Symbiosis Flashcards
What is symbiosis?
A co-evolved relationship between two species.
What are the types of symbiosis?
Parasitic or mutualistic.
How does parasitism work?
A parasitic organism derives its nutrition or energy from another organism (host).
What is the effect of parasitism on both parties?
The host is harmed by the loss of resources while the parasite gains resources. (+/-)
Why don’t parasites kill the host?
They often have a limited metabolism and cannot survive without the host. For example, a tapeworm absorbs already digested food as it doesn’t have its own digestive system (degenerate).
What are the three ways parasites are transmitted?
- direct contact
- release of resistant stages
- use of a vector
Example of direct contact transmission of parasites?
Head lice are passed from person to person through direct contact.
How are parasites transmitted through the release of resistant stages?
Some parasites use resistant larvae of pupae which can survive adverse environmental conditions until they come into contact with a new host. A delay in transmission.
How are parasites transmitted through the use of a vector?
Usually a biting insect that transmits a disease or parasite from one organism to another. For example, mosquitoes pass the parasitic organism plasmodium through its saliva however are not affected by the parasite.
Explain indirect life cycles of parasites.
Some parasitic life cycles involve an intermediate (secondary) host to allow them to complete their life cycle. For example, a parasite infects a snail’s eyes making it look like a caterpillar which a bird then eats and becomes the definitive (primary) host.
What is the difference between the use of a vector and the indirect life cycle of a parasite?
When a parasite goes through an indirect life cycle, the intermediate host is affected by the host and exploited - unlike the vector.
What is mutualism?
When both organisms benefit from an interdependent relationship.
What is an example of mutualism?
The plover bird eats leftover food from the crocodile’s teeth, providing food for the bird and preventing infection for the crocodile - both benefiting.
What are three different forms of mutualism?
- both organisms provide a service
- one organism provides a service and another receives a resource
- both organisms receive a resource.
