Earth's rich biodiversity is vital for the very survival of mankind. The reasons for conserving biodiversity are narrowly utilitarian, broadly utilitarian and ethical. Besides the direct benefits (food, fibre, firewood, pharmaceuticals, etc.), there are many indirect benefits we receives through ecosystem services such as pollination, pest control, climate moderation and flood control. Each and every living being has some intrinsic value. We derive countless economic benefits from the living things. Living things play a major role in many ecosystems.
All the species in the ecosystem are interlinked. When a species becomes extinct, the plant and animal species associated with it in an obligatory way also becomes extinct. When a host fish species becomes extinct, its unique assemblage of parasites also meets the same fate. Another example is the case of coevolved plant - pollinator mutualism where extinction of one leads to extinction of the other.
