I don't think that everything we experience or do in our lives can be pigeon-holed into either 'evolutionary advantageous' or 'spiritual'. To me that is a very simplistic (not to mention blinkered) way to view the world.Love of other species (pets), How is that evolutionarily advantageous?
Love of music and art, What purpose does that serve?
A: It nurtures the spirit.
In the interests of open mindedness you should really add an 'IMO' to your answer. A person with a greater grasp of biology than me would probably tell you about music, art, etc triggering receptors in the brain, releasing endorphins or some such.
BTW it's worth adding that the body's cells are not all replaced simultaneously. People don't take delivery of a shiny new body every seven years. Each new cell we produce contains our own genetic code.
Meaning: You are your body.