Here is a passage from The Selfish Gene
If selection goes on between groups within species, and between species, why should it not also go on between larger groupings? Species are grouped into genera, genera into orders and orders into classes. Lions and antelopes are both members of class Mammalia, as are we. Should we then not expect lions to refrain from killing antelopes, 'for the good of the mammals'? Surely they should hunt birds or reptiles instead, in order to prevent the extinction of the class. But then, what of the need to perpetuate the whole phylum of vertebrates?
So shouldn't it eat the other animals? Also in the next line, it says about vertebrates that since reptiles and birds are vertebrates, the lion should go for invertebrates.
It sounds illogical, but what stops lion from eating his "relatives", or from sparing a deer? And till what extent is the term "relatives" valid?
Is the question is too broad, please give a source where I can get an answer.