Relationship between Mutation and Natural Selection

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The relationship between mutation and natural selection is that both of these are the mechanisms of evolution that take place generation after generation from parents to offsprings bringing about various adaptations and ultimately speciation.

Mutations occur by chance or randomly whereas, natural selection occurs due to the environment’s selective pressure on an organism.

Mutations occur throughout the natural world and over time many successive mutations causes a large-scale natural selection leading to macroevolution.

If mutation is the fuel then, natural selection is the car that runs on that fuel. Other factors like Genetic drift and gene flow also helps in the working of natural selection.

Scientists call mutations as the raw materials of evolution because mutations can improve the survival or reproduction of the species genetically. And if the mutation is good then the process of natural selection will cause the mutation to become much more common over time.

First, let’s understand the proper meaning of mutation and natural selection, and then we’ll know about the relationships between them. So, just keep reading…

Frog

What is Mutation?

A mutation is a permanent alteration of a gene’s DNA base sequence, such that the sequence differs from what is found in most organisms.

Mutations alter the normal/default arrangement of the four nitrogenous bases in sections of DNA strands.

Mutations range in size, that it can be small alteration or large alteration of the DNA base sequence.

Small alterations can affect a single DNA building block (base pair), and large alterations can affect a large segment of a chromosome that includes multiple genes.

Mutation causes new sudden inheritable discontinuous variations that arise due to the alteration of DNA sequences and changes in the genotype of an organism. This is a phenomenon that leads to variation.

Gene mutations can be classified in two major ways: Hereditary mutations that occur during a person’s life are inherited from a parent, and Acquired mutations that occur during a person’s life are neither inherited nor can be passed to the next generation.

Evolution occurs due to the hereditary mutations because these can be inherited from the parents to the offsprings.

Gene mutations can be of two types: Point Mutation that arises due to change in a single base pair of DNA, and Frameshift Mutation that arises due to loss (deletions) or gains (insertions) on one or two bases in the DNA.

Example of mutation in evolution: Humans and Platypuses share about 82% of similar genes showing that once they both had a common ancestor. Differences had occurred due to many levels of genetic mutations over time leading to evolution.


What is Natural Selection?

Natural selection is a key mechanism of evolution. It is nature’s way of conducting evolution due to the impact of the various selective pressures by the environment on the organism causing various adaptations.

Natural selection in evolution is a cause or reason that supports the organisms to better adapt to their environment in order to better survive and produce more offspring that can withstand the environment.

According to natural selection, 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 over time.

Natural selection unlike mutation is always beneficial to the organisms and brings only positive adaptations that help it better survive and reproduce.

Genetic drift, gene flow, and natural selection, along with gene mutations cause useful variations that are transmitted to the offspring and appear more prominently in future generations. These variations keep on accumulation and after a number of generations cause speciation.

There are three types of natural selection: directional selection, stabilizing selection, and disruptive selection.

Example of natural selection in evolution: Deer mice that migrated to the sand hills of Nebraska changed from dark brown to light brown to better hide from predators in the sand.


How are Mutation and Natural Selection related? Let’s Know!

1. Both Mutation and Natural Selection are the mechanisms of evolution

Evolution is the framework to understand the origination of new species. They are five mechanisms of evolution and these are mutation, genetic drift, gene flow, non-random mating, and natural selection.

Each mechanism of evolution can be characterized by how it affects fitness, adaptation, the average phenotype of a trait in a population, and the genetic diversity of the population.

Mechanism of evolution is the working of the evolution process that helps us better understand how, when, and why the organisms have evolved.

Both mutation and natural selection are the working mechanisms of evolution. Mutation causes genotypic variations in the living body whereas, natural selection brings both phenotypic and genotypic variations.

Mutation is a type of microevolution that happens several times over many generations causing huge variations.

Natural selection is a type of macroevolution that takes more than thousands of years to happen.

Hardy-Weinberg equilibrium states that when no population is evolving, then the allele frequencies will stay the same across generations.

So, both Mutation and Natural Selection are the mechanisms of evolution that violate the Hardy-Weinberg equilibrium. Thus, stating that they both can together cause evolution.

2. Both Mutation and Natural Selection leads to 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. So, this is controlled by adaptations.

In the evolutionary theory of mutation, adaptation is defined as the introduction of new beneficial variation that has a positive effect on the fitness of the offspring.

Mutation can cause both beneficial and harmful types of variations over time. The harmful variations lead to death or extinction in the population, whereas beneficial variation can cause adaptations.

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 in order to survive and reproduce.

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 and that’s adaptation.

3. Both Mutation and Natural Selection leads to speciation

We have previously learned that mutation is a microevolutionary concept whereas, natural selection is a macroevolutionary concept.

It’s because the mutation is a small-scale evolution that leads to changing a few genes leading to the creation of new alleles within a population. This leads to the change in allele frequencies in a gene pool.

Whereas, natural selection is a very large-scale evolution that results from the sum total of all of the mutations (microevolutions) that took place within a population. This can lead to the formation of new species i.e speciation.

Therefore, it is very clear that both mutation and natural selection helps in adaptation which is beneficial to the organism and its population.

And when successive adaptations take place it leads to the formation of new species from the ancestral ones either by way of convergent evolution or divergent evolution, which is also called speciation.


Key Relations Between Mutation and Natural Selection

1. Both mutation and natural selection lead to adaptations. Many successive mutations lead to adaptations genetically due to change in gene sequences over time. Natural selection causes adaptations in species due to the various selection pressures by the environment.

2. Both mutation and natural selection are the mechanisms or patterns of evolution. Mutation is a pattern of microevolution. Natural Selection is a pattern of macroevolution.

3. Both mutation and natural selection brings on beneficial variations in the offsprings. Mutation can be harmful or beneficial for the organism but, natural selection is always beneficial.

4. Both mutation and natural selection bring on inheritable characteristics that pass from one generation to the next. Mutation can be inheritable or non-heritable (acquired). Natural selection changes are always inheritable.

5. Mutation along with genetic drift, gene flow, and natural selection leads to the formation of new species (speciation). Both mutation and natural selection have to occur together to cause speciation.

6. Both mutation and natural selection violate the Hardy-Weinberg equilibrium stating that populations evolve over time.

7. Both mutation and natural selection can lead to both convergent and divergent type of evolution.

8. Mutations may be random, but are not entirely random, a new study suggests. Natural selection is not at all random but of selective type.


An example of both Mutation and Natural Selection occurring during the evolution of Hyla treefrog species

Hyla versicolor, a tetraploid (4N) treefrog, which is reported to have originated via multiple hybridization events from three diploid (2N) ancestors.

Its complex reticulate history provides insights into the roles that polyploidy and hybridization can play in the origin of species and that mutation and natural selection are its evolutionary mechanisms.

The evolution of the gray treefrog, Hyla versicolor, is an example of mutation and its potential effects that had occurred around 575,000 to 375,000 years ago.

When an ancestral Hyla chrysocelis gray treefrog failed to sort its 24 chromosomes during meiosis, the result was H. versicolor gray treefrog.

H. versicolor treefrog is identical in size, shape, and color to H. chrysocelis but has 48 chromosomes and a mating call that is different from the original H. chrysocelis.

But, did you wonder why despite having 48 chromosomes H. versicolor treefrog is still identical in size, shape, and color to H. chrysocelis treefrog that only has only 24 chromosomes.

It’s because of the notable similarities between the populations of H. versicolor and H. chrysocelis species that were caused by similar selection pressures due to natural selection evolutionary mechanisms in their shared environment.

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