On October 14, 2012, my son Allan and I toured New York City's American Museum of Natural History. We were on a three-day father-son vacation, covering off the Federal Reserve Bank, The United States Court of International Trade, the United Nations Building, including a pre-American-Revolution church cemetery, among other sites and sights.
I had wanted to see the Museum's Hall of Human Origins... you know.. skulls and bones 'n things...
Pondering Evolution has always been a passion of mine, and a walk through the 'Hall' was something I knew I would find thought-provoking.
But besides the skulls and bones, I had wanted to see the Laetoli Footprints from Tanzania, discovered by one of Mary Leakey's workers... Funny, eh... he's only labeled as a 'worker'.. I wonder why he doesn't have a name... after all, it wasn't Mary who found them... The footprints appear to be two bipeds walking together.. some 3.6 million years ago. Not only bipeds, but hominids... The museum has them in a diorama, with figures of a male and female australopithecines, the male, arm around the female, walking... kinda nice to know that love is some 3 million years old, if not older. One comment though... they had it right back then... why wear pants?
And tonight, thinking about this recent trip to the Big Apple brought me back to an old paper I had written in the late eighties. It's old now, but that's were my head was then, and I guess, as evidenced by the NYC trip, and where it still plays at times.
In a nutshell, I'm amazed that some clumps of matter can 'think'... and beyond that, some of those clumps can communicate with other clumps... and those clumps can read this post 'right now'. .. By the way, how did a clump like you happen to be here, 'right now? And, while those clumps can do all those things, others, like rocks on a road, cannot.. My first post here kinda is in the same theme...
And with all that preamble, here's some 1980's thinking about the evolution of the human animal, and in a way, the story of your next door neighbour's family that goes 'way back...
Of course, I'd welcome your comments..
What do we mean by the label 'human'? Is a human a physical manifestation, a skeletal type, a species, or something else? Donald Johanson (1982:100), describing the classification of Homo habilis discovered by the Leaky team at Olduvai in 1964, wrote:
"But should that species be Homo? Why not another kind of Australopithecus? How small a brain could a hominid have and still qualify as human? In fact, how did one even define a human?
It may seem ridiculous for science to have been talking about humans and pre-humans and proto-humans for more that a century without ever nailing down what a human was. Ridiculous or not, that was the situation. We do not have, even today, an agreed-on definition of human-kind, a clear set of specifications that will enable any anthropologist in the world to say quickly and with confidence, 'This one is a human, that one isn't'."
Although most anthropologists and paleoanthropologists seem to define a human by the physical characteristics of skeletal structure, I feel that a human cannot be rigidly defined using these attributes. The human being, from my point of view, is a state of being, a state of consciousness. Kenneth P. Oakly (1968:3), in his book, Man the Tool Maker, cites Sir Wilfred Le Gros Clark as commenting:
'Probably the differentiation of man from ape will ultimately rest on a functional rather than on an anatomical basis, the criterion of humanity being the ability to speak and to make tools.' This amounts to saying that the real difference between what we call an ape and what we call a man is one of mental capacity. It is worth considering the psychology of apes with this point of view in mind.'
Evolutionarily speaking, this makes it impossible to categorize a fossil as human, or not human, since there is no direct method to determine the organism's mental capacity or state of consciousness. As a result, scientists concentrate their efforts of definition to the concrete, measurable, and available artifacts periodically surfaced from the beds of history.
Even so, their definitions of 'human' can never be complete without a knowledge of the animal's capacity for information processing, self awareness, and ingenuity, for we are the species that generally feels itself as unique and somehow apart from the rest of nature by this dubious quality of our intellect.
This presents a problem, in that if a definition, as extended by Le Gros Clark, is based strictly on a mental capacity, or what I call a state of being, there must exist some limit to what we call human. A problem because, there exist, many of our kind that may not exceed that level of discrimination for a variety of physiological reasons. To say that they should not be classed as 'humans' is almost unthinkable.
