Recent debates on legitimacy and accuracy of biblical texts has led to parallel discourses on the status of religion in the light of modern scientific knowledge. One of the hotly debated issues is that of the theory of evolution. Observations by this author indicate a general lack of knowledge on this topic particularly by opponents of it, resulting in distorted caricatures of the theory as they attempt to bring it into question. The objective of this article is to provide an overview of some of the fundamental tenets of the theory of evolution, what is posits, some of the evidence that supports it, and current research.
It should be noted however that this author is not a trained evolutionary biologist and is not attempting to present himself as one. Also this article should not be considered as a comprehensive or exhaustive presentation, but rather a general overview from a “layman’s’ perspective.
The study of evolutionary biology can be traced back to Victorian England and the study of fossils, which at the time was a big and fashionable pursuit and hobby of the educated classes. With time it appeared that the fossil evidence was pointing to an explanation of the diversity of life forms on earth in that various species present changed over time. The mechanism and specific processes causing this was unknown because in the Victorian era microscopes, DNA, and even electricity were yet to be discovered or invented. Two British biologists namely Charles Darwin and Alfred Wallace working separately and independently published papers that applied formal knowledge in biology and other sciences such as morphology, geology etc to conclude that indeed all species living today has evolved over time from a common ancestor by incremental changes over time as organisms adapted over several generations to suit their environment. However it was Darwin whose named became more famous due to the fact that he took on the ultimate question – “…therefore what is the origin of man?” Darwin boldly predicted that if the evolution was correct then humans were also part of this ‘tree of life” and that we humans originated from other life forms most likely from one of the ape species. This conclusion led to uproar not only among the general public, and the clergy but also among his fellow biologists, because at the time the mechanisms of inheritance of traits, genetics and other relevant related fields was unknown. However Darwin stood his ground, and as of today evolution is the only theory capable of explaining the diversity of life we see today and it is central unifying theory of all biology. As one biologist quipped, “…nothing in biology makes sense without evolution …” So what is evolution and how does it work, and valid predictions does it make?
Evolution can be formally defined as the change in inherited traits of a population of organisms over many generations. As groups of these populations split and branch off to live in new or different environments they then evolve independently of their “relatives” and may eventually diversify into a new species.
The exact mechanism by which traits are passed on from one generation to the next is provided by the study of genetics, a field that started when a Catholic priest from Czechoslovakia named Gregor Mendel documented how and why certain characteristics of beans he cultivated in his garden were inherited over several generations. However it was not until Crick and Watson discovered the DNA molecule and others deciphered the genetic code in the 1950s that the exact process was revealed. It turns out that the conclusions of Darwin based on morphology, genetics, molecular biology (DNA) all lead to the exact same conclusions. Evolution is real and on-going.
Some of the misconceptions are that evolution claims knowledge of the origin of life. No. This is false. Evolution is based on the fact that life is already here, and explains the diversity of life. The origin of life falls under a separate field of study called Abiogenesis. Evolution has nothing to say about Abiogenesis, big bang theory, god, demons, or witches, it only speaks to the diversity of current life forms. Another question raised is “… well why are monkeys not turning into humans now, or why are cats not giving birth to dogs?, …” Well because evolution theory does not make that prediction. From the definition evolution happens to populations not individuals. It requires inherited traits accumulated over several generations of a population to then be expressed in later generations of that population.
Another criticism is that evolution suggests humans have no purpose or the universe itself has no purpose. The claim is made that if that is the case then life itself is meaningless Well, actually that is the case, and there is nothing wrong with it. Nature is in indifferent. Why does life need a purpose? There was no purpose to it until humans invented religion and put themselves at the top of the pecking order and gave themselves the right to “rule” over all nature and even other “lesser” humans. One may ask well humans think they have a special purpose what about the remaining thousands of species in the world? Do dogs have special divine purpose? And what about the infinitely large number of other planets, stars etc some of which we are even yet to discover, do they have a special purpose too? And what is the purpose of the stars in the constellation Virgo and the many yet undiscovered planets that may also be there and even other life forms that may be in the universe? How do they have purpose (from our perspective) if we have not yet discovered them. There is no purpose, it all depends on what we as civilized beings wish to make a purpose. Has anyone ever noticed that on earth almost 99% of all animals die by being attacked and eaten by other animals, including humans who are devoured by viruses and bacteria? So what is the purpose of that?
