How Evolution works - the journey of billion years

The mechanisms of evolution What is evolution? Evolution is the development of life on Earth. It’s a process that started billions of years ago and continues today. Evolution explains to us how life has developed in an extremely varied way. It shows us how the first Protozoan was able to transform into the millions of different species that we know today. Evolution is then the answer to the question we all asked ourselves when we saw a Dachshund and a Great Dane together:

How is it possible for ascendants to have descendants so different from them? 

To answer this question, let's take a close look at animals, excluding other life forms such as fungi and plants. The first question to ask is this:

Photo by Eugene Zhyvchik on Unsplash

 how can a single animal develop into whole new species of animals?

 Ah, just a quick question before that: what exactly is a species? A species is a group of animals capable of reproducing among themselves, with offspring also capable of reproducing in turn. To better understand this answer, we need to focus more specifically on the following points: The singularity of creatures, guaranteed through excess reproduction and heredity, and a second key point: selection. Let's start with the singularity. Every creature that exists is unique, and that is essential for evolution. The members of a species may be very similar in appearance; however, they all have slightly different characteristics and features. They can be a little bigger, bigger, stronger, or thicker than their companions.

what is the reason for these differences?

 Let's take a closer look at a creature. Every creature is made of cells. These cells have a nucleus. The nucleus contains the chromosomes, and the chromosomes carry DNA. DNA is made up of different genes, and it is these genes that carry the information of life. They contain the instructions and orders to communicate to the cells, and determine the characteristics and traits of the creature concerned. And it is precisely this DNA that is unique to each creature. It is slightly different from one individual to another, and that is why each has slightly different characteristics.

But how was this huge piece of DNA created?

 One of the key factors is the excessive production of offspring. In the wild, we can observe that creatures generally produce much more offspring than is necessary to the survival of the species, with many premature deaths of their offspring. There is often even more offspring than the environment in which they are born can support. It is one of the factors that increases the diversity of a species. The more descendants produced, the more there are small differences from one to the other, and that's what nature wants: as many small differences as possible.

 The second major cause of the singularity of individuals appears in heredity itself. In fact, heredity means the passage of DNA to its descendants. Two very interesting factors come into play in this process: recombination and mutation. Recombination is the random mix of DNA from two creatures. When two creatures fall in love and mate, they recombine their genes twice. The first time, they do it on their own when they generate gametes - that is, sperm and egg cells. Gametes take half of the genes and mix them up. The second recombination takes place when the male inseminates the female. Parents each provide 50% of their DNA, in other words, 50% of their own traits and characteristics. They are then recombined, or mixed, and all this gives new offspring. These descendants have a random mixture of DNA, and therefore of the traits and characteristics of their parents.

This increases diversity and differences within the same species even further, but mutations are also important for evolution. Mutations are random changes in DNA. They can also be described as copy errors inside DNA, triggered by toxins or other chemicals, or by radiation. A mutation exists when part of the DNA is damaged. These changes are often negative, and can result in diseases such as cancer. However, they can also have neutral or positive effects, like blue eyes for humans, which is the result of such a mutation. In all cases, a mutation must affect a gamete, whether male or female, because only the DNA of the gametes is transmitted to its descendants. This is also the reason why we protect our sexual attributes during X-rays, the other parts of our body being less risky.

 To summarize, in the process of inheritance, creatures transmit their characteristics to their descendants in the form of DNA. Recombination and mutation modify the DNA so that each child is different from its parents, and receive a random mix of characteristics from their parents. There is a keyword here: random. All of these processes are based on luck.

Random recombination and mutations give individuals with random traits and characteristics, who in turn mix these randomly, and transmit them. But how can one be so dependent on luck, when all living creatures are perfectly adapted to their environment, for example, the stick insect, the fly bird (hummingbird), the frogfish (antennae)?

 The answer is provided by the second key point: selection. Each individual is subject to a natural process of evolution. As we have seen, each individual is different from his neighbor, and there are endless variations within the same species. Environmental influence has an effect on living creatures. These factors include: predators, parasites, animals of the same species, toxins, changes in habitat, or climate. Selection is a process to which each individual is subject.

Each creature has a unique blend of physical and characteristic traits. This mixture helps them to survive in their environment, or not, as the case may be. Whoever has an improper mixture will be rejected from his environment. Those with the right mix survive, and can pass on their improved and adapted traits and characteristics. This is why diversity is so important. This is why the creatures make so much effort to produce as different offspring as possible. They increase the likelihood that at least one of their offspring will pass the natural selection process. They optimize their chances of survival. to illustrate this, take the example of this group of finches living on an isolated island.

The story of finches

These are among the most famous animals in the world of science, they are known as the "Darwin finches" after they discovered them, and here is the story of these finches. A few hundred years ago, a small group of finches was discarded on the Galapagos Islands in the middle of the Pacific, probably by a big storm. The finches were in a completely new environment for them. A true finch paradise: plenty of food and no predators. They reproduced quickly and in numbers. The islands were quickly invaded by finches. As a result, food became increasingly scarce. Finch paradise was threatened by famine, and friendly finches became competitors. It was at this point that the selection took place. Their individualities and their small differences, in our case their slight differences in mouthpieces, had the effect that some of these birds were not put in competition with their congeners. The beaks of some of these finches were more suitable for digging and finding earthworms. Other finches were able to use their beaks to break seeds.

Finches somehow created ecological niches, in which they were abstracted from the stiff competition from other finches. They quickly started to mate preferably with finches from the same "niche". After several generations, these particular characteristics were optimized, allowing finches to exploit their niches properly. The differences between worm eaters and seed crackers became so great that they are no longer able to reproduce among themselves. Different species have emerged. Today there are 14 different species of finches living on the Galapagos Islands, all descendants of the same group of finches stuck.

This is how new species are created by evolution:

Through the interaction of unique individuals, excessive production of offspring, recombination and hereditary mutation, and finally, through selection. Why is it so important? This explains where the variety of life comes from, and why living creatures are so well suited to their habitat. But it affects us personally. Everyone is the result of 3.5 billion years of evolution, and that includes you too. Your ancestors fought and adapted to survive. This survival was extremely uncertain. If we consider the fact that 99% of species that once lived today are extinct, then you can think of yourself as the successful part. The dinosaurs are gone, but you're alive, because you are incredibly special, as are all of the beers that exist today: irreproducible and unique in the universe.

No comments:

Post a Comment

We Specialize in

Suggesting Career paths

We help you to decide which path to choose as a career to succeed.

Search your dream job

We provide you with Latest job vacancies listings, and guides to help you land on your dream job.

Interview tips

We give you tips to prepare for a job Interview, and tackle odd situations.

Skill Development

We help you elevate your career, by enhancing your skills through various guides.

Career Change

We guide you, in times you need to change career paths.

Job vacancies Updates

We provide you with latest updates regarding jobs from private and Government sector.