Broadcasting the natural environment with antibiotics can create resistant strains of bacteria and it may cause changes in natural systems that have evolved for millions of years. Some species of animals rely on bacteria in their intestinal tract to be able to digest their food. Termites, for example, have protozoa or bacteria in their guts that actually digest the cellulose that they feed on. These termites cannot survive without these mutualistic relationships. Even humans rely on bacteria to aid in the digestion of food.
Diseases play a natural role in wildlife population control.
Naturally existing diseases can apply natural selection pressures on individuals in a population and weed out individuals that are less fit. Bowden, Idaho The duck-billed platypus is a remarkable animal and is most closely related to the echidna. Both are egg-laying mammals in the order Monotremata. There is only one single living genus and species of platypus, and it is only found in Australia. Echidnas occur in Australia, Tasmania and Papua New Guinea.