This article will describe and explore the Theory of Evolution. It will attempt to describe the theory, defining its main elements, and also take a brief look at the historical changes to the Theory – a kind of evolution of the Theory of Evolution! In addition, the article will seek to discuss the evidences used by the proponents of this theory and then provide a synopsis of the counter arguments.
Introduction
The Theory of Evolution has become the de facto standard used in the West, and indeed beyond, to explain the existence of creation and life. It is described as rational and scientific; many statements are made to demonstrate the strength of the Theory – such as the number of scientists who have given it their blessings and its widespread acceptance beyond the scientific community. Nonetheless, there is a strong perception existing in our day and age of the credibility of the Theory of Evolution. To some extent, it is discussed and taught in schools and educational establishments and promoted in the mainstream media. In stark contrast, other arguments that explain the existence of life are considered to be irrational, backward and steeped in ignorance borne out of belief in religion. In other words, there are essentially two clear camps: the ‘scientific’ and progressive camp which espouses the virtues of the Theory, and the apparently ‘unscientific’ contingent which clings to outmoded explanations such as the existence of a Creator. In recent times, thanks in no small part to various Christian elements in the U.S., the clashes between these two sides have become more visible and the tempo seems to have been raised. There have been calls for a restructuring to the way in which the Theory is taught to children, or at the very least provision for a balanced approach, so that the young are taught about other explanations as well. Many establishments have insisted on giving religious teaching the priority, leading to conflict with those who believe religion should have no such role in schools.
The Theory of Evolution
The theory of evolution is sometimes described using complex and convoluted language, which can be a significant source of confusion. What adds to the confusion is the fact that aspects of the theory do undergo change and revision. In this article I will try to explain the main points that constitute the theory, on which those who propose this theory are agreed, without getting bogged down in the finer details or indeed the many arguments and assumptions in relation to areas where there may be some difference of opinion and divergence of views. I have also tried to simplify the description so it can be understood without recourse to a dictionary and constant definition of scientific terminology.
To understand the thrust of the theory, it is useful to have an idea of some of the concepts that are used and an appreciation of the context.
Firstly, the definition: biological evolution is defined as descent with modification from a common ancestor. In this context, descent means going down from one generation through to the following generations. Modification alludes to alterations in genetic make-up and changes in gene frequencies. This definition encompasses what is known as small-scale evolution (changes in gene frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations).
Of course biological evolution is not simply a matter of change over time. Lots of things change over time: trees lose their leaves, mountain ranges rise and erode, but they aren't examples of biological evolution because they don't involve descent through genetic inheritance.
Secondly, a key central idea of biological evolution is that all life on Earth shares a common ancestor, just as our cousins and we share a common grandmother. It is argued that through the process of descent with modification, the common ancestor of life on Earth gave rise to the diversity that we see documented in the fossil record and around us today. Evolution means that we are all distant cousins: humans and oak trees, hummingbirds and whales.
The process of evolution produces a pattern of relationships between species. As lineages evolve and split and modifications are inherited, their evolutionary paths diverge. This produces a branching pattern of evolutionary relationships. These relationships can be reconstructed and represented on a "family tree," called a phylogeny.
As a consequence of this ‘family tree’ understanding, it is important to remember that:
1. Humans did not evolve from chimpanzees. Humans and chimpanzees are evolutionary cousins and share a recent common ancestor that was neither chimpanzee nor human.
2. Humans are not "higher" or "more evolved" than other living lineages. Since these lineages split, humans and chimpanzees have each evolved traits unique to their own lineages.
Thirdly, another important aspect of evolution is the linking of speciation events to time i.e. trying to understand when different species evolved. Using various methods, such as radiometric dating, scientists are able to conclude that life began 3.8 billion years ago, and insects diversified 290 million years ago, but the human and chimpanzee lineages diverged only five million years ago.
To give an analogy for this, imagine squeezing the billions of years of the history of life on Earth into a single minute. Then it would take about 50 seconds for multi-cellular life to evolve, another four seconds for vertebrates to invade the land, and another four seconds for flowers to evolve — and only in the last 0.002 seconds would "modern" humans arise.
So, the claim is made that evolution is the process by which modern organisms have descended from ancient ancestors. Evolution is apparently responsible for both the remarkable similarities we see across all life and the amazing diversity of that life — but exactly how does it work?
Fundamental to the process is genetic variation upon which selective forces can act in order for evolution to occur. Evolution only occurs when there is a change in gene frequency within a population over time. These genetic differences are heritable and can be passed on to the next generation — which is what really matters in evolution: long term change. Therefore, we need to examine the actual mechanisms of evolution.
In essence there are four basic processes, which constitute the mechanisms of evolution. These are mutation, migration, genetic drift and natural selection.
Mutation refers to the actual changes in the DNA within cells. The DNA affects how an organism looks, behaves and so on. Thus a change in the DNA can alter all aspects of its life.
When cells divide the DNA is copied exactly as it is. However, on occasion, it is possible for they’re to be a discrepancy in the copying of the DNA. This difference is considered a mutation. It must be kept in mind that mutations are random – and so do not normally depend on external factors. That said, it is possible for there to be mutation as a result of exposure to radiation or chemicals, causing the DNA to break down. In this case, when the cells repair the DNA, the result is not a perfect repair – and so the resultant DNA is a mutation.
Whether a particular mutation occurs is not related to how useful that mutation would be. The mutation in the genes can yield a beneficial, neutral or harmful change for the organism.
Although mutation can occur with any gene, it is the mutation that affects genes, which can be transmitted from one generation to the next that is of interest, since this is a form of evolution. If genes mutate and cannot be passed to future generations, then these mutations cannot be considered as having any relation to evolution. These are called Somatic Mutations and occur in non-reproductive cells. Hence the genes that are affected by mutation related to biological evolution are the reproductive cells, like eggs and sperm. Any mutations in the sex cells mean that potentially the change (the mutation) can be passed onto following generations. These mutations are labelled Germ Line Mutations.
Migration is the flow of genes from one population to another. This Gene Flow can include various different events, such as pollen being blown to a new destination or people moving to new cities or countries. In a situation where genes are carried to a population where those genes previously did not exist, gene flow becomes a very important source of genetic variation.
Thus, as well as being mechanisms of evolution, Mutation and Migration also constitute sources of genetic variation. Another source of genetic variation is sex, which can introduce new gene combinations into a population.
Genetic drift refers to the situation where, just ‘by chance’, some individuals leave behind a few more descendents and thus genes than other individuals. This happens to all populations since there can be no avoidance of chance. So for example, every time somebody steps on an insect with a certain characteristic, this reduces the number within that particular population and hence means there is one less insect remaining to pass on its genes to a new generation. Conversely, this also means that there are now more insects with different characteristics within the same population, who are able to pass on their genes. Clearly, this shows that genetic drift affects the genetic makeup of a population through entirely random means.
Natural Selection is the fourth cog in the wheel of evolution. This in itself requires three components: variation in traits, differential reproduction and heredity. To understand this, consider a population of beetles. Some beetles are brown and others are green – this is a variation in a trait or a characteristic.
The environment is not able to support unlimited growth of the population and so not all individuals are able to reproduce to their full potential. For example, we could say that green beetles are easily visible on the ground and so tend to get eaten more by birds – so less survive to reproduce compared to brown beetles. In other words, we have differential reproduction.
Finally, the brown beetles have brown baby beetles since this trait has a genetic basis i.e. they pass on a gene that determines the colour to be brown. This is what is meant by heredity. Putting these components together, evolution by natural selection is seen at work. The more advantageous trait of brown colour becomes more common in the population with time and if this process continues, then eventually all the beetles will be brown.
It is claimed that natural selection is also able to shape behaviour. The mating rituals that many birds have, the wiggle dance that bee’s do or the human capacity to learn language, have genetic components.
In some cases, natural selection can be observed directly. Data shows that the shape of finches' beaks on the Galapagos Islands is related to weather patterns: after droughts, the finch population has deeper, stronger beaks that let them eat tougher seeds.
In other cases, human activity has led to environmental changes that have caused populations to evolve through natural selection. A striking example is that of the population of dark moths in the 19th century in England, which rose and fell in parallel to industrial pollution. These changes can often be observed and documented.
‘Fitness’ is a concept used to describe how good a particular organism is at leaving its set of genes in the next generation compared with others with a different set of genes. Going back to the example of beetles, if brown beetles were to consistently leave more off spring than green beetles, then they would be considered to have a higher fitness. Fitness however does depend on the environment in which an organism lives. Also, from this perspective, the fittest individual is not necessarily the strongest, fastest or biggest. What matters is leaving it’s genes in the next generation and so survival ability, finding a mate and producing off spring is more important. This sub-category of natural selection in relation to finding a mate and reproductive behaviour is labelled sexual selection.
Another category of natural selection is artificial selection. This is where, instead of nature, humans consciously select for or against particular features in organisms. For example, the human may allow only organisms with the desired feature to reproduce or may provide more resources to the organisms with the desired feature. Historically, farmers and breeders have used this idea of selection to cause major changes in the features of their plants and animals.
