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Natural Selection

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Earth is a planet that is fulfilled with various kinds of species. They might be a species of plant or animal. There is a specific process behind this large number of species. The process is known as Evolution. Evolution is a never-ending process. And this process is still going on in nature. Evolution states that all the species that exist in this nature come from one single species. Time by time, from that species, many more species developed in nature. But Evolution can’t able/ to do this form of operation. Evolution is not a single process. Rather, it is the combination of some process or subprocesses. Among those processes, one of the very important processes is Natural Selection.

What is Natural Selection?

Natural selection is the process or sub-process in Evolution. Scientists seem natural selection is the key driving force for evolution. This process act as the external pressure on the species to evolve. A particular species is evolved by the pressure of the external force in such a way that the species can able to survive in the changing nature, then that external force is known as Natural Selection. And the species that survived in nature will be called the Nature Selected Species.

In a certain nature, there might be some species available. But suddenly, there might be some changes in nature. This change might happen from nature itself. Or sometimes external factors are responsible for the changes. Whatever the reason behind the change is, there are some changes in nature. Now, in the changing nature, the species are being forced to change their features according to the change of nature. This is important to survive in that certain nature. This external pressure on the species is termed Natural Selection. If the species can survive in nature, then they will live. Otherwise, they have to go extinct from nature.

Also Read- Darwin Postulates

Mechanism of Natural Selection

The mechanism of natural selection is a process that can be divided into five sub-processes. These are the subprocesses that play an important role in the Evolution process. Subprocesses might not be any specific process, but they have a large importance in natural selection. That is why they are accepted as a step in natural selection. The mechanism process of natural selection is termed the VISTA process. This term is obtained from the beginning letter of the processes. These processes are Variation (V), Inheritance (I), Selection (S), Time (T) & Adaptation (A).

  • Variation (V): This is not the integrated process in the mechanism of Natural selection. Natural selection doesn’t start the variation process in any species. Variation is the process that comes from a genetic mutation. Also, environmental change starts the variation process. In a species, two different subspecies occur due to the variation. The variation is the trigger point in the natural selection process. If a species has many variations, then there is a need to have a competition to survive in a harsh environment. From this background, the natural selection process starts.
  • Inheritance (I): Now, this is the step from where the natural selection starts running. As the competition in different variations takes place. There is a need to gain new traits for the species to live in that harsh environment. Through the willingness of the species, they gain new traits between them. But it is not the end. It should be transferred to the next generation. This transfer process is executed by the inheritance process. Whatever new trait is gained by the species, should be transferred to the next generation for the few other steps of natural selection.
  • Selection (S): This is the core process of the natural selection process. When the new trait is available in the species, then this process starts. This means, when a species is ready to face the challenges of nature, then this process starts. Now, it is the time to prove the fittest to survive. In the variations of the species, those who have successfully inherited the traits among them can able to survive in nature. All the other species will disappear from nature. This is the selection process of nature. This is the main vital step among all of these steps.
  • Time (T): This is not considered a step in natural selection. The Time step referred to the normal period. Here, some amount of time provides for the surviving species to stabilize. After the selection process, when many variations will disappear from nature, there is a period provided to let them stabilize. This time frame can be a million years.
  • Adaptation (A): Now, as the species are survived in nature, and they also spend a large amount of time in the harsh environment, it is time to adapt to the changes. This means, whatever trait is gained in the inheritance time, will be adopted by the species. This means, that the next generation will have that trait in them to survive in nature for again millions of years. This adaptation will help them again in some harsh environments. This adaptation might be so intensive that, the species changes itself to completely a new form. This means from one species; they developed another species. This is the core & simple process of natural selection. And from this evolution takes place.

Types of Natural Selection

During the natural selection process, there is the existence of three types of subspecies of a particular species. These subspecies might be different based on some parameters. Like one sub-species might differ from another sub-species by color. Sometimes, they are different from each other by their weight. These are the parameters. Often scientists disagree to call them subspecies. As they belong to the same group or species. But due to genetic mutation, there might be a change in offspring color, weight, etc. These parameters play in the types of natural selection.

There are three types of Natural Selection are present. These types are formed by the existence of the parameter of nature.

  1. Stabilizing Selection: In this type of selection process, for any certain condition, the intermediate parameter will survive in nature. All other extreme conditions will be disappeared from nature.
  2. Directional Selection: In this type of selection process, for any certain condition, the earlier extreme parameter will be disappeared from nature. And in place of that, another extreme condition will take place.
  3. Disruptive Selection: In this type of selection process, for any certain condition, both the extreme parameter will survive in nature. The intermediate condition will be disappeared from nature..

