How do the extinctions of other creatures affect humans directly and indirectly?

If the animal is a staple in the diet of humans, it may have a direct impact on the diet of humans such as if the tuna went extinct. If the animal is not a staple, it may still have an impact due to the fact that it may be a key food source for another animal which is a staple of the human diet. If plankton went extinct, everything that ate them, such as most fish, would then go extinct. Just as if honeybees became instinct, the pollination of our crops and produce would cease.

Beyond just eating animals, the extinction of creatures can affect our lives in other ways. A poll by the American Museum of Natural History finds that seven in 10 biologists believe that mass extinction poses a colossal threat to human existence, a more serious environmental problem than even its contributor, global warming; and that the dangers of mass extinction are woefully underestimated by almost everyone outside science.

All these disappearing species are part of a fragile membrane of organisms wrapped around the Earth so thinly, that it "cannot be seen edgewise from a space shuttle, yet so internally complex that most species composing it remain undiscovered". We owe everything to this membrane of life. Literally everything. The air we breathe. The food we eat. The materials of our homes, clothes, books, computers, medicines. Goods and services that we can't even imagine we'll someday need will come from species we have yet to identify. The proverbial cure for cancer. The genetic fountain of youth. Immortality. Mortality. The living membrane we so recklessly destroy is existence itself.