Gray wolves disappeared from yellowstone national park because

Gray wolves disappeared from the Yellow Stone National Park, because when the National Park was built during the early 1800s, 1872 to be exact, Gray wolves were not protected by the park itself, there were no laws to protect these species, which is why hunters, who come across the park, hunts these gray wolves until their population decreased.

It is meant that like tapestry scientific theories often need to pull out since they are not relevant and often times the whole chain of theories may be pulled out.