Importance of Natural Selection

Natural selection is the process behind the modern earth or nature. Natural selection is the key force in the evolution process. This is the force that acts upon the species from the environment. In absence of this force, evolution might not possible. As if there is no external pressure, then why the species will try to evolve? If the nature is same as in the ancient period, then there is no need to change the livelihood of any species. As there is a sudden change in nature, every species want to balance itself with that changes. As they want to survive in nature. This helps them to become more & more adaptive species. These changes also create some variation. As the environment changes with the geography. So, one species in one geography will differ from the other species. So, the importance of Natural Selection is unbelievable in the modern world.

Examples of Natural Selection

Human Baby Weight

Human baby weight is the best example of Natural Selection. Here also the three parameters work to define this example. As the parameter is weight, then there might be three variations. One is the heavyweight; one is the intermediate weight & another is the less weight. So, only intermediate-weight babies survive in nature. A heavily weighted baby has less amount of percentage to survive in nature. As for a mother, there might be some issues to give birth to a heavyweight baby. And the baby which has lightweight will not survive in nature due to malnutrition. So, it seems that the intermediate parameter offspring can be able to survive in nature. So, this is a prominent example of the Stabilizing Selection.

Eggs of Robin Bird

The eggs of the robin bird are also an example of natural selection. There might be some similarities with the process of the human baby. As they both works on the same type of natural selection. Robin birds lay four eggs at a time. Among those four eggs, some eggs have large clutches. In some eggs, the clutches are very small. In the intermediate class, the eggs are in the appropriate size. So, the intermediate-sized eggs will only survive. As the large size eggs will produce malnutrition chicks. On the other hand, the small eggs might not produce chicks properly. So, the intermediate-sized eggs will only produce chicks. As the intermediate parameter survives in nature, so it is also an example of Stabilizing Selection.

White-Black Peppered Moth

This is another example of natural selection. Before the industrial revolution in the UK, there is a large number of white peppered moth present. By comparing with the black peppered moth, their number is much more. So, there are several deficiencies of the black peppered moth. But during & after the industrial revolution in the UK, the pollution level gets high. As a result, the bark of the trees becomes blackish. In that background, white peppered moths are more rarely attacked by predators. But the black peppered moth can able to camouflaged in that background. As the result, the white-peppered moth becomes less in number & the black-peppered moth starts growing rapidly. So, it seems that there is a change in direction. Earlier, the white peppered moth was dominant. But now the black peppered moth is dominant. So, this is an example of Directional Selection.

Himalayan Squirrel

Himalayan squirrels are another example of natural selection. Here also, the three parameters will be discussed. Here, the parameter is the color, so three will be three types of colored squirrels are present. There are black-colored, white-colored & gray-colored squirrels present. In the Himalayas due to sudden changes in nature, there is a change in the number of squirrels. The black-colored squirrels can able to hide in the shadow of the rocks. Where the white-colored squirrels can able to hide in the snow. But the gray-colored squirrel can’t able to hide either in the shadow of the rock or in the snow. So, they started getting the target of the predators. So, the number of gray-colored squirrels started decreasing. Where two extreme parameters can able to survive in nature. As the intermediate parameter can able to survive in nature. So, it is an example of Disruptive Selection.

FAQs on Natural Selection

Question 1: What is Natural Selection?


Natural selection is a process of evolution where a special parameter is accepted by nature & the offspring that have that parameter will only survive in nature. And all others will be extinct from nature. This phenomenon is known as Natural Selection.

Question 2: Which type of natural selection is superior?


Among the three types of natural selection, Stabilizing Selection is the most superior one. In Directional Selection, special parameter offspring need to be removed from nature forcefully. And in Disruptive Selection, two extreme parameter species live in nature. That is also not the best way to survive. 

Question 3: Which theory first claims the influence of Natural Selection?


At first, Lamarck’s Theory introduced the idea of Natural Selection. Later, Charles Darwin introduces Natural Selection Theory. There the influence of natural selection is noted.

Question 4: According to the scientists, who discovered the Natural Selection term?


Though Lamark first introduced the process of Natural Selection, Darwin first coined the term Natural Selection in his Natural Selection Theory. So, scientists claim that Darwin discovered Natural Selection term.

Question 5: The neck of the giraffe comes under which type of natural selection type?


The neck of the giraffe comes under the Directional Selection type. As earlier, some giraffes have small necks. But as nature changes, there is a need to have a large neck. So, the direction is being changed. So, it will be the directional selection process.

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Last Updated : 30 Dec, 2022
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