Charles Darwin: the theory of evolution and microbes
Charles Darwin, the British naturalist, laid the foundation for the theory of evolution, revolutionising the scientific world 200 years ago. He discovered that all living organisms, from animals to microbes, share a common ancestor.
The father of the Theory of Evolution
In the early 19th century, it was widely believed that all species were created as they exist today. Religion played a key role in this belief. However, Darwin came to a different conclusion during his expedition to the Galápagos Islands. He observed variations among species, such as finches on different islands. Each island had its own variety, with beaks perfectly suited to the available food.
This observation led Darwin to the idea that species change over time. He proposed that these changes result from natural selection, a process in which organisms that are best adapted to their environment survive and reproduce, while others go extinct.
Natural selection
Darwin introduced the concept of natural selection in his book On the Origin of Species (1859). But what does it mean? All organisms must continually adapt to changes in their environment—whether due to the emergence of new predators or climate shifts. The better an organism can adapt, the greater its chances of survival.
The evolution of microbes
This process of adaptation applies not only to animals and plants but also to microorganisms, such as bacteria and viruses. These organisms constantly evolve to adapt to new circumstances, developing resistance to antibiotics or defending themselves against other microbes. This ongoing adaptation serves as evidence of Darwin’s theory, which remains relevant today.
Darwin’s scientific impact
Long before the discovery of DNA—the blueprint of all life—Charles Darwin laid the groundwork for the theory of evolution and natural selection. He was the first to sketch a "Tree of Life," representing the branching relationships between different species. Each split on the tree indicates a change in an organism, marking the emergence of a new species.
The tree of life
As with most scientific discoveries, Darwin’s ideas have evolved over time. After reading Darwin’s work, British philosopher Herbert Spencer coined the term "survival of the fittest," where "fittest" refers to the best-adapted organism. Adaptations, such as changes in beak shape that improve an organism's ability to gather food, increase its chances of survival. Over thousands of years, these adaptations can become so significant that populations can no longer interbreed. In biology, this is referred to as the emergence of a new species.
More than survival
Natural selection is sometimes a matter of chance. For instance, if a bird develops a bright colour that neither hinders its survival nor attracts predators, but instead helps it attract a mate, this trait is likely to persist. These changes, driven by natural selection and random mutations, are responsible for the incredible diversity of life we see today.