I just ran across this from April 16, 2012, smithsonianmag.com
“A New Aquatic Ape Theory.” It’s the frustration of being the tree falling in the forest, that no one is hearing. The gist of the article is covering a paper published in 2009 by Richard Wrangham of Harvard where, it appears, he proposed that “shallow aquatic habitats allowed hominids to thrive in savannas, enabling our ancestors to move from tropical forests to open grasslands.
“About 2.5 million to 1.4 million years ago, when the genus Homo emerged, Africa became drier. During certain seasons, already dry savannas became even more arid, making it difficult for hominids to find adequate food. But Wrangham’s team argues that even in this inhospitable environment there were oases: wetlands and lake shores. In these aquatic habitats, water lilies, cattails, herbs and other plants would have had edible, nutritious underground parts—roots and tubers—that would have been available year-round. These ‘fallback’ foods would have gotten hominids through the lean times.”
Readers of this blog and AAT chat sites from long before that know that I proposed this theory perhaps twenty-five years ago or better. You just have to go back to early posts on this blog to see those very arguments. In fact, I’d fairly recently written an update that I wasn't going to post to the blog because I’d already said it; but because parts of it are rather fun reading, anyway, I thought that posting in light of Wrangham’s report might be worthwhile.
Wrangham, if you’re not familiar with him (I’m not), achieved notoriety recently for theories propounded in a book Catching Fire (which I have not read) that suggest that cooking was an early advancer of our physical development. It hadn’t occurred to me that there would have been any question about that, but, apparently, there was. In any event, Wrangham cemented it in people’s minds that barbecue changed our entire being, not just what we had on Saturday night. Richard, it appears, isn’t afraid to advance the obvious as the solution. I’m only hoping he came up with the idea long before 2009. Not the fire bit, the living by water bit; because only a fool—and there a lot of the out there—would deny that we already are a semiaquatic animal. Only a fool.
I never quite finished this, but it's close enough for folk music. I was rushed. Without further ado, the long, boring “Why I’m Not a Savannista Anymore.”
Confessions of a Lay Person
I am confused. I am a lay person and I don’t “do” science. I do have an avocational interest in evolution, human evolution in particular, and I try to make sense of what I glean from the popular media.
Which is okay. This is an exciting time for all science, but human evolutionary science has been thrown for a loop these past years with new discoveries and understandings appearing, like phantoms out of the jungle, at an astounding rate. It’s been fun to watch. From Ardi to the Denisovans, a lot of old paradigms have seriously cracked.
But, I gotta tell you, there are some things which don’t add up. Can I borrow your time in the hopes that someone will have an answer for me, be able to tie together these few loose ends? I’m sure that, if I’d paid more attention in Biology 101, I wouldn’t have to ask these questions.
Admittedly, garnering my information from the media warps the knowledge stream considerably, but it is what it is. Maybe it’s all a matter of poor communication.
Might as well begin by pointing out what my problems are, and then we’ll try and figure out how I got here. Let me begin by stating three positions I’ve heard:
—Fish/aquatic life moved from the sea to the land to avoid predators;
—Proto-people descended from the trees and began to walk upright in response to thinning forests;
—And a question posed recently in The New Yorker, is there an evolutionary basis for altruism?
Those are the basics; the details can get a little complex. We have to look at how I perceive what I’ve absorbed from the media.
It’s my understanding that all life on Earth issues from a primitive, self-replicating molecule or string of molecules that had to have come with an equally primitive set of operating instructions including how to find and recognize building (eating) materials and how to reproduce. That’s at the very minimum. Those operating instructions would be the precursors to DNA. How those operating instructions could have grown into long strands of DNA is, as yet, unanswered; or if it has been answered, I haven’t seen it. Once again, the precarious nature of the popular press.
Regardless of how they got there, it’s my understanding that DNA can only change through mutations, which are caused regularly but randomly throughout the chain by exterior forces. That may be a false presumption, but it’s the one I’ve been given. Ask me not about combinatorial DNA.
At that, then, I have a creature who can find food, knows how to reproduce, and whose instructions can only be changed arbitrarily. One would have to presume that any change in instructions would be most likely disastrous, if not neutral, and that ones that were beneficial would be few and far between. On the other hand, those with the beneficial mutation would eventually replace those without. Math alone will do that.
This, of course, is predicated on the assumption that, if nothing else, life wants to live. Wherever that drive comes from, once it’s established, it apparently goes to any lengths to perpetuate itself. That seems to be the basic set of instructions that all life has: go forth and multiply. Nothing more; nothing less. My understanding is that’s it. There are no more instructions; from then on everything is left to chance. And has been since the beginning.
And that’s where the trouble lies. That’s where I lose my way.
