[RWebb]

Bighorn (wild) sheep mostly were extirpated because of diseases from domestic sheep when they were introduced - if the state Game Dept.s stop introducing Bighorns you lose the wild sheep in wild places and you don't learn why the introductions are failing. The intros in oregon are doing pretty well overall. Obviously, Bighorns were able to coxist with mtn. lions and other predators for millions of years.

Extinctions over evolutionary time happen (background rates) but the rate is far slower than today; human caused extinction rates are thousands of times that of background rates - for amphibians they are maybe 40,000x

There are numerous ethical, moral and religious reasons to prevent extinction as well as many economic reasons (Google 'ecosystem services').

Congress already considered why it was important when they passed the Endangered Species Act and no doubt so did President nixon when he signed it into law.

Ultimately, allowing a species to go extinct is like burning down a with library with unique collections in it.