Then why do we try to define some thing as 'human'? The fact is our kind does exist, we are a species by definition, and we are searching for our origins for a number of reasons. We are asking the questions 'what happened to make us mankind?' 'when did we arise?', and 'how did we get here?'. In attempting to answer these questions, the objective has to be viewed as a pin-pointing of the beginning of the genus Homo. This leads to the definition of the various species of Homo, and the subsequent question of the origins of man, the Human Being. Is Homo sapiens , habilis, erectus, or some other species of animal the beginning of the human state of consciousness?
This approach also presents another problem identified by Johanson, in discussing the definition of species. The definition includes the characteristic of genetic isolation (not being able to produce fertile offspring). He goes on to say that species can be isolated both horizontally (physically, such as by geography, or behaviorally, such as by non-recognition of another as suitable partners), and vertically by way of time
Isolation in single populations is also achieved through time. Here the separation is not so much horizontal as vertical. We are concerned with descending lineages, and the changes that take place over many generations within groups, not between them. Homo erectus did not produce several types that now, a million years later, confront each other as biological strangers. Human beings the world over can and do interbreed today. What Homo Erectus did was sire descendants who might not recognize him as a sexual partner. It would be interesting to know if a modern man and a million-year old Homo Erectus woman could together produce a fertile child. The strong hunch is that they could; such evolution as has taken place is probably not the kind that would prevent a successful mating. But that does not flaw the validity of the species definition given above, because the two cannot mate. They are reproductively isolated by time. Therefore, somewhere along the evolutionary path that leads from one species to another a species line may be drawn if, in the opinion of the anatomists, the differences between them are significant. (1982:144)
If we subscribe to the theory of evolution, we must at some point between the first living cells of the Precambrian and creatures such as the one we called Albert Einstein, create species dividing lines, or at least grey fuzzy divisional areas, that allow distinction. Presently, anatomists use the concept of significant differences in skeletal structure to segregate species.
I feel that this method of distinction is limited in that the separations are too gross: too gross because from one day to the next, or one year to the next, we cannot say that a dividing line exists between individuals from the physiological perspective. If we consider Joahanson's statements above, vertical isolation can only be identified in large gaps of time, after which physiological changes have occurred.
I believe that physiological characteristics are a result of natural selection based on what behaviors animals exhibit, a view noted by Fedigan (1982:32). The chicken and egg question of environment vs. behavior does not logically exist for me. Life is obviously environment-based, but once initiated, life continues to actively survive only by constantly behaving in the environment. When an organism stops behaving, the biological machine eventually dies, either from starvation, or predation. The environment does not prod or prompt; it is stable, or it kills. Behavior in the individual allows an organism to live. My understanding can best be explained by the following paragraphs.
The evolution of large canines in baboons has been explained such that larger canines were advantageous to the species for survival reasons, and that 'largeness' was therefore selected. What has not been explained adequately is how that selection came about.
I see the selection of larger canines ultimately going back to the generalized dental structure of early primates, to a point where there was relatively no difference in size between canines and other teeth. Selection for larger canines began when the organism which was ancestor to the baboon took a behavior trait from its repertoire of eating behaviors and used as a method for defense (biting). It could be argued that the environmental pressure was not defense, but that it was a change in the food type which required larger canines. Since baboons do not have a diet that depends on use of large canines, I feel that this type of pressure was not important enough to cause the adaptive advantage necessary for selection in its ancestors.
On the other hand, if predation was an every day concern of the baboon ancestor (and other early primates also), then having a set of impressive canines (both in effect and visually), would lead to an advantage for survival, in both a defensive and social sense.
Once the behavior was put in use, the enlargement of canines would be fairly rapid, as long as predation was a factor in survival. At that point in time, and only then, could descendants exhibit subsequent behaviors which would allow for modifying defensive biting behaviors towards less destructive group behaviors such as threat displays, or behaviors which allow the opportunity to take advantage of different food sources, thus explaining the predominance of canines in various forms of primates.
