Darwin's co-discoverer of evolution, Alfred Wallace, was a firm believer in interventionism and he has yet to be proved wrong, that missing link between man and apes still eludes us. In fact in 1911 Sir Arthur Keep listed the anatomical characteristics peculiar to each primate species and gave the following results :
now this is a very large difference
OK so there is 98 % genetic similarity between humans and chimps so why should 2 % difference account for such vast anatomical disparity ? also note that mankind has only 46 chromosomes compared to the chimps and gorillas who have 48, natural selection cannot explain this.
Now lets look at the process of natural selection, gene mutation. Most mutations are not beneficial to a species only a very small percentage are considered beneficial and the chances that they will be able to spread through the generations are slim ( just because one animal mutates beneficially it does not mean that that animal will reproduce and or pass on it's new genes)
Natural selection is very very slow, large evolutionary jumps - macro mutations - are unlikely to be preserved since they would more than likely be detrimental to a species which has already adapted to it's environment. In fact most changes will fail to be implemented. Imagine a novel, most changes to the text will damage the original to some degree it would be exceedingly rare for a change to have a beneficial effect.
Another fact to consider is that beneficial mutations will tend to be diluted, so to gain a foothold requires small isolated populations, for example the Galapagos islands of visited by Darwin during his famous " Voyage of the Beagle"
So evolution within a species is slow, now evolution to another species is slower still- the long goodbye, generally thought to be caused by geographical separation
Now though speciation statistically very difficult to achieve there are some 30 million different species on earth and an estimated 3 billion may have existed and died out. However with the exception of viruses evolution is still an incredibly slow process, 100,000 years for the emergence of a new species would be considered as sudden, in fact large changes occur over periods of 10's of millions of years and macro changes over 100,s of millions of years
Now the strange thing is that mankind BENEFITED from SEVERAL MACRO MUTATIONS in the course of only 6 MILLION YEARS, something is not quite right here.
The general consensus of anthropological opinion is that the chimps and the humans split from a common ancestor about 5- 7 million years ago, with gorillas having made the long goodbye a bit earlier. For this to occur 3 groups of common ape ancestors had to become geographically separated and thence evolve independently
There are 3 possible contenders for the claim to being the first bipedal hominid :
1 Lucy, found in Africa (Australopithecus Afrensis ) she lived about 3.6 - 3.2 million years ago, she is only about a 40 % complete skeleton
2. Australopithecus Ramidus, about 4.4 million years old found in Ethiopia, a 70 % complete skeleton
3. Australopithecus Anamensis, from Kenya, about 4.1 - 3.9 million years old
None of these have been defiantly proven to be bipedal and confusingly none seem to be closely related to each other. There is a complete lack of fossil evidence for the preceding 10 million years so we cannot determine when these 3 separated into different species from the apes or whether there were earlier Australopithecus types.
Now lets move forward in time, about 2.5 million years ago we have Africanus, 1.8 million years ago we find Robustus and 1.5 million years ago we have Advanced Australopethicus, this species is more man like than the others so is known as near man or Homo Hablis ( handy man ). Homo Habilis were the first truly man like beings that walked upright and used stone tools ( as far as the evidence we have shows)
Around 1.5 million years ago Homo Erectus appears, with a much larger brain size he designed more sophisticated tools. it seems that Homo Erectus left Africa and spread to China, Australasia and Europe about 1 million to 700,000 years ago
It seems likely that modern Homo Sapiens is directly descended from Homo Erectus..
During the past decade, eight new early hominin species have been discovered, making it one of the most fruitful periods in paleoanthropology ever. Most of them are
older than Australopithecus afarensis, and several come from outside of East Africa. They are Ardipithecus ramidus(Ethiopia, 4.5 million years), Australopithecus anamensis (Kenya, 4.2 to
3.9 million years), Australopithecus bahrelghazali (Chad, 3 to 3.5 million years; see figure 19.7), Australopithecus garhi (Ethiopia, 2.5 million years), Orrorin tugenensis(Kenya, 6 mil-
lion years), Kenyanthropus platyops(Kenya, 3.5 million years), the specimen mentioned at the opening of this unit, Sahelanthropus tchadensis (Chad, 6 to 7 million years), and lastly, announced in March 2004, Ardipithecus Kadabba, represented mainly by teeth, and suggested as an ancestor of A. ramidus (Ethiopia, 5.5 to 5.8 million years). Clearly, a good deal of rethinking is needed about where the hominin clade arose, and the shape of the evolutionary tree.
