Platyhelminthes

Position in the Animal Kingdom

Type of symmetry - bilateral

Number of internal spaces - none

Type of body cavity - acelomate

Number of germ layers - three

Phylum Characteristics

Body form-flattened

Type of nervous system-two nerve cords

Type of excretory system-one opening. water collecting tubules. flame cells

Type of reproductive system-asexual

Type of digestive system-one opening with muscular tube

Type of motion-cilia and host's circulation

Generic life cycle of parasitic species-larva then host one then attaches to host two



Ecological Relationships

Modes of living-active

Hosts for Parasites-Humans, animals, molluscs

Economic Impact-Hardly any

Class Tubellaria

Modes of life-epidermal cilia

Type of Life cycle-involves more than one host

Locomotion-ciliary gliding and muscular contractions

Digestive System-no digestive cavity. branched gut.

Excretion and osmoregulation-flame cells

Sense organs-none

Reproduction-asexual


Class Trematoda

Mode of life-oral suckers and hooks

Hosts are…gastropod mollusc and a vertebrate

Special structures…has hooks and suckers

Major adaptations for parasitism-suckers to attach

Life cycle is…complex and has 2 hosts

What body systems are infected-liver and intestines



Human liver fluke

i. Geographic location-Asia and Eastern Europe

ii. Infect what organisms-human liver

iii. Typical life cycle-pass through several immediate hosts before being ingested in a human

iv. Economic effect (positive and negative)


Human blood fluke-

i. Geographic location-warm regions and fresh waters

ii. Infect what organisms-humans

iii. Typical life cycle-main host and secondary host

iv. Economic effect (positive and negative)-gets rid of waste



Sheep liver fluke

i. Geographic location-wetter regions

ii. Infect what organisms-sheep and cattle

iii. Typical life cycle- eggs laid in liver and try to find intermediate host snails.

iv. Economic effect (positive and negative)



Class Cestoda

Common name is…tapeworms

Mode of life-no locomotor organs

Hosts are…usually has 2 hosts

Special structures…has attachment hooks

Life cycle is…primary host and 1 or more secondary host

What body systems are infected-intestines


Beef tapeworm

i. Geographic location-Africa, Eastern Europe, Latin America

ii. Infect what organisms-cattle and humans

iii. Typical life cycle-cattle is intermediate host and human is definitive host

iv. Economic effect (positive and negative)


Dog tapeworm

i. Geographic location-everywhere

ii. Infect what organisms- intestines of meat eating organisms

iii. Typical life cycle- two hosts

iv. Economic effect (positive and negative)