>>507438471
... terrestrial ecology is unloving and cruel: all things above the plant level must eat other things to stay alive themselves and there are exceptions even to the plant world's general beneficence, such as parasitic and insect-eating plants. In most cases the life-form victimized as food is eaten alive — the worst form of sadism the Marquis himself would dream up.

There is a kindred cruelty inherent in the predatory ecology: lower forms of life are held in bondage and prevented from evolving further because they are essentially needed in the life support-systems of more highly evolved forms.

Examples:
1) bacteria in termites' and other insects' intestinal tracts
2) similar bacteria in mammalian and human intestinal tracts
3) specialized protozoa in animal circulatory and nervous systems: leucocytes, erythrocytes, neurons.