Symbioisis: Parasitism & Mutualism
Symbiosis — co-evolved intimate relationships between members of two different species.
(a) Parasitic relationships and transmission — a parasite benefits in terms of energy or nutrients, whereas its host is harmed by the loss of these resources.
Transmission of parasites to new hosts using direct contact, resistant stages and vectors. Some parasitic lifecycles involve secondary hosts. Parasites often have limited metabolism and cannot survive out of contact with a host.
(b) Mutualism including evolution of mitochondria and chloroplasts. Both mutualistic partner species benefit in an interdependent relationship.