One key aspect of natural selection is known as adaptation. An adaptation is a feature that is common in a population because it seems to provide an improved function. Adaptations can take many forms: a behaviour that allows better evasion of predators, a protein that functions better at body temperature, or an anatomical feature that allows the organism to access a valuable new resource — all of these might be adaptations. For example, mimicry of leaves by insects is an adaptation for evading predators or the use of echolocation by bats to help them catch insects. Similarly, the creosote bush is a desert-dwelling plant that produces toxins that prevent other plants from growing nearby, thus reducing competition for nutrients and water.
To summarise, all of the mechanisms discussed above (mutation, migration, genetic drift and natural selection) can cause changes in the frequencies of genes in populations, and so all of them are mechanisms of evolutionary change. However, it is worth keeping in mind that natural selection and genetic drift cannot operate unless there is genetic variation — that is, unless some individuals are genetically different from others.
A historical perspective
Although Charles Darwin is synonymous with the Theory of Evolution, he was not the first naturalist to propose that species changed over time into new species i.e. that life evolves. In the eighteenth century, a naturalist called Buffon along with others began to introduce the idea that life might not have been fixed since creation. By the end of the 1700s, palaeontologists had swelled the fossil collections of Europe, offering a picture of the past at odds with an unchanging natural world. And in 1801, a French naturalist named Jean Baptiste Pierre Antoine de Monet; Chevalier de Lamarck took a great conceptual step and proposed a full-blown theory of evolution.
Lamarck was struck by the similarities of many of the animals he studied, and was impressed too by the burgeoning fossil record. It led him to argue that life was not fixed. When environments changed, organisms had to change their behaviour to survive. If they began to use an organ more than they had in the past, it would increase in its lifetime. If a giraffe stretched its neck for leaves, for example, a "nervous fluid" would flow into its neck and make it longer. Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations. Meanwhile organs that organisms stopped using would shrink (called vestigial structures).
Lamarck was mocked and attacked by many of his contemporary naturalists such as Cuvier. While they questioned him on scientific grounds, many of them were also disturbed by the theological implications of his work. Lamarck was proposing that life took on its current form through natural processes, not through miraculous interventions. For British naturalists in particular, steeped as they were in natural theology, this was appalling. They believed that nature was a reflection of God's benevolent design. To them, it seemed Lamarck was claiming that it was the result of blind primal forces. Shunned by the scientific community, Lamarck died in 1829 in poverty and obscurity.
In many ways, Darwin's central argument was very different from Lamarck's. He argued that complexity evolved simply as a result of life adapting to its local conditions from one generation to the next. He also argued that species could go extinct rather than change into new forms. But Darwin relied on much the same evidence for evolution that Lamarck did and Darwin wrongly accepted that changes acquired during an organism's lifetime could be passed on to its offspring.
Lamarckian inheritance remained popular throughout the 1800s, in large part because scientists did not yet understand how heredity works. With the discovery of genes, it was finally abandoned for the most part. But Lamarck, whom Darwin described as "this justly celebrated naturalist," remains a major figure in the history of biology for envisioning evolutionary change for the first time.
Throughout the nineteenth century, heredity remained a puzzle to scientists. How was it that children ended up looking similar to, but not exactly like, their parents? These questions fascinated and frustrated Charles Darwin deeply. After all, heredity lies at the heart of evolution.
Ironically, it was just as Darwin was publishing the Origin of Species in 1859 that someone got the first real glimpse of the biological machinery behind heredity. In a secluded monastery in what is now the Czech Republic, a monk named Gregor Mendel was studying heredity in a garden of peas. Through his experiments, Mendel discovered what later scientists called "dominant" and "recessive" alleles i.e. part of genetics.
Darwin and a British biologist called Alfred Russel Wallace had independently conceived of a natural, even observable, way for life to change: a process Darwin called natural selection. Within a few decades, most scientists accepted that evolution and the descent of species from common ancestors were real. But natural selection had a harder time finding acceptance.
Even in 1900, whilst many scientists were rediscovering Mendel's insights, they continued to remain opposed to natural selection. After all, Darwin had talked of natural selection gradually altering a species by working on tiny variations. But the Mendelist’s found major differences between traits encoded by alleles. In order to jump from one allele to another, evolution must make giant jumps—an idea that seemed to clash with Darwin.
But in the 1920s geneticists began to recognize that natural selection could indeed act on genes. For one thing, it became clear that any given trait was usually the product of many genes rather than a single one. A mutation to any one of the genes involved could create small changes to the trait rather than some drastic transformation. Just as importantly, several scientists — foremost among them Ronald Fisher, JBS Haldane and Sewall Wright — showed how natural selection could operate in a Mendelian world. They carried out breeding experiments like previous geneticists, but they also did something new: they built sophisticated mathematical models of evolution.
Known as "population genetics," their approach revealed how mutations arise and, if they are favoured by natural selection, can spread through a population. Even a slight advantage can let genes spread rapidly through a group of animals or plants and drive other forms extinct. Evolution, these population geneticists argued, is carried out mainly by small mutations, since drastic mutations would almost always be harmful rather than helpful.
Thus, population genetics became one of the key elements of what would be called the Modern Synthesis.
In 1937, a Soviet-born geneticist named Theodosius Dobzhansky wrote a landmark book called Genetics and the Origin of Species. Dobzhansky's ability to combine genetics and natural history attracted many other biologists to join him in the effort to find a unified explanation of how evolution happens. Their combined work known as "The Modern Synthesis" brought together genetics, palaeontology and many other sciences into one powerful explanation of evolution, showing how mutations and natural selection could produce large-scale evolutionary change.
While evolutionary biologists were fashioning the Modern Synthesis, geneticists around the world searched furiously for the molecules that carried genetic information. They knew that cells contained several different types of molecules, such as proteins and nucleic acids. But which had the capacity to bear information and be copied into new cells?
The answer came through the discovery of DNA by Francis Crick and James Watson, which revolutionized evolutionary biology. Mutations, researchers realized, change the structure of the DNA. A single base pair may change, or a set of genes may be duplicated. Hence, those mutations that confer a selective advantage to an individual become more common over time, and ultimately these mutant genes could drive the older versions out of existence.
Evidences used by the proponents of the Theory
The mechanisms covered thus far are the basic building blocks of the theory of evolution. The next logical step is to look at the evidence that is given to claim these processes are responsible for both micro and macroevolution. In other words, what evidence is there that evolution has occurred and is responsible for the variety of life around us, and also is there evidence that demonstrates the mechanisms discussed in this article are indeed behind all these changes?
Those who support the theory of evolution present proofs that can loosely be gathered into a number of categories. We will examine these in turn.
The primary source of proof for the theory comes from Fossil Evidence. The argument is that fossil records provide excellent snapshots of the past and when assembled they illustrate evolutionary change over many millions of years.
As well as being actual remains of organisms, and thus giving an understanding as to the shape, appearance and skeletal structure, fossils can give additional clues. For example, they can indicate interactions that took place many years previously. A fossil may contain punctures or holes that could be teeth records of various animals, allowing scientists to extrapolate about what kind of organism may have been responsible, the shape of its jaws, and so on.
Fossils can tell us about the growth patterns in ancient animals. For example, examining a cross section of a bone that has been found, it is possible to see the number of blood vessels; this in turn would indicate the speed of growth and so on.
An important section of fossil records are transitional forms. These are fossils or organisms that show the intermediate states between ancient organisms and their descendents. Since scientists have found so many transitional forms, it is claimed there is an abundance of evidence for evolution. An example of this is the case of the beluga whale. The beluga whale has its nostrils at the top of its skull. A fossil record of an animal that is considered to be related to today’s whales and dolphins, called Pakicetus, had its nostrils at the front of its skull. This animal lived about 50 million years ago. So scientists would expect that there might be a transitional form i.e. an animal that had some variation in the position of its nostrils compared to Pakicetus and the beluga whale. In fact, fossil records have been discovered of a skull, about 25 million years old, where the nostrils are in the middle of the skull. This animal has been labelled Aetiocetus.
So Aetiocetus could plausibly be the transitional form, linking Pakicetus to the beluga whale and demonstrating a steady evolution.
The second source of evidence is garnered from studying homologies. Evolutionary theory predicts that organisms that come from the same ancestor will share similarities. These similar characteristics are known as homologies. As mentioned earlier, the logic is essentially that historically every species shares a common ancestor. As we move forward in time, new species evolve, but since they share a number of common ancestors, so we would expect them to share some characteristics that exist or existed in those ancestors. A crude example would be that of humans and apes. At some stage, going back in time, there was a common ancestor from which both species evolved. So humans and chimpanzees would have similar characteristics, based on the fact that they share common ancestors. Another example of homology is that of leaves. If we were to examine the leaves of say the pitcher plant (which has leaves shaped to capture insects), the Venus Flytrap, the Poinsettia (which has bright red leaves) and the cactus plant (where its leaves are essentially spines) then we would see that each type of leave has a different shape and function. Yet they are all derived from a common ancestral form.
