Saturday, 20 June 2009

Human Evolution on Trial - Into Australia

Human Evolution on Trial - Into Australia

The Australian Aborigines’ long isolation at a remote point of the human star provides useful evidence supporting the wave theory of Human Evolution. Their isolation from developments in other parts of the world meant they preserved elements of a very ancient stone technology when Europeans first reached there. This primitive technology in no way indicates they were, or are, any less intelligent or able than any others of us are. They are quite capable of becoming lawyers, economists or accountants. Both the technology and the culture people possess are simply accidents of history. Many technological and cultural innovations in other parts of the world simply failed to reach that continent although there is evidence some technologies originally taken into Australia were actually lost there. The jury will continue to see many more examples of change failing to reach marginal areas.

he map of the world based on the first principal component of genetic variation (therefore accounting for the greatest proportion of genetic variation among all humans) shows one extreme is widespread. It includes all of Africa and most of Europe, Arabia and Turkey. The opposite extreme is confined to the pre-European Australians (Cavalli-Sforza et al 1994). This presumably indicates many genetic changes in the rest of the world also failed to reach Australia. Interestingly the map shows Asians and American Indians could be a sort of hybrid between Australian Aborigines and the western people (map 16).

The Dreamtime

As far as I’m aware there is no certain evidence humans were in Australia as long ago as 50,000 years but dates of 30,000 to 40,000 are generally accepted. Although there is no direct evidence humans were involved in the extinction of the large animals in Australia the timing of “Extinctions” [What Have We Done?] indicates humans were present by at least 50,000 years ago. Where the archaeological evidence and the extinction evidence don’t quite agree go with the extinctions. The earliest human remains found in Australia are of what has been described as “anatomically modern man” although in many ways it could be called “ultra-modern”. This population is known as Mungo Man as the remains were found near what is today a dried up Lake Mungo. Remains of similar-looking people have been found at other sites in Australia. Alan Thorne claims to have dated one Mungo Man skeleton (although many people believe it is actually a woman) at 60,000 years (Adcock et al 2001). This date is irrelevant for the main claims about the particular skeleton (“MtEve” [Mungo Man]) and there is no obvious reason why the skeleton’s date must be wrong although it is disputed. The particular Mungo Man didn’t belong to the mtEve line, although closer to that line than to Neanderthal lines. It parted from the mtEve line about 250,000 years ago.

There has been debate about the actual pattern of migration both into and within Australia. Most people interpret the evidence within Australia as showing an expansion round the coast and up the rivers. You will soon see humans had to cross open water to even get there and so this makes sense. The argument then becomes how quickly did humans move into the continent’s interior? D. R. Woodward has suggested, quite reasonably I think, that the early immigrants were confined to watered areas (quoted in Mellars 1990). The reasoning is that they lacked containers for carrying water. Australia actually became much wetter 50,000 years ago than it is today and so access to the large grazing animals of the interior could have happened by then. The animals rapidly became extinct.

All modern Australian Aborigine mitochondrial DNA lines descend from mtEve. But whether modern humans or Homo sapiens reached Southeast Asia (and then Australia) via either India (a sub-point of the human star) or via China is not known, certainly not by me.

One theory offered is that modern humans with a coastal economy they had developed in Africa expanded through Arabia and then into Southeast Asia either along the coast of India or via the Indus and Ganges Rivers (Olson 2002). But the defence mentioned several times in Part IV that most elements of the ancient Acheulean and Levallois techniques didn’t make it to Southeast Asia. This shows there has always been a great deal of separation between east and west, the Movius line mentioned in “Technology” [Lower Palaeolithic]. But Y-chromosome line K almost certainly, and mtDNA line M possibly, arrived in Southeast Asia through India (see “MtEve” [Interpretation]). You will see that they are probably part of a later movement into Australia though. Apart from this there is really no evidence for the theory although again it could be argued absence of evidence is not evidence of absence, the theory of negativity. There are actually many difficulties with the theory though. The coast is a narrow ecological zone and any rapidly moving group of human migrants would probably suffer inbreeding depression within the required number of generations. And, of course, if they had actually already invented primitive boats they could have expanded through any well-watered regions.

If we accept the idea migration routes tend to be used many times we could assume modern humans are more likely to have moved through Central Asia, the middle of the human star, and then to Southeast Asia. If they carried a water-centred culture they may have followed rivers, marshes and lakes during wetter climate conditions.

And of course the coastal culture found in Africa may be the result of an expansion of technology back from Southeast Asia or New Guinea (“Out of Africa” [Asia]). It would make sense that open water travel evolved in a region where any people who possessed it had a selective advantage. It would be easier to develop the technology with practice over short distances. A region with many small, closely packed islands would be perfect.

