Amateur naturalist Charles Darwin expounded on his version of the theory of evolution in 1859 when he published his book "The Origin of Species." In its simplest form, Darwin theorized that life, plant and animal, were not created but resulted from a series of blind chances. Lightning striking a warm pond zapped life into inanimate cells. The cells reproduced and differentiated into the various life forms we have today.
The theory of evolution or Darwinism theorized that life sprang out of nothing, though it took billions of years to do so. Simple life became more complex over time. According to the theory, evolution continues to this day, though the immediate processes are so minuscule that such evolutionary gains are difficult to measure.
According to Darwin's theory of evolution, those organisms most able to adapt to their environment did so, while those that did not died out. Only those able to adapt passed on their genes to a new, stronger generation. Those that were ill or weak either died due to their inability to survive the environment or were dispatched by stronger organisms of their kind.