"Don't put all your eggs in one basket."
The spinebill and the hummingbird both have long beaks and the capacity to hover, perfect for sipping nectar from long, narrow flowers. This remarkable co-evolutionary adaptation symbolises the specialisation of form and function in nature. The great diversity of forms, functions, and interactions in nature and humanity are the source for evolved systemic complexity. The role and value of diversity in nature, culture, and permaculture is itself complex, dynamic, and at times apparently contradictory. Diversity needs to be seen as a result of the balance and tension in nature between variety and possibility on the one hand, and productivity and power on the other.
It is now widely recognised that monoculture is a major cause of vulnerability to pests and diseases, and therefore of the widespread use of toxic chemicals and energy to control these. Polyculture is one of the most important and widely recognised applications of the use of diversity but is by no means the only one.
Diversity in different cultivated systems reflects the unique nature of the site, situation, and cultural context. The diversity of structures, both living and built, is an important aspect of this principle, as is the diversity within species and populations, including human communities.
The proverb "don't put all your eggs in one basket" embodies the common sense understanding that diversity provides insurance against the vagaries of nature and everyday life.