Adaptive Radiation And Evolution

Evolution is the successive modification in inherited traits over a huge span of time, usually over generations. Environmental factors like climate, temperature, availability of resources, etc. have a great role to play in the same. Darwin put forward the concept of evolution during his journey to the Galapagos Islands. In the Galapagos Islands, he observed an evolutionary process which is literally known as adaptive radiation.  Let us learn more about adaptive radiation with examples.

Adaptive Radiation

According to Darwin’s Theory of Evolution, living organisms change their physical and anatomical structure over a long period of time for better adaptations to the changing environment. The initiation of the point of evolution was when organisms wanted to exploit a niche and they were not able to do so with their existing body design or structural component. Organisms started to split and adopt various versions for better survival.

Adaptive radiation is the evolutionary process by which many species originate from one species in an area and radiate to different areas. This phenomenon was first observed by Darwin when he traveled to a place called the Galapagos Island. There he observed that there were finches with different types of beaks. So, he concluded that all of these inches radiated on the same island from a single ancestor Finch. All of these finches developed beaks according to the kind of food available to them. Hence, they evolved from the conventional seed-eating finches to vegetarian and insectivorous finches. They later came to be known as Darwin’s finches.

Adaptive Radiation Darwin’s finches

Adaptive Radiation- Darwin’s finches

Adaptive Radiation: An Example

Adaptive radiation explains the reason for biodiversity. The concept of adaptive radiation could be simplified through the following example. Consider a family consisting of four children. They have the same parents and origin, grew under the same circumstances and moved to different regions for a better opportunity. Now each one of them has their own adaptation according to their lifestyle and place they stay.  Here the lineage splits and radiates different characteristics.

Adaptive Radiation

Adaptive Radiation

Another example for the adaptive radiation is the development of different Australian Marsupials from a single ancestral stock in the Australian subcontinent. This explains divergent evolution for the ancestral stock from which a number of species arise. But, if in a given geographical area, several adaptive radiations take place for various species, it gives rise to convergent evolution.

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Practise This Question

In the developmental history of mammalian heart, it is observed that it passes through a two-chambered fish like heart, three-chambered frog-like heart and finally four-chambered stage. To which hypothesis can this above cited statement be approximated?