Yet another example of homology is the forelimb of tetrapods (vertebrates with legs). Frogs, birds, rabbits and lizards all have different forelimbs, reflecting their different lifestyles. But those different forelimbs all share the same set of bones - the humerus, the radius, and the ulna. These are the same bones seen in fossils of the extinct transitional animal, Eusthenopteron, which demonstrates their common ancestry.
Comparing the anatomies of different living things, looking at cellular similarities and differences and studying embryological development can reveal homologies.
Studying the embryological development of living things (i.e. prior to birth) provides clues to the evolution of present-day organisms. During some stages of development, organisms exhibit ancestral features in whole or incomplete form. For example, some species of living snakes have hind limb-buds as early embryos but rapidly lose the buds and develop into legless adults. The study of developmental stages of snakes, combined with fossil evidence of snakes with hind limbs, supports the hypothesis that snakes evolved from a limbed ancestor.
Similarly, toothed whales have full sets of teeth throughout their lives. Baleen whales, however, only possess teeth in the early foetal stage and lose them before birth. The possession of teeth in foetal baleen whales provides evidence of common ancestry with toothed whales and other mammals. In addition, fossil evidence indicates that the late Oligocene whale Aetiocetus (the same Aetiocetus - our transitional friend with the nostrils in the middle of its skull), which is considered to be the earliest example of baleen whales, also bore a full set of teeth.
From a cellular and molecular level we find fundamental similarities between the cells of living things, which can be explained by the theory of evolution. All organisms are made of cells, which consist of membranes filled with water containing genetic material, proteins, lipids, carbohydrates, salts and other substances. The cells of most living things use sugar for fuel while producing proteins as building blocks and messengers. Comparing a typical animal cell with that of a plant, there are only three structures unique to one or the other (these are the cell wall, the centriole and the chloroplast). All other aspects are similar, such as the nucleus, cytoplasm and the vacuole.
Comparison of genes between species also reveals striking similarities – for example, even roundworms share 25% of their genes with humans. In many ways, DNA is itself a homology for all living things – i.e. everything has DNA and so this is a common trait that must have come from a common ancestor.
In a nutshell, homologies are used as proof for the theory, since the existence of similarities between groups of organisms is an indication of common ancestors and thus evolution.
A third source of evidence for evolution is the fact that there has been sufficient time for this process to have produced the diversity we see. The age of the earth has been determined through both relative dating (i.e. examining the different layers of rocks on the surface of the earth) and numerical dating which relies on the decay of radioactive elements such as uranium and potassium. The conclusion made is that the timescales involved are adequate for evolution to take its course.
Artificial selection, mentioned earlier, is also an evidence for evolution. This is because people have been using selective breeding with plants and animals for many hundreds of years, and this breeding has shown how species can change dramatically. It can be argued that artificial selection has the ability to modify the forms and behaviours of populations to the point they are seemingly very different to their ancestors. So artificial selection is a model that helps with understanding natural selection.
The variation in the environment and ecology is also a proof of sorts. As predicted by evolutionary theory, populations evolve in response to their surroundings. In any ecosystem there are finite opportunities to make a living. Organisms either have the genetic tools to take advantage of those opportunities or they do not.
For example, house sparrows arrived in North America from Europe in the nineteenth century. Since then, genetic variation within the population and selection in various habitats, have allowed them to inhabit most of the continent. House sparrows in the north are larger and darker coloured than those in the south. Darker colours absorb sunlight better than light colours and larger size allows less surface area per unit volume, thus reducing heat loss — both advantages in a cold climate. This is an example of natural selection acting upon a population, producing microevolution on a continental scale.
Finally, experiments also show that populations can evolve. As an example, John Endler of the University of California has conducted experiments with guppies (a type of fish) of Trinidad that clearly show selection at work. The scenario is as follows: female guppies prefer colourful males for mating purposes. Predatory fish also "prefer" colourful males, but for a less complimentary purpose — a source of food that is easy to spot. Some portions of the streams where guppies live have fewer predators than others and in these locations the males are more colourful. Not surprisingly, males in locations where there are more predators tend to be less colourful.
When Dr. Endler transferred predatory fish to the regions with brightly coloured male guppies, selection acted rapidly to produce a population of duller males. So this demonstrates that persistent variation within a population provides the raw material for rapid evolution when environmental conditions change.
Arguments against the Theory of Evolution
The previous section outlined some of the proofs that are presented for the theory of evolution. We will now consider briefly a few of the arguments against the theory.
1. The theory of evolution is usually described as fact, and many people see it like this due to a moulding of public opinion. Yet the trouble is that it is simply a theory. And like many theories it is wont to constantly chop and change. Indeed we can see on numerous occasions how it has changed over time and undergone revisions. For example, according to Darwin himself, "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down”.
Another example is the proposition of a slightly different model in recent times. Called "punctuated equilibrium", this model rejects the Darwinist idea of a cumulative, step-by-step evolution and holds that evolution took place instead in big, discontinuous "jumps". This is because those who ascribe to it believe the fossil record does not support gradual evolution. Sadly for the proponents, Niles Eldredge and Stephen Gould (American palaeontologists) their own theory is bankrupt – since for one thing, it conflicts with the understanding that genes cannot undergo radical mutations.
2. The sources of proof given for the theory essentially rely on retro-fitting the supposed evidence to the theory i.e. the theory states evolution occurred from a common ancestor, and then study of fossils and homologies is used to indicate that indeed the theory is correct and evolution does occur. But equally we could state there is a creator who created the amazing diversity of life and also the similarities between species – in fact this is more plausible. Thus fossils and homologies would just as much, if not more, support this ‘theory’ of a Creator.
3. Fossils are a record of what may have existed. They do not indicate anything more than this. By examining a fossil we could equally state that the organism was created as opposed to evolving from an ancestor. The fossil record is also very much incomplete – there are massive, gaping holes. This presents a staggering problem for proponents of the Theory. The somewhat weak argument is that the bulk of the fossil record may have been destroyed or is yet to be discovered. According to Neville George, a professor of Palaeontology at Glasgow University:
“There is no need to apologise any longer for the poverty of the fossil record. In some ways, it has become almost unmanageably rich and discovery is outpacing integration…” Yet he goes on to say, “The fossil record nevertheless continues to be composed mainly of gaps”.
Contrary to what evolutionists claim, there are only limited (if any) transitional forms. Importantly, for example, we don’t see transitional forms that show the alleged evolution of apes to humans [and to try and explain the many loopholes regarding this, there is a current debate among evolutionists themselves about whether it occurred in steps or smoothly which we alluded to earlier i.e. punctuated equilibrium]. The fossil record back then (and still today) is nearly totally void of transitional species. If species are continually mutating, never constant, why do we find several of the same, certain prehistoric creatures, but never any that appear to be in transition? Why do palaeontologists find lots of dinosaurs but never where dinosaurs come from, nor what they turned into?
In Darwin's own words, 'Why, if species have descended by insensibly fine gradations, do we not everywhere see innumerable transitional forms? Why is not all nature in confusion instead of species being, as we see them, well defined?' It is an excellent question, which he answers himself, 'I can give no satisfactory answer.'
Indeed British evolutionist Derek Ager admits, “The point emerges that if we examine the fossil record in detail, whether at the level of orders or of species, we find - over and over again - not gradual evolution, but the sudden explosion of one group at the expense of another”.
Yet another problem in using the fossil record as evidence for evolution is that under closer examination, it appears to be a proof for exactly the opposite argument – i.e. creation. For example, one of the oldest strata of the earth in which fossils of living creatures have been found is that of the Cambrian, which has an estimated age of 500-550 million years. The living creatures found in the strata belonging to the Cambrian period seemed to emerge all of a sudden in the fossil record – there appeared to be no ancestors, although in relatively recent times palaeontologists believe fossils have been found dating from the preceding Vendian (or Ediacaran) period. The fossils found in the Cambrian rocks belonged to snails, trilobites, sponges, earthworms, jellyfish, sea hedgehogs, and other complex invertebrates. This wide mosaic of living organisms made up of such a great number of complex creatures emerged so suddenly that this miraculous event is referred to as the "Cambrian Explosion" in geological literature.
“A half-billion years ago, the remarkably complex forms of animals we see today suddenly appeared. This moment, right at the start of Earth's Cambrian Period, some 550 million years ago, marks the evolutionary explosion that filled the seas with the world's first complex creatures. The large animal phyla of today were present already in the early Cambrian and they were as distinct from each other as they are today”.
And one of the most vociferous advocates for atheism and evolution in today’s age, Richard Dawkins, comments “the Cambrian strata of rocks, vintage about 600 million years, are the oldest ones in which we find most of the major invertebrate groups. And we find many of them already in an advanced state of evolution, the very first time they appear. It is as though they were just planted there, without any evolutionary history. Needless to say, this appearance of sudden planting has delighted creationists”.