In the case of baboons, I feel the subsequent use of canines as a inter-group display mechanism would play a strong part in male-male competitions, selecting for limited threat behavior rather than unlimited destruction of individuals through fights to the death. The effectiveness of the display would depend on the relative size of the teeth, and as such, bigger would be better. Thus canine growth would continue until limited by disadvantageous size of the jaw structures.
If we look at human canines, we find that they are not large at all, therefore indicating that the human lineage broke off from the baboon lineage prior to the use of canines as a defense strategy. Others may counter that the canines could have reduced in size due to the fact that they were not required by our lineage, but I find it difficult to find a environmental pressure that would require the exhibition of behaviors that would allow such a selection for smaller canines. I also feel the argument that the phenotype with more generalized dental structures was allowed to exist, and therefore lead to a reduction, to be questionable. What we would see in that case, is what we see in the case of the great apes; a stabilization of the dental structure at a level within the range of variability for canines which have previously been selected for size.
The key point in this canine size argument is that behavior had to be exhibited to allow the natural selection of physical characteristics.
To continue with the discussion of anatomical differences as a criteria for species differentiation, I feel that this method can only be used as proof that the lineage has indeed differentiated, and that the true differentiation happened in behavior much earlier to the significant change in skeletal structure. This means that the line or grey area of discrimination has to be drawn using something other than bones.
That line, or that area, I feel, lies in the ability of the genotype to process and communicate information from and about the environment, described by Fedigan (1982:32) quoting from Kropfer, calling the genotype an 'information-generating device'. In the present, many feel that the quality that separates the human animal from the rest of the animal kingdom, is that we as human beings, are the best at processing environmental data, deriving information and transmitting that information.
In summary then, I believe behavior, in response to the environment, to be the first act in the process of natural selection.
If we were to compare the present-day species of primates on an anatomical basis, we would find that the criteria for species distinction to be fairly clear. Each species is, in form, different and separated reproductively, either behaviorally or genetically.
If we make comparisons on the basis of behavior, we find that behaviorally, the primates differ, but not to the same extremes and definites noted in their physical comparisons. Using the results of these behavioral comparisons, we can derive a set of similarities which may be viewed as 'common' to all, or specific groups of primates.
These similarities, I suggest are the set of surviving qualities of the common ancestor stock from which all evolved. The differences would indicate the various branches along the evolutionary path from the common ancestor to the present day species.
In combination with the existing physiological comparison data such as immunological distance comparisons, we then could validate the age of certain behavior patterns. For example, a behavior pattern common between Chimpanzees, Gorillas, and Man would have existed prior to the split of the lineages making up the three species. A behavior common to the gorilla and chimpanzee, but unique to man would indicate a behavior that was exhibited and selected for in the case of man versus the environment during his unique evolutionary development.
What then can we segregate from primate behaviors as common, and what can we say is unique to each species? Comparisons of species behaviors at a general level indicate that primate species are pretty much the same as one another. In most cases, all care for the young, the young have relatively longer infant dependency periods than other mammals, play is a significant factor in development, and social learning is a major factor in the development of healthy individuals.
If we consider intellect as a criterion, we begin to realize that differences will be those of degree rather than kind.
From an intellectual point of view, Goodall (1976:47) has shown that Chimpanzees are tool users; using rocks as hammers to open palm nut kernels; sticks to extract honey from bees' nests; and using grass stems to fish for termites. Studies at Yerkes with the chimpanzee Sultan, have demonstrated that species' problem solving abilities, insight, and learning.
When we consider communication abilities, other than actual verbal speech, we are faced with the same variations in degree. The Gardners in 1979, demonstrated that Chimpanzee Washoe could be taught to communicate with American Sign Language. At Yerkes, chimpanzee Lana uses communicates via a computer keyboard.