Another point raised by “creationists” is that the earth is “fine tuned” for life or that the universe is fine tuned for the presence of life on this earth. This is incorrect. Our galaxy alone by current estimates has over 125 billion stars 90% of which we currently do not even have the technology to even observe in detail. If even 0.01% have extra-solar planets that makes 1.25 million star systems that may have life, and there are estimated so far over 200 billion galaxies in the observable universe. So the idea that this particular location is “fine tuned” for life or is special to have life is simply absurd, arrogant and very childish. Also how is earth fine tuned for life? As I said earlier at least 99% of all animals are attacked and eaten by other animals, some even eaten alive. Almost 95% of all species that ever lived are extinct. Inclement weather, earthquakes, volcanoes, tsunamis etc are part of our natural world and yet they have devastating consequences for one life form or the other. Meteorites and Gamma ray bursts have the potential of hitting us and extinguishing life at any moment like what is believed to have killed the dinosaurs. So the fact that we may not be aware of it as we are too busy working 9 -5 and praying for miracles is not an excuse. So no, there is no fine tuning or fine tuner anywhere, and none is needed, it is rather life that has evolved and adapted to the conditions here in order to survive and continue. Species that do not adapt accordingly die out and disappear.
And the final critique I will mention is that “…oh so all life happened by chance?.....” No it did not. And evolution does not posit that. There are particular processes that are random so yes those aspects may be by chance for example mutations, chromosomal fusions, deletions and gene insertions, but the overall process is not by chance. Others say well the likelihood of such events occurring is so small that it is impossible. Another fallacy. Anyone who actually understands math and statistics will know that all probabilities are less than or equal to one, and when you multiply fractions you get even smaller outcomes. So multiplying the probabilities of independent events a few times gives smaller and smaller numbers. If we consider what we do today on our way to work as compared to doing something else. If we were to calculate the probabilities we would get mind-bogglingly small numbers, and yet what we did today happened, and once it happens the probability is one. So once something happens the improbability is irrelevant. For example it is highly improbable that at 10:00 am today I will get out of my chair and go for a drink, but since it happened that probability is now one and its previous improbability is not relevant. So improbability does not imply impossibility.
Darwinian evolution has made some bold predictions for example that humans share common ancestor with the Apes. This prediction was made based on fossil evidence alone. In 2000 the human genome project unraveled the entire human genetic code. In 2005 the genome of the chimpanzee was decoded, and lo-and-behold it was proved beyond all reasonable doubt that we share a common ancestor. Chimpanzees and humans have 99% identical genetic structure. Specific structures in the DNA of Chimps were found exactly the same in humans and performed exactly the same function. This could only be explained by common descent. In fact such similarities existing not just between humans and chimps but across the entire phylogenic branch called mammals, indicating that all mammals rose from a common ancestor. The main difference between human and other primates is the fusion of two chromosomes into one in humans (Human chromosome Number 2) and yet the two fused components are EXACTLY the same individual chromosomes found in all other primates (aka Apes). The implication is an ape-like common ancestor of humans and chimps at some point had a direct head-to-head-fusion of chromosomes resulting in the profound changes of that species. From the markers on the DNA we can calculate when this event occurred. Current estimates place it at approximately 10 million years ago. This shocking insight led pioneering biologist Craig Venter to quip “…evolution is not theory anymore …”
However this chromosomal event alone did not make this new line from the common ancestor instantly become human. There were an number of significant changes over the next 6 – 8 million years driven by climate change, population pressures and natural selection, that led to the rise of several “intermediate” species that led to humans. The remains of these creatures have been found and documented extensively in the field of paleontology. Some of their names include Ardipithicus Ramidus, Australopithicus Afarensis, Homo Habilis, Homo Erectus, Homo Neanderthalis, and Homo Idaltu. If this theory was wrong we would not see these species in the timelines we have found them to be in, and we would not find them in specific locations in specific eras. For example if we found Homo Habilis was ancestor of Homo Erectus that lived exclusively in Africa. Homo Erectus howver lived at first in Africa and then in Asia. A descendant of Homo Erectus in Europe was Homo Neanderthalis, the so called cave men. So if we were to find Homo Erectus remains in Europe that were older than Homo Habilis, or if we were to find Homo Neanderthalis remains in Africa then we would immediately know there is a problem in the theory. But this NEVER happens. All the fossils found and dated so far show exactly what is predicted by evolution.
