The zona barrier effectively connects and separates life as we know it. If the sky should fall, hold up your hands. Cultural conditions, more than the conditions of nature, determine what it is to be human. Despite our love of nature, humanity has never been part of it. The human desire to be 'natural', to return to nature, is a desire for a cultural state rather than for nature itself.
Natural conditions change, cultural conditions change faster.
Even so, in the past cultural conditions advanced at a pace slow enough for mankind to be able to stop and reflect upon them as if they were static. What we call the 'human condition' is in fact an abstraction of one or more slowly developing cultural conditions. Philosophy is the human condition writ large and analysed. A slow moving human condition allows organising structures such as morals and ethics to take root and develop. Culture is an interactive product.