Francine Patterson (1978) has trained Koko, a female Lowland Gorilla, to use American Sign Language. With the language, Koko expresses her emotions, refers to past, present, and future events, defines objects, and provides a name for her pet kitten (Vessels:1985). On the accidental death of her kitten, Koko cried, and later requested another kitten as a replacement (Garrett: 1985). These demonstrations indicate that in the area of communication, we are very close indeed.
In the area of culture, we begin to see a separation of man and the other primates. Again the difference is one of degree. As Fedigan (1982: 132) cites Jolly,
'A great deal of the behavior of primates can be called cultural in the sense that it is transmitted by learning from generation to generation. This is true not only of social behavior, but behavior towards the environment, as simple a thing as the home range of a group' (1972: 350).
Fedigan goes on to discuss the use of the terms 'proto-culture', 'pre-culture', and 'subculture' in reference to studies on Japanese monkeys as an example of transmission of behaviors between individuals of a group. Although it is still considered a controversial topic, I feel that there is, in fact, culture within the non-human primate societies. Behaviors are passed between individuals; chimpanzees learn termite fishing, Macaques learn food washing and separation, and monkeys and apes learn mothering behaviors. What differs is the amount and types of things passed from one generation to the next. Homo sapiens passes, besides behaviors, information. Information concerning values, histories, cosmologies etcetera.
In Homo sapiens, the human being, the range of behavioral responses is widely varied, most likely because of our evolutionary path we faced, the amount of information passed between generations, and the intellectual gyrations and judgments using that information to view and rationalize our behaviors.
Comparing the behaviors of monkeys and man, we see that social behaviors are similar, and although present, the range of mental abilities leave little question that there is a greater distance between them than between the great apes and man (Tiger,1971:152). In all aspects considered above, there are recognizable, definite differences of degree.
If we concentrate on the great apes and man, the differences, both physiologically, and behaviorally are not very far apart. Human beings (Homo Sapiens) differ in the range of behaviors and the variability of these behaviors. Our intellectual abilities indicate improved reasoning and problem solving abilities, we communicate in a verbal and more symbolic language, and our cultural variation is extremely wide.
To return now to the original questions, 'Where did it happen?' 'What happened?' and 'When did it happen?', I feel that the fork in the evolutionary path which lead to man should be placed prior to the branch which lead to the great apes, for the great apes have similar intellectual abilities, and yet their physical structure has been modified towards more specificity. For example, the length of the canines indicate that the dental structure has moved from the generalized pattern to a specialized pattern selected for, either defense or processing different food types. This indicates to me that the animal that became man did not face the same environmental pressures as his concurrent relatives. It continued in a generalized pattern on the model of the ape and man ancestor, refining the qualities of consciousness rather than modifying body shape.
The key point is that the ancestor to man and ape was an intellectual being of sorts prior to being physically recognized as Homo.
My argument is this: Should the great apes have an innate ability for such behaviors as cultural transmission, and especially communication, if these behaviors were not selected for prior to the separation of lineages? I think not. What happened in the case of the apes, is that they had no need to develop these qualities further. Their environment provided stable conditions not requiring extensive use of mental abilities as a method of immediate survival.
I believe that the above abilities are characteristics acquired sometime after the break of apes and man from the monkeys, for we see that the behavioral basis for these characteristics are evident to degrees in all of present primate species, but particularly well developed in apes and man.
But in the area of communication, I believe that what we are currently finding in the apes, is the common behavioral element that the animal that became modern day greater apes, and the same animal that became man exhibited in a time of need, as an adaptation to its environmental situation. It was this behavior (for information processing is a behavior) selected for in the animal, which lead to the physical changes allowing a group of those creatures to become man.
