Protecting endangered species protects the interests of humans  Protecting endangered species helps protect humans: Humans actually benefit in a large number of ways from the protection of endangered species and thus continuing biodiversity. Firstly, the diversity of life and living systems is considered by many scientists to be a necessary condition for human development. We live in a world built on a carefully balanced ecosystem in which all species play a role, and the removal of species from this can cause negative consequences for the whole ecosystem, including humans. [1] There is also the potential for almost any species to hold currently-unknown future benefits to humans through products they could provide. One example of this is the scrub mint, an endangered plant species which has been found to contain an anti-fungal agent and a natural insecticide, and thus holds great potential for use that benefits humans. [2] Endangered species have also been known to hold the key to medical breakthroughs which save human lives. One example of this is the Pacific yew (a tree species) which became the source of taxol, one of the most potent anticancer compounds ever discovered. [3] Biodiversity also helps protect humans in that different species' differing reactions to ecological problems may in fact act as a kind of 'early warning' system of developing problems which may one day negatively affect people. This was the case with the (now banned) dichlorodiphenyltrichloroethane (DDT) pesticide, as the deterioration of the bald eagle and the peregrine falcon through their exposure to DDT in fact alerted humans to the potential health hazards of this pesticide, not just to animals but also to humans. [4] Thus the preservation of endangered species helps to protect humans, as this means plants and animals continue to play their specific role in the world's ecosystem which humans rely on, can act as an 'early warning' for problems which may affect humans, and may hold the key to scientific and medical breakthroughs which can greatly benefit humanity. Al this could be lost through the careless extinction of plant and animal species.  [1] Ishwaran, N., &amp; Erdelen, W. “Biodiversity Futures”, Frontiers in Ecology and the Environment, 3[4]. May 2005   [2] Wilcove, D. S., &amp; Master L. L. “How Many Endangered Species are there in the United States?”. Frontiers in Ecology and the Environment, 3[8]. October 2008.   [3] Wilcove, D. S., &amp; Master L. L. “How Many Endangered Species are there in the United States?”. Frontiers in Ecology and the Environment, 3[8]. October 2008.   [4] Wilcove, D. S., &amp; Master L. L. “How Many Endangered Species are there in the United States?”. Frontiers in Ecology and the Environment, 3[8]. October 2008.