AP BIOLOGY

Detailed explanation-1: -There are three primary anthropogenic processes that lead to species endangerment and extinction-overharvesting; the introduction of nonnative species, including the spread of disease; and habitat destruction. For most endangered species in the United States today, the most serious threat is habitat destruction.

Detailed explanation-2: -The current extinction crisis is entirely of our own making. More than a century of habitat destruction, pollution, the spread of invasive species, overharvest from the wild, climate change, population growth and other human activities have pushed nature to the brink.

Detailed explanation-3: -In fact, habitat destruction impacts more species than all other threats combined (Figures 1 and 2) and is the dominant threat to an extraordinary 40 times more species than climate change (Figure 2). For the vast majority of species, it is the destruction of terrestrial eco-systems that is the primary problem.