What is meant by Evolutionary Adaptations?

Evolutionary adaptation is the process through which organisms adapt or adjust to their surroundings to increase the chances of survival, mating, and reproduction. An organism's behavior, physiology, and structure are adjusted or changed to make it more suited to its environment.

How does natural selection lead to adaptations?

Natural selection is the force that drives adaptations to evolve. Organisms’ morphological and behavioral traits adapt through the process of natural selection throughout generations. It helps them function better in the face of environmental stresses or challenges such as the presence of their competitors, parasites, predators, etc.

Natural selection results in adaptation, or a population characterized by individuals that are physically, behaviorally, and physiologically well-suited to surviving and reproducing in a particular environment. The selective survival and reproduction of individuals in a population with a beneficial heritable trait results in an increase in the proportion of individuals with that trait in the following generations. Natural selection does not generate adaptations in a population; rather, it selects the adaptations that are most fitted to a changing or evolving environment from those that already exist. Natural selection will alter the makeup of a population by filtering out those who aren't well adapted.   

The peppered moth of England is an example. Melanic or dark and dominant white were the two main types. The melanic or dark variety was perfectly adapted when the industrial revolution and the burning of coal transformed the environment. The majority of the moth population became melanic. Once the pollution generated by the industrial revolution was reduced, the population returned to a predominantly white population.

How is evolution related to adaptation?

As favorable adaptations build over time, that leads to evolution. The tendency of beneficial traits to increase in frequency in a population is the driving force behind adaptive evolution. Evolution occurs when beneficial traits that increase the organism's probability of surviving and reproducing undergo positive selection. Evolution is the process by which a species evolves. Evolution is defined as changes in the frequency of alleles in organisms through successive generations in genetic terms. These modifications are caused by genetic mutations. The connection between hereditary adaptations and evolution is that the species has evolved into a new species when the acquired adaptations become so abundant. It means that the emerging organism's genetic material is no longer compatible with the ancestral form of the organisms.

Darwin's theory of evolution of new adaptations

Darwin believed that new traits emerged by chance and that if those traits aided an organism's reproduction potential, the trait would be passed down to the descendants. In the case of the giraffes, Darwin's theory of evolution by natural selection would imply that the giraffe's long neck was acquired by accident. Because of its long neck, the individual was capable of reaching sources of food that the other individuals couldn't. With greater resources, the giraffe was able to live longer as well as reproduce more, resulting in more long-neck giraffes. Those who were born with significantly longer legs continued to be favored by subsequent generations.

Adaptive radiation

Adaptive radiation is the evolutionary radiation in several specialized directions from a common and generalized ancestral species. It can also be the entry of organisms of an original species to new adaptive zones. It is characterized by an increase in the morphological and ecological diversity of a single, rapidly diversifying lineage. In another way, it is the phenomenon in which members of the same or closely related species evolve in different lines under different environmental conditions and acquire different morphological features and modes of life. This is an evolutionary process driven by natural selection. The evolution caused by adaptive radiation is known as divergent evolution. The result of divergent evolution is the formation of several species from a common ancestor. The descendant species are differently adapted to different habits and habitats to reduce competition among them.

The cause and significance of adaptive radiation

The common impelling cause of adaptive radiation is the need for better sources of food, better environmental conditions, better safety from predation, and better breeding grounds. The inborn spirit to conquer new habitats may also contribute to adaptive radiation. Usually, animals spread mostly to areas that are unoccupied by their predators and competitors.

Adaptive radiation is significant in that it enables animals to occupy all available habitats and niches. It also brings about the formation of new taxa and the expansion of animal diversity. It plays a significant role in macroevolution also.

Adaptive radiation in Darwin's finches

Darwin's finches, also known as Galapagos finches, are 14 closely related species of dull-colored birds, observed by Charles Darwin on the Galapagos Islands during his voyage in the Beagle in 1835. Thirteen inhabit the Galápagos islands, and one is a resident of Cocos island. The finches were similar in size and coloration, but different from each other in their feeding habits and feeding adaptations, and also in the shape and size of their beaks. Their beaks were adapted to the food available on the island on which they lived. Darwin believed that all these species evolved from a common ancestor. The ancestral species reached the islands from the mainland. Because the ecological conditions on each island differed, they evolved independently into new species on each island.

Convergent evolution

Convergent evolution describes the process by which species that are neither monophyletic nor closely connected evolve similar adaptations to similar ecological habitats or niches on their own. To be more specific, it is the phenomenon in which genetically and phylogenetically unrelated species of organisms, under the same or similar environmental conditions or niches, evolve along the same line. Through convergent evolution, unrelated organisms acquire similar morphological features, adaptations, modes of life, and behavior. The independent evolution of wings in birds, insects, pterosaurs, and bats is an example of convergent evolution. 

Context and Applications

This topic is significant in the exams at school, graduate, and post-graduate levels, especially for bachelors in zoology/botany and masters in zoology/botany.

Practice Problems

Question 1: What conclusions did Darwin draw from the Galapagos islands' diverse species?

1. Evolution happens to adapt to their surroundings.
2. Convergent evolution.
3. After a period, species become extinct.
4. None of the above.

Answer: Option a is correct.

Explanation: In the case of Darwin's finches, the ancestral species reached the islands from the mainland. Because the ecological conditions on each island differed, they evolved independently into new species on each island.

Question 2: _______ is the process through which organisms adapt or adjust to their surroundings to increase the chances of survival, mating, and reproduction.

1. Evolutionary adaptation.
2. Evolution
3. Natural selection
4. None of the above.

Answer: Option a is correct.

Explanation: Evolutionary adaptation is the process through which organisms adapt or adjust to their surroundings to increase the chances of survival, mating, and reproduction.

Question 3: _________is the process by which a species evolves over time.

1. Natural selection
2. Adaptation
3. Evolution
4. All of the above.

Answer: Option c is correct.

Explanation: As favorable adaptations build over time, evolution happens. Evolution is the process by which a species evolves.

Question 4: According to natural theory, animals are more adapted to an environment _______ than animals that are not.

1. Reproduce and survive more.
2. Extinct rapidly.
3. Larger
4. None of the above.

Answer: Option a is correct.

Explanation: The selective survival and reproduction of individuals in a population with a beneficial heritable trait results in an increase in the proportion of individuals with the trait in the following generations.

Question 5: The convergent evolution is true for ______.

1. Closely related species.
2. Unrelated species.
3. Both a and b.
4. None of the above.

Answer: Option b is correct.

Explanation: Convergent evolution is the phenomenon in which genetically and phylogenetically unrelated species of organisms, under the same or similar environmental conditions or niches, evolve along the same line.