Sadaputa Dasa
IN A 1987 ARTICLE in the prestigious journal Nature, three biochemists published a study of mitochondrial DNA's from 147 people living on five continents. The biochemists stated, "All these mitochondrial DNA's stem from one woman who is postulated to have lived about 200,000 years ago, probably in Africa." (Rebecca Cann, Mark Stoneking, and Allen Wilson, "Mitochondial DNA and Human Evolution," Nature, Vol. 325, January 1, 1987.)
The story became a sensation. The woman was called the African Eve, and Newsweek put her on its cover. There she was the single ancestor of all living human beings.
Eve was one in a population of primitive human beings. But all human lineages not deriving from her have perished. For students of human evolution, one important implication of this finding was that Asian populations of Homo erectus, including the famous Peking ape men, must not have been among our ancestors. Those ape men couldn't have descended from Eve, it was thought, because they lived in Asia before 200,000 years ago.
Mitochondrial DNA (mtDNA) carries genetic instructions for the energy-making factories of human cells. Unlike other genetic material, it is transmitted to offspring only from the mother, with no contribution from the father. This means that the descent of mtDNA makes a simple branching tree that is easy to study.
Computer studies on the sample of 147 people (who represent the world population) show that the original ancestral trunk divided into two branches. Only Africans descended from one branch. The rest of the population, as well as some Africans, descended from the other. The inference was that the stem was African. In 1991 another analysis of exact mtDNA sequences from 189 people confirmed this and indicated that Eve was roughly our ten-thousandth great-grandmother.
The Fall of Eve
Unfortunately, however, Eve quickly fell down. In 1992 the geneticist Alan Templeton of Washington University stated in the journal Science, "The inference that the tree of humankind is rooted in Africa is not supported by the data." (Sharon Begley, "Eve Takes Another Fall," Newsweek, 3/1/92.) It seems that the African Eve theory evolved from errors in computer analysis.
The ancestral trees had been drawn from mtDNA sequences through what is called the principle of parsimony. The figure below gives a rough idea of how this was done. To create the figure, I used sequences of four letters to stand for the genetic information in mtDNA. In (1) I started with abcd as the original ancestor, and by making single changes, or mutations, I produced descendants avcd and abud. Then from avcd I got two more descendants, avcn and rvcd, again by single mutations.
Let's suppose we are given the sequences avcn, rvcd, and abud and we are asked to deduce their ancestry. How would we go about this? The method used by the scientists studying mtDNA was to say that ancestors and descendants should be as similar as possible. One way to measure how similar they are is to count the number of mutations from ancestor to descendant in the tree of descent. A tree with few mutations shows high similarity, so it is a good candidate for the real ancestral tree. Such a tree is said to be parsimonious.
For example, tree (1) has four mutations, and tree (3) has eight. Scientists would argue that (1) is therefore more likely to resemble the real ancestral tree. This seems promising, since in this case tree (1) is in fact the real tree. But tree (2) requires five mutations, and so it is nearly as parsimonious. Yet (2) shows a completely different pattern of ancestors.
The problem with the parsimonious tree method is that in a complex case there are literally millions of trees that are equally parsimonious. Searching through them all on a main-frame computer can take months. According to Templeton, the original findings on African Eve came from computer runs that missed important trees. When further runs were made, a tree with African roots turned out no more likely than one with European or Asian roots.
The parsimonious tree method rests on the idea that similar organisms should share close common ancestors, and less similar organisms more distant ones. This idea is the central motivating concept behind the theory of evolution. Since the span of recorded human history is too short to show evolutionary changes that mean very much, evolutionists are forced to reconstruct the history of living species by comparing likenesses and differences in living and fossil organisms.
For example, man and ape are said to share a close common ancestor because man and ape are very similar. In the late nineteenth century there was a famous debate between the anatomists Thomas Huxley and Richard Owen over whether or not human beings were cousins of apes. Owen maintained that they weren't, because a feature of the human brain, the hippocampus major, was not found in the brains of apes. But Huxley won the debate by showing that apes really do have a hippocampus major. Before triumphantly presenting his evidence for this to the British Association of Science, Huxley had written to his wife, "By next Friday evening they will all be convinced that they are monkeys." (Wendt, 1972, p. 71.)
Why Man and Ape Are Similar
Of course, man and ape really are similar. So if they don't descend from a close common ancestor, how can one account for this? Biblical creationists propose that God created man and ape separately by divine decree. To many scientists this story seems unsatisfactory. The geneticist Francisco Ayala indicated why in a discussion of the close likenesses between human beings and chimpanzees. He remarked, "These creationists are implying God is a cheat, making things look identical when they are not. I consider that to be blasphemous." (Joel Davis, "Blow to Creation Myth," Omni, August, 1980.) In other words, why would God fake a record of apparent historical change?
