How+does+this+affect+humans?

It is clear that humans are one of the causes of the extinction of animals yet, do we get impacted by it?
 * The extinction of keystone species could hurt our ability to make food, materials for clothing and building, and medicine.
 * Polar bears allowed humans to find out what was wrong with the environment they lived in and the situation. However, without polar bears, humans will struggle to find out.