Conserving wild species doesn't seem like it would be that controversial. No one wants to see an extinction. But at the same time, don't we believe that every animal matters? If every animal matters, how can we justify killing some to save others? And how do we determine what deserves saving in the first place? We sit down with Emma Marris to talk about her new book, "Wild Souls: Freedom and Flourishing in the Non-Human World".