[Mr. Bird]

No, I believe there's no such thing as "variation within species to adapt to the environment"

OK, silly person. Let's set aside the very real variations within the finch populations. What about the phenotypical variations among homo sapiens, i.e. the variances in melanin content between equatorial populations and their same-species cousins in Europe?

[Truth666]

Thanks for your second contribution. We have a second case :
"phenotypical variations among homo sapiens, i.e. the variances in melanin content between equatorial populations and their same-species cousins in Europe"
BTW, if you think this is a even better case, I wonder why you didn't present it in the first place ...