One huge problem with evolutionary theory is how big changes could take place at all. For all living creatures, the link between one generation and the next is DNA (Deoxyribonucleic Acid), the amazing code struc­ture that describes every feature of an individual. Criminals have been convicted in recent years when traces of their DNA left at the scene of a crime have been picked up by police investigators, sometimes decades later. What exactly is DNA?

We have become used to talking about ‘digital’ information – digital television, digital sound re­cording and digital cameras. What we mean is that a detailed description of the sound or picture is being transmitted as a string of standardised units with spaces between them, which can be reassembled at the other end into an identical musical sound, or photo, or word.

Older readers will remember Morse code. This was a system for transmitting words by wire or radio. Each letter of the alphabet was represented by a se­ries of dots or dashes. A dot on paper became a short sound on the radio, and a dash a long sound. Thus the letter ‘S’was dot, dot, dot, space, and the letter ‘O’ dash, dash, dash, space. So if a coastguard heard on his headphones “··· _ _ _ ···” he knew someone was sending out an ‘SOS’, which was the international appeal for aid (short for “Save Our Souls”).

Instead of a dot and a dash, modern computers use ‘switched on’ and ‘switched off ’ as the two alter­native states, represented by the symbols ‘I’ and ‘0’. Rather like Morse code, these are built up in strings of ‘I’S and ‘0’S, followed by a marker to indicate the end of the string. So, for example, the letter A could be represented by 0001, B by 0010, C by 0011 and so on. In music, the air pressure from each sound is sampled many times a second and its value recorded as a string of ‘I’S and ‘0’S, followed by a marker. Enormous strings of these on/off pairs, stored on a memory stick or a rotating hard disk or a DVD, are used to define the first chord of a Mozart concerto, or the top left corner of a picture of the Mona Lisa, or the text you are reading now. We use tiny memory cards, inserted into our camera or mobile phone, to store huge amounts of this digital information in a small space – hundreds of pictures, or a thousand songs. New, even more compact devices are coming along all the time.

Nature’s digital code

Long before the digital age began, an incredibly more sophisticated system of information storage was being used inside every living cell. In living cells, instead of two alternatives (‘on/off’), the DNA information string is constructed from a choice of four slightly different chemical ‘bases’. The bases are assembled like rungs on a ladder. The side pieces of the ladder are made from sugar and phosphate. Each rung of the ladder is built from a alternative chemical ‘bases’. These can be labelled ‘A’, ‘G’, ‘T’ and ‘C’. In practice, ‘A’ and ‘T’ always go together to make up a rung, and ‘G’ is always linked to ‘C’. Generally the individual bases on one strand are then grouped in sets of three to make up one unit of information. This gives a total of sixty four possible combinations. However, the same unit of information can be built up from more than one triplet sequence. In practice, the 64 possible triplet combinations in DNA act as codes for 20 standard units of information, plus a ‘stop’ code to mark the end of a string. This information system is therefore considerably more powerful than the two possible combinations in our computer systems. The reason why 20 is such an important number we shall see in a moment.

Your chromosome library

The whole ladder, which can be hundreds of mil­lions of rungs long, is twisted into a tight double helix, shaped like the springs in an exercise ma­chine, to compress it into a tiny space. Packaged into a sausage-like outer envelope, it is called a chromosome. Human beings have 23 pairs of chromosomes inside each body cell. It has been calculated that in one human cell the total length of the ladders, stretched out, would be about two metres (only a powerful electron microscope could see this detail). So efficient is this DNA coding system that it has been calculated that it could store all the books that have ever been written in the space occupied by a pin head. In fact, inside every cell of your body is a complete definition of how to construct you as an individual, right down to the size of your ears and the dimple on your chin, plus instructions to tell you how to suckle your mother’S breast within minutes of being born, and how to walk, and run, and reproduce.

How is the information in the chromosomes used? The bodies of all living creatures contain thou­sands of different kinds of proteins, and proteins are strings of amino acids – like pearls on a necklace. There are twenty different amino acids – the basic building blocks of life. When the code from the ladder of DNA bases is read back in a living cell, the information is used to place new amino acids one by one in a particular order. (Actually, some parts of the ladder are thought to control how the amino acids are used by the cell).

Let us follow what happens when a simple one-celled organism divides. First, the DNA ladder is split in half lengthwise, and a mirror image of each half is generated, with all the millions of bases A, G, T and C replicated in the original order. After this the original cell splits in two, and one complete copy of the ladder passes into each daughter cell. We now have two identical cells instead of one, each with its own string of DNA to tell it what to do.