4. The basic mechanism for gene variation is mutation. And it is known that mutations are random and limited in their scope. We should note that what is not a point of debate here is the fact that genes undergo mutation; neither is there a point of conflict with the various biological processes within organisms. For example, we know that insects can build up resistance against forms of pesticide over time – in fact, in the same manner humans have long believed that taking poison in small quantities can help survive what would normally be a fatal dose. These observations do not really constitute evolution. However, even if we agreed to define these particular cases as examples of microevolution, the fact is that they can be explained by what we have come to know through scientific study and resulting conclusions. The argument for a Creator also accepts scientific facts and conclusions – it no more denies the laws of biology being created, than it denies the laws of physics being put in place by the Creator. Hence, change within the framework of the laws of biology is possible – and there is sufficient evidence for this. The main problem however is with macroevolution. To even begin to consider macroevolution, mutations would need to be dramatic – trying to get round this, it is claimed that there has been sufficient time for many small scale mutations to eventually yield the different species we see. But frankly this isn’t plausible – we have seen no evidence to support such a claim - and so this is again nothing more than a pure hypothesis.
In addition, there are many other problems with the mutation argument. If mutations occur, they actually cause harmful effects and not beneficial ones. We can witness the effects of mutations caused in humans following radiation poisoning at Hiroshima, Nagasaki and Chernobyl – that is, a litany of death, disability and illness.
According to the evolutionist scientist Warren Weavers commenting in the report prepared by the Committee on Genetic Effects of Atomic Radiation, which had been formed to investigate mutations that may have been caused by the nuclear weapons used in the Second World War:
“Many will be puzzled about the statement that practically all known mutant genes are harmful. For mutations are necessary parts of the process of evolution. How can good effects - evolution to higher forms of life - results from mutations practically all of which are harmful?”
Similarly, another scientist B.G. Ranganathan states in his book ‘Origins?’ that “Mutations are small, random, and harmful. They rarely occur and the best possibility is that they will be ineffectual. These four characteristics of mutations imply that mutations cannot lead to an evolutionary development. A random change in a highly specialised organism is either ineffectual or harmful. A random change in a watch cannot improve the watch. It will most probably harm it or at best be ineffectual. An earthquake does not improve the city, it brings destruction”.
Finally, mutations do not actually add any new information to an organisms DNA. During a mutation, the genetic information is either destroyed or rearranged, but since there is no new information, it is impossible for mutations to cause a new trait or organ within a living organism.
5. Artificial selection (breeding) and sexual selection do produce new combinations but these are limited in their scope. They are restricted to a finite set of possible gene combinations. So breeding cannot introduce a radically new species – it simply gives a result based on the limited pool of combined genes. It cannot give a result outside of this. E.g. Horse plus donkey gives a mule. Or an African married to a Caucasian can result in off spring described as half-cast. The latter cannot produce a human whose skin colour is red or purple, etc.
6. The odds are heavily stacked against evolution. Evolution cannot answer where the first cell came from. The best guess is that came about through a random coincidence. Fred Hoyle, a well-known English mathematician and astronomer, and someone who believes in evolution, made the analogy that the chances of the first cell forming in this manner were comparable with the chance that a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials present. And according to Professor of Applied Mathematics and astronomy from University College (Cardiff, Wales), Chandra Wickramasinghe:
“The likelihood of the spontaneous formation of life from inanimate matter is one to a number with 40,000 noughts after it... It is big enough to bury Darwin and the whole theory of evolution. There was no primeval soup, neither on this planet nor on any other, and if the beginnings of life were not random, they must therefore have been the product of purposeful intelligence”. In other words the random formation of such a first cell is an impossibility.
But still let’s assume we suddenly have a cell. The first cell would then have to self-reproduce otherwise there would only ever be one cell. This becomes problematic for evolutionists so they suggest self-replication – i.e. the first cell has the ability to clone itself. However, organic matter can only self reproduces if it exists as a fully developed cell with existing support structures such as the particular environment and energy. This then requires more leaps of faith – so let’s make another assumption, this time that the cell does have a complex structure and the ability to reproduce. But, for evolution, mutation needs to happen. So firstly, since mutation is random, even given an absolute age, mutation might not occur. And secondly, mutation can only take place if the cell is forced to repair itself or if it makes a copy of itself. Thus, for a handful of cells, to copy and mutate successfully and form different cells and for this process to continue onwards to produce the complexity of life we see is something, which cannot happen. Leaving aside time, and the random nature of mutation, just the series of mutations necessary to produce even the simplest of species are impossible.
7. There is no actual hard evidence for the process of evolution itself. We don’t witness evolution. All that experiments (such as the one involving guppies) or observations in the field (such as the house sparrows example) demonstrate is a form of selection. But this is not real evolution – the fact that a population may change due to various factors (such as environment, predators, etc) or that it may become extinct is not a change from one species to another. So even if we can see natural selection of sorts, this is based on rational factors, and is not evolution.
8. Evolution cannot answer why only the human species has the clear faculty of intelligence, thought and reasoning that has allowed it to progress. It cannot explain the existence of emotions, except through an undefined notion such as chemicals within the body. And it is unable to offer any satisfactory explanation for issues such as the existence of the soul – indeed according to evolutionary theory, there cannot be a soul, rather life itself must be caused by the functioning of cells since after all everything has evolved from a single cell.
9. Adaptation is mentioned as a feature of evolution. That is, the manner in which organisms have evolved beneficial characteristics adapted to their environment, which help them survive. So one example we gave earlier was that of stick insects, where their body itself is a form of camouflage protecting them against predators. However, evolutionists themselves state that mutation is random and can lead to beneficial as well as harmful results. The environment cannot influence the occurrence or form of any mutation. So in this case, the evolutionary argument would have to be that today’s stick insects evolved from ancestors, which did randomly mutate to have this beneficial characteristic of camouflage. Those within the population that didn’t inherit this mutation would have died out due to their inability to survive. But once again, claiming that a series of mutations occurred, that lead to stick insects possessing characteristics that are suited to their environment, is nothing but conjecture. As before, we could equally state that a Creator has created various species and organisms of life with these inherent varying characteristics. So, organisms were in fact created with characteristics that we interpret as beneficial to them, instead of these traits evolving through time. Thus, the fact that many organisms seem well matched to their environments cannot be cited as any kind of proof or indication of evolution.
10. Let’s take a look at another argument that shows the fallacy of evolution. Many organisms and parts of organisms do not appear to have evolved from lesser things because they are 'irreducibly complex' life forms. Irreducible complexity is a concept that has been developed to describe something that is made of interacting parts that all work together. To understand this, take the example of a mousetrap. A mousetrap cannot be assembled through gradual improvement. You cannot start with a wooden base, catching a few mice, then add a hammer, and catch more, then add a spring, improving it further. To even begin catching mice one must assemble all the components completely with design and intent. Furthermore, if one of these parts changes or evolves independently, the entire thing will stop working. The mousetrap, for instance, will become useless if even one part malfunctions.
Likewise, many biological structures are irreducibly complex. Bats are a well-known example. They are said to have evolved from a small rodent whose front toes became wings. This presents a multitude of problems. As the front toes grow skin between them, the creature has limbs that are too long to run, or even walk well, yet too short to help it fly. There is no plausible way that a bat wing can evolve from a rodent's front toes. In fact, the fossil record supports this, because the first time bats are seen in the fossil record, they have completely developed wings and are virtually identical to modern bats.
Consider another example, that of the eye. Suppose that before animals had sight, one species decided it would be advantageous to be able to decrypt light rays. So, what is evolved first? The retina? The iris? The eye is made of many tiny parts, each totally useless without the others. The probability that a genetic mutation that would create each of these at the same time, in the same organism, is zero. If, however, one organism evolved just a retina, then the logic of Darwin suggests that the only solution is to rid oneself of useless traits replacing them with beneficial ones, so the idea of the eye evolving one segment at a time is also bogus.
Conclusion
In a time where the theory of evolution has been catapulted to the level of fact, it is useful for us to have a firm grasp of what this theory is, and with the emerging discussion gaining more and more profile (that between creationism on the one side and evolutionary thought on the other) it is vital that we are able to show the strength of the correct argument.
One big problem of presenting the topic of evolution is finding a reasonable balance: on the one hand, simplifying and leaving out some of the terminology risks not being able to convey the subject matter accurately; on the other, by not revising and simplifying at all, there is a distinct possibility that only those with a solid understanding of biology and science will grasp what is being presented. This article has attempted to run through the basic mechanics of the theory, proofs that are presented for it and some of the arguments against evolution. Many points are too elaborate and wide ranging to touch upon in this discussion. In any event, there is an abundance of material available regarding the theory and surrounding issues that discuss these aspects in much more detail and is worth exploring for those that are interested in doing so. The theory is often cloaked in scientific language and complex terminology, and presented as a solid and viable explanation for the existence of life. Although the focus and objective of the article was not to prove the fallacy of the theory, but rather to be informative with respect to the whole discussion regarding evolution as a concept, nevertheless it has hopefully been shown that evolutionary understanding, far from being fact, is nothing more than speculation and hypothesis.
