There are christians, mainly in the USA, but also over here, who believe in something called 'intelligent design' (ID). They say that ID should be taught alongside evolution in science lessons. This would be ok if ID was science, but its not, its simply a belief with no basis in fact.
But lets give the christians the benefit of the doubt. Lets consider the arguments. The christians (because they are all christians) say that living things and the component parts they are made of are so complex that they could only exist because of a great designer (i.e. their god). They also allege that evolution is 'just a theory'. One of the examples they love to quote is the eye. How could such an organ evolve? Surely its just too complex?
Well it isn't, and if you understand how evolution works its not too difficult to see how an eye could evolve. What evolution needs is lots of time, and we have five billion years, a driving force - genetic mutation, and a mechanism - natural selection. All living things contain the genetic material DNA, and DNA is subject to mutations. Most mutations are harmful but some are beneficial. the key to all this is that the mechanism of natural selection benefits those living things which are well adapted to their environment, and are able to reproduce. Reproduction is crucial because if you can't reproduce you can't pass on your DNA to future generations.
Beneficial mutations make it more likely that an individual will be able to compete better with its rivals, and will reproduce, therefore passing on the beneficial mutation to its offspring. So, over hundreds of millions of years its not too difficult to see how small incremental beneficial mutations could lead to significant changes - like going from no eye at all to an eye. Even an organism with very limited sight, say just sensitivity to light, would have an advantage over its unsighted rivals.
Far from being just a theory there is a large body of evidence which supports evolution. Charles Darwin's theory was based on observation, not belief.
Consider this - the christian's god spent six days creating the earth and all that's supposed to be in it. That's one hell of a lot of design. There are millions of living things and billions of component parts. Even the omnipotent god must have had to work hard. But why? Surely it would be smarter to have a mechanism like evolution to do all the work for you? No need for any ID. Yet the christian god never did think of evolution as a solution to producing bewildering complexity. But Darwin did. ID is not intelligent design, its dumb. What does that say about these christians and their god?