Evolution is not the same as natural selection. Natural selection is a mechanism, or cause, of evolution that brings adaptations that make an organism better suited to its environment.
Evolution is related to natural selection as only a way that supports and causes evolution. Evolution deserves better adaptations of the organisms to their environment, and natural selection is a gradual process of how the organisms adapt themselves to evolve to better withstand the environment and pass the adapted characters to their offsprings.
Evolution is a gradual process that leads to various changes and adaptations in the living organism and its population over time from generation after generation.
The changes and adaptations help the offspring to better adapt to the environment as compared to that of their parents.
Natural selection in evolution is a cause or reason that supports the organisms to better adapt to their environment in order to survive and produce more offspring that can withstand the environment.
So, there’s not a big difference between natural selection and evolution. They can’t be 100% related to one another but, is mostly related.
It’s mostly related because natural selection is only a way amongst the other ways to cause evolution. And apart from natural selection, there are other ways like genetic drift, phenotypic plasticity, and non-genetic inheritance that also causes evolution.
The relationships between Natural Selection and Evolution
Evolution is less about the genes themselves and more about the interaction between the genes and the environment, this describes natural selection.
Below are some of the relationships between natural selection and evolution that will help you relate both natural selection and evolution together.
1. In adaptations
Any type of evolutionary change deserves that the organism is better changed or altered both phylogenetically and genetically in order to better fit its environment.
In the evolutionary theory of natural selection, adaptation is defined as the biological mechanism by which organisms adjust to new environments or in their current environment.
Natural selection means that adaptions occur naturally without any artificial involvement. When the organism finds it very hard to live in its habitat it develops various ways phylogenetically and genetically to make its survival a lot easier.
In this way, it can better adapt to its habitat (environment) and these adapted characters get passed to next-generation.
And, in the next-generations, these adapted characters are more finely adapted to better suit their habitat.
Adaptations can help an organism to better develop itself as compared to that of its ancestors to find food and water, protect itself, or manage itself in extreme environments.
Evolution needs adaptations and natural selection is just the cause for adaptation that brings various physical or behavioral traits that make an organism better suited to its environment.
2. Inheritable variations
Inheritance is a primary reason in evolution and natural selection also supports inheritance.
Genes cause inheritance and alleles (different version of same genes) causes variations in living organisms over the course of evolution.
The role of genetics in evolution can be seen during genetic variation. Genetic variation is an important force in evolution as it allows natural selection to increase or decrease the frequency of alleles already present in the population.
When an organism gets better adapted to its environment, it develops various genetic changes that express those adapting characters. And, a majority of those adapting characters are actually inheritable in nature from generation after generation.
Just for example: The gene for body fur color can have the allele for black fur color, tan fur color, or brown fur color in a mouse population. If the allele for black fur color is expressed than the organism will have black fur. If brown fur color allele is expressed than the organisms will have brown fur, and so on.
So, how are those alleles for different body fur color is formed? The formation is probably due to the adaptation in that mouse population in order to better survive from its predators in their type of environments.
These adapted alleles get passed to the next generation and bring on the same changes if expressed. It’s because these are heritable and genetic in nature.
3. In ensuring survival and reproduction of the species
One of the key features of Darwin’s theory of the evolutionary origin by Natural Selection is the survival of the fittest and the better formation of new species.
Evolution wants that the best fit individuals survive and they create their progenies that are also the best fit in the harsh environment.
Natural selection in its way supports this concept of evolution by featuring the concept of the survival of the fittest and the formation of new species from those fittest ones.
The survival of the fittest in natural selection states that nature selects only those individuals who are with favorable variations and are best adapted to the environment. The less fit and unfit organisms die and are eventually destroyed.
And the formation of new species in natural selection states that the fit organisms that have developed useful variations reproduce their offsprings generation after generation that are also fit in the harsh environment.
Thus variations keep on accumulating over time and after a number of generations, the offspring become so distinct thus forming a new species that ensures the survival and reproduction of new species.
4. In selecting genetic mutations
Mutation is actually the principal reason for any type of variability. Mutation is important as the first step of evolution because it creates a new DNA sequence for a particular gene, thus creating a new allele.
Natural selection selects those genetic mutations that make the organism most suited to its environment and therefore more likely to survive and reproduce. Thus, supporting a better type of evolution.
In this way, animals of the same species who end up in different environments can evolve in completely different ways.
Mutation leads to genetic variations in living organisms over time. Mutations can be helpful, or harmful in its various aspects.
Nature only selects helpful mutations that can express helpful variations in the organism to better withstand the environment.
If the mutations are harmful, the organism die and are destroyed over time and becomes soon extinct.
Moreover, natural selection doesn’t favor mutations that express traits that are somehow inherently superior.
Instead, it favors mutations that are beneficial that are those that can help an organism to better survive and reproduce more effectively than its competitors/peers in a specific environment.
5. In changing the allele frequencies
Evolution in terms of genetic can be defined as the change in allele frequency in a population over time from generation after generation. It’s an occurrence due to natural selection.
When scientists try to determine whether a population is evolving genetically, they study its allele frequencies.
If they see the change in allele frequencies in a population as compared to that of the ancestral population than it is sure that the population is evolving in terms of genetics.
A population is nothing but a group of individuals of the same species that mate and produce offspring.
It’s when the members of a population interbreed, they share a common group of genes called a gene pool.
And, allele frequency is the number of times an allele occurs in a gene pool, compared to the total number of alleles in that pool
The frequencies of all the alleles of a given gene often are graphed together as an allele frequency distribution histogram. And, together with population genetics, it helps determine and study evolutionary genetics precisely.
For example: In the mouse population, the allele frequency of the dominant B allele (black fur) is
40% and the allele frequency of the recessive b allele (brown fur) is 60%. Now, if we see that the frequency of the B allele drops to 30% we can conclude that the population of the mouse is evolving.
6. In adaptive radiation
Adaptive radiation is an evolutionary process in which an ancestral form gives rise to new species that are better adapted to new habitats and new ways of life.
In simple words, it is the diversification of a group of organisms in a population into new forms filling different ecological niches and forming new adapted populations over time.
Adaptive radiation is actually a type of natural selection that is often used to refer to the outcome of a situation in which a single species arrives at a situation or location where there are no important competitors.
Adaptive radiation actually leads to the relatively fast evolution of many species from a single common ancestor. It generally occurs when an organism enters a new area and different traits affect its survival.
An example of adaptive radiation is the development of mammals after the extinction of dinosaurs.
Another notable example of adaptive radiation is the presence of finches (small black birds) in the Galapagos Island. These birds have originated from a common ancestral seed-eating bird and then radiated to different geographical areas and have gradually undergone adaptive radiation, especially in their type of beaks.
In these finches for instance adaptive radiation is seen as when the species that eat large seeds tended to have large-tough beaks, while those that eat insects had thin-sharp beaks. All have originated from their ancestral seed-eating finches.