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Introduction
The Theory of Evolution has become the de facto standard used in the West, and indeed beyond, to explain the existence of creation and life. It is described as rational and scientific; many statements are made to demonstrate the strength of the Theory – such as the number of scientists who have given it their blessings and its widespread acceptance beyond the scientific community. Nonetheless, there is a strong perception existing in our day and age of the credibility of the Theory of Evolution. To some extent, it is discussed and taught in schools and educational establishments and promoted in the mainstream media. In stark contrast, other arguments that explain the existence of life are considered to be irrational, backward and steeped in ignorance borne out of belief in religion. In other words, there are essentially two clear camps: the ‘scientific’ and progressive camp which espouses the virtues of the Theory, and the apparently ‘unscientific’ contingent which clings to outmoded explanations such as the existence of a Creator. In recent times, thanks in no small part to various Christian elements in the U.S., the clashes between these two sides have become more visible and the tempo seems to have been raised. There have been calls for a restructuring to the way in which the Theory is taught to children, or at the very least provision for a balanced approach, so that the young are taught about other explanations as well. Many establishments have insisted on giving religious teaching the priority, leading to conflict with those who believe religion should have no such role in schools.
The Theory of Evolution
The theory of evolution is sometimes described using complex and convoluted language, which can be a significant source of confusion. What adds to the confusion is the fact that aspects of the theory do undergo change and revision. In this article I will try to explain the main points that constitute the theory, on which those who propose this theory are agreed, without getting bogged down in the finer details or indeed the many arguments and assumptions in relation to areas where there may be some difference of opinion and divergence of views. I have also tried to simplify the description so it can be understood without recourse to a dictionary and constant definition of scientific terminology.
To understand the thrust of the theory, it is useful to have an idea of some of the concepts that are used and an appreciation of the context.
Firstly, the definition: biological evolution is defined as descent with modification from a common ancestor. In this context, descent means going down from one generation through to the following generations. Modification alludes to alterations in genetic make-up and changes in gene frequencies. This definition encompasses what is known as small-scale evolution (changes in gene frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations).
Of course biological evolution is not simply a matter of change over time. Lots of things change over time: trees lose their leaves, mountain ranges rise and erode, but they aren't examples of biological evolution because they don't involve descent through genetic inheritance.
Secondly, a key central idea of biological evolution is that all life on Earth shares a common ancestor, just as our cousins and we share a common grandmother. It is argued that through the process of descent with modification, the common ancestor of life on Earth gave rise to the diversity that we see documented in the fossil record and around us today. Evolution means that we are all distant cousins: humans and oak trees, hummingbirds and whales.
The process of evolution produces a pattern of relationships between species. As lineages evolve and split and modifications are inherited, their evolutionary paths diverge. This produces a branching pattern of evolutionary relationships. These relationships can be reconstructed and represented on a "family tree," called a phylogeny.
As a consequence of this ‘family tree’ understanding, it is important to remember that:
1. Humans did not evolve from chimpanzees. Humans and chimpanzees are evolutionary cousins and share a recent common ancestor that was neither chimpanzee nor human.
2. Humans are not "higher" or "more evolved" than other living lineages. Since these lineages split, humans and chimpanzees have each evolved traits unique to their own lineages.
Thirdly, another important aspect of evolution is the linking of speciation events to time i.e. trying to understand when different species evolved. Using various methods, such as radiometric dating, scientists are able to conclude that life began 3.8 billion years ago, and insects diversified 290 million years ago, but the human and chimpanzee lineages diverged only five million years ago.
To give an analogy for this, imagine squeezing the billions of years of the history of life on Earth into a single minute. Then it would take about 50 seconds for multi-cellular life to evolve, another four seconds for vertebrates to invade the land, and another four seconds for flowers to evolve — and only in the last 0.002 seconds would "modern" humans arise.
So, the claim is made that evolution is the process by which modern organisms have descended from ancient ancestors. Evolution is apparently responsible for both the remarkable similarities we see across all life and the amazing diversity of that life — but exactly how does it work?
Fundamental to the process is genetic variation upon which selective forces can act in order for evolution to occur. Evolution only occurs when there is a change in gene frequency within a population over time. These genetic differences are heritable and can be passed on to the next generation — which is what really matters in evolution: long term change. Therefore, we need to examine the actual mechanisms of evolution.
In essence there are four basic processes, which constitute the mechanisms of evolution. These are mutation, migration, genetic drift and natural selection.
Mutation refers to the actual changes in the DNA within cells. The DNA affects how an organism looks, behaves and so on. Thus a change in the DNA can alter all aspects of its life.
When cells divide the DNA is copied exactly as it is. However, on occasion, it is possible for they’re to be a discrepancy in the copying of the DNA. This difference is considered a mutation. It must be kept in mind that mutations are random – and so do not normally depend on external factors. That said, it is possible for there to be mutation as a result of exposure to radiation or chemicals, causing the DNA to break down. In this case, when the cells repair the DNA, the result is not a perfect repair – and so the resultant DNA is a mutation.
Whether a particular mutation occurs is not related to how useful that mutation would be. The mutation in the genes can yield a beneficial, neutral or harmful change for the organism.
Although mutation can occur with any gene, it is the mutation that affects genes, which can be transmitted from one generation to the next that is of interest, since this is a form of evolution. If genes mutate and cannot be passed to future generations, then these mutations cannot be considered as having any relation to evolution. These are called Somatic Mutations and occur in non-reproductive cells. Hence the genes that are affected by mutation related to biological evolution are the reproductive cells, like eggs and sperm. Any mutations in the sex cells mean that potentially the change (the mutation) can be passed onto following generations. These mutations are labelled Germ Line Mutations.
Migration is the flow of genes from one population to another. This Gene Flow can include various different events, such as pollen being blown to a new destination or people moving to new cities or countries. In a situation where genes are carried to a population where those genes previously did not exist, gene flow becomes a very important source of genetic variation.
Thus, as well as being mechanisms of evolution, Mutation and Migration also constitute sources of genetic variation. Another source of genetic variation is sex, which can introduce new gene combinations into a population.
Genetic drift refers to the situation where, just ‘by chance’, some individuals leave behind a few more descendents and thus genes than other individuals. This happens to all populations since there can be no avoidance of chance. So for example, every time somebody steps on an insect with a certain characteristic, this reduces the number within that particular population and hence means there is one less insect remaining to pass on its genes to a new generation. Conversely, this also means that there are now more insects with different characteristics within the same population, who are able to pass on their genes. Clearly, this shows that genetic drift affects the genetic makeup of a population through entirely random means.
Natural Selection is the fourth cog in the wheel of evolution. This in itself requires three components: variation in traits, differential reproduction and heredity. To understand this, consider a population of beetles. Some beetles are brown and others are green – this is a variation in a trait or a characteristic.
The environment is not able to support unlimited growth of the population and so not all individuals are able to reproduce to their full potential. For example, we could say that green beetles are easily visible on the ground and so tend to get eaten more by birds – so less survive to reproduce compared to brown beetles. In other words, we have differential reproduction.
Finally, the brown beetles have brown baby beetles since this trait has a genetic basis i.e. they pass on a gene that determines the colour to be brown. This is what is meant by heredity. Putting these components together, evolution by natural selection is seen at work. The more advantageous trait of brown colour becomes more common in the population with time and if this process continues, then eventually all the beetles will be brown.
It is claimed that natural selection is also able to shape behaviour. The mating rituals that many birds have, the wiggle dance that bee’s do or the human capacity to learn language, have genetic components.
In some cases, natural selection can be observed directly. Data shows that the shape of finches' beaks on the Galapagos Islands is related to weather patterns: after droughts, the finch population has deeper, stronger beaks that let them eat tougher seeds.
In other cases, human activity has led to environmental changes that have caused populations to evolve through natural selection. A striking example is that of the population of dark moths in the 19th century in England, which rose and fell in parallel to industrial pollution. These changes can often be observed and documented.
‘Fitness’ is a concept used to describe how good a particular organism is at leaving its set of genes in the next generation compared with others with a different set of genes. Going back to the example of beetles, if brown beetles were to consistently leave more off spring than green beetles, then they would be considered to have a higher fitness. Fitness however does depend on the environment in which an organism lives. Also, from this perspective, the fittest individual is not necessarily the strongest, fastest or biggest. What matters is leaving it’s genes in the next generation and so survival ability, finding a mate and producing off spring is more important. This sub-category of natural selection in relation to finding a mate and reproductive behaviour is labelled sexual selection.
Another category of natural selection is artificial selection. This is where, instead of nature, humans consciously select for or against particular features in organisms. For example, the human may allow only organisms with the desired feature to reproduce or may provide more resources to the organisms with the desired feature. Historically, farmers and breeders have used this idea of selection to cause major changes in the features of their plants and animals.
One key aspect of natural selection is known as adaptation. An adaptation is a feature that is common in a population because it seems to provide an improved function. Adaptations can take many forms: a behaviour that allows better evasion of predators, a protein that functions better at body temperature, or an anatomical feature that allows the organism to access a valuable new resource — all of these might be adaptations. For example, mimicry of leaves by insects is an adaptation for evading predators or the use of echolocation by bats to help them catch insects. Similarly, the creosote bush is a desert-dwelling plant that produces toxins that prevent other plants from growing nearby, thus reducing competition for nutrients and water.
