Need some help refuting this creation argument...

[Darkstar]

And don't forget that it is not one animal at a time that carries mutations but the whole of the breeding line allowing for many different genetic changes simultaneously.
There are for example 6 billion non-identical humans at the moment.

And that's just the humans:

At any time, it is estimated that there are some 10 quintillion (10,000,000,000,000,000,000) individual insects alive.

http://www.si.edu/Encyclopedia_SI/nmnh/b...bugnos.htm