Evolution, as it is so often referred to in the media, is better defined as macro-evolution (please see Is there any scientific evidence against evolution?). This is a process requiring vertical changes - an expression of new genetic information (the tadpole turning into a man would be an example of macro-evolution)! The tadpole's transition from juvenile to adult is called, "microevolution", or, "horizontal variation" - which is the lateral redistribution of existing genetic information. No one has ever observed a tadpole transitioning into anything other than a frog. This happens routinely because that was built into the organism's genetic code. And because of this, it will never transition into anything else.
Consider both fish and chicken eggs, they too make a similar transition from young to adult. This is just simply their individual maturity processes which is routinely repeated without ever any expression of new genetic information but sometimes expressions of mutations - mistakes.
Evolutionists argue that these little changes happen slowly, and over long periods of time, and eventually the mutations (mistakes) lead to big changes - expressions of new genetic information which has never been observed. An expression of new genetic information would be inconsistent with the laws of thermodynamics.