“The constant flows of energy and matter within the complex network structures of life mean that new forms and structures can emerge spontaneously, a feature of life known as emergence. Life not just a constantly repeating cycle; life consists of systems whose processes continually generate novelty.
This constant, dynamic change allows systems to be resilient (Walker and Salt 2006, 78). Resilience is the ability of a system to accommodate disturbance and still retain its basic function and structure. Ecosystems are resilient because they are made of component parts at a range of scales. When a disturbance happens, small parts react and recover quickly while larger, slower parts maintain the continuity of the system. For example, when floods scour a riverbank, the small and fast parts are affected: individual trees are uprooted, birds must find other places to nest, and new trees subsequently sprout and grow. The large and slow parts – the role of birds, the role of trees, and the function of the riverbank ecosystem – absorb the shock and continue on.
Emergence and resilience happened in a big way early in the history of life. Photosynthesis, the ability to manufacture food from sunlight, was invented by ancient bacteria who used not sunlight and water but sunlight and hydrogen sulfide, a gas that was being discharged in large quantities by volcanoes. About two billion years ago the greatest pollution disaster in Earth’s history threatened to wipe out all life on the planet: photosynthetic blue-green bacteria had begun emitting oxygen for the first time, and it began to accumulate. This reactive gas happened to be highly toxic to the life forms then living on the planet, the anaerobic bacteria. Many species were completely wiped out. Others were driven underground, to live in muds at the bottoms of lakes and oceans. Today we find these same anaerobic bacteria living in the guts of all animals, where we provide the anaerobic environment they need while they digest our food for us. But in this early oxygenated atmosphere, in a dramatic example of emergence some life forms actually developed the ability to breathe this formerly toxic chemical (Hazen 2012, 228-229).
When we talk about the evolution of life, we may think of what we learned in school about competition and survival of the fittest. But while it is true that competition plays a role in determining which organisms survive long enough to reproduce, it turns out that cooperation is even more fundamental to life. A form of cooperation called symbiosis occurs when two different organisms live with and interact with each other, benefitting both of them. Symbiosis led to the development of the cells that now make up all plants and animals (Margulis and Sagan 2000, 103-106).”
pp. 33-34, Sustainability: Principles and Practice, Margaret Robertson