Hello and welcome munkeyhead.
I cant prove there is a god to an athiest no more then he can prove to me that I and a palm tree decended from the first irreducibly complex life without intelligent intervention.
Two things to say here;
a) Scientists don't talk in terms of proof, that is the realm of mathematics. Scientists use
evidence to draw conclusions that describe phenomena as accurately as possible. Scientific theories are never considered to be 100% unimpeachably correct. Such certainty is the preserve of religion.
b) No evolutionist has ever suggested that humans descended from palm trees. Honestly. Humans are not descended from palm trees. Animals and plants do indeed share common ancestry, but they parted company long, long before there was any such thing as a palm tree. Whoever told you that this is what the theory of evolution says was very wrong indeed and I recommend taking what they tell you with a pinch of salt in future. (Added by Edit; It has been pointed out to me that this isn't what you were saying. See below.)
Edited by Granny Magda, : Whoops!
Mutate and Survive