To illustrate the idea behind Ayala's comment, consider the legs of mammals. In all known land mammals the leg bones are homologous, or similar in form. Thus all mammals have a recognizable thigh bone, shin bone, and so on. Now imagine that genetic engineering becomes highly perfected. A genetic engineer might want to create an animal with legs suitable for a particular environment. But would he do this by simply modifying the shapes of the standard mammalian leg bones to make another typical mammalian leg? Why not create a whole new set of bones suit-able for the task at hand? And if human engineers might do this, why not God? The answer that God's will is inscrutable doesn't sit well with many scientists.
It is certainly not possible to second guess the will of God. But the Vedic literature offers an account of the origin of species that explains the patterns of similarity among living organisms. According to the Srimad-Bhagavatam, living beings have descended, with modification, from an original created being. All species, therefore, are linked by a family tree of ancestors and descendants. Forms sharing similar features inherit those features from ancestral forms that had them. So the theory given in theBhagavatam accounts for the likenesses and differences between species in a way comparable to that of the theory of evolution.
But these two theories are not the same. The neo-Darwinian theory of evolution says that species descended from primitive one-celled organisms and gradually developed into forms more and more complex. In contrast, the Bhagavatam says that Brahma, the original created being, is superhuman. Brahma generated beings called prajapatis, who are inferior to him. These in turn produced generations of lesser beings, culminating in plants, animals, and human beings as we know them. From theprajapatis on down, these successive generations generally came into being by sexual reproduction.
The theory of evolution says that species have emerged by mutation and natural selection, with no intelligent guidance. But the Bhagavatam maintains that the entire process of generating species is planned in detail by God.
Intelligent Designer
This point brings us back to the question why species should be linked by patterns of homology.
Several points can be made. The first is that a genetic engineer designing one special-purpose mammal might find it convenient to introduce one special design. But if he wanted to create an entire ecosystem of interacting organisms, he might want to do it with a general scheme in which he could produce different types of organisms by modifying standard plans. So a standard mammalian plan could be used as the starting point for producing various mammals, and similar plans could be used for birds, fish, and so on. It would be most efficient to organize these plans into a parsimonious tree to make short the design work needed.
This idea can overcome one of the drawbacks of the theory of evolution. Many living organisms have complex structures that evolutionists have a hard time accounting for by mutations and natural selection. Observed intermediate forms linking organisms that have these structures to those that don't are notoriously lacking. Evolutionists have often found it hard to imagine convincing possibilities for what these intermediate forms might be. But the structures are easy to account for if we posit an intelligent designer.
To illustrate this point, consider the problem of writing computer programs. A programmer will often write a new program by taking an old one and modifying it. After doing this for a while, he winds up producing a family tree of programs. But the changes required to go from one program to the next are often extensive. They're not the kind you'd be likely to get by randomly zapping the first program with mutations and waiting to get a new program that operates in the required way.
The point could be made, however, that a finite human engineer may need efficient design methods but God is unlimited and doesn't need them. Why then should He use them? We can't second guess God, but a possible answer is waiting for us to consider in the Bhagavatam (2.1.36). There Krsna, the Supreme Personality of Godhead, is celebrated as the topmost artist:
Varieties of birds are indications of His masterful artistic sense. Manu, the father of mankind, is the emblem of His standard intelligence, and humanity is His residence. The celestial species of human beings, like the Gandharvas, Vidyadharas, Caranas, and Apsaras, all represent His musical rhythm, and the demoniac soldiers are representations of His wonderful prowess.
Orderly patterns of design are also natural in artistic works. Just as Bach dexterously combines and modifies different themes in his fugues, so the Supreme Artist may orchestrate the world of life in a way that shows order, parsimony, and luxuriant novelty of form. The patterns of parsimonious change follow naturally from the procreation of species. The novelty flows from Krsna's creative intelligence and cannot be accounted for by neo-Darwinian theory.
Subtle Energies
This brings us to our last point. The life forms descending from Brahma include many species unknown to us. The higher species, beginning with Brahma himself, have bodies made mostly of subtle types of energy distinct from the energies studied in modern physics. Manu, the Gandharvas, and the Vidyadharas are examples of such beings.
We may speak of the energies studied by modern physics as gross matter. The bodies of ordinary human beings, animals, and plants are all made of this type of matter. If they have descended from beings with bodies made of subtle energy, then there must be a process of transformation whereby gross forms are generated from subtle. Such a process, the Bhagavatam says, does in fact exist.
So the Bhagavatam's explanation of the origin of species makes the following two predictions: (1) There should exist subtly embodied beings that include the precursors of grossly embodied organisms, and (2) there should be a process of generating gross form from subtle form. It would be interesting to see if there is any empirical evidence that might corroborate these predictions.
Sadaputa Dasa (Richard L. Thompson) earned his Ph.D. in mathematics from Cornell University. He is the author of several books, of which the most recent is Vedic Cosmography and Astronomy.