Ch. 8: Phylum Platyhelminthes

Question 1

What organism in this phylum?

Answer 1

Flatworms

Question 2

What body symmetry do they possess?

Answer 2

Bilateral

Question 3

Are Platyhelminthes triploblastic or diploblastic?

Answer 3

Triploblastic

Question 4

What type of body cavity do they have?

Answer 4

Acoelomates (no body cavity)

Question 5

What type of reproduction do they perform?

Answer 5

Asexual; fragmentation

Question 6

What structures are unique to this phylum?

Answer 6

Rhabdoids

• Rod-like structure, “mucus” producers
• Help with desiccation and locomotion

Question 7

What two changes come with bilateral symmetry?

Answer 7

1. Centralization of sensory organs

2. Anterior vs. posterior

Question 8

What type of digestive system do they possess?

Answer 8

Incomplete (no anus)

Question 9

How do they perform excretion?

Answer 9

By diffusion and proto-nephridia

- Flame cells in proto-nephridia filter and get rid of residuals

Question 10

Adaptations to parasitism

Answer 10

1. High reproductive ability
2. Ability to stick to the host
3. Simplification of systems

Question 11

Intermediate host

Answer 11

Host with eggs or larval parasite

Question 12

Definitive host

Answer 12

Host with adult parasite

Question 13

Classes in Phylum Platyhelminthes

Answer 13

1. Turbellaria
2. Monogenea
3. Trematoda
4. Cestoda

Question 14

Class Turbellaria

Answer 14

• Single host

- Ecto-parasite

Question 15

Class Trematoda

Answer 15

• Endoparasite
• At least one intermediate host
• Epidermis modified to a syncytial tegument

Question 16

Cestoda

Answer 16

• Tapeworms
• Endoparasite
• At least one intermediate host
• One free-living form in between hosts
• syncytial tegument