Here’s how I see chance. A man goes to the casino. He hits the jackpot; he wins a million dollars. He needed that million dollars; his home was about to be foreclosed and the bank wanted their car back. Did he win the million dollars because he was lucky, or because he needed the money? My understanding is that he was lucky. I mean, the result was great: he got what he needed, the weight was lifted off his back. But did his need for money help him win the jackpot? When you, look at someone who has won the jackpot, do you think, gee, he/she sure must have needed that money?
Let’s go back to that fish wanting to get onshore. If a fish were to move onshore to avoid predators, how would that happen? How many evolutionary steps would it take for a fish to evolve into a land animal? How many mutations? Just to escape that predator? How would moving out of the water a little bit and then a little bit more over hundreds-of-thousands, if not millions of years, ever escape one from a predator? If there weren’t any use in being just a little bit out of the water, how would that trait be passed on? Would it be waiting for a multiplier mutation to allow the fish to pop out of the water even further? But if the popping out were useless at that point, would multipliers keep piling up randomly until one day the fish could walk out of the water and survive the predators? If that were the case, wouldn’t it happen to all aquatic life, predators too? I’m having trouble picturing all this. A waiting for Godot fish, waiting till it can miraculously walk on land and escape the nemesis of the deep. It seems that the odds of that randomly happening would be zilch.
It seems much more likely to me that a shore-dwelling fish might find that the land vegetation growing near the shore provided good food, a vegetarian fish. Let’s say that fish really became dependent on the abundant land vegetation that happened to droop or fall into the stream. Let’s presume that any little mutation that helped that fish acquire more of that plant would be spread throughout the species. Let’s presume that staying out of the water as long as possible meant getting the most food. Let’s presume that any mutation that allowed the fish to stay out of the water longer would be passed on to the entire species. In that way, little by little a fish could find itself out of the water happily munching on ferns or lichens or small English crumpets. Of course, being out of the water would have its side benefits, no more predators; but that would probably be balanced by having to get used to the weather. The tipping point, I think, wouldn’t be safety, it would be food.
Follow me this far? Because the implication is that, if mutations are ruled by chance, then evolution is ruled by chance. If evolution is ruled by chance, then there’s no march, no direction to evolution. It means that evolution is governed by opportunity, not by the result. The fish evolved out of the water because it could find better food, there was an opportunity to evolve in that direction should the chance arise. Even though at first the fish slowly moving out of the water wouldn’t be any safer from any predators, so that wouldn’t have provided any incentive; but the increased food supply would incrementally keep getting better and provide enough value to the species that such traits would be saved. The fish didn’t evolve to live outside the water because it was safer, even though that was the result. After an extinction event we don’t get an explosion of species because there are all those niches needing to be filled (or that it would be a good idea to fill); we get the explosion because all those niches are empty.
It seems to me that’s the same problem with the second position: that people took to the ground because the trees were thinning. Once again, I have trouble seeing how that would work. If the previous paragraph is true and evolution is governed by opportunity, not by the result, then we have to ask what opportunities enticed the forest dwellers onto the land? Not forced them, enticed them?
Moreover, where did they get the time? Remember that at this time, 2 1/2 million years or so ago, our ancestors were little more than chimpanzees; we’d made the split, but we hadn’t progressed very far. We had no “culture” to protect us at that time; we suffered the same natural laws as any other animal. That’s where the time comes in.
Again, I’m no scientist and I don’t know how these things work; I’ve got to trust that I can winnow through what I read and hear. I hear a lot about global warming. I hear a lot about species going extinct. By the thousands. All over the world because their habitats are disappearing. I hear some habitats are merely shifting and that some animals/plants can accommodate the move. They arrive earlier in the year or don’t migrate anymore. Mostly, though, I hear the habitats are destroyed or there’s no corridor between remaining remnants. Then I hear that species die. Funny, you’d think I’d hear of species adapting. That’s what we’re to believe proto-people did. If those folks could learn how to walk upright out on the savannah, why can’t the polar bear head into the woods? Why can one species adapt and the others fail? What made us unique?
For every other species, they appear to go extinct rather than adapt because environmental conditions change much more rapidly than evolutionary adaptation. The general rule seems to be that, if a habitat disappears from underneath a species, that species will disappear. If someone could point to a bunch of species contradicting that rule, let me know. Heck, even one would be interesting.
Perhaps people are the one.
Perhaps they’re not.
There are alternative scenarios. People could have been drawn out of the trees. There may have been opportunities presented to them which rewarded standing up on two feet, regardless of what the forest was doing. It’s another case of not looking at the results but, instead, look for the cause, look for the opportunity. The assumption is that people were forced out of the trees (but the chimps weren’t?) and then learned to adapt to their new surroundings by learning to walk upright. One can only surmise that, after the thinning of the forest but before the adaptation of upright walking, when they were still only adapted to climbing trees, they must have been easy pickings. Unless, of course, it didn’t happen that way.
