Key Area 5: Symbiosis Flashcards
What is Symbiosis?
A co-evolved intimate relationship between members of two different species
(Members of the two species live in direct contact with each other)
Examples of Symbiotic Relationships
- Parasitism
- Mutualism
What is Parasitism?
Parasitism is a symbiosis in which one symbiont (the parasite) gains nutrients from the other symbiont (the host )
What happens in Parasitism?
The host is harmed by the loss of these resources and the parasite benefits
What is a Symbiont?
An organism living in symbiosis with another
Parasites often have a…?
Limited Metabolism and cannot survive if they are not in contact with their host
How can Parasites be transmitted?
- Direct contact
- Via resistant stages
- Via a vector
What is Direct contact?
The Paradite is passed from host to host by physical contat e.g. head lice in humans
How can a parasite be passed on via resistant stages?
The Parasite can survive without a host in the environ,ent by having a resistant stage in their lifecycle
Example of a parasite that can be transmitted via resistant stages
Giaradia in a wide variety of mammals including cats, dogs and humans
What is a Vector?
An organism that carries something like a parasite to a new host
Example of a vector
The Plasmodium parasite which causes malaria is transferred between hosts by a mosquito vector
What are the two types of Parasitic Life Cycles?
- Direct Lifecycles
- Indirect life cycles
What is a direct lifecycle?
The entire lifecycle of the parasite can be completed with just a single host species. The parasite is transmitted directly from one host to the next without an intermediate host of another species e.g. the lifecycle of a flea
What is an Indirect lifecycle?
When two different species are required in order to complete the parasite’s lifecycle. The species in which the parasite carries out reproductio is called the secondary (or intermediate) host