To summarise, all of the mechanisms discussed above (mutation, migration, genetic drift and natural selection) can cause changes in the frequencies of genes in populations, and so all of them are mechanisms of evolutionary change. However, it is worth keeping in mind that natural selection and genetic drift cannot operate unless there is genetic variation — that is, unless some individuals are genetically different from others.
A historical perspective
Although Charles Darwin is synonymous with the Theory of Evolution, he was not the first naturalist to propose that species changed over time into new species i.e. that life evolves. In the eighteenth century, a naturalist called Buffon along with others began to introduce the idea that life might not have been fixed since creation. By the end of the 1700s, palaeontologists had swelled the fossil collections of Europe, offering a picture of the past at odds with an unchanging natural world. And in 1801, a French naturalist named Jean Baptiste Pierre Antoine de Monet; Chevalier de Lamarck took a great conceptual step and proposed a full-blown theory of evolution.
Lamarck was struck by the similarities of many of the animals he studied, and was impressed too by the burgeoning fossil record. It led him to argue that life was not fixed. When environments changed, organisms had to change their behaviour to survive. If they began to use an organ more than they had in the past, it would increase in its lifetime. If a giraffe stretched its neck for leaves, for example, a "nervous fluid" would flow into its neck and make it longer. Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations. Meanwhile organs that organisms stopped using would shrink (called vestigial structures).
Lamarck was mocked and attacked by many of his contemporary naturalists such as Cuvier. While they questioned him on scientific grounds, many of them were also disturbed by the theological implications of his work. Lamarck was proposing that life took on its current form through natural processes, not through miraculous interventions. For British naturalists in particular, steeped as they were in natural theology, this was appalling. They believed that nature was a reflection of God's benevolent design. To them, it seemed Lamarck was claiming that it was the result of blind primal forces. Shunned by the scientific community, Lamarck died in 1829 in poverty and obscurity.
In many ways, Darwin's central argument was very different from Lamarck's. He argued that complexity evolved simply as a result of life adapting to its local conditions from one generation to the next. He also argued that species could go extinct rather than change into new forms. But Darwin relied on much the same evidence for evolution that Lamarck did and Darwin wrongly accepted that changes acquired during an organism's lifetime could be passed on to its offspring.
Lamarckian inheritance remained popular throughout the 1800s, in large part because scientists did not yet understand how heredity works. With the discovery of genes, it was finally abandoned for the most part. But Lamarck, whom Darwin described as "this justly celebrated naturalist," remains a major figure in the history of biology for envisioning evolutionary change for the first time.
Throughout the nineteenth century, heredity remained a puzzle to scientists. How was it that children ended up looking similar to, but not exactly like, their parents? These questions fascinated and frustrated Charles Darwin deeply. After all, heredity lies at the heart of evolution.
Ironically, it was just as Darwin was publishing the Origin of Species in 1859 that someone got the first real glimpse of the biological machinery behind heredity. In a secluded monastery in what is now the Czech Republic, a monk named Gregor Mendel was studying heredity in a garden of peas. Through his experiments, Mendel discovered what later scientists called "dominant" and "recessive" alleles i.e. part of genetics.
Darwin and a British biologist called Alfred Russel Wallace had independently conceived of a natural, even observable, way for life to change: a process Darwin called natural selection. Within a few decades, most scientists accepted that evolution and the descent of species from common ancestors were real. But natural selection had a harder time finding acceptance.
Even in 1900, whilst many scientists were rediscovering Mendel's insights, they continued to remain opposed to natural selection. After all, Darwin had talked of natural selection gradually altering a species by working on tiny variations. But the Mendelist’s found major differences between traits encoded by alleles. In order to jump from one allele to another, evolution must make giant jumps—an idea that seemed to clash with Darwin.
But in the 1920s geneticists began to recognize that natural selection could indeed act on genes. For one thing, it became clear that any given trait was usually the product of many genes rather than a single one. A mutation to any one of the genes involved could create small changes to the trait rather than some drastic transformation. Just as importantly, several scientists — foremost among them Ronald Fisher, JBS Haldane and Sewall Wright — showed how natural selection could operate in a Mendelian world. They carried out breeding experiments like previous geneticists, but they also did something new: they built sophisticated mathematical models of evolution.
Known as "population genetics," their approach revealed how mutations arise and, if they are favoured by natural selection, can spread through a population. Even a slight advantage can let genes spread rapidly through a group of animals or plants and drive other forms extinct. Evolution, these population geneticists argued, is carried out mainly by small mutations, since drastic mutations would almost always be harmful rather than helpful.
Thus, population genetics became one of the key elements of what would be called the Modern Synthesis.
In 1937, a Soviet-born geneticist named Theodosius Dobzhansky wrote a landmark book called Genetics and the Origin of Species. Dobzhansky's ability to combine genetics and natural history attracted many other biologists to join him in the effort to find a unified explanation of how evolution happens. Their combined work known as "The Modern Synthesis" brought together genetics, palaeontology and many other sciences into one powerful explanation of evolution, showing how mutations and natural selection could produce large-scale evolutionary change.
While evolutionary biologists were fashioning the Modern Synthesis, geneticists around the world searched furiously for the molecules that carried genetic information. They knew that cells contained several different types of molecules, such as proteins and nucleic acids. But which had the capacity to bear information and be copied into new cells?
The answer came through the discovery of DNA by Francis Crick and James Watson, which revolutionized evolutionary biology. Mutations, researchers realized, change the structure of the DNA. A single base pair may change, or a set of genes may be duplicated. Hence, those mutations that confer a selective advantage to an individual become more common over time, and ultimately these mutant genes could drive the older versions out of existence.
Evidences used by the proponents of the Theory
The mechanisms covered thus far are the basic building blocks of the theory of evolution. The next logical step is to look at the evidence that is given to claim these processes are responsible for both micro and macroevolution. In other words, what evidence is there that evolution has occurred and is responsible for the variety of life around us, and also is there evidence that demonstrates the mechanisms discussed in this article are indeed behind all these changes?
Those who support the theory of evolution present proofs that can loosely be gathered into a number of categories. We will examine these in turn.
The primary source of proof for the theory comes from Fossil Evidence. The argument is that fossil records provide excellent snapshots of the past and when assembled they illustrate evolutionary change over many millions of years.
As well as being actual remains of organisms, and thus giving an understanding as to the shape, appearance and skeletal structure, fossils can give additional clues. For example, they can indicate interactions that took place many years previously. A fossil may contain punctures or holes that could be teeth records of various animals, allowing scientists to extrapolate about what kind of organism may have been responsible, the shape of its jaws, and so on.
Fossils can tell us about the growth patterns in ancient animals. For example, examining a cross section of a bone that has been found, it is possible to see the number of blood vessels; this in turn would indicate the speed of growth and so on.
An important section of fossil records are transitional forms. These are fossils or organisms that show the intermediate states between ancient organisms and their descendents. Since scientists have found so many transitional forms, it is claimed there is an abundance of evidence for evolution. An example of this is the case of the beluga whale. The beluga whale has its nostrils at the top of its skull. A fossil record of an animal that is considered to be related to today’s whales and dolphins, called Pakicetus, had its nostrils at the front of its skull. This animal lived about 50 million years ago. So scientists would expect that there might be a transitional form i.e. an animal that had some variation in the position of its nostrils compared to Pakicetus and the beluga whale. In fact, fossil records have been discovered of a skull, about 25 million years old, where the nostrils are in the middle of the skull. This animal has been labelled Aetiocetus.
So Aetiocetus could plausibly be the transitional form, linking Pakicetus to the beluga whale and demonstrating a steady evolution.
The second source of evidence is garnered from studying homologies. Evolutionary theory predicts that organisms that come from the same ancestor will share similarities. These similar characteristics are known as homologies. As mentioned earlier, the logic is essentially that historically every species shares a common ancestor. As we move forward in time, new species evolve, but since they share a number of common ancestors, so we would expect them to share some characteristics that exist or existed in those ancestors. A crude example would be that of humans and apes. At some stage, going back in time, there was a common ancestor from which both species evolved. So humans and chimpanzees would have similar characteristics, based on the fact that they share common ancestors. Another example of homology is that of leaves. If we were to examine the leaves of say the pitcher plant (which has leaves shaped to capture insects), the Venus Flytrap, the Poinsettia (which has bright red leaves) and the cactus plant (where its leaves are essentially spines) then we would see that each type of leave has a different shape and function. Yet they are all derived from a common ancestral form.
Yet another example of homology is the forelimb of tetrapods (vertebrates with legs). Frogs, birds, rabbits and lizards all have different forelimbs, reflecting their different lifestyles. But those different forelimbs all share the same set of bones - the humerus, the radius, and the ulna. These are the same bones seen in fossils of the extinct transitional animal, Eusthenopteron, which demonstrates their common ancestry.
Comparing the anatomies of different living things, looking at cellular similarities and differences and studying embryological development can reveal homologies.
