intro and definitions

Question 1

what is parasitology

Answer 1

a study of a branch of biology, specifically the study of parasites

Question 2

give an example of a parasite which is used in biological control

Answer 2

Tetrastichus julis, a parasitoid wasp which lays eggs in the larvae of the cereal leaf beetle which feed on it whilst it is still alive

Question 2

give an example of an animal which has evolved to use parasitism to overcome abiotic restraints

Answer 2

Fresh water muscles and Glochidia (larval stage of fresh water mussels)
fresh water mussels use fish as an intermediate host to allow larvae to reach upstream against the current to colonise the upper stream when larvae are excreted

Question 2

what is symbiosis

Answer 2

greek translation- living together
two species deriving mutual benefit from the association
or
wide range of associations ranging from phoresies to parasitism

Question 3

define phoresy

Answer 3

using a second organism for transportation such as mites on dung insects

Question 4

define inquilinism

Answer 4

using a second organism for housing such as epiphytic plants like orchids on trees- they do not take energy from the host

Question 5

define metabiosis

Answer 5

a more indirect dependency in which the second organism uses something the first created, after the death of the first e.g. hermit crabs which use gastropod shells to protect their bodies

Question 6

outline the flow chart which breaks down symbiosis into phoresy, commensalism, exploitation, mutualism

Answer 6

organised based on trophic interactions
phoresy- no trophic interaction or ill affect to the host

commensalism- indirect trophic interactions with no harm to the host such as sharing food and other resources

mutualism- direct trophic interaction which benefits both individuals

exploitation- direct trophic interactions which causes harm to one individual = BROKEN DOWN INTO FURTHER DEFINTIONS

Question 7

Define commensalism

Answer 7

the association where one member derives benefit from the association whereas for the other the association is neither beneficial or harmful
- vary in strength and duration

Question 8

define mutualism

Answer 8

a direct trophic interactions where both species benefit by the interaction- at some points the association is intimate and obligatory where if the two organisms are separated neither will survive

Question 9

give some examples of mutualism

Answer 9

termites and their gut symbionts (ie flagellates)
termites unable to digest cellulose so flagellates do it for them and the termites provide a stable environment

zoothanthelle and coral

Question 10

give an example of a short term mutualistic relationship

Answer 10

ocean fish (mola mola) and albatrosses
ocean fish present food source from parasitic worms which the birds feed of removing parasite from fish

Question 11

using a flow chart explain how the different terms, predator, parasitoid, micro predator and parasite are separated from exploitation

Answer 11

predator- organism always killed and organism kills many hosts
parasitoid - when organism always killed by individual but only has one host
micro predator- sometimes killed but has many hosts
parasite- sometimes killed but has only one host

Question 12

what is a parasite

Answer 12

an organism living in or on another organism, obtaining from it part, or all, of its organic nutriment usually to detriment of its host aka incomplete predation

Question 13

whats a pathogen

Answer 13

an organism that causes disease in the host

Question 14

explain how the parasite diplostomum spathaceum affects behaviour of its intermediate host of a fish

Answer 14

causes cataract in rainbow trout so it cant see, causes it to swim higher up in the water column so more easy to be predated on by birds

Question 15

give an example of non-animal parasites

Answer 15

fungi
parasitic plants e.g. mistletoe or dodder

Question 15

what are the main transmission pathways for parasites

Answer 15

• contamination= faeco-oral pathways
• soil transmitted helminths = burrow into your feet
• trophic transmission= eating parasite
• sexual transmission= Trichomonas only human parasite
• vector borne

Question 16

whats the difference between a definitive host and an intermediate

Answer 16

when parasite undergoes sexual reproduction and the infections doesn’t always lead to illness but sometimes can= where the host wants to end up

intermediate- harbours parasite for short period where it may complete developmental stages

Question 17

what is the difference between a reservoir host and an amplifier host

Answer 17

R= host which harbours parasite but is asymptomatic, often non lethal to host
A= host where parasite multiples to high concentrations, can be lethal to host

Question 18

what are some effects of the parasite Toxoplasma gondii which cause toxoplasmosis

Answer 18

1) physiological effects on babies
2) behavioural effects seen in mice which attract to smell of cat urine so it can reach definitive host of cat

Question 18

what did lafferty 2006 find

Answer 18

found correlation, not causation, that infection T.gondii can alter behaviour of humans
- neuroticism
- uncertainty avoidance
- women’s sexual behaviour
- likelihood of going to prison
- cause of schizophrenia