Truthfully, this is where I get stuck. If it didn’t happen that way, how could it have happened? And if it did happen that way, where’s the evidence?
Lacking evidence, I’ve made up my own scenario. I don’t think anyone left the trees because they had to. I think they left the trees because they found more/better food while standing up. Once again, I’m relying on the understanding that any successful mutation has to benefit the entire species, and that it would take innumerable mutations to change from a tree-dwelling to a terrestrial creature, and that each mutation along the way would have to be immediately beneficial else it would disappear or remain neutral. It’s like the fish and the food, each step towards upright walking would have to be beneficial, not just the end result (as if there were an “end result” beyond the current status). Something beneficial is going to have to happen each step of the way towards bipedalism; one can’t keep slowly standing up in hopes there will be a payoff when you get up straight; there has to be benefit in each mutation. And benefit, we remember from the beginning of those self-replicating molecules, can only be in one of two forms: it either helps with food gathering or reproduction; nothing else matters.
I figure it’s not sex. I doubt that people stood up because sex was better that way or that we had more kids that way; on the contrary, it appears that standing up made birth more difficult. There had to have been some powerful incentive to stand up if it made reproduction so difficult. The only other permissible incentive is food. (With the usual caveat that, if you can think of another incentive, give me a shake.) For some reason, standing up allowed us to eat better. Whatever the reason, it pretty much has to be related to our ability to find food. It probably had nothing to do with a thinning forest. Evolution doesn’t go away from anything, it only goes towards something, right? A species can only evolve in the direction chance and opportunity permit.
So, what would entice an ape out of the trees to permanently hang out on the ground? What food would have been available to us as bipeds that wasn’t available to us as knuckle walkers? The chimps and gorillas seem to survive just fine living in both worlds. Why did we give up the trees, they didn’t? We were lucky, eventually our posture allowed us to take over the entire world, but, surely, that’s not why we stood up. We could only have stood up to eat better; taking over the world was pure luck.
How, though, would bipedalism help us eat better?
I’ve heard theories. I’ve heard that, perhaps, standing up offered a smaller target to the sun so we didn’t overheat while out on the savannah hunting. Hmm? I have visions of hunters trekking across the plains, leaning towards the sun so that it only shines on the tops of their heads. As the day stretches on, they become almost parallel to the ground. I don’t think so. Nope.
I’ve heard that, maybe, we stood up to see over the tall grasses either to spot game or predators. Maybe. And at the same time we were willing to give up any ability to run fast or climb out of harm’s way? How did we ever survive? How come no other animal successfully did this? How come every other animal learned to stand up, check out the surroundings, and then get down on all fours and run like hell? How come we were willing to give up our chance to escape just to peak above the grass? How come there’s not a race of bipedal prairie dogs?
I’ve heard that it’s possible we took to standing up to carry food to our families. Again, us and nobody else? Look around you, don’t most of the larger animals carry food to their young? Such as, virtually all of them? Mammals, indeed, have it built in; but even after the young have stopped suckling, the parents generally spend a long time bringing solid food to their offspring. None has seen it advisable to stand up to do so. None. Does that not give you pause to wonder how it could have happened to humans? Did we/do we spend so much time carting food around that it was worthwhile to stand up and do it permanently? Doesn’t seem like it.
Other reasons? Wading around after clams and seaweed? All day? Not likely. We may well have taken to scavenging the shoreline and the swamps, but I doubt we’d have given up the safety of the trees just to do it.
Well, what then?
A change in diet?
A change in diet? How on earth could a change in diet make one want to stand up? There is the fruit-picking theory, that we stood up to gather fruit and nuts. But, really, if you’re going after fruit and nuts, wouldn’t it be better to stay in the trees? How would standing up help one gain access to more/better fruit? You’d give up climbing the trees for standing on the ground and throwing sticks? Really? I don’t think it was fruit and nuts that got us standing up. I don’t.
I think it was meat.
Let’s step back a minute and delve more into popular science: hello NOVA. In the past decades we’ve learned that humans are not the only tool users. Not even the only primate tool users. In fact, all apes are known to use tools of one sort or another. The chimpanzees, we’ve learned, not only go fishing for termites with long twigs, they’re perfectly capable of sharpening a stick with their teeth and going after bush babies, a lesser primate, using the stick as a thrusting spear. That was a shock. Furthermore, they’re not above heaving rocks at an enemy, albeit, underhand.
It could be that chimps acquired this habit after the split with humans, but it’s more likely that the progenitor of both species was already using such tools better than six million years ago. Fast forward to the first known shaped-stone tool use among humans, something like 2 1/2 million years ago. That gives humans 3 1/3 million years to progress from tooth-sharpened sticks and tossed rocks to hand-axes. (If these numbers aren’t exactly to your liking, fill in those of your choice; you have the basic concept.)