Studying the embryological development of living things (i.e. prior to birth) provides clues to the evolution of present-day organisms. During some stages of development, organisms exhibit ancestral features in whole or incomplete form. For example, some species of living snakes have hind limb-buds as early embryos but rapidly lose the buds and develop into legless adults. The study of developmental stages of snakes, combined with fossil evidence of snakes with hind limbs, supports the hypothesis that snakes evolved from a limbed ancestor.
Similarly, toothed whales have full sets of teeth throughout their lives. Baleen whales, however, only possess teeth in the early foetal stage and lose them before birth. The possession of teeth in foetal baleen whales provides evidence of common ancestry with toothed whales and other mammals. In addition, fossil evidence indicates that the late Oligocene whale Aetiocetus (the same Aetiocetus - our transitional friend with the nostrils in the middle of its skull), which is considered to be the earliest example of baleen whales, also bore a full set of teeth.
From a cellular and molecular level we find fundamental similarities between the cells of living things, which can be explained by the theory of evolution. All organisms are made of cells, which consist of membranes filled with water containing genetic material, proteins, lipids, carbohydrates, salts and other substances. The cells of most living things use sugar for fuel while producing proteins as building blocks and messengers. Comparing a typical animal cell with that of a plant, there are only three structures unique to one or the other (these are the cell wall, the centriole and the chloroplast). All other aspects are similar, such as the nucleus, cytoplasm and the vacuole.
Comparison of genes between species also reveals striking similarities – for example, even roundworms share 25% of their genes with humans. In many ways, DNA is itself a homology for all living things – i.e. everything has DNA and so this is a common trait that must have come from a common ancestor.
In a nutshell, homologies are used as proof for the theory, since the existence of similarities between groups of organisms is an indication of common ancestors and thus evolution.
A third source of evidence for evolution is the fact that there has been sufficient time for this process to have produced the diversity we see. The age of the earth has been determined through both relative dating (i.e. examining the different layers of rocks on the surface of the earth) and numerical dating which relies on the decay of radioactive elements such as uranium and potassium. The conclusion made is that the timescales involved are adequate for evolution to take its course.
Artificial selection, mentioned earlier, is also an evidence for evolution. This is because people have been using selective breeding with plants and animals for many hundreds of years, and this breeding has shown how species can change dramatically. It can be argued that artificial selection has the ability to modify the forms and behaviours of populations to the point they are seemingly very different to their ancestors. So artificial selection is a model that helps with understanding natural selection.
The variation in the environment and ecology is also a proof of sorts. As predicted by evolutionary theory, populations evolve in response to their surroundings. In any ecosystem there are finite opportunities to make a living. Organisms either have the genetic tools to take advantage of those opportunities or they do not.
For example, house sparrows arrived in North America from Europe in the nineteenth century. Since then, genetic variation within the population and selection in various habitats, have allowed them to inhabit most of the continent. House sparrows in the north are larger and darker coloured than those in the south. Darker colours absorb sunlight better than light colours and larger size allows less surface area per unit volume, thus reducing heat loss — both advantages in a cold climate. This is an example of natural selection acting upon a population, producing microevolution on a continental scale.
Finally, experiments also show that populations can evolve. As an example, John Endler of the University of California has conducted experiments with guppies (a type of fish) of Trinidad that clearly show selection at work. The scenario is as follows: female guppies prefer colourful males for mating purposes. Predatory fish also "prefer" colourful males, but for a less complimentary purpose — a source of food that is easy to spot. Some portions of the streams where guppies live have fewer predators than others and in these locations the males are more colourful. Not surprisingly, males in locations where there are more predators tend to be less colourful.
When Dr. Endler transferred predatory fish to the regions with brightly coloured male guppies, selection acted rapidly to produce a population of duller males. So this demonstrates that persistent variation within a population provides the raw material for rapid evolution when environmental conditions change.
Arguments against the Theory of Evolution
The previous section outlined some of the proofs that are presented for the theory of evolution. We will now consider briefly a few of the arguments against the theory.
1. The theory of evolution is usually described as fact, and many people see it like this due to a moulding of public opinion. Yet the trouble is that it is simply a theory. And like many theories it is wont to constantly chop and change. Indeed we can see on numerous occasions how it has changed over time and undergone revisions. For example, according to Darwin himself, "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down”.
Another example is the proposition of a slightly different model in recent times. Called "punctuated equilibrium", this model rejects the Darwinist idea of a cumulative, step-by-step evolution and holds that evolution took place instead in big, discontinuous "jumps". This is because those who ascribe to it believe the fossil record does not support gradual evolution. Sadly for the proponents, Niles Eldredge and Stephen Gould (American palaeontologists) their own theory is bankrupt – since for one thing, it conflicts with the understanding that genes cannot undergo radical mutations.
2. The sources of proof given for the theory essentially rely on retro-fitting the supposed evidence to the theory i.e. the theory states evolution occurred from a common ancestor, and then study of fossils and homologies is used to indicate that indeed the theory is correct and evolution does occur. But equally we could state there is a creator who created the amazing diversity of life and also the similarities between species – in fact this is more plausible. Thus fossils and homologies would just as much, if not more, support this ‘theory’ of a Creator.
3. Fossils are a record of what may have existed. They do not indicate anything more than this. By examining a fossil we could equally state that the organism was created as opposed to evolving from an ancestor. The fossil record is also very much incomplete – there are massive, gaping holes. This presents a staggering problem for proponents of the Theory. The somewhat weak argument is that the bulk of the fossil record may have been destroyed or is yet to be discovered. According to Neville George, a professor of Palaeontology at Glasgow University:
“There is no need to apologise any longer for the poverty of the fossil record. In some ways, it has become almost unmanageably rich and discovery is outpacing integration…” Yet he goes on to say, “The fossil record nevertheless continues to be composed mainly of gaps”.
Contrary to what evolutionists claim, there are only limited (if any) transitional forms. Importantly, for example, we don’t see transitional forms that show the alleged evolution of apes to humans [and to try and explain the many loopholes regarding this, there is a current debate among evolutionists themselves about whether it occurred in steps or smoothly which we alluded to earlier i.e. punctuated equilibrium]. The fossil record back then (and still today) is nearly totally void of transitional species. If species are continually mutating, never constant, why do we find several of the same, certain prehistoric creatures, but never any that appear to be in transition? Why do palaeontologists find lots of dinosaurs but never where dinosaurs come from, nor what they turned into?
In Darwin's own words, 'Why, if species have descended by insensibly fine gradations, do we not everywhere see innumerable transitional forms? Why is not all nature in confusion instead of species being, as we see them, well defined?' It is an excellent question, which he answers himself, 'I can give no satisfactory answer.'
Indeed British evolutionist Derek Ager admits, “The point emerges that if we examine the fossil record in detail, whether at the level of orders or of species, we find - over and over again - not gradual evolution, but the sudden explosion of one group at the expense of another”.
Yet another problem in using the fossil record as evidence for evolution is that under closer examination, it appears to be a proof for exactly the opposite argument – i.e. creation. For example, one of the oldest strata of the earth in which fossils of living creatures have been found is that of the Cambrian, which has an estimated age of 500-550 million years. The living creatures found in the strata belonging to the Cambrian period seemed to emerge all of a sudden in the fossil record – there appeared to be no ancestors, although in relatively recent times palaeontologists believe fossils have been found dating from the preceding Vendian (or Ediacaran) period. The fossils found in the Cambrian rocks belonged to snails, trilobites, sponges, earthworms, jellyfish, sea hedgehogs, and other complex invertebrates. This wide mosaic of living organisms made up of such a great number of complex creatures emerged so suddenly that this miraculous event is referred to as the "Cambrian Explosion" in geological literature.
“A half-billion years ago, the remarkably complex forms of animals we see today suddenly appeared. This moment, right at the start of Earth's Cambrian Period, some 550 million years ago, marks the evolutionary explosion that filled the seas with the world's first complex creatures. The large animal phyla of today were present already in the early Cambrian and they were as distinct from each other as they are today”.
And one of the most vociferous advocates for atheism and evolution in today’s age, Richard Dawkins, comments “the Cambrian strata of rocks, vintage about 600 million years, are the oldest ones in which we find most of the major invertebrate groups. And we find many of them already in an advanced state of evolution, the very first time they appear. It is as though they were just planted there, without any evolutionary history. Needless to say, this appearance of sudden planting has delighted creationists”.
4. The basic mechanism for gene variation is mutation. And it is known that mutations are random and limited in their scope. We should note that what is not a point of debate here is the fact that genes undergo mutation; neither is there a point of conflict with the various biological processes within organisms. For example, we know that insects can build up resistance against forms of pesticide over time – in fact, in the same manner humans have long believed that taking poison in small quantities can help survive what would normally be a fatal dose. These observations do not really constitute evolution. However, even if we agreed to define these particular cases as examples of microevolution, the fact is that they can be explained by what we have come to know through scientific study and resulting conclusions. The argument for a Creator also accepts scientific facts and conclusions – it no more denies the laws of biology being created, than it denies the laws of physics being put in place by the Creator. Hence, change within the framework of the laws of biology is possible – and there is sufficient evidence for this. The main problem however is with macroevolution. To even begin to consider macroevolution, mutations would need to be dramatic – trying to get round this, it is claimed that there has been sufficient time for many small scale mutations to eventually yield the different species we see. But frankly this isn’t plausible – we have seen no evidence to support such a claim - and so this is again nothing more than a pure hypothesis.