As in the case of canine development, once selected, and obviously advantageous, the rapidity of human development (a state of being) would have been phenomenal. That human development did not lead directly to implementation of new and elaborate technologies immediately, is not really an issue. As other primates have existed for ages in their niches, the human did also. There is no need to use technology if the environment does not require technology. Hence we cannot rely on the evidence of tools to indicate that the animal had become human. But when demanded the intellect of the animal could and would produce a tool, and eventually a complex technology.
This brings us to another question; if the ape/man ancestor had the potential for communication, what kind of environmental pressure would allow the selection of individuals with improved communication abilities? We must keep in mind that a portion of the other side of the family also survived - they are here today in the forms of the great apes. They survived without following a similar route, they did not need to adapt to the environmental pressure in a similar direction (Leakey, 1977:189).
Why was communication behavior so important that those who exhibited those propensities would isolate themselves to become a separate species?
Many would suggest the need for communication through hunting, brought about by the dwindling of forests and decreasing fruit and vegetable matter available for consumption. This, I find, is an inadequate solution, since baboons, for ever how long they have been on the savanna, have managed to eke out a living, including foraging and hunting. The !kung still do the same. Evidence from Goodall (1976) indicates that Chimpanzees also hunt, and that there appears to be cooperation in hunting, and yet the Chimpanzees have not required the need for an elaborate method of communication to accomplish these feats.
What we are searching for is the need for communication for the animal which would become man, and its reason for being. If other animals could survive without communication, then food, or acquisition of food, could not be the prime factor in creating an adaptive advantage.
Let us review the problem. The ancestor of ape and man had the mental potential to communicate since both ape and man have this ability in the present. The difference is that the ape is structurally different in the construction of the pharynx, and I therefore argue that both ape and man modified their vocal structures in differing directions after their separations from the common stock, and communication in man somehow was enhanced to its current state.
Let us look deeper into communication for a possible answer. What is the basis of communication? Communication is the transfer of ideas or messages from one being to another. Primates do not have a monopoly on non-verbal communication, all animals use some form, whether chemically in pheromones, calls, or body language. The uniqueness of primate communication, especially in the great apes, and man, is the message transmitted.
The messages, besides being mating calls, threats, or fear reactions, convey emotional content from the point of view of feelings between individuals (Goodal, 1971:235-239). This implies that an individual is aware of another individual and can realize that the awareness is reciprocal, and to some extent, empathetic. This type of awareness requires a strong identification of self, and the realization that the individual can have some effect on another. This awareness is evident in the alliance and coalition behaviors of many primates, and therefore that level of consciousness had to be in place prior to the split of man and ape from their ancestor. If so, what pressure caused that type of awareness?
I suggest that this is the result of an semi-arboreal animal shifting to a terrestrial environment. If we compare even among the apes, the Gibbon does not impress us intellectually, as much as the more terrestrial apes. They have taken advantage of their ecology and have remained a normal animal, doing normal animal behaviors (Fedigan 1982:262-265, Lee 1983, Tiger, 1971:74). The monkey even less. Of the monkeys, we find that those that spend a great deal of their time on the ground seem to be more socially organized and endowed with more intellectual abilities than those which spend their time in the trees, for example the Macaques (Sagan, 1977:126, Fedigan, 1982).
What moving to the ground has done is generate a feeling of insecurity because of a lack of innate abilities to handle the new environment, for example acentric behavior in patas monkeys (Morgan, 1973:195, Fedigan, 1982:242).
This insecurity, or fear, puts the individual in a state of consciousness which demands the awareness of self for survival. One must realize that one does exist, and that one's actions (behaviors) have a definite bearing on whether or not on survives from one instant to the next.
As I have defined consciousness earlier, I see it as the state of being aware of one's self in a manner that one understands that the environment can be influenced for the one's benefit. In this specific case the environment includes predators as a part of the environment which can be influenced.
The insecurity of a new environment, of not having innate and appropriate behaviors to deal with the encounters, lead to the creation of a self-consciousness essential for survival.
