Change is constant in our cosmos. These progressions have steered to life; and even life is a subject to change. What kind of change? It began with a prominent scientist named Charles Darwin. The theory of evolution by natural selection, first formulated in Darwin’s book “On the Origin of Species” in 1859, is the process by which organisms change over time as a result of changes in heritable physical or behavioural traits. Changes that allow an organism to better adapt to its environment will help it survive and have more offspring; but Darwin is unconsciously studying the effects of something much bigger science yet-to-know discovery of all time – the molecular blueprint of life known as DNA.
Evolution is fascinating because it attempts to answer one of the most basic human questions: Where did life, and human beings, come from? The theory of evolution proposes that life and humans arose through a natural process. A very large number of people do not believe this, which is something that keeps evolution in the news. Billions of years ago, according to the theory of evolution, chemicals randomly organized themselves into a self-replicating molecule. This spark of life was the seed of every living thing we see today (as well as those we no longer see, like dinosaurs). That simplest life form, through the processes of mutation and natural selection, has been shaped into every living species on the planet.
Evolution is a process that began billions of years ago and still runs up to this day. Evolution has told us how the colossal diversity of life advanced. It showed us that how ancient bacteria can be the ancestor of millions of species living to this day. Evolution answers the question of why are there so many physical dissimilarities we have like seeing a domesticated cat similar to a wild cat such as a lion. How is it possible to have an ancestor that looked so different to them?
Evolution is the development of life on earth. To comprehend it much better, we need to take a closer look at the animal kingdom excluding fungi, plants, bacteria, and Protista. First, let’s ask question on how can a single animal developed to several species. Speaking of species, what is species exactly is?
Species is a group of living organism that is capable of reproducing to one another. A dog to a dog or a cat to a cat is an example of species while their offspring are also able to reproduce in recurrence. A dog will produces a dog while a cat produces a cat. To understand it better we need to know certain points: First, the uniqueness of every organism is guaranteed by excess reproduction of offspring and heredity, second, the natural selection.
- Evolution may proceed because of uniqueness.
Uniqueness is simply being unalike from others. Every creature is of unique specimen which by then essential to the progression of evolution. Your sibling might look similarly as you but both of you have something in different. One of you might be smarter, braver, bigger, smaller, taller, etc. but what is the reason of your differences?
Every living creature has cells. These cells have nucleus. A nucleus has chromosomes. Chromosomes have DNA. A t molecular level, these DNA comprises of genes. Genes are considered the blueprint to which how our body should behave or appear physically. They contain orders from your parent’s cells the traits you will soon display. Precisely, this DNA is unique to each creature. But how is this enormous differences created?
- The excessive production of offspring.
One key factor of uniqueness is the excess production of offspring. This happens when parents produce more offspring than it should. The more offspring, the more diverse the gene pool to be selected. Creatures are wired to produce more for the survival of their own species. Competition to their surrounding and even to their siblings has initiated death to some unlucky beings. And this is what Nature wants, the more little differences the better and more diverse it is.
- The second major cause of uniqueness is heredity.
This time it doesn’t take place only to the offspring itself but to the offspring which became parents. Heredity means the forwarding of DNA to offspring. This time, the genes are handed down for the progression of generations to follow. We all familiar with heredity when our ancestors have given something to us as an heirloom such as house or a necklace but this heredity is all away down at molecular level where your actual cells behave as they are according to the genes your parents have given you. There two key things that happen in this process – the recombination and mutation.
- Recombination affects the hereditary materials that make an offspring.
The recombination is the random mixing of genes of two different creatures. When two creatures mate, they recombine their DNA twice. The first time they do this is individually; inside their body they form sperm cell and egg cell. The gametes take half of the genes and shuffle them. The second one happens when a male inseminates a female. Their genes are randomly shuffled again and thus forming a new offspring – fifty per cent from father and fifty per cent from the mother. These offspring has random characteristics their parents have producing diversity towards their genes even further.
- Mutation is also important for evolution.
Mutations are random changes in DNA itself. Right here, the body has not control over mutation but rather it is an occurrence of a molecular mistake triggered by toxins, chemical substances or radiation. This point in time, the DNA is altered can form some serious changes. This can be harmful or beneficial to an organism. Some mutations can develop diseases like cancer or oddities like blue eye colour in humans. It is the sperm or the egg is affected with this because they are the only DNA in the gametes is passed in the offspring. When these irregularities passed to the offspring, the diversity of life will soon be vaster.
In conclusion, recombination and mutation change the DNA so that each child looks different to its siblings and receive a random mix of the characteristics of their parents creating further diversity. The key word here is “random”. All of these processes are based on chance. But, how there could be such chance if organisms are perfectly random to their environment? The answer is natural selection. Each individual is subjected to a process called Natural Selection.
- Natural Selection as Darwin theorized.
As stated before, each animal is different from the other and there is an extensive variation within a species. The effects of changes not only happen inside but also from the outside environment. These are selection factors which include: predators, parasites, animals of the same species, toxins, and changes in habitat or in the climate. Now, every creature has different mix of traits and characteristics which will help them cope with certain environmental factors or not as the case may be. Anyone with unsuitable mix will be cast off from living while creatures with suitable characteristics for their environment remain to continue its line. This is why diversity is important – the survival of the fittest.
This is why creatures need to produce different offspring as much as possible as nature permits. They increase the likelihood that at least one of their offspring passes nature’s gene filtration process. They maximize their chances of survival. This is how new species is created by evolution: through the interaction of unique individuals, the excess production of offspring, recombination and mutation in heredity, and finally, through selection.
Why is this so important? It tells us where the variety of life comes from and why living creatures are so perfectly adapted to their habitats. But it also affects us personally. Every person is the result of 3.5 billion years of evolution, and that includes you. Our ancestors fought and adapted in order to survive. This survival was extremely uncertain thing. If we consider the fact that 99% of all species that have ever lived are extinct, then you can consider yourself part of the success story. The dinosaurs have disappeared but you are alive because you are incredibly special, just like other creatures that exist today – irreproducible and unique in the arms of cosmos.