Against change

This process for cell division and reassembly is extremely reliable. In fact the only possibility for permanent change to occur between one genera­tion and the next is through a re-arrangement of the DNA sequences, called a mutation. Mutations are rare, and random, but they increase during exposure to radiation or powerful chemicals. They usually result in a loss of a feature that was there before. For example, the ancestor of today’S egg-laying hen was the Jungle Fowl of Borneo. The male Jungle Fowl is a very colourful individual, but the female is camouflaged with spots on her feathers. Over the centuries of domestication, mutations have resulted in a loss of colour, so that modern hens are plain brown or white. Often mutations are harmful. A white hen is fine in a farmyard, but a white Jungle Fowl would be very obvious as she sat on her eggs. Losing her colours would be fatal. It would betray her position to her predators. Cancer cells also contain mutations which cause them to divide very rapidly. Mutations are present in diseases like sickle-cell anaemia. Fortunately the body has repair mechanisms that identify and correct or eliminate most mutations as soon as they occur, so that they do not survive.

The important point is that over time periods measured in thousands of years (evolutionists would claim millions of years) this system of reproduction, rather than encouraging change, actually prevents it. For example, scientists have carried out experiments on fruit flies, inducing mutations with chemicals to try to breed a new species. All that happened was that as more and more mutations were introduced, the fruit flies become sterile. They were clearly identifiable as fruit flies, but they were unable to reproduce so that no changes could be passed on to another generation. Species like bees have remained essentially the same over very long periods of time. Bees have been found, trapped in beads of fossil am­ber, which look virtually identical to modern bees. Even over hundreds of thousands of generations, no changes have taken place. Darwin assumed that if a new, useful characteristic arose in one generation it would automatically be passed to the next. But modern genetics shows that the whole system tends to preserve the status quo, and rather than adding an advantage, most mutations are harmful. This does not leave much scope for an increase in complexity. Small changes are possible, because within the gene pool of each species there are variations which will permit a moth, for example, to become darker or lighter. But it still stays a moth. It does not change into a new species.

The DNA programme

Before we leave this topic, we need to ask how this incredible system for recording information came about in the first place. Every living creature, from a ‘simple’ one-celled bacterium to an enormous blue whale, has the same four-base DNA coding system. It is the arrangement and order of the bases in its ‘ladder’ that provides the instructions to make that individual or plant unique. The DNA helix is like a computer programme. Read off from one end, rung after rung, it instructs the very first cell that is formed, when the male human sperm fuses with the female egg, to divide repeatedly. Somehow (the mechanism is still not understood) some of these new cells then read off from their DNA an instruction to cluster together to create, say, a liver cell, or part of the heart, or the lens of the eye. Within seventy-two hours, all the basic parts of your body were laid down. A different DNA ‘programme’ produces a horse, or a bed bug.

What is the implication? Without the DNA ‘programme’, the most primitive form of life would not have been able to reproduce. The simplest cell capable of reproducing contains at least three hundred proteins. And each protein is made up of a string of between 50 and 1000 amino acids long, which have to be present in a precise order for that protein to work. The manufacture of each of those proteins is controlled by a corresponding sequence of bases in the DNA ladder. Let us suppose that in conditions of warmth, in an environment with a range of atoms, perhaps in a deep sea volcanic vent, certain chemical reactions took place which created a range of simple amino acids. These would be useless alone. They need to be joined together end to end to make a useful protein. To control the assembly of the string, we would need the DNA ladder. Suppose there was also a selection of bases available, plus sugars and phosphates to provide a framework to support them. What chance would there be of these bases arranging themselves in a ladder formation, with a meaningful sequence? It does not make sense. Yet without the DNA ladder to ‘remember’ the correct order of assembly, the process could not be repeated. We could not have life on earth, because by definition a living cell must be capable of producing a copy of itself to continue into the next generation.

The evolutionist at this point usually says, “Well, it is here now, so it must have happened!” But that is not logical. An independent mind, examining such a brilliant system of recording information, would recognize it as a masterpiece of engineering. Such recording devices never come about without an intelligent designer or a team of designers who think it all through.

After thousands of years, the nearest our in­formation technology specialists have come to it, is the memory card in a mobile phone. But that is clumsy, by a factor of millions to one, compared to this minute mechanism that controls every cell in your body, and runs it for a lifetime, and directs it to reproduce before you die, so that there can be a son or daughter to take your place.

What we are saying is that the cell, the most basic unit of life, is so complex that it demands a designer. The Bible says that designer was the Lord God. The record in Genesis chapters one and two is a summary. It does not tell us how God did what He did. It just says that He took the dust of the earth, built it into man, and then breathed into the inert body the breath of life. Only in the last century have we been able to decipher what goes on inside the cells that make up that remarkable body.

The Design Argument

This approach, examining the mechanisms found in some of the amazing creatures and plants that populate the globe and asking, “could these have come about by chance mutations?” is often called “The Design Argument”. It requires no deep technical knowledge. It is the approach of a child, questioning the world in which they find themselves. Sometimes a child can see the wood, while grown-ups with university degrees are busy focusing on the trees! Jesus said that unless we have the outlook of a child, we cannot enter the Kingdom of God.

What we propose to do now is to look at some fascinating examples of the way plants and animals live and reproduce, and then ask the question – “could this have evolved?”