“So far the idea of pain has scarcely connected itself with that of sacrifice, for, as we have seen in the course of our studies, the astral bodies of plants are not sufficiently organized to give rise to any acute sensations either of pleasure or of pain.
But as we consider the law of sacrifice in its working in the animal kingdom, we cannot avoid the recognition of the pain there involved in the breaking up of forms.
It is true that the amount of pain caused by the preying of one animal upon another in “the state of nature” is comparatively trivial in each case, but still some pain occurs.
It is also true that man, in the part he has played in helping to evolve animals, has much aggravated the amount of pain, and has strengthened instead of diminishing the predatory instincts of carnivorous animals;
still, he did not implant those instincts, though he took advantage of them for his own purposes, and innumerable varieties of animals, with the evolution of which man has had directly nothing to do, prey upon each other, the forms being sacrificed to the support of other forms, as in the mineral and vegetable kingdoms.
The struggle for existence went on long before man appeared on the scene, and accelerated the evolution alike of life and of forms, while the pains accompanying the destruction of forms began the long task of impressing on the evolving Monad the transitiory nature of all forms, and the difference between the forms that perished and the life that persisted.”
Annie Besant
The Mark Of God: Understanding Your "I AM Presence" 