Wallace’s Line

At times of low sea level much of Southeast Asia becomes one continuous continent or at least a series of more, larger and closer islands. It doesn’t take much of a fall in sea level to connect Australia to New Guinea across the Arafura Sea either. But there is a gap between Australia / New Guinea and Southeast Asia that has always been open water. It is called Wallace’s Line, named after the wildlife collector Alfred Wallace. His correspondence from the region pushed Charles Darwin into publishing his great book “On the Origin of Species by Means of Natural Selection”. Wallace noticed creatures to the east and west of the line are very different. In fact most land creatures have been unable to cross Wallace’s line. It even separates the marsupials from the placental mammals.

Whichever route they took to Southeast Asia the earliest ancestors of the Australian Aborigines, Papuans and Melanesians must next have somehow crossed Wallace’s Line. Presumably they crossed some time between the onset of low sea level starting about 75,000 years ago and the presumed slight rise of sea level about 50,000 years ago (“Neanderthals et al” [Climate]). The first Australians must therefore have arrived on some sort of boat, but certainly not on a luxury yacht. Bundles of reeds, bark or bamboo tied together, or simply logs, would be sufficient. A drier climate following the big freeze about 75,000 years ago may have provided more open conditions on land as well.

It is not known whether the first arrivals in Australia and New Guinea crossed Wallace’s line via Southern Indonesia (southerly route) or through Palawan and the Philippines (northerly route). But the evidence indicates that the first Australians were similar to the populations in China, Borneo and the Philippines at the time (Alan Thorne quoted in Stringer and Mckie 1996). They certainly don’t exhibit any characteristics of the most common Southeast Asian type of that time who appear to retain older Homo erectus features. These are the “Solo Man” from Java who the jury met in “Species or Not” [Expansion]. Therefore the first people Into Australia probably came by the northerly route. They would have used much the same migration route as did the much more recent Austronesian-speaking people or ancestral Polynesians (map 6). But the movement under discussion here was at a time of much lower sea level.

Whichever way they came the distance across water was less but still substantial. Japan, Taiwan and possibly some of the Ryukyu Islands were almost certainly then connected to the mainland and the shoreline of the expanded islands of the Philippines and Indonesia were closer to the mainland coast than they are today. Early versions of a common Australian Y-chromosome, C, are found throughout the region (“MtEve” [The Trees]).

Kow Swamp

In Australia fossils of a different population to Mungo Man have been found at Cohuna, Talgai and Kow Swamp. They have been dated much more recently than Mungo Man to around 15,000 to 20,000 years ago and do exhibit some characteristics found in late Homo erectus populations in Java (Jennings 1979). Even Chris Stringer and Robin McKie (1996) concede one Kow Swamp fossil “does have a skull form reminiscent of some Javanese fossils”. Some Kow Swamp characteristics are also present in some modern Australian Aborigines (Milford Wolpoff and Alan Thorne quoted in Curtis, Swisher and Lewin 2001). Many people claim that modern Australian Aborigines are a hybrid of the Mungo Man and Kow Swamp populations with neither extreme now present in the stabilised hybrid (Flood 1988). Others have suggested the two extremes actually developed within Australia (Stringer and Gamble 1993) but it is difficult to conceive of any mechanism for an original diversification and subsequent recombining in such a relatively small continent. It is much more likely to result from two separate migrations.

It is also difficult to explain the similarities between the Kow Swamp people and Asian Homo erectus by parallel evolution. Single origin supporters have argued the Australian Kow Swamp people look as much like early Africans as they do Solo Man from Southeast Asia (Stringer and McKie 1996). This is precisely what we would expect in a stabilised hybrid population. It also introduces the problem of why was the earlier Mungo population so different? Mitochondrial DNA evidence from the Kow Swamp fossils shows that they did belong to the mtEve line but the wave theory of evolution tells us their physical appearance could have been due to the survival of older nuclear DNA (and see Adcock et al 2001).

That fossil and mtDNA evidence implies a mix of Homo erectus and Homo sapiens features in the human star’s Australian point suggests very strongly that these species too could form hybrids. They had only been separated for up to one and a half million years. Actually that is probably long enough in some cases to form separate species but genes of Homo heidelbergensis had presumably earlier flowed south from the East Asian point into Southeast Asia, the ancient Australian point. It is also probable that once again, combined technologies had led to a population explosion and the boundaries became porous (“Species or Not” [Both of Them]). Ground-edged stone tools were introduced to Northern Australia about the time of the Kow Swamp fossils. If these people were responsible for this introduction it would destroy the idea that Homo erectus had only primitive technology and was stupid and Homo sapiens possessed advanced technology and were cleverer.

