17.2 - Parasitism

parasitism

one species benefits while the other is harmed

parasite characteristics

• smaller than host

• live on or in host for extended period of time

• doesn’t usually kill the host but can

how are parasites differentiated

by size - microparasites and macroparasites

microparasites

small and often intracellular living within cells and multiple directly within host e.g viruses, bacteria and protozoa

macroparasites

grow on or in host but don’t multiply in them. produce infectious stages where they release into the environment to find new hosts e.g. helminths, nematodes and tapeworms

What are some of the key characteristics of parasite habitats and do these present any challenges for parasites?

the habitats are alive and grow, move, evolve including parasite defences and recover from parasites. Evolving defences can prevent parasites from benefiting from the interaction

What is the difference between a monoxenic and heteroxenic life cycle?

monoxenic life cycle occurs within a single host species, while a heteroxenic life cycle involves multiple hosts at different stages of the parasite's development.

Explain the concept of kleptoparasitism and how it differs from what we might normally classify as parasitism

where 1 species steals food or resources gathered by another rather than directly harming the host. Differs as o.g parasitism involves living at expense of host’s health, kleptoparasites benefit from the labour of others without necessarily affecting their well-being 

e.g. of kleptoparasitism

groups of hyenas surround lions with a kill and chase them off before stealing their food - also occurs vice versa