According to the World Wildlife Federation, biodiversity affects humans in terms of natural resources and ecosystem services. The Federation points out that biodiversity is a foundational issue for all life on planet earth.
The Federation notes that humans are part of a Web connecting all life. This Web includes animals, the atmosphere, humans, land and water. All of these are components of a global ecosystem. The Federation also notes that a serious reduction in some of these components can greatly affect others. Reduced biodiversity would affect the food that's available for human consumption due to food being more vulnerable to pests or disease because there is less of the global ecosystem that previously protected that food. Similarly, reduced biodiversity may greatly affect how much fresh water is available for human beings, potentially creating economic and health instabilities. The Federation points out that, at minimum, 50,000 plant species are harvested for medicine that heals and saves the lives of human beings. A reduction in the number of those plants will have an immediate impact on the kinds and amounts of medicine produced for humans. A reduction in biodiversity can also affect the number of fish and wild animals that can be harvested. According to the Federation, a reduction in the number of these animals directly affects the livelihood of humans in numerous countries.