Well doesn’t evolution have to start somewhere??
Maybe a Liger is not a new ‘species’, just like when they mix chihuahas and Miniture Pinchers. What do you get? People call them mutts or just mixed breed. But lets say that somehow this new breed beat out the other two breed in nature (ie; tigers and lions) sometime in the future. If this new breed (the Liger) was stronger, smarter, faster and better; the dominant species. Wouldn’t that be a small step of evolution??