Parasite

Definition

A parasite is an organism that lives on or inside a host organism and benefits at the host’s expense. Parasites often cause harm to their hosts, ranging from mild discomfort to severe disease or death.

5 Must Know Facts For Your Next Test

1. Parasites can be categorized into three main types: protozoa, helminths, and ectoparasites.
2. Parasitism is a type of symbiotic relationship where one organism benefits while the other is harmed.
3. Parasites have evolved various mechanisms to evade the host's immune system.
4. Some parasites require multiple hosts to complete their life cycles, such as Plasmodium spp., which causes malaria.
5. Parasitic relationships can influence community structure by affecting population dynamics of both hosts and other species.

Review Questions

• What are the main types of parasites?
• How does parasitism differ from other types of symbiotic relationships?
• Why might a parasite need multiple hosts to complete its life cycle?

Related terms

Symbiosis:

Symbiosis is an interaction between two different organisms living in close physical association.

Host: A host is an organism that supports a parasite, providing nourishment and shelter.

Mutualism:

Mutualism is a type of symbiotic relationship where both organisms involved benefit.