What are predators, parasites and pathogens (viruses and disease)?
Predators, parasites and pathogens are organisms making a living at the expense of other organisms, their prey or hosts. Predators usually kill or eat their prey, which are about the same size or smaller that the predator. Cats prey on mice; hawks on snakes, and so on. Parasites are generally smaller in comparison to their hosts and do not kill or eat them, but obtain their food from body fluids or in some other non-fatal waytapeworm, ticks, etc. Pathogens are microorganisms, usually bacteria or viruses, that sicken the host by living within itpolio virus, tubercle bacilli, etc. What are the other kinds of coactions? Commensalism – commensals may be microorganism such as the coliform bacteria that live on your intestine, a slightly larger mite, which live in the oil glands around your nose, or ordinary-sized animals such as the house mice and house sparrow that live in or on your house rather in or on you. Individuals of commensal species gain some advantage from the relationship. Mutu
