unit 2 worms

Question 1

What is the phylum that segmented worms belong to?

Answer 1

Annelida

Annelida is a phylum that includes segmented worms, known for their metameric body structure.

Question 2

What are the two main ends of an annelid called?

Answer 2

Prostomium and pygidium

The anterior end is the prostomium, while the posterior end is the pygidium.

Question 3

What is the term for the repeated segments in annelids?

Answer 3

Metamerism

Metamerism refers to the segmentation of the body into repeated units.

Question 4

What structures are used for respiration in annelids?

Answer 4

Moist cuticle and metanephridia

Annelids respire through their moist cuticle and excrete waste using paired metanephridia.

Question 5

What type of reproduction do annelids exhibit?

Answer 5

Monoecious or dioecious

Annelids can be either hermaphroditic (monoecious) or have separate sexes (dioecious).

Question 6

What class of annelids includes earthworms?

Answer 6

Oligochaeta

The class Oligochaeta contains species such as earthworms, characterized by few long hairs.

Question 7

How do oligochaetes respire?

Answer 7

Through their moist cuticle

Oligochaetes lack specialized structures for gas exchange and rely on their moist cuticle for oxygen diffusion.

Question 8

What is the function of the typhlosole in oligochaetes?

Answer 8

Increases surface area of the digestive tract

The typhlosole is an invagination that enhances the absorption area in the digestive system.

Question 9

What is the excretory system of oligochaetes primarily composed of?

Answer 9

Metanephridia

Each segment of oligochaetes contains a pair of metanephridia for excretion.

Question 10

What type of blood vessels do oligochaetes have?

Answer 10

Dorsal and ventral blood vessels

Oligochaetes possess a circulatory system with a dorsal and ventral blood vessel along with aortic arches.

Question 11

What is the nervous system structure of oligochaetes?

Answer 11

Bi-lobed brain and ventral nerve cord

Oligochaetes have a simple nervous system with a bi-lobed brain and a ventral nerve cord.

Question 12

What class of annelids includes marine worms?

Answer 12

Polychaeta

The class Polychaeta contains around 10,000 species of marine worms, known for their parapodia.

Question 13

What are parapodia used for in polychaetes?

Answer 13

Respiration and locomotion

Parapodia are paired extensions that aid in both breathing and movement.

Question 14

What are the specialized reproductive segments in polychaetes called?

Answer 14

Atoke and epitoke

Atoke refers to the non-reproductive form, while epitoke is the reproductive form that swims to the surface to release gametes.

Question 15

What is a characteristic feature of leeches in the class Hirudinida?

Answer 15

Suckers at both ends

Leeches are known for their body plan that includes suckers at both the anterior and posterior ends.

Question 16

How many segments do most leeches have?

Answer 16

Usually 34 segments

Leeches typically exhibit a body structure that appears to have more segments due to superficial annuli.

Question 17

What is the primary excretory product of terrestrial annelids?

Answer 17

Urea

Terrestrial annelids primarily excrete urea, while aquatic species excrete ammonia.

Question 18

True or False: Oligochaetes and Hirudinae are considered sister taxa.

Answer 18

True

Phylogenetic studies suggest that oligochaetes and hirudinae share a close evolutionary relationship.