This Kow Swamp or Solo Man population’s arrival in Australia can be explained by their acquiring elements of the boating technology off the people who had come from further north in Asia. They improved the technology and then in turn moved across Wallace’s line. They also probably moved the other way. By 10,000 years ago the hybrid people in Southeast Asia had developed into the people we met in “Pacific Population” [Hoabinhian]. You saw there that map 5 provides evidence for an expansion at some time from Southeast Asia. The Y-chromosome and mtDNA evidence suggests the same thing (“MtEve” [Interpretation]). This would have given rise to similar looking people right from India to the Northern Solomon Islands and Australia. More recently rising sea level at the end of the ice age isolated populations in Island Southeast Asia and led to human extinction in many places. This opened the way for the Austronesian people’s expansion once they had further developed their boating technology. Another example of a migration route once used being used several times.

Indo-Pacific and Pama-Nyungan

Language relationships within Australia and New Guinea provides further evidence that the progressive improvements in technology that allowed the gradual human expansion into the Pacific (see Part II) was simply a continuation of earlier patterns in the region.

Australian languages are usually divided into two distinct families: “Pama-Nyungan”, widespread in Australia, and, demonstrating amazing flair and originality, “Non-Pama-Nyungan” confined just to the continent’s northwest. They each show a huge level of diversity, presumably indicating a long period of diversification. This division into two language families almost certainly indicates two separate migrations although Josephine Flood (1988) says the two language families probably derive from a single ancestral language. The name Pama-Nyungan is a combination of the words for “one man” from the northeastern and southwestern ends of Australia and for many reasons it is presumed to be the earlier language family in Australia. The Non-Pama-Nyungan languages were introduced more recently.

On the other hand New Guinea had more prehistoric contact with the outside world (Howe 1984). It has a huge number of languages in at least three separate families.

I mentioned in “Pacific Population” [Mixing] that one branch of the Austric language family, Austronesian, was introduced to several coastal regions of New Guinea. Is it possible that some of the other, older languages are related to one or both Australian families?

Most languages of New Guinea are classified into one large sub-family: the “Trans New Guinea Phylum”. This is classified as part of the “Indo-Pacific family”. As I said in “Polynesian Origins” [Language Families] the languages of the Andaman Islands and the extinct Tasmanian language also belong to this family. All the non-Austronesian languages found in Melanesia beyond New Guinea also belong to the Indo-Pacific group (Howe 1984). This tends to further support the idea their boating ability was superior to that of the earlier migrants. They were able to reach further into the islands. We can presume this improved boating technology was also carried north and west back into Asia (and possibly as far as Central America? And what about Africa?). It is my guess the Indo-Pacific languages were widely spoken through Southern China and Southeast Asia before being replaced from about 10,000 years ago by the Austric language expansion (“Polynesian Origins” [Taiwan]).

Cavalli-Sforza et al (1994) suggests there may be some ancient relationship between these Indo-Pacific languages of New Guinea / Melanesia and the Non-Pama-Nyungan languages found in Northwestern Australia. This makes sense to me.

Around 35,000 to 25,000 years ago there was a decline of rainforest and an expansion of scrub steppe in Australia. This may have been due to climate deterioration but seems to be a greater decline than in similar previous events. It may be related to the final extinction of the large herbivores and a further increase in fires (“Extinctions” [How did we do it?]). And humans seem to have first reached New Britain, New Ireland and the Northern Solomon Islands (Western Melanesia) about 30,000 years ago.

That the Indo-Pacific languages of the Trans New Guinea Phylum arrived in New Guinea via the Sahul Shelf is supported by the fact they tend to be found to the south of the central mountain chain. They are present north of the mountains where it has been relatively easy to cross through mountain passes. I suspect the Indo-Pacific languages have largely replaced a third New Guinea language family, the “Sepik-Ramu group”.

Cavalli-Sforza (1994) goes on to suggest this Sepik-Ramu group, confined to the island’s extreme northeast, may represent remnants from an even earlier language. The original population that had passed through New Guinea on their way to Australia probably spoke this language. If we accept this possibility the Sepik-Ramu group would have a connection with the ancient Pama-Nyungan languages of Australia.


This, then, is the defence’s explanation for the above evidence:

The ancestors of the first Australians moved down the eastern coastal regions of Asia from the north. Their technology already included some basic boating ability which allowed the proto-Pama-Nyungan / Sepik-Ramu people to be the first onto the closer islands. They reached New Guinea and Australia some time between about 70,000 and 50,000 years ago. They probably carried Y-chromosome line C and mtDNA line N and her descendant R’s daughter line P. The fossils found at Lake Mungo represent this physical type.

