What is the relationship between Adaptation and Natural Selection?

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Adaptation and Natural Selection are two of the prominent working concepts in evolution. Although they happen together but they are distinct from each other.

When we think of animals with extreme adaptations, the giraffe definitely comes to mind. And, we often say that natural selection is the driving force that had helped in the evolution of giraffes.

Was upon a time in an ecosystem, some giraffes had long necks and others had short ones. Something around millions of years ago, caused low-lying shrubs to die out, thus the giraffes with short necks were not able to get enough food.

After a few generations, all the giraffes adapted long necks and, those with short necks died and became extinct due to natural selection.

The two forces that drove giraffes towards elongating their necks are simple. The need to eat and the need to breed.

So, how come the two words adaptations and natural selection work in proper co-ordination and are often related? What’s the catch?

We’ll understand it all here in this article. So, just keep reading…

What actually is adaptation?

Adaptation is actually the evolved trait that was developed once ago during the evolution of any species to help it better survive and reproduce in its kind of environment.

The adaptation causes beneficial variations that are inheritable only in nature, and it can increase a descendent organism’s chances of surviving, mating, and reproducing than the ancestral organism.

Living things are better adapted to the habitat or environment they live in. Adaptation can develop beneficial physical features, better changes that affect the behavior of an organism, and physiological developments.

Many successive small scale microevolutions like genetic mutations, gene flow, genetic drift, random-mating, natural selection along with other evolutionary mechanisms can cause variations that are inherited from generation after generation to cause adaption in the species of a population.

For example, in the case of giraffes that were with short necks did not get enough food due to the lack of short shrubs and plants. So, they tried to adapt themselves to eating leaves of tall plants and trees in order to better survive and over time reproduced long neck giraffes.


What actually is natural selection?

If adaptation is the introduction of useful genetic traits or variations, then natural selection is a macroevolutionary mechanism that introduces those adaptations in an organism generation after generation.

Natural Selection is a way how adaptation takes place in an organism due to the selective pressure of the environment thus leading to evolution.

The principle of natural selection is that nature only selects those individuals that are better able to survive and continue their future generations. So, the fit organism better tries to adapt themselves through adaptation over time leading to the creation of new species of fit organisms through speciation.

Natural selection is simply the tendency of beneficial traits to increase in frequency in a population. This occurs when the trait is beneficial (increasing the organism’s chance of survival, mating, and reproducing), and heritable (it can be passed down through generations).

For example, The finches (small black birds) in the Galapagos Island shows that those species that eat large seeds tend to have large-tough beaks, while those that eat insects have thin-sharp beaks. All have originated from their ancestral seed-eating finches through large-scale natural selection.


ANSWERED: What is the relationship between Adaptation and Natural Selection?

Natural Selection and adaptation are very distinct from each but are often used together in order to promote the cause of evolution in an organism.

These two may sound similar or even confusing to some, as these are two of the important and related concepts in evolution that deal with the change in traits and adjustment of the species causing microevolution and macroevolution respectively.

The relationship between adaptation and natural selection is that adaption is caused by the mechanisms of evolution which are mutation, genetic drift, gene flow, non-random mating, along with natural selection. Thus, natural selection is only an evolutionary action or mechanism that causes adaptations.

Well, adaptation is the way how organisms develop better characteristics at the genetic level, physiological level, psychological level, reproductive level, morphological level, and anatomical level to better develop themselves over its course of evolution.

And, natural selection is one of the mechanisms of evolution that helps adaptations to occur successfully due to the selective pressures pushed upon the organisms by their surrounding environment where they live.

Adaption leads to the adjustment of the organisms so that they can better survive and reproduce. The harmful genetic traits that are passed to the next generation are removed and only the beneficial genetic traits in the next generations cause adaptation.

Natural Selection is the mechanism that chooses only chooses those beneficial genetic traits that can lead to adaptation and remove the harmful traits. And in this way, this mechanism causes the transfer of beneficial traits only so that speciation occurs leading to better adaptation of the species in its environment.


Key relationships between Adaptation and Natural Selection

1. As advantageous adaptations accumulate over time, evolution occurs. That evolution can be due to natural selection if it’s impacted by nature.

2. Small adaptations alone can’t cause evolution therefore no speciation. Only if the inherited adaptations get accumulated and become numerous than the resulting organism’s DNA changes from the ancestral DNA version of the organisms, then only natural selection can occur leading to speciation.

3. Mutation can lead to random changes in the genes DNA sequence, and only if those changes are beneficial they gets adapted. Beneficial mutations are passed on through natural selection.

4. Adaptations lead to traits that increase an individual’s chance of survival, mating, and reproduction. Natural Selection is a working mechanism that states how, when, where these adaptations will increase in frequency in a population.

5. Variations in a population lead to adaptations and many of such adaptations cause evolution that is due to natural selection majorly.

6. The difference between adaptation and natural selection is that adaptation is the characteristic that is shown during evolution whereas, natural selection is the mechanism that causes evolution.

7. Adaptation due to mutation, gene flow, non-random mating, and genetic drift are ways of microevolution, that is evolution on small-scale that may or may not be so clearly visible. Whereas, adaptation due to natural selection is a way of macroevolution that occurs in large scale and are always clearly visible as the result is speciation.


The following examples support evolution through Adaptations via. Natural Selection

Example 1: Industrial Melanism in Biston betularia

Industrial Melanism is an example of natural selection that refers to a phenomenon in which the animals take on a darker coloration of their skin, fur, feathers due to its adaption towards the increasing industrial pollution over several generations.

The adaptation of Biston betularia is one of the most famous and well-documented examples of Industrial Melanism.

It is an adaptation where the white-colored peppered moths (Biston betularia) living in an industrial area developed melanin pigments to match their body colors to that of the tree trunks.

This led to the formation of dark-coloured moths (Biston betularia) over a period of 50 years of evolution.

Tutt’s hypothesis stated that the dark moths were more visible to predators on unpolluted trees, while the light white-moths were more visible to predators on bark blackened by industrial pollution.

So, due to adaptation by natural selection, dark-coloured moths (Biston betularia) were formed from the white ones majorly, leading to better survival and reproduction of the moths by camouflaging and escaping from their predators.

READ MORE: What is Industrial Melanism? (Explained in Detail)

Example 2: Adaptive Radiation in fiches of the Galapagos Islands

Adaptive radiation is an evolutionary process in which an ancestral form gives rise to new species adapted to new habitats and new ways of life.

Adaptive radiation usually occurs when the ancestral population of a species gets new exploitable resources.

In adaptive radiation, adaptive simply means “adaptation” and radiation simply means “diversification.”

Adaptive radiation usually means how the species will adapt itself to the environment by natural selection and in doing so it will diversify itself into many different species with each species being adapted differently.

The finches (small black birds) in the Galapagos Island shows that those species that eat large seeds tend to have large-tough beaks, while those that eat insects have thin-sharp beaks.

All have originated from their ancestral seed-eating finches through large-scale macroevolution.

Darwin observed that the finches species on each island that were isolated from the other islands appeared to be closely related.

He concluded that the finches on these isolated islands must have been originated from the nearby continent, but because they were separated from the other species on the continent, they gradually evolved into something different over thousands of years depending on their type of habitat of their island.

Darwin’s observation showed that these finches were not found in similar climatic zones elsewhere on Earth but especially in the Galapagos Islands.

This literally proves how adaptation may have occurred and how adaptive radiation through natural selection may have lead to the evolution of these finches.

READ MORE: Why Does Adaptive Radiation Occur? Let’s Know!


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