In addition, there are many other problems with the mutation argument. If mutations occur, they actually cause harmful effects and not beneficial ones. We can witness the effects of mutations caused in humans following radiation poisoning at Hiroshima, Nagasaki and Chernobyl – that is, a litany of death, disability and illness.
According to the evolutionist scientist Warren Weavers commenting in the report prepared by the Committee on Genetic Effects of Atomic Radiation, which had been formed to investigate mutations that may have been caused by the nuclear weapons used in the Second World War:
“Many will be puzzled about the statement that practically all known mutant genes are harmful. For mutations are necessary parts of the process of evolution. How can good effects - evolution to higher forms of life - results from mutations practically all of which are harmful?”
Similarly, another scientist B.G. Ranganathan states in his book ‘Origins?’ that “Mutations are small, random, and harmful. They rarely occur and the best possibility is that they will be ineffectual. These four characteristics of mutations imply that mutations cannot lead to an evolutionary development. A random change in a highly specialised organism is either ineffectual or harmful. A random change in a watch cannot improve the watch. It will most probably harm it or at best be ineffectual. An earthquake does not improve the city, it brings destruction”.
Finally, mutations do not actually add any new information to an organisms DNA. During a mutation, the genetic information is either destroyed or rearranged, but since there is no new information, it is impossible for mutations to cause a new trait or organ within a living organism.
5. Artificial selection (breeding) and sexual selection do produce new combinations but these are limited in their scope. They are restricted to a finite set of possible gene combinations. So breeding cannot introduce a radically new species – it simply gives a result based on the limited pool of combined genes. It cannot give a result outside of this. E.g. Horse plus donkey gives a mule. Or an African married to a Caucasian can result in off spring described as half-cast. The latter cannot produce a human whose skin colour is red or purple, etc.
6. The odds are heavily stacked against evolution. Evolution cannot answer where the first cell came from. The best guess is that came about through a random coincidence. Fred Hoyle, a well-known English mathematician and astronomer, and someone who believes in evolution, made the analogy that the chances of the first cell forming in this manner were comparable with the chance that a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials present. And according to Professor of Applied Mathematics and astronomy from University College (Cardiff, Wales), Chandra Wickramasinghe:
“The likelihood of the spontaneous formation of life from inanimate matter is one to a number with 40,000 noughts after it... It is big enough to bury Darwin and the whole theory of evolution. There was no primeval soup, neither on this planet nor on any other, and if the beginnings of life were not random, they must therefore have been the product of purposeful intelligence”. In other words the random formation of such a first cell is an impossibility.
But still let’s assume we suddenly have a cell. The first cell would then have to self-reproduce otherwise there would only ever be one cell. This becomes problematic for evolutionists so they suggest self-replication – i.e. the first cell has the ability to clone itself. However, organic matter can only self reproduces if it exists as a fully developed cell with existing support structures such as the particular environment and energy. This then requires more leaps of faith – so let’s make another assumption, this time that the cell does have a complex structure and the ability to reproduce. But, for evolution, mutation needs to happen. So firstly, since mutation is random, even given an absolute age, mutation might not occur. And secondly, mutation can only take place if the cell is forced to repair itself or if it makes a copy of itself. Thus, for a handful of cells, to copy and mutate successfully and form different cells and for this process to continue onwards to produce the complexity of life we see is something, which cannot happen. Leaving aside time, and the random nature of mutation, just the series of mutations necessary to produce even the simplest of species are impossible.
7. There is no actual hard evidence for the process of evolution itself. We don’t witness evolution. All that experiments (such as the one involving guppies) or observations in the field (such as the house sparrows example) demonstrate is a form of selection. But this is not real evolution – the fact that a population may change due to various factors (such as environment, predators, etc) or that it may become extinct is not a change from one species to another. So even if we can see natural selection of sorts, this is based on rational factors, and is not evolution.
8. Evolution cannot answer why only the human species has the clear faculty of intelligence, thought and reasoning that has allowed it to progress. It cannot explain the existence of emotions, except through an undefined notion such as chemicals within the body. And it is unable to offer any satisfactory explanation for issues such as the existence of the soul – indeed according to evolutionary theory, there cannot be a soul, rather life itself must be caused by the functioning of cells since after all everything has evolved from a single cell.
9. Adaptation is mentioned as a feature of evolution. That is, the manner in which organisms have evolved beneficial characteristics adapted to their environment, which help them survive. So one example we gave earlier was that of stick insects, where their body itself is a form of camouflage protecting them against predators. However, evolutionists themselves state that mutation is random and can lead to beneficial as well as harmful results. The environment cannot influence the occurrence or form of any mutation. So in this case, the evolutionary argument would have to be that today’s stick insects evolved from ancestors, which did randomly mutate to have this beneficial characteristic of camouflage. Those within the population that didn’t inherit this mutation would have died out due to their inability to survive. But once again, claiming that a series of mutations occurred, that lead to stick insects possessing characteristics that are suited to their environment, is nothing but conjecture. As before, we could equally state that a Creator has created various species and organisms of life with these inherent varying characteristics. So, organisms were in fact created with characteristics that we interpret as beneficial to them, instead of these traits evolving through time. Thus, the fact that many organisms seem well matched to their environments cannot be cited as any kind of proof or indication of evolution.
10. Let’s take a look at another argument that shows the fallacy of evolution. Many organisms and parts of organisms do not appear to have evolved from lesser things because they are 'irreducibly complex' life forms. Irreducible complexity is a concept that has been developed to describe something that is made of interacting parts that all work together. To understand this, take the example of a mousetrap. A mousetrap cannot be assembled through gradual improvement. You cannot start with a wooden base, catching a few mice, then add a hammer, and catch more, then add a spring, improving it further. To even begin catching mice one must assemble all the components completely with design and intent. Furthermore, if one of these parts changes or evolves independently, the entire thing will stop working. The mousetrap, for instance, will become useless if even one part malfunctions.
Likewise, many biological structures are irreducibly complex. Bats are a well-known example. They are said to have evolved from a small rodent whose front toes became wings. This presents a multitude of problems. As the front toes grow skin between them, the creature has limbs that are too long to run, or even walk well, yet too short to help it fly. There is no plausible way that a bat wing can evolve from a rodent's front toes. In fact, the fossil record supports this, because the first time bats are seen in the fossil record, they have completely developed wings and are virtually identical to modern bats.
Consider another example, that of the eye. Suppose that before animals had sight, one species decided it would be advantageous to be able to decrypt light rays. So, what is evolved first? The retina? The iris? The eye is made of many tiny parts, each totally useless without the others. The probability that a genetic mutation that would create each of these at the same time, in the same organism, is zero. If, however, one organism evolved just a retina, then the logic of Darwin suggests that the only solution is to rid oneself of useless traits replacing them with beneficial ones, so the idea of the eye evolving one segment at a time is also bogus.
Conclusion
In a time where the theory of evolution has been catapulted to the level of fact, it is useful for us to have a firm grasp of what this theory is, and with the emerging discussion gaining more and more profile (that between creationism on the one side and evolutionary thought on the other) it is vital that we are able to show the strength of the correct argument.
One big problem of presenting the topic of evolution is finding a reasonable balance: on the one hand, simplifying and leaving out some of the terminology risks not being able to convey the subject matter accurately; on the other, by not revising and simplifying at all, there is a distinct possibility that only those with a solid understanding of biology and science will grasp what is being presented. This article has attempted to run through the basic mechanics of the theory, proofs that are presented for it and some of the arguments against evolution. Many points are too elaborate and wide ranging to touch upon in this discussion. In any event, there is an abundance of material available regarding the theory and surrounding issues that discuss these aspects in much more detail and is worth exploring for those that are interested in doing so. The theory is often cloaked in scientific language and complex terminology, and presented as a solid and viable explanation for the existence of life. Although the focus and objective of the article was not to prove the fallacy of the theory, but rather to be informative with respect to the whole discussion regarding evolution as a concept, nevertheless it has hopefully been shown that evolutionary understanding, far from being fact, is nothing more than speculation and hypothesis.
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Comments
may Allah give you ajar for writing this.
what is the correct view with this issue??
jzk
Brother. Concerning the "Ilm ul ghaib" - the knowledge of the unseen, we humans should not even participate in these matters and should not talk about them. When Allah swt says He has risen over His throne (32:4), that's all we need to know. We don't and we strictly shouldn't discuss the whereabouts of His throne, how does it look like, how heavy it is, etc because 1) He swt hasn't told us of these issues and 2) what benefit will it give us. The classical scholars and indeed some of the tabieen never even divulged into these discussions.
Hope that helps inshallah and may Allah swt forgive me if I have said anything wrong