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EDIt Continued..so Salhelanthropus Tchadensis has pushed the line back to around 6-7 million years, some 2 million yeras or so from what i had earlier stated
The cranium is rather apelike, especially the prominent brow ridges, while the face
is much more humanlike, being quite flat, unlike in australo-pithecines. The position of the foramen magnum convinced Brunet that the species was bipedal
The Stangeness of Man
So why are we so different from the apes ? why have we developed at such an extraordinary rate whilst our ape cousins have remained virtually unchanged over 6 million years ?
The general opinion is that we evolved more quickly because we stood upright, thus releasing our arms to begin tool making and by a feedback mechanism our intelligence was stimulated to develop. Scientific experimentation seems to agree with this, increased stimulation leads to increased complexity of the neural pathways in the brain. But what of the kangaroo and otter, both extremely dexterous and could have used advanced tools, but never did; and there are many examples of animals that use tools but have never developed beyond rudimentary intelligence..
The advantage of an upright posture is linked to the migration to open savanna and the brain cooling effect of raising the head from the ground, however many other animals live on open savanna and are not bipedal.
Bipedalsism would in fact have been an initial disadvantage, making early hominids easier prey for animals such as lions
Does size really matter ?
An increased brain size does not necessarily mean increased intelligence, compare an elephants 11 LB brain to our 3 LB brain. improvements come through better "wiring" not larger size.. Improvements of the brain should, evolutionarily, have occurred over large numbers of relatively small steps, with natural selection driving changes in size and efficiency
Now remember that we have very little fossil evidence to go on and brain matter does not fossilize so we have to rely on skull cranium size for our figures.. Lets look at some cranial sizes :
Afrensis 500 cc
Habilis/Australopethecus 700 cc
Then as we move forward to 1.5 million years ago we have a sudden leap with Homo Erectus having a cranial capacity of 900 - 1000 cc, if we assume that this increase in size was accompanied by an increase in intelligence ( see my caveat on elephant brain size ), then what we have is a highly unlikely macro mutation. Unless of course Erectus is a totally separate species who's ancestors have not been found - quite possible.
Then after 1.2 to 1.3 million years with no major changes Erectus has spread out to China, Australasia and Europe and then, kapam !! Homo Sapiens appears with a cranial capacity of 950 cc - 1450 cc.. If as most anthropologists suggest we are the descendant of Homo Erectus then something remarkable occurred at the change over point.
So what we have is about 200,000 years ago an explosive evolutionary change from Homo Erectus to Homo Sapiens, Here is where we should be searching for a missing link, a Super Erectus, perhaps the Biblical nephillum ? "and the sons of gods saw the daughters of men and took them for their wives"
Cro-Magnon and Neanderthal
It had been generally believed that early Homo Sapiens ( Cro- Magnon man) appeared only 35,000 years ago and descended from Neanderthal who died out at the same time, however it is now known that European Cro-Magnon's are anatomically no different from the Homo Sapiens found in the middle east dating to 100,000 years ago.
Homo Sapiens did not descend from Neanderthal, evidence from Israel shows they coexisted 100,000 - 90,000 years ago, another fascinating discovery in Israel show that about 60,000 year old Neanderthal's possessed a hyoid bone very similar to our, the hyoid bone in the defining bone for speech capability, though their upper anatomy would have limited their range of sounds, they none the less were at least capable of speech, and speech is one of the prerequisites for advancement in civilization.
So we now regard Neanderthal as a fully fledged Homo Sapiens , though still different from us who anthropologists now suitably term Homo Sapiens Sapiens !!!. in fact modern opinion is that we both evolved from a common pre Homo Sapiens.
Some time during the last 1 million years there was a major, though very brief transition from archaic, pre Homo sapiens to modern Homo sapiens. This resulted in the reorganization of the brain and the anatomy as well as the development of a culture with it's attendant reliance on advanced tool making. We also see the emergence of art and symbolism as well as language
But when did this change occur ? unfortunately radio carbon dating is just not up to the task of pinpointing a specific era. using a range of more reliable techniques we have been able to guestimate the earliest know appearance of this archaic Homo Sapiens to about 120 - 110,000 years ago, these remains were found in Israel
Not impossible, but highly improbable
After millions of years of relatively little progress with stone tools Homo sapiens suddenly leaps onto the stage about 200,000 years ago, with a 50 % larger brain capacity, advanced anatomy and the capability of speech. Then for some reason he lives quietly for another say 160,000 years tinkering with stone tools until about 40,000 years ago some spark triggers something within him. He expands northwards at a rapid rate encompassing much of the globe by 13,000 years ago. 1000 years later he discovers agriculture, 6000 years later and he has created great civilizations and has acquired advanced astronomical knowledge, and now 6000 years later he is looking to journey to those stars.
The rate of evolutionary and cultural change simply does not fit in with the natural selection process, it should have taken us 100's of million of years, perhaps 1000's of millions of years to get where we are to day
No..something just is not right here !!