Chapter 16 Nematoda

Question 1

Phylum of Nematoda

Answer 1

o	Bilaterally summetrical
o	Unsegmented pseudosoelomates
o	Body generally elongate
o	Cylindrical
o	Covered by cuticle
o	Mouth terminal surrounded by lips
o	Sexes separate
o	Anterior body: papilliform sensory organ and 2 amphids (chemoreceptor)
o	Digestive tract complete
o	With sub terminal anus
o	Excretory system
o	Longitudinally muscles
o	No respiratory or circulatory systems
o	Oviparous, ovoviviparous, viviparous
o	Egg, 4 juvenile (larva stages), and adult

Question 2

Ecdysozoa

Answer 2

Exoskeleton

Question 3

Ecdysis

Answer 3

Molt, shedding

Question 4

cryptobiosis (hypobiosis)

Answer 4

lag phase
Adaptation
Can survive in extreme environment
Extreme hibernation essentially dead

Question 5

Parasitic Nematodes

Answer 5

Hookworms
Pinworms
Worms that cause Trichinosis, Elephantiasis, and River Blindness

Question 6

Parasitic Nematode characteristics

Answer 6

Range in sizes
Colorless
Sexual dimorphism and evident
Primitive body cavity
Simple digestive system
flexible external covering
roundworm
cylindrical bodies
non-segmented
bilaterally symmetrical
Tapered at both ends

Question 7

Structure

Answer 7

The outer tube
Inner tube
Between the tubes

Question 8

Elastic cuticle

Answer 8

Epicuticle, exocuticle, mesocuticle, endocuticle

Question 9

hypodermis

Answer 9

cellular or syncytial

a layer of longitudinal muscle

Question 10

Basic life of seven stages

Answer 10

an egg
four larval stages
two adult stages separate for males and females

Question 11

Molting steps

Answer 11

Synthesis of a new cuticle by the hypodermis

Exsheathment: a process by which the old cuticle is loosened and ruptured followed

Question 12

Oviparous

Answer 12

Egg laying nematodes

Question 13

Viviparous

Answer 13

Producing larvae

Question 14

Ovoviviparous

Answer 14

laying eggs containing fully formed larvae which hatch out immediately