Question

why is diversity important for human life

Answer 1

biodiversity bosts ecosystem productivity no spaces no matter how small

Answer 2

Maintaining biodiversity ultimately helps maintain of human health; many medicines are derived from plants and, recently, animal toxins.
Agricultural Diversity

Maintaining genetic biodiversity of wild species of our crops that are related to domesticated species ensures our continued food supply.
Human Health

Contemporary societies that live close to the land often have a broad knowledge of the medicinal uses of plants growing in their area. Most plants produce secondary plant compounds, which are toxins used to protect the plants from insects and other animals that eat them, but some of which also work as medicines. For centuries in Europe, older knowledge about the medicinal uses of plants was compiled in herbals: books that identified plants and their uses. Humans are not the only species to use plants for medicinal reasons: the great apes (orangutans, chimpanzees, bonobos, and gorillas) have all been observed self-medicating with plants.
Managing Fisheries

Overfishing leads to fishery extinctions, loss of a food source, and affects many other species in ways that may be impossible to predict.