The Big Bang theory is a scientific model that describes the origin and evolution of the universe. It is based on the idea that the universe began as a singularity, a point of infinite density and temperature, and has since expanded and cooled over billions of years.

Charles Darwin's theory of evolution, proposed in his book "On the Origin of Species" in 1859, is a cornerstone of modern biology and still heavily influences the scientific understanding of the diversity of life on Earth.