Our evolutionary journey

So what is evolution?

Evolution is the process of development of life on earth. The process which started billions of years ago is still continuing till today. Evolution tells us how this process of such diversification of life developed. It is because of evolution that the primitive protozoa became so many different species we see today and also the ones that are already extinct. It is the answer to why we see the cat and the dog together in our neighborhood.

But how is it possible that from the same ancestors we as the descendants look so different? We will focus on the animals and exclude the fungi and plants. The first question that arises is how it is possible for one animal to develop into a new species of animal.

But first let us see what a species is?

It is a group of similar animals that has the capability to produce offspring’s by mating and to continue this process one generation to the next. The uniqueness of a creature can only be guaranteed by excess production of offspring’s and heredity and the process of selection.

Uniqueness. Every creature is unique and this is important for evolution. The members of a particular species will have almost similar appearances but the traits and characteristics will differ slightly. One may be bigger, the other may be smaller, and another may be fatter than their fellow animals. What is the reason for these differences? Every creature on this earth is made up of cells and each cell has a nucleus which in turn hold the chromosomes and which in turn hold the DNA. DNA has the genes which are the information carriers of life as it carries all the instructions for the cells which in overall determine the characteristics and traits of that particular animal. Everyone has its unique DNA that’s why each of us is slightly different.

This amounts to an enormous range or variety of DNA’s. When humans were 1 billion in population then there were so many different range of unique DNA and now with more than 7 billion, the range of DNA is also increasing. One key factor is the excess production of offspring’s. More the offspring, more the variety of DNA. In nature we notice that every animal produces more offspring than required for the survival of its species and many of these offspring’s die in young age. With more offspring there are more little differences from one to another. This is what nature demands – many offspring’s with as many small differences as possible.

Heredity. It means the passing of DNA to the offspring. This process involves recombination and mutation. When two creatures mate they recombine their genes two times. The first time it happens in the individual body in the sperm and end cells. The sperm and egg cells take half of their genes and shuffle them that is each sperm and egg is carrying 50 percent of the traits of its host. The second time it happens in the process of mating when the male inseminate the female. In mating when the sperm and egg meets it completes the 100 percent and thereby producing a unique offspring. So now the new offspring has a random mix of DNA giving it its unique characteristics and traits taken from the parents. This increases the diversity within the species.

Mutation is also important that makes random changes in the DNA. It can be due to radiation or harmful chemicals. So in a life time the mutation of DNA can occur and its effect is mostly harmful like causing diseases. It can also have other neutral effects like the blue eyes.

All these processes are random.

Selection. Environmental factors like predators, toxins, habitat, climate and parasites have effect on living creatures. Every individual creature is subjected to the selection process. The uniqueness of individual creature decides its surviving the environment or not surviving it. Anyone with an unsuitable mix will be weeded out. The right mix will help them survive and give the opportunity to pass on their genes. This is the reason diversity of creature is important and for this reason creatures produce more offspring as possible. This increases the chance of at least one offspring pass on the nature’s selection process. The chances of survival of that species are maximized.

The following real story will make things clearer as to how this whole process works:-

A few centuries ago a group of finches (a particular kind of bird) were most probably blown by a storm from their original habitat to a group of island in Galapagos in the Pacific Ocean. Now they were in a new environment where they had enough food source and no predators to be afraid of. So they reproduced rapidly but it also resulted in the food supply getting scarce. This is where selection process intervened. Their uniqueness were in there beaks. Some had beaks which were suitable for digging worms out of the earth and some were suitable for breaking seeds. Soon they started to mate with their own specialty type. Over many generations these different characteristics got enhanced and led to the evolution a new species of finches. Now there are 14 different species, all descendants of the first group of stranded finches.

Why is it important? Because it tell us how so many varieties of species developed that are adopted to their environment. Every species including you have gone through 3.5 billion years of evolution. Our ancestors fought and adopted to survive, but it was an extremely uncertain thing. You are the part of the success story considering that about 99 percent of all the species are extinct.

The dinosaurs are extinct but you are alive reading this boring article because you are super special- just like all other creatures you see around you. We are unique in the universe until we get weeded out by any of the process mentioned above.