2.5 parasitism Flashcards
Ecological niche
A summary of the tolerances and requirements of a species.
Fundamental niche
The niche that an organism will occupy with no interspecific competition.
Realised niche
The niche that an organism occupies when there is interspecific competition present.
Competitive exclusion principle
Where when two species are in intense competition with each other and have extremely similar fundamental and realised niches one will decline to local extinction.
Resource partitioning
Where two different species with different realised niche coexist with each other by compromising which each other over resources.
Parasite definition
An organism which forms a symbiotic relationship with a host and benefits by gaining nutrients and energy at the expense of a host.
Benefits of parasitism to the parasites
Gain nutrients and energy from host.
Reproductive potential do parasites
Parasites have high reproductive potential compared to host since many parasites can survive on one host.
Degenerate meaning
When a parasite lacks vital organs to survive without host, such as a digestive system.
Fasciola acaris
Flatworm
Endoparasite
A parasite which remains inside a host.
Ectoparasite
A parasite which remains on the outside of the host.
Vector definition
An organism which allows for transmission of parasites from one host to another.
Schistosomes lifecycle
Schistosomes sexually reproduce inside the human (definite host).
Fertilised eggs pass out human faeces and into water.
They develop into larvae and infect water snails. (Intermediate host)
Asexual reproduction occurs inside the water snail.
Exit the snail and penetrate human entering the bloodstream.
Definite (primary) host
The host that a parasite will reach sexual maturity by detrimentally effecting
Intermediate host
The host which a parasite requires to complete its lifecycle, such as carrying out asexual reproduction to increase transmission.
Schistosomes
A form of flatworm which causes the disease schistosomiasis.
Schistosomes intermediate host
Water snails
Schistosomes definite hosts
Humans
Malaria pathogen
Plasmodium
Why is plasmodium so difficult to treat
It can hide in the liver or on inner walls of blood vessels in a dormant state, remaining undetected by the immune system
Malaria lifecycle
Plasmodium enters the human bloodstream by being bitten by an infected mosquito.
Humans are the intermediate host and therefore plasmodium undergoes asexual reproduction in the liver and red blood cells.
Red blood cells burst and gametocytes are released into the bloodstream.
Mosquito bites infected human and plasmodium enters the definite host.
Gametocytes mature into gametes allowing for sexual reproduction inside the mosquito.
Plasmodium reaches sexual maturity.
Mosquito infects another human.
Plasmodium definite host
Mosquito
Plasmodium intermediate host
Human
Structure of viruses
Has a viral head with DNA surrounded by protein coat.
Has a tail which is a hollow tube made of protein
Has tail fibre which is made of protein
Viral replication process
Virus binds to the membrane of a host cell.
Virus gains using lipid membrane on the surface of the protein coat and injects DNA into the host.
Viral DNA enters the nucleus and is replicated using host enzymes and nucleotides.
Viral DNA is translated into viral protein coats by host organelles
Viruses are assembled by protein coats surrounding the virus DNA
host is broken open by virus and virus repeats the cycle.
Viruses lipid membrane function
Viruses have a lipid membrane on their surface allowing the viruses to gain access to a cell and avoid detection from the immune system.