I would think that is evidence that there is more to the story of intelligence than simply having one’s hands free, then.
Be that as it may, the trend in dinosaurian evolution (particularly theropods, the bipedal meat-eaters, to which birds also belong) was a combination of reduction of the number of fingers and restriction of movement of the hands. Birds have only two fused fingers (and a “bastard” thumb - the alula), and their wrists can only move in very restricted ways. Thus, while theropods were essentially “hands free”, there was still only so much they could do with them. Having said that, there was a trend in some lineages toward increased cranial capacity. So who knows, maybe they were on their way to evolving what we would consider intelligence when they were snuffed out. Or, maybe not.
I’m not even sure if “Scientific proof for why only one race of animals walks upright” is syntactically correct, but I know it doesn’t make semantic sense. Why are we the only species that walks upright? All of the other ones who did died out.
My “prove it” comment was directed at your assertion that our variations cannot be explained by science. To assert this is ludicrous, as you have no idea what future science will be capable of. Furthermore, unless there’s some mental process that doesn’t have a physical analogue, it’s all chemicals and electricity, and anything dealing with that is (in principle) scientifically explainable.
Many dinosaurs walked upright, yes, but dinosaurs had sharp claws and teeth, and in many cases, had double-digit tonnage. When you’re put together as a massive killing machine, what use are tools to you? There was no need to develop tools to survive. They probably couldn’t even have made tools if they were smart enough, since their hands were designed for rending and tearing, and probably had little in the way of dexterity. Could they have eventually developed into a human-level species? Maybe, but I guess the meteor cut short the evolutionary process and instead forced dinosaurs to evolve into birds.
Birds walk upright, but it’s obvious that their “arms” aren’t equipped to design or use tools. They walk upright to help engage flight, and so they don’t have to use their wings to crawl, or simply use their legs to push their upper torsos around on the ground. While some birds (like the penguin) don’t use wings to fly, their wings are still obviously incapable of the amount of dexterity needed for tool use. Their arms are designed for swimming, which is how they move, hunt and flee when necessary, something traditional hands aren’t great for. Why should such an intricate part of a penguin radically evolve into something that would probably have made them extinct in pretty short notice?
Why did humans start walking upright? The best theory I’ve heard is that a certain type (perhaps physically weaker) of ape that lived somewhere in Africa needed the ability to stand upright to survive. In Africa, with large plains full of tall grass, an animal that can’t smell or hear a predator coming (since humans have fairly poor senses of smell and hearing compared to many animals, I assume our ancestors were the same) is dogmeat if it’s also too low to the ground to see it coming. So these apes stood upright to see over the top of the grass, where they could easily see the movement of a large predator sneaking up on them. This eventually led to being naturally upright through the magic of evolution.
Omega:
You should throw out your 1950s books on human evolution and buy some newer ones.
Seriously, I hope you don’t fall for the “had to stand up to see over the savanah grasses” theory for upright posture. The origin of bipedality in human ancestors is one of the great unsolved mysteries of evolution. Any paleoanthropologist worth his salt would tell you we have no idea how it came about.
Ever seen a picture of a bonobo standing upright? Down right scary. You half expect him to walk up to you and say “How do you do?” At any rate, apes are much more upright already than monkeys and they don’t walk on the palms of their hands. Oddly, gibbons (so called lesser apes) scamper about in a sort of upright posture when they are on the ground (whichh is not too often). They look like a little kid skip-jumping while holding his arms in the air.
Dinosaurs were bipedal, which is different from “walking upright”. Their spines were still largely held horizontally.
Birds had evolved to their more-or-less modern forms well before the asteroid struck.
**
Such would require the magic of Lamarckian evolution - specifically the inheritance of acquired traits. Besides which, if the grass were tall enough that they couldn’t see over it without standing on their tippy-toes, it would seem to me that it would work equally well to conceal them from predators.
In my speculative opinion: humans simply hit upon what just happened to turn out to be a very “good trick” indeed, and we profited from it greatly. Of course, we often tend to anthropomorphize our own importance… but then that’s part of what makes us so neat.
Most predators have advanced senses of smell, which is how they track prey in the first place.
And I’m no expert on evolution (obviously) which is why I said that grass thing is the “best” theory I’ve heard.
If that is what you meant, then why are you barking “prove it” at me? Geez, all I meant from the beginning is that science as we know it does not have an answer for the existence of human beings… our characteristics, our emotions, our differences from the rest of the animal kingdom… it’s all a mystery right now. I like to hear people admit to this, because so few scientists/evolutionists have the balls to suck up their pride and admit it.
Prove it? please. There is more to this discussion than walking upright. And I worded that question by trying to fit in the word proof since you asked for proof from me. You go ahead and wait for your scientific proof. And bring a book because you are going to be waiting a long time. As for me, I have already decided to not let science blind my eyes from the possibilities out there. I got a hunch about our race, and it ain’t scientific, it’s spiritual. And it has observable evidence, the Bible. You have your faith in “future science”, I have my faith in a scientifically unexplainable world and an existing book and certain scrolls found in the Dead Sea.
…Funny. Christians and Evolutionists aren’t all that different after all. They both have faith!
Ultra, who knows what future archeology is capable of?
Heh heh
I was perhaps wrong in saying that * Homo Neandertalis * was fully human, as they had several significant differences to modern people, including possibly less development in the speech - related areas of the brain, and perhaps less blood supply to the larynx.
Nevertheless, they seem to have had sufficient capacity for abstract thought to sometimes bury their dead with what appears to have been a ceremony of some description, and to have created some possible decorative artefacts.
Difficult to imagine these things without an advanced language,
perhaps they used signing (as some have suggested?)
I’ll throw out a few random thoughts too:
I think humans have become successful due to a lack of specialisation. Every other creature has evolved to suit a very particular ecological niche which they are extremely specialised at exploiting or, at least, surviving in.
Contrary to this, humans have become more and more unspecialised (as a species), enabling the exploitation of greater areas of the planet. We live from below sea level up to 15,000 ft above. We live in freezing cold tundra to searing hot deserts, and all habitats in between.
With the exception of dogs, parasitic bacteria and lice, no other creatures or species have as varied a habitat (globally) than humans. (IIRC)
This venturing into a non-specific relationship with nature would have helped to perpetuate the species to all corners of the globe, ensuring not only survival but dominance.
I like this point…and you could speculate that this lack of specialisation is reflected in the human brain - we have loads of specialised modules, but there is also ‘something’ that seems to pull it all together. Animals’ brains are perfectly adapted to a particular ecological niche, but our brains are adapted for flexibility.
Fuel, science is not concerned with the “why” of the “existence” of human beings in the metaphysical sense you seem to be aiming for. The scientific answer to “why X happens” is really an answer to “how come” X happens. And scientifically, the only meaning of something being unique is that there is nothing else like it. So “why is man the only upright+intelligent land mammal” is scientifically answered by " 'cuz there ain’t 'nother".