Key Area 3.5 Symbiosis Flashcards
What is symbiosis?
A co-evolved intimate relationship between 2 members of different species.
What are the 2 types of symbiosis?
Parasitism and mutualism.
What is parasitism?
The parasite benefits in terms of nutrients or energy, whereas the host is harmed by the loss of these nutrients.
What can parasites usually not do without a host?
Survive.
What do some parasites life cycles include?
A secondary host.
What is an example of a parasite which has a secondary host in its life cycle?
Pork the worm, human is the primary host and the pig is the secondary host.
What are the 3 ways that parasites are transmitted to their hosts?
Direct contact
Release resistant stages
Vectors.
Describe and give an example of how direct contact transmits a parasite to the host.
Passed between individuals during physical contact e.g. Human head lice.
Describe and give an example of how releasing a resistant stage transmits a parasite to the host.
some parasites use resistant larvae and pupae, which can survive adverse environmental conditions until a new host comes in contact with them. E.g. Cat fleas.
Describe and give an example of how vectors transmit a parasite to a host.
An organism carries a parasite to a new host e.g. mosquito acts as a vector for malaria.
What is mutualism?
In mutualism both species benefit from the independent relationship.
Give 2 examples of mutualism.
Lichens are formed by algae and fungi living together. Algae can photosynthesise and make food, which is shared by the fungus. The fungus in turn shelters the algae from a harsh climate.
‘Cleaner’ fish feed off the dead skin and parasites of larger fish such as sharks. This provides the cleaner fish with food and protection and keeps the larger fish clean and less prone to infections.
