Evolution is the process by which organisms gradually change over time. This change is inheritable over successive generations and is vital in deciding the survival of the organism. Let’s glance at the basic concept of evolution with some examples.
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Basic Concept of Evolution
The definition of evolution is the orderly progression from one state to another. According to the principle of evolution, an entity develops over time through a slow series of changes that take it from a simple to a more complex state. Also the evolution of animals explains how their diversity developed. Here, let’s look at some examples of evolution to understand the concept better.
Examples of Evolution
Evolution is the result of genetic changes interacting with natural selection. Natural selection takes into account a species’ choice to pass on advantageous genes as well as how successful it can use its traits to survive in its environment. Here are a few examples of how some species have evolved over many generations.
Peppered Moths
During the Industrial Revolution, peppered moths experienced industrial melanism in England.
The grey moth accounted for about 99% of peppered moth populations in the early 1800s. In non-industrial places of Scotland and northern England, that form still dominates. Over a period of about 50 years, a black form replaced the grey form in England’s industrial areas.
Grey moths were popular before the Industrial Revolution because they blended in with the tree bark on which they rested. Birds could easily see the black moth because of its contrast with the lighter, lichen-covered bark.
But at the beginning of the Industrial Revolution, factories burned soft coal and released soot and other air pollutants. The lichens where the moths were resting were killed by soot. The black soot also covered the tree trunks. Grey moths were now easily distinguished by bird predators from the black tree trunk’s background. This served as a good disguise for black moths.
Also Check: Flashcards for NEET Biology – Evolution
Mexican Tetra
Mexican tetra or blind cavefish is another example of evolution. The shift in ecological conditions by the ancestors of modern cave populations, who had previously lived on the surface, changed their phenotype. This included a wide range of changes in light-dependent biological processes. The absence of eyes was among the most startling changes that occurred. The reason this is known as a regressive trait is that the surface fish that first inhabited caves had eyes. The Mexican tetra’s blind form differs from the surface-dwelling form in a number of ways, including having taste buds all over its head, unpigmented skin and being able to store four times as much energy as fat, which helps it cope with erratic food supplies more successfully
Darwin’s Finches
Darwin is associated with his theory of evolution based on natural selection. The concept of adaptive radiation in evolution is also well-explained by Darwin’s finches.
Adaptive radiation is the diversification of a dominant evolutionary group into numerous subsidiary types that have evolved to fit different adaptive zones. The Galapagos islands were inhabited by ancient finches that originated from the continent of South America. With few predators and few seed-eating varieties, finches diversified into 14 distinct species.
The sizes and shapes of the beaks, which are associated with pronounced differences in feeding habits, are the most obvious differences between the species. Powerful beaks were designed specifically for crushing seeds in ground finches. The large-beaked finch consumes large, hard fruit, while the small-beaked finch consumes small grass seeds.
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