Why, you may ask, did this pre-split chimp-human (chuman?) take up sharpening sticks in the first place? You might as well ask, why weren’t they satisfied with termites and bananas? What’s so special about meat? Other than it’s concentrated food. Have you ever noticed how much more time a zebra spends eating than a lion does? I have. Out here on the veldt (not really) I notice the lions spend most of the day lazing around while the zebras are eating every chance they get. Such as when they’re not being chased by lions. It’s the meat. Vegetarians simply have to spend a lot more time crunching away just to get the same food energy that a carnivore does. A lot more.
I’ll tell you what I think happened. I think the split between us and the chimps happened because we really got into meat eating. I think that, before the split, like chimps today, we only used tools occasionally. When we decided to go after bush babies, we would find a stick, sharpen it, and go after them, only to abandon the stick after the hunt. Next hunt, new stick.
But one chimp developed a habit, it sharpened a sick and held on to it. No particular reason, he just liked to sharpen sticks and hold onto them. As a side effect, when a bush baby hole popped into view, he was at the ready; consequently, he ate better than his neighbors. He passed that spear-holding trait onto his kids and his grandkids and they ate and prospered better than any of the others in their tribe. Eventually, everybody was sharpening and hanging onto sticks. Suddenly, the whole tribe was eating better than anyone else in the forest. Eventually, holding a spear at the ready became habitual; those who did it more, prospered more. Slowly, those who were better at handling their spears prospered more than those who were clumsy. Likewise, those who became better at throwing stones were also able to eat better, and, if they had a few stones always at hand, so much the better. The drift towards habitually carrying tools had begun. We were separating from the chimps. That’s how I see it, anyway.
Eventually, of course, successfully carrying tools (i.e. weapons) at all times meant that we inexorably switched from habitual to obligatory bipedalism. There was no way back; we were upright.
Huh? How does that sound? Doesn’t that make more sense than peeping over the grass or carrying rodents back to the kids, not to mention lessening the chance of sunstroke. Could it have taken us 3 1/2 million years to stand up and shape hand tools? Seems fast to me, but could be, we were clever. We do know that something got us to stand up and make hand axes by 2 1/2 million years ago, and we know it had to do with food, and we’re pretty sure it didn’t have to do with pancakes. I’d go with meat and weapons.
If that theory is correct, that habitual tool-carrying led to obligate bipedalism, it throws new light on the ability of our ancestors to expand their hunting range. They might still camp in the forest, but they could now contemplate ranging out after bigger game. Twenty or thirty Australopithecines armed with rocks and spears would be formidable even for a pride of lions. Fifty or sixty together could take over about anything.
That’s it. That how I see we came down out of the trees. Admittedly, it’s a wild guess, but it sounds good, no?
A bonus point is that, if our ancestors still liked to hang around trees even after they learned to walk; it makes it easier to imagine that a branch of that family, us, liked to hang around, not only the woods, but down by the water. We were the guys who learned how to sail and eat seafood. We prospered. We now live all over the world, provided it has potable water and is close to navigable water. Even the farmers and the herders live near water; we’ve never gotten over that.
Now, about that altruism. The New Yorker asks if its an inheritable trait? They meant it in a good way.
A problem I have with altruism being an inheritable trait is that altruism is a value judgement, not a scientific measurement. It’s akin to asking, is being a good farmer an inheritable trait? Is there a genetic basis for good farming?
Intellectually, altruism assumes free will, something for which we don’t have clear evidence. The core definition of “altruism,” if I have it right, is doing good for another at personal cost to oneself. This presumes we’re in control of our thoughts and actions, another case of something that might or might not be true. It’s not clear that consciousness, no matter how advanced, is anything more than a monitoring and transmission station. It’s very fast and it gives us the illusion we’re doing the thinking for operational purposes, but I’m not sure we know how that’s done. My guess is that thinking is done at the cellular level or below and is primarily a matter of counting switches, yeses and nos. It’s why we can ponder some problems forever without making up our minds or why we can “instinctively” jump in front of a train to save someone. In neither case is our consciousness making the decision, it’s only transmitting data. I think if we had to think about thinking, we’d be frozen in our tracks.
Let’s go back, then, to that pre-cellular creature and its mutations. We’ve already determined two things: one, that mutations can only be adopted if they improve either feeding or reproduction; and two, successful mutations have to benefit the entire species in order to survive. The process, it would appear, means that the operating package that each member of a species gets gives instructions that propel the organism one way or another simply by checking the situation against its given template. If the monitoring station sends the propitious signals, go for it. No thinking necessary, just compare to the template. That system would work all the way up to us. We never really think, we just do what our sub-engine—oh heck, let’s just call it a subconscious—decides.
3 years ago