The loss of biodiversity means the loss of all life supported by inter-connected dynamics which supply air, water and nutrients. Biodiversity is in effect, everything evolved on earth that is not mere mineral or inanimate chemical.
In school, many students have learned about the food chain, or even the great chain of being. The chain theory, however, is obsolete and has been replaced by the new comprehension that all life complements other life. Life exists in a web of interconnected bits.
It is not just the survival of fittest, but the interaction of everything that lives and dies which creates the carbon cycle, the hydrology cycle, the replenishment of the soil and the restoration, daily and ongoing, of the water and air that support life upon earth. Without insects, pollinators, and seed depositors, there is no way to propagate or continue sustainable populations of plants and animals, no less human beings.
For example, cattle when fed on grasslands do not rely upon the monoculture of artificially fertilized corn. Grazing cattle do not add concentrated methane, or deteriorate landscapes. In their naturally evolved context, cattle replenish and support biodiversity. In the factory farm, they are yet another aberration that adds to the loss of biodiversity.
Another simple way to look at it, it to see that which evolved in nature arrived at the present system of life on earth that in “circle of life” fashion, continues to ensure life on earth. As humans developed agriculture, then cities and factories, biodiversity began to decline. Most mega-fauna (large animals) were hunted to extinction eons ago. Pollution, garbage, waste, deforestation, mining and much more human activity, notably burning of fossil fuels, threatens current remaining biodiversity, and, so too, the future of life. This bleak future is avoidable, as described by E.O. Wilson, in his book, the Future of Life.
Also since modern times, those things brought about by humans that threaten biodiversity can all be reduced to the idea of waste. Annihilation of the American Bison for example, shows how one missing creature virtually extinguished native American ways of life. In nature, there is no waste. All debris and death gives rise to life. The idea of garbage, toxins, waste, plastic and contaminants threatens all biodiversity because artificial waste, in huge quantity, cannot be digested by nature.
The great Pacific garbage patch, a plastic floating Texas size mess, kills marine animals and birds because they have no natural ability to digest, or disentangle from plastic trash. Glass would be a simple technology to protect such life, but few people care because they do not know loss of biodiversity threatens human life, too.
A new view of economy, that which enriches life and discourages waste, will define the coming age of recognizing the importance of biodiversity to human health. A new relationship which welcomes humanity as belonging to nature will ensure that humanity lives, thrives and finds connection to all that is diverse.