In the nineteenth century, Charles Darwin and Alfred Russel Wallace advanced a new theory to explain the origins of life on earth and the evolution of different lifeforms. They called it the theory of evolution by natural selection. Natural selection is the key mechanism by which all organisms have evolved. Today, many call the theory 'the theory of evolution' or 'Darwin's theory of evolution' (since Wallace is not as well-known).
Yes, the theory of evolution is correct
The theory is correct because it is supported by an abundance of historical and scientific data. It is also explanatorily successful and the bedrock of biology. In a nutshell, the theory says that all lifeforms have emerged with variations from species that existed before them. This evolution happened through a phenomenon called natural selection. Natural selection can be described as "survival of the fittest" since the "fittest" organisms—the ones that are most cut out for their environment—are the ones that have the highest rate of reproduction and the greatest chance of passing on their best traits. A change in environment will spark a gradual change in those traits that help with survival.
No, the theory of evolution is flawed on many levels
The theory is full of holes and up against serious challenges it cannot overcome. For many learned scientists and philosophers, it is defunct. Darwin's theory cannot account for human intelligence and speech. The human mind is far too complex and so is human speech. Blind, random, directionless processes—the phenomenon of natural selection—can never produce the mind, human speech, the cell, or DNA. The mathematical, philosophical, and scientific flaws in Darwin's theory have already been elucidated.
The fossil record is incomplete
If evolution happened through the gradual development and multiplication of slight variations, which is what evolutionists claim, then the fossil record should exhibit dead organisms closely constellated together with scarcely differentiated strata. But this is not the case. The record is filled with gaps.
Biologists are quick to fall into circular reasoning. To explain how an organism survived, they refer to its fitness, and to explain its fitness, they refer to how it survived. In trying to explain complex biological systems like the eye, evolutionary biologists fall right into error.