Parasitism

Question 1

Evolution of parasitism: number of times that a parasitic lifestyle has evolved

Answer 1

31 times in all phyla
Phylum Platyhelminthes: One
Phylum Annelida: One
Phylum Molluska: One
Phylum Nematoda: Five
Phylum Arthropoda: Ten
Phylum Chordata: Five

Question 2

Types of Parasitology

Answer 2

Intermediate hosts
Primary Host
Aberrant Host

Question 3

Intermediate Hosts

Answer 3

Hosts of immature (larval) forms

Question 4

Primary Host

Answer 4

Hosts of mature forms

Question 5

Aberrant Host

Answer 5

Any intermediate of primary host in which normal development of the parasite ceases

Question 6

Ectoparasitism

Answer 6

Parasite lives on outside of host’s body; feeds on blood or soft tissue
Low host specificity
Simple life styles
Ex: Arthropods, Annelids, Chordates

Question 7

Endoparasitism

Answer 7

Parasite lives inside host's body; feeds on blood, soft tissue, or ingested food
Higher host specificity
Multiple hosts common
Complex life style
Ex: Nematodes, Platyhelminthes

Question 8

Prevalence

Answer 8

of hosts with parasites / # of hosts examined

Question 9

Incidence

Answer 9

% of new cases in time T / % of uninfected hosts in time T

Question 10

Intensity

Answer 10

Average # of individual parasites in a host

Question 11

Density

Answer 11

Average # of individual parasites in one organ

Question 12

Low host specificity

Answer 12

Many species can serves as a host to a parasite

Question 13

High host specificity

Answer 13

Only a limited or single species can serve as a host to a parasite