Evolution through mutation

Evolution through mutation: Nature’s perfect strategy

Evolution is the gradual process of change in the living world through which species adapt over time. The main driving force behind this change is mutation – small but significant changes in genetic material. Although the word mutation is often used negatively, in reality, it is essential for biodiversity and adaptation.

🔍 What is Mutation?

Mutation is a change in the structure or sequence of DNA. It can be a single nucleotide change or a large-scale rearrangement of genes. These changes can occur spontaneously, such as errors during cell division, or due to external environmental influences – like radiation, chemicals, etc.

🌱 The Engine of Evolution

Every organism has the potential for mutations in its genes. Most mutations may not have any visible effect, but some can change the organism’s structure, behavior, or adaptability. If the change aligns well with the environment, the organism gains an advantage in survival and reproduction. As a result, the altered gene spreads to the next generation.

🐦 Real-Life Examples

This continuous process is the essence of evolution. Mutation is directly linked to Charles Darwin’s theory of “natural selection.” Nature selects those organisms whose mutations help them survive. In other words, mutations that aid survival become permanent, because others fail to survive and their lineage disappears.

1. Darwin’s Finch Birds

Darwin observed finch birds in the Galápagos Islands, noting differences in their beak structures. These differences were primarily the result of mutations, which adapted to the dietary habits of different islands. Finches with strong beaks could crack hard seeds, while those with slender beaks could catch insects. This diversity was crucial for their survival.

In the city where I live, there are many doves and squirrels, which also exist in Bangladesh. But the ones here are larger in size, while those in Bangladesh are much smaller. That’s because here they get plenty of food. In Bangladesh, due to food scarcity, the generations that were smaller in size were the ones that survived.

Tigers are generally the largest cat species, larger than lions. But not the tigers of the Sundarbans. Sundarbans tigers are quite small in size. This is due to the scarcity of food and the harsh environment there. So, is that why Sundarbans tigers are small? Not exactly. Over thousands of years, the tiger generations that mutated to be smaller were able to survive in the tough conditions, while the larger ones either died or migrated elsewhere.

2. Lactose Tolerance (Ability to Digest Milk)

In ancient times, most adults couldn’t digest milk. But in some populations of Europe and South Asia, a mutation occurred that kept the lactose enzyme active into adulthood. This change allowed milk to be consumed as food, and those who could digest it gained an extra source of nutrition and survival advantage. (Although I personally still struggle to digest dairy products easily)

3. Sickle Cell Anemia and Malaria Resistance

The sickle cell mutation causes a blood disorder, but individuals with one copy of the gene are resistant to malaria. This mutation is more common in parts of Africa where malaria is prevalent. It’s a classic example of how a harmful mutation can become beneficial in certain environmental conditions.

🔚 Final Thoughts

If mutation is the seed of evolution, then natural selection is the gardener of that garden. Together, they have brought diversity to the living world, allowing organisms to adapt to their environments over time. Real-life examples prove that evolution occurs through mutation – it’s one of nature’s remarkable strategies, still ongoing today.

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Blogger Ananta Bijoy Das used to write excellent articles on these topics. You’ll find many of his writings online. Sadly, in Bangladesh, science education is so disliked that he was murdered by fundamentalists and extremists. A large portion of the general public even justified the killing. Why? Because evolution doesn’t align with their religious doctrines, and promoting evolution education exposes the hollowness, superstitions, and manipulations of religion!