What meaning does love have to an atheist?

[Darwinian]

If God does not exist, if there is no eternal spiritual realm beyond the temporal material realm where reason and emotion have their ultimate foundations what meaning does love have? In an atheist worldview where love has no spiritual/non-material foundations what is the difference between the love of a man for his wife and a couple of pigs mating? If love only exists in a material form and is just a series of reactions of chemicals in our brain than what is the difference between a parent's for their child and a junkie getting high?

All you're doing is making wild assertions based on religious and theological teachings which, as far as I can tell, have nothing to do with logic, reason or common sense. In your religious views you state that you are 'undecided'. If this is so then this must be some strange usage of the word 'undecided' that I have previously been unaware of!

I put it to you that you are in fact a deeply religious individual who thinks that he/she can 'out smart' us poor ignorant atheists with you deeply philosophical and morally superior knowledge. If that is the case then be prepared for a rough ride!