5.2.3. Rotifers

Question 1

• a band of cilia around the middle of the larva that propels the larva through the water

Answer 1

trochophore

Question 2

-a horseshoe-shaped feeding structure; composed of a crown of ciliated tentacles that generates water currents

Answer 2

lophophore

Question 3

Name four subphyla of the Lophotrochozoan clade

Answer 3

Rotifers; Acanthocephala; Ectoprocta; Brachiopoda

Question 4

A ciliated corona surrounding a mouth; muscular pharynx (mastax) present with jaw-like features; nonchitinous cuticle; parthenogenesis is common; both freshwater and marine species. About 2,000 species

Answer 4

Rotifera

Question 5

1. Triploblastic, bilateral, unsegmented, pseudocoelomate
2. Complete digestive system, regionally specialized
3. Anterior end often has a ciliated organ called a corona
4. Posterior end with toes and adhesive glands
5. Well-developed cuticle
6. Protonephridia with flame cells
7. Males generally reduced in number or absent; parthenogenesis common

Answer 5

rotifera

Question 6

3 Class of Phylum Rotifera

Answer 6

Class Seisonidea
Class Bdelloidea
Class Monogononta

Question 7

This class of a single genus of marine rotifers that are commensals of crustaceans; large and elongate body with reduced corona.

Answer 7

Class Seisonidea

Question 8

A class of rotifera that has Anterior end retractile and bearing two trochal disks; mastax adapted for grinding; paired ovaries; cylindrical body; males absent.

Answer 8

Class Bdelloidea

Question 9

Rotifers with one ovary; mastax not designed for grinding; produce mictic and amictic eggs. Males appear only sporadically

Answer 9

Class Monogononta

Question 10

are endoparasites in the intestinal tract of vertebrates (especially fishes).

Answer 10

adult Acanthocephalans

Question 11

The body of the adult is elongate and composed of a short anterior proboscis, a neck region, and a trunk. The ____ is covered with recurved spines, hence, the name “spiny-headed worms.” The retractable proboscis provides the means of attachment in the host’s intestine.
● absorb food directly through the tegument from the host by specific membrane transport mechanisms and pinocytosis.
● The sexes are separate, and the male has a protrusible penis. Fertilization is internal, and eggs develop in the ___. A gravid female __________________ may contain up to 10 million embryonated eggs.

Answer 11

Acanthocephalans
proboscis
pseudocoelom
Macroacanthorhynchus hirudinaceus

Question 12

represent an assemblage of 6,000 species of small, colonial invertebrates that inhabit marine and freshwater habitats around the globe.

Answer 12

Bryozoans (phylum Bryozoa)

Question 13

1. Coelomate, colonial lophotrochozoans
2. Lophophore circular or U-shaped
3. Gut U-shaped; anus opens outside base of lophophore tentacles
4. Circulatory and excretory structures absent
5. Colonies produced by asexual budding; zooid often polymorphic
6. Gas exchange occurs through the body surface
7. Sessile in marine and freshwater habitats

Answer 13

bryozoans

Question 14

Members of this phylum live in sessile colonies of ___ (Gr. zoon, living animal; an individual member of a colony of animals produced by incomplete budding or fission)

Answer 14

bryozoan; zooids

Question 15

Bryozoan

The colony is called a ___, and the secreted exoskeleton of a zooid is the ___.

3. The ____ includes the lophophore and soft viscera (muscles, digestive tract, and nerve centers) that are movable within the exoskeleton.
4. The opening through which the lophophore can be extended is called the ____.

Answer 15

zoarium; zoecium
polypide
orifice

Question 16

possess a mantle, which secretes a shell composed of dorsal and ventral valves; are usually attached to the substratum directly or by a pedicel.

Answer 16

Brachiopods

Question 17

1. Triploblastic, coelomate, bilaterally symmetrical
2. U-shaped gut with or without an anus
3. Body enclosed in dorsal and ventral valves
4. Nervous system with a ganglionated circumesophageal ring
5. Open circulatory system with one or more hearts
6. No gas exchange organs
7. Horse-shoe-shaped lophophore in anterior mantle cavity

Answer 17

Brachiopods

Question 18

Name Two types of Brachiopods

Answer 18

Inarticulata/ articulata

Question 19

The inarticulate brachiopod ____. Ligulauses its pedicel to draw itself into its burrow.

Answer 19

Inarticulata; Ligula

Question 20

Drawing of an articulate brachiopod, Terebratella. The valves have a tooth-and socket articulation, and the ventral valve is slightly larger than the dorsal valve. A short pedicel anchors the brachiopod to its substrate

Answer 20

Articulata