Variation

Variation is the marked difference or deviation from previous generations of the same species. It is the reason that no one is matching to anyone else except with the rare occasions of identical twins. It’s the reason that while we all come from the same species we all look different, why kittens from the same litter may have different coats, or why the new is never quite the same as the old.

The premise of variation comes from Darwin’s theories on natural selection which he developed during his travels on the HMS Beagle in 1838 whilst acting as a Natural Philosopher for the ship. When the voyage started he was still in training to be a pastor, a firm believer in God and the creation of life by God; but on that voyage he came across evidence that would change the world. Not only did he realise that the ‘Noachian Flood could not have happened in the manner of the bible’, but also that the creation story could not be true except over hundreds of thousands of years. This he realised in the Galapagos Islands through the finches and the tortoises and other animals from the areas which, strangely enough, varied from island to island.

How could he explain why the finches on one island had a different shaped beak to the next? Or why the tortoises on the more rocky islands had longer necks with peaks in their shells unlike those islands with more foliage? Why was there so much difference between each island when obviously they were all the same species? Darwin realised that all finches must have had a common ancestor on the mainland, just as the tortoises did, and as he began to realise one thing the rest began to fit into place and his conclusions lead him to his believe in the three key stages of evolution.

Firstly a plant or animal would produce a large amount of offspring, each with individual variations to the parent; then would come a struggle for survival. Those born with beneficial variations would survive whereas other would not, leaving on those who could survive to produce more offspring and the cycle would go on, each time those with better adaptations to another would survive and pass on the right genes. Nature, Darwin decided, was ‘all about the survival of the fittest’, and after the death of his eldest daughter, he went back on his word to Captain Robert Fitzroy of the HMS Beagle and published his book, the Origin of Species. This novel, complete with the three stages he had witnessed during his travels, was destined to become not only one of the most controversial reads but also one of the most influential.

If variation was the slow changes between generations though… How was it that it seemed an entirely new species had been developed from the original? It seemed that variation could be continuous to such an extent that it did in fact create a whole new breed of animal. This is what had happened with the diverse differences were passed on over so many generations it became ingrained into the genotype and hence the phenotype of the species, creating an entirely new one.

Genes and the realisation that it was those which dictated the variables that changed species came later. Scientists revealed that variation was caused by the change in the arrangement of genes and the DNA within them. This was why in some cases the variation was continuous, causing adaptations such as with the tortoises and finches, and why others were discontinuous as with eye colour or hair colour. Darwin, of course, did not know of genes to the extent that we did, he simply understood the principles of phenotype.

Today, we see variations everyday; in each other and in the rest of existence. Each time you see a nest full of eggs or a young baby in a perambulator, we are seeing natural selection in action. Each of the new generation will be different to the parents and over time characteristics will be ingrained into the family. It increases biodiversity in the same way, as each of us turns out different to our ancestors new genotypes are formed and the chain carries on. It’s one of the most important reasons for variation; survival and multiplicity.