When we try to psychoanalyze life on earth we often end up arguing whether something is genetically or culturally inherited. I believe the juxtaposition is rather silly. Everything exists as a result of both. Their effects intertwine, spanning across time and space. Trying to isolate nurture from nature is like trying to pick out the eggs from a cake mix. It is improbable to happen.
False Dichotomy
The main reason many people fall into this logical fallacy is due to the simplifying nature of the human mind. Thinking takes effort. This is why we have invented Evil vs Good, Nature vs Nurture, Reward vs Punishment. We think that there are only two options in regards to how we evaluate something because considering more options messes up with our heads.
Life is never about black or white. Life is all about shades of gray. A recipe of different ingredients that are blend together in different proportions in order to deliver different cake flavors. No cake is made out of only flour or sugar.
The Epigenetic Mixing Pot
Genes don't just pop out of nowhere. Same applies to behavior. Epigenetics teach us that changes in organisms happen all the time due to different gene expression rather than alteration of the genetic code itself. The process takes a long or short time depending on what kind of cake nature is preparing.
Some of nature's cakes need more genetic steering before adding nurturing. Some others rely more on nurturing. Much like any steering pot, size matters in regards to how something gets mixed.
Nature is a psychotic cook with unpredictable mood swings
Depending in what goes around her, Mother Nature decides how to go about her cake mixing,... or not. If there are too many stress agents, nature strengthens the genetics part. If she feels "OK" then culture is added plentifully. Heck, everything can be just fine and Mother Nature might decide to make her own mixing for no reason whatsoever.Quantity Over Quality
Being such a sloppy cook nature decides to make thousands, even millions of different cakes without paying too much attention on how the ingredients mix. She figures that if she makes many, at least some of them will actually turn out good. And this is exactly what we observe in our phylogenetic trees. 99.9% of all species that ever existed are now extinct.
Final Word
We don't see ourselves going crazy about baking soda, sugar, eggs or salt when making a cake. We know that if we screw up any of these ingredients then our cake will suck. We are more moderate in our approach because we understand the dynamics of baking. We acknowledge how important each ingredient is in order to construct a unique composite. Nature and Nurture work alongside thousands of constituents in order to create, preserve and propagate an organism. They cannot be separated, only observed as part of a greater sum.