Evolution

Charles Darwin (1809 - 1882), the English naturalist and geologist, best known for his contributions to evolutionary theory
Charles Darwin (1809 - 1882)

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

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.

Natural selection

These are the key points of evolution by natural selection:

  • Individuals in a species show a wide range of variation.
  • Inherited variation is due to differences in their genes.
  • Individuals with the features that are best suited to the environment are more likely to survive and reproduce.
  • The genes that allow these individuals to be successful are passed to their offspring.
  • Individuals that are poorly adapted to their environment are less likely to survive and reproduce. This means that their genes are less likely to be passed to the next generation.
  • Over many generations these small differences add up to the new evolution of species.

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.