Phylum Platyhelminthes & Rotifera

Question 1

Tissues and Organs Derived from Mesoderm

Answer 1

Muscle cells, parenchymal cells and components of the complex reproductive system

Question 2

Locomotion in Platyhelminthes and feeding

Answer 2

Dugesia mostly uses ciliary crawling but utilizes longitudinal muscles to change direction
Leptoplana wriggles using a concert of longitudinal muscles and cilia, as well as what appears to be circular muscles

Use of radial muscles and longitudinal muscles to move food through the pharynx similar to peristaltic motion

Question 3

Parasitic Adaptations

Answer 3

Suckers, life cycle complexity, many eggs, food absorption

Question 4

Clonorchis sinensis lifecycle

Answer 4

Human definitive host, eggs passed in feces, eggs eaten by snail (miracidium, sporocyst, redia, cercariae), cercariae burrow into fish and forms a metacercariae, eaten by human

Question 5

Tania pisiformis lifecycle

Answer 5

Cystircus in the human intestine develops into adult with many proglottids, deposited in feces, eggs eaten by a pig, oncosphere burrows into the gut wall, carried in the blood to muscle and encysts as cystircus, eaten by human

Question 6

Morphology of Rotifer

Answer 6

Corona (head) with many cilia, trophi within the mastax in the neck region
The trunk contains protonephridium, the stomach, ovaries and anus
The foot has 2 toes that secrete cement to keep it on the substrate
They have an exoskeleton made of cytoskeletal elements that are not moulted

Question 7

Rotifer feeding and locomotion

Answer 7

The ciliated corona creates an incurrent that draws food into the mouth
This beating of cilia is also responsible for the locomotion