A change in the structure and function of an organism that results from a natural process by which an organism is better fitted to survive and also multiply in an environment is called adaptation.
What is Adaptation Theory?
Adaptation theory is also referred to as the theory of survival of the fittest which is an organism’s ability to adapt to an environment and adjust with time. The scientist who came up with his theory is Charles Darwin who conducted experiments in Galapagos island in the 1830s. Before Darwin, there were many other scientists such as Empedocles, Aristotle, William Paley, Lamarck and Buffon who accepted the fact that species change with time but did not understand the underlying cause for this change or that adaptation was a continuous process which does not have a final form.
Adaptation theory suggested that with habitat change, there are three other changes that take place: habitat tracking, genetic change, and extinction.
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Habitat Tracking: When an organism which used to live in the environment, finds another environment which is similar to the previous one to which it has inhabited before.
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Extinction: When species are not able to adapt to the new environment or move out and find a new environment to live in, they eventually die out and become extinct.
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Genetic Change: Genetic change is natural selection that allows the organism with slight mutations to survive better in an environment when compared to the other organisms in a given area.
Example – Darwin observed the turtles living on two islands. The turtles in one island ate from the lower ground due to which they had shorter legs and straight shells. When these turtles migrated to another island, where the food resources were at a height, turtles with longer legs were able to eat and survive and reproduce. With time their necks also grew longer, and their shells became round and these adaptations were passed on to generations for the turtles living on that island.
What Causes Adaptation?
Adaptation could occur due to mutation or natural selection. Mutation is the sudden genetic change which could be accidental or random. Mutation will arise due to any change in the nucleotide sequence of DNA and if a single pair of nucleotides is replaced. Certain mutations are harmful to human beings while certain mutations could be advantageous to the survival of an organism in the struggle for existence.
Example – A bird is born with a long beak and this helps it capture food and therefore survive better. This bird is, therefore, able to survive better and breed more. This gene continues to be inherited generation after generation.
Natural selection is the process in which individuals with survival advantages will survive in an environment and those with less advantageous traits will die due to the pressure from the environment. In an area, the resources are fixed or limited. There is competition among the species of that area to fight for the available resources. In a population, some individuals have the traits which could be structural or behavioural that make them better at surviving and reproducing. In the struggle for existence, some individuals show variable variations that have a reproductive advantage and produce more offspring than other species. Any unfavourable variation selects out against their presence, conferring a selective disadvantage on that organism.
Example – Different species of finches existed on Galapagos island, the variation among them was in their beak characteristics. Nature selected the most suitable beak against the less useful ones.
What are the Different Types of Adaptations?
Adaptations could be of various types:
1. Structural Adaptations
Structural adaptations are the changes to the structure of a living organism to adapt better to an environment. These structural modifications affect an animal at many different levels and such changes are highly visible adaptations, one can fully identify these changes with naked eyes.
Example – How desert plants have adapted to the desert conditions where there is a very little amount of water available and the temperature is high. Plants called succulents have adapted to the desert conditions by storing water within themselves to compensate for the lower water availability.
2. Behavioural Adaptation
Behavioural adaptation is the change in the behavior of an organism to survive better in an environment. Behavioural adaptations are not easy to identify and many a time requires careful field and laboratory studies to bring them to board light.
Example – Migration- bird migrates to the south in winter as there is more food available, but some birds also do migrate for the purpose of reproduction.
3. Physiological Adaptations
Physiological adaptations are a body process that helps an organism survive/reproduce better in an environment. These adaptations could be the different ways in which an organism responds to the stimuli from the environment. These changes are typically based on body chemistry and metabolism, thus usually can’t be seen from the outside. Laboratory studies that measure the contents of various body fluids are often needed to trace these types of Adaptations.
Example – An animal which is living in cold regions will have features like thick fur and short ears to reduce the heat loss. The physiological adaptation here is the shivering to generate more heat when it gets cold.
4. Coadaptation
Co-adaptation when two or more species are symbiotically bound to each other for their survival and adapt together, it is called co-adaptation.
Example – Humming birds have long beaks which helps the bird capture nectar from specific plants during which it gets dusted with pollen grains. In this way, the pollen grains are distributed, and the hummingbirds get their food.
Why is Adaptation Important for Species?
Every organism has a natural habitat which is home to the organism. This is where the basic needs of the organism like food, shelter, water and other needs are met. All organisms need to adapt to their habitats to be able to survive. An adaptation is a change to the structure or behaviour of the organism which helps the organism survive better in the habitat. This means the organism will have to adapt to the climatic conditions, predators and compete for the same resources with the other organisms living in that habitat.
Animals live in an environment where there are several factors like climate, the kinds of plants and other animals that may be predators or might compete with them for resources. The animal must adapt to all these factors to survive.
Adaptation protects the animals from their predators. One good example is the ability to camouflage. Camouflage is an adaptation that helps an organism blend in with the surroundings so that it is not noticeable. Adaptations also help the organism protect themselves from the harsh weather. In Alaska, where the temperature is very low the animals store food in their body and protect themselves from the cold climate with thick furs.
Conclusion
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