About 30,000 years ago Indo-Pacific, or Non-Pama-Nyungan-speaking, people were able to expand from further south into islands in the area today covered by the Arafura Sea (Sahul Shelf). People in the region had improved the boating technology the earlier immigrants had brought in. Their economy had become primarily coastal, swamp, lake and river. They carried mtDNA lines M and Q and Y-chromosome line K. The Kow Swamp fossils represent this type.

The defence suggests the two migrations into Australia / New Guinea were actually simply separated by the slight rise in sea level that occurred between about 50,000 and 30,000 years ago. The second movement from Southeast Asia must in turn have been completed before the recent rise in sea level that started about 10,000 years ago. My feeling is that there was intermittent migration from 30,000 years ago.

Map 17 shows the order of movements into Australia and New Guinea. It is based on both the third principal component of genetic distribution in Australia and the second principal component for New Guinea (Cavalli-Sforza et al 1994). The shaded area represents the genetic pattern derived from these two maps. This construction may be evidence for a second migration into Australia and New Guinea that arrived in the region of the Arafura Sea at a time of low sea level. During ice ages the Arafura Sea would have been dry land, or at least a series of islands and during wet periods many large lakes, ideal for boating, form through Central Australia. The second principal component for Australia (not shown here) reinforces the idea of a genetic movement into the Northwest of Australia.

Cavalli-Sforza’s maps don’t provide any genetic information for the Melanesian islands and so they are not shaded but I suspect they should be. Tasmania is not included in the pattern either. The pre-European population is extinct but they were considered to be more Melanesian looking than are the people from mainland Australia. For example they had tight, curly hair rather than long, wavy hair. This difference is easily explained by the interpretation of the evidence offered here.

More Evidence

The central genetic area of Australia in map 17 also coincides reasonably well with the distribution of stone points (including pirri points). (*see also) Their distribution probably shows there is an established route of movement down through the centre of Australia during moister periods. The pirri points were introduced about 5000 years ago (Flood 1988) and indicate a technological spread rather than genetic. Their introduction is probably related to the spread of people south from Taiwan and the dingo’s introduction mentioned in “Pacific Population” [Mixing].

At the same time Austronesian languages were introduced to many Melanesian islands (“Polynesian Origins” [Language Families]). But genetic evidence cannot distinguish groups speaking the two language families. In spite of the very different languages gene flow has obliterated any original genetic difference. All this is further evidence in support of the wave theory of our evolution.

In “Pacific Population” [Mixing] the defence showed how the Polynesians were basically a hybrid of populations from the two eastern points of the human star. The jury has now seen that people in the Australian point were in turn the product of a complex mixture of human migrations. By now we have even been able to trace many of these migrations right back to and even beyond our origin as a species and we are but a short step from history. We will soon be able to use the wave theory to help us understand the beginning of that history, especially the connections and contradictions between what the Old Testament of the Bible and what the wave theory tells us. And as we now follow European history from the Upper Palaeolithic until today the jury will see that the processes that led to our evolution from Australopithecus to Homo erectus continue. But before we sneak back and have a look at the origin of the northern part of the mix we need to understand the evolution of culture.

See next :: 'Culture'

Witnesses Called

Adcock et al (2001) Mitochondrial DNA Sequences in Ancient Australians. Proc. Natl. Acad. Sci. Vol. 98 pp. 537-542.

Cavalli-Sforza, Luigi Luca, Menozzi, Paolo and Piazzi, Alberto (1994) The History and Geography of Human Genes. Princeton University Press, New Jersey.

Curtis, Garniss, Swisher, Carl and Lewin, Roger (2001) Java Man. Little, Brown and Company, London.

Flood, Josephine (1988) Archaeology of the Dreamtime. Collins, Australia.

Howe, K. R. (1984) Where the Waves Fall. George Allen and Unwin, Australia.

Jennings, Jesse D. (1979) The Prehistory of Polynesia. Australian National University

Press, Canberra.

Mellars, Paul ed. (1990) The Emergence of Modern Humans. Edinburgh University

Press, Great Britain.

Olson, Steve (2002) Mapping Human History. Houghton Mifflin Company, New York.

Stringer, Christopher and Gamble, Clive (1993) In Search of the Neanderthals. Thames

and Hudson, Great Britain.

Stringer, Christopher and McKie, Robin (1996) African Exodus. Random House, UK.

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