Introduction to Evolution

Evolution connects all living things, as all living things have evolved from common ancestors by the process of natural selection. Evolution is the unifying principle of biology for this reason, and it is the fundamental tenet guiding current research and understanding of biology. 

Our understanding of evolution has its own history, though. Up until the 19th century, people had always thought that species did not change with time. Around this time though, there were many scientists a-buzzing with ideas about how life came to be as it was.

One curious guy, called Charles Darwin, was particularly mystified by the tremendous diversity of Life, both between species and among organisms of the same species. Darwin travelled the world aboard a ship called the Beagle, collecting tons of animal, plant and fossil specimens, and also maintained intense correspondence with other illustrious scientists, which brought him news and clues from around the globe that fueled his curiosity.

Darwin found his next clue close to home: domestication or artificial selection. Humans have been changing species around them for tens of thousands of years, choosing the fastest horses to breed, to create more fast horses. Think of all the breeds of dogs you - beagles, setters, bulldogs, and more – all of these dogs belong to the same species! They all look so different because humans have been breeding them to choose specific features.

Darwin suggested that a similar process occurred in Nature, where environmental pressures select some organisms over others depending on how fit they were for that particular niche. For example a dry environment would select the organisms that use water more efficiently. The fitter organisms survive the longest and are more likely to reproduce, creating more organisms with the same “fitter” traits. He called this process natural selection. Over time, the species evolves to become more fit to its environment.

Darwin realized that life was so diverse because it had evolved to fit all the varied niches in our environment.

Darwin’s theories were tremendously insightful! But Darwin didn’t know how traits were passed from one generation to the next. It took the work of many other scientists, including a little-known monk called Gregor Mendel to figure out the basic laws of inheritance.

Today scientists continue to study and test evolution! They have discovered processes and mechanisms, like migration and mutation. They have also studied further some cool aspects of evolution, like the process where species that look very different actually evolve to look more similar!

Biologists and evolutionary biologists around the globe continue today to study evolution and refine its theory, and many questions remain open!