For the semi-arboreal moving to a terrestrial environment, the effects of food utilization, and more immediate, predation would have been almost disastrous. Almost, except that as in the example of canine development, the mental behavior of self awareness allowed the survival of an animal whose mental abilities would have been quickly refined. This I believe, is a quality of the ancestor of man and ape, a common quality carried down to the present species. It lead to the elaborate and diversified social behaviors of the semi- terrestrial and terrestrial primate that are reported today, and it implies that the greater apes did spend some period of their development in an unfamiliar environment.
It was this quality which was refined further through communication and culture in the animal that became man. According to Johanson (1982: 361-363), the period of dwindling forests began during the Miocene, approximately fifteen million years ago. With them, the dryopithecids also disappeared about eight or nine million years ago, 'perhaps already beginning to show the long-term dangers of an extreme 'K' reproductive strategy when faced with a less-than-ideal environment.' (1982: 363).
I suggest that the animal that became ape and man behaved differently than those who perished. He became self conscious, and aware, probably between eight and seven million years ago. To support this I can only offer an article I read in a dentists office (title and date 1984? forgotten) on immunological comparisons of great apes and man where an estimated branch off period for man and gorillas was set at seven million years ago. Since chimpanzees and gorillas have an ability to communicate through sign language, I feel this common trait with man was developed in this period, prior to the split of lineages.
We still have the problem of why communication was so important to the animal which became man. With the ability to be self conscious (the awareness that what one does, affects ones continued existence), and with the common primate behaviors of transmission of modifiable behaviors, the need for information would increase tremendously should the animal stay in the new environment. In contrast, the ancestors of the great apes returned to the forests and fringes, man's ancestors did not. They continued in comparatively open landscape refining the qualities which allowed survival.
Through 7 to 3 million years ago, with the concept of self established, the concept of objects other than self had 4 million years to develop. At this stage, Homo habilis was making stone tools; a technology had started, cultural transmission of behaviors was in progress. Whether or not he was our ancestor is not the point I want to make, but that somewhere in the 4 million year period, the need to transmit more than procedural behaviors such as stone tool making did arise. The animal(s) who increasingly gestured, or modified call and emotive behaviors to identify objects other than self would from that point on be primarily culturally selected rather than naturally selected. For when a mind realizes self through insecurity, it attempts to regain the security of the mother infant bond (Fedigan, 1982:126) by modifying these behaviors again into the behaviors of adult dyadic relationships.
These choices of relationship, I believe were first initiated through the mother infant bonds since mothering involves an awareness for an-other being (child). They would have been further refined via matrilineages, individual movement between groups , and group fissioning. Since female choice has been demonstrated and observed in monkeys and apes by several researchers (Fedigan 1982: 282-285), and these choices seem to be made for protective, care-taking, non aggressive, and idiosyncratic reasons, I find no problem in an aware female choosing males of similar disposition for their partners, thus allowing for the transmission of improved culture over time.
No longer would it be enough to have physical companionship, alliance or coalition. What the animal would want, would be a reassurance that the other felt as it did. It would choose idiosyncratically. It would need to send a message, and receive a reply; it would need to talk. It would select from the group, those animals who were best at sending messages, and discriminate against those that did not. It would behaviorally isolate itself relatively rapidly, becoming horizontally separate from the others. It and its kind would become a species by definition.
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1982, Primate Paradigms, Montreal: Eden Press.
Garrett, Wilbur E.
1985, April Editorial. National Geographic, 167 (4): 409
Goodall, Jane van Lawick
1976, In The Shadow Of Man, Glasgow: Wm. Collins & Sons.
Johanson, Donald, and Edey, Maitland
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Leakey, Richard, and Roger Lewin
1977 Origins, New York: E.P. Dutton.
Lee Phyllis C.
1983, Home Range, Territory, And Intergroup Encounters In Primate Social Relationships. Robert A. Hinde, ed. Sunderland: Sinauer Associates.
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