For the last 5 years or so, Corporate world is buzzing with this word called, Diversity. Diversity of gender, ethnicity, backgrounds... even diversity of thought. All of this because researchers realized maintaining diversity is healthy for not just culture of the organization but for profitability and sustainability.
Simple lesson... this lesson applies to natural world too... higher the diversity of species, richer the planet and obviously more sustainable
The diversity found in nature always had a purpose. Every bit of creation, living or otherwise, is interdependent in the food chain.
Humans at the top of the food chain are dependent on both plants and animals for food. The plants we eat, depend on herbivores to spread their seed, on bees, insects and butterflies to pollinate and reproduce. The chicken or fish we eat, survive on worms and those worms suvive on plants or microorganisms. We rely on the carnivores to monitor the number of herbivores, otherwise they will eat up all the plants.
One way or the other, if the balance is broken, a day will come when we run out of food and resort to cannibalism.