key area 3.6 - symbiosis

Question 1

symbiosis definition

Answer 1

• the relationship between two different species in direct contact with one another

Question 2

types of symbiosis

Answer 2

• mutualism
• parasitism

Question 3

parasitism

Answer 3

• the parasite benefits at the expense of the host who is often damaged
• stable relationship because without the host the parasite would not be able to exist due to their limited metabolism
• some live inside host some live outside
• eg tapeworm, mosquito

Question 4

mutualism

Answer 4

• both organisms in the relationship are interdependent on each other and both benefit from the relationship

Question 5

transmission of parasites

Answer 5

• direction contact - passed from host to host though physical contact
• release of resistant stages - some stages in the life cycle of the parasite that can withstand adverse conditions until they come into contact with a new host
• use of a vector - intermediate organism that transfers the parasite from one organism to another

Question 6

direct life cycle

Answer 6

• life cycle that only involves one species of host
• common amongst parasites which feed on the outside of their host

Question 7

indirect life cycle

Answer 7

• in the primary host the parasite undergoes sexual reproduction
• the secondary host allows the parasite to complete its lifecycle and/or allows asexual reproduction to occur
• increases chance of survival

Question 8

interdependence

Answer 8

• relationship that exists between two partners involved in a mutualistic relationship