Another prediction. Fossil evidence shows conclusively the presence in Europe of a human-like species now known as Neanderthal Man. The fossils suggested a separate species DNA was recovered from one such individual dated to have lived 40 to 100 thousand years ago. The Neanderthal genome as been deciphered and it showed they were a separate species from us humans. Further tests on humans revealed that some Europeans and Asians have up to 45 Neanderthal genes suggesting there was a brief period where the two species interbred. To date no religious body has come out to express their position on Neanderthal. Why? Are they afraid to make fools of themselves in the light of mountains of evidence, and the fact that no religious book documents anything about this hominid species?
Another piece of evidence is from endogenous retroviruses (ERVs). As we all know viruses can only reproduce inside of living cells. This because they use the host cells DNA to replicate their own DNA (well RNA). In some cases due to the replication process part of the virus genetic material may get stuck in the host cell and become part of its DNA. If this occurs in say a sperm cell the sperm cell will carry this added material when it combines with a female egg cell. And pass it on to its offspring. The remnants of the virus will now become part of the DNA of the new individual and will pass it on to ALL its descendants. At this time it has become endogenous. ERVs are another way of demonstrating common ancestry of individuals and species. The human genome project led by Craig Venter identified several thousand ERVs in the human DNA (8% of our genome) that were classified into 24 groups. By tracking these ERVs in other species one can extrapolate the relationship of one species to another, and when these events occurred. For example all ERVs in humans are found in Chimps but not vice versa. This implies humans separated from chimps and not vice versa. We have traced human ERVs in rats. This can only mean one thing, we share common ancestor. There is simply no other explanation. Unless the Hebrew speaking god put fragments of a rat virus in human DNA just for fun and forgot to tell us in his bible. Similar analyses enabled us to confirm that birds evolved from reptiles. Mind you this had already been predicted from the fossil record with the discovery of Archaeopteryx, a small dinosaur (dinosaurs were technically reptiles) that had feathers on its body.
Our next piece of evidence comes from geology. Geologists can tell us where we can find rock formations of certain ages or certain periods of history or pre-history. A few years ago one team that was studying amphibians concluded that amphibians would have evolved from fish in a certain era called the Devonian period. So based on the fish fossils they could estimate when and which rock formation we should see some of the earliest amphibians in the fossil record. Through geology a rock formation from the Devonian was identified to be in northern Canada. So paleontologists went there to look for it and YES, in 2003 they found what has so far been the oldest amphibian fossil and possible candidate for the first amphibian to evolve in the water and move to live on land. It was named Tiktaalik. This creature lived in the Devonian period 385 million years ago. So again the theory makes a testable prediction. If we find dinosaur fossils I this rock then we would know that geology as well as evolutionary theory are both wrong or one is wrong at best. But exactly as predicted the expected result was found. This same idea was used by others to trace the evolution of whales from a hoofed pig-like land creature that lived in Pakistan at around 40 million years ago, called Pakicetus.
So at this point we would like to invite the “creationists” to come out and provide their evidence for the current diversity and complexity of life on earth. Hopefully they will provide testable proofs and not throw scripture quotations in our face or threaten us with eternal burning in hellfire or eating of five fishes by 2000 people based on the miraculous sharing power of some zombie who has only 23 chromosomes because he did not have an earthly male parent.
So it is now over to them to provide counter claims and counter evidence.
Peace and Love.
kwaku ba © July 2010
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