Evolution (or the theory of evolution by natural selection) is a scientific theory which states that all living beings in the world are related and are sprung from a common ancestor.
The concept of evolution was first proposed by Charles Darwin and Alfred Russell Wallace in the 1859 book ‘The Origin of Species’. In the book, they postulated that inheritable traits which increases a population of species’ chances of reproducing will become more common, passed down from one generation to another. Similarly, traits that make it harder for the species to reproduce will gradually become rarer until the characteristics will cease to exist altogether. This branching out over time paves the way for the creation of new species.
The theory of evolution works with two important evolutionary theories, namely: ‘theory of common descent’, whereby it is stated that all living creatures comes from a single, simple prehistoric organism; and the ‘theory of modification by natural selection’, which explains the trigger by which the actual process of evolution takes place.
Simply put, the first evolutionary theory implies that every living thing in the world, from humans to microorganisms, came from a single ancestor, the very first life form in the Earth. The second evolutionary theory implies that the simple cells from billions of years ago perfected the process of reproduction by improving on effective processes and getting rid of ineffective ones. Through this process and through chance processes such as mutation, simple cells gave birth to complex life forms such as plants and animals.
Recently, humans have worked on speeding up the evolutionary processes (rather successfully) through genetic engineering. Examples of this are genetically modified crops, cattle and livestock.