Scientific analysis of fossils shows that species have changed over long periods of time. This change is evolution. Many theories have been put forward to explain how evolution happens. The theory accepted by most scientists is the theory of natural selection. Charles Darwin first proposed this theory.
Charles Darwin was an English naturalist. He studied variation in plants and animals during a five-year voyage around the world in the 19th century. Darwin later studied hundreds more animal and plant species. In 1858, after nearly 30 years of research, he proposed his theory of evolution by natural selection. He explained his ideas about evolution in a book On the Origin of Species, published in 1859.
Darwin's ideas caused a lot of controversy at the time. Today, some religious views about the creation of the world and the organisms in it conflict with the scientific consensus about evolution.
These are the key points of evolution by natural selection:
Given enough time, a population may change so much it may even become a new species, unable to reproduce successfully with individuals of the original species.