Acoelomorpha, Platyzoa, and Mesozoa Flashcards
While most of the platyhelminthes are free living or endoparasites, which one of the following taxa has an ectoparasitic life cycle?
Monogenea
Members of phylum Platyhelminthes are called flatworms because their bodies are flattened
dorsoventrally.
Cells that secrete mucus in the epidermis of the Turbellaria are called
rhabdites
The body of the parasitic flatworms is covered in a syncytial layer called
tegument
While the previous phyla have used intracellular digestion, within these three phyla extracellular digestion is the norm. Extracellular digestion means that
proteolytic enzymes are secreted into the gut.
Another name for a protonephridium is a
flame cell.
The cells that form a meshwork filling the spaces between muscles and organs that develops from mesoderm is called
parenchyma
Protonephridia function in
osmoregulation.
The nervous system of the flatworms has sensory, motor, and association nerves, and it is organized into a ________ pattern.
ladderlike
Light-sensitive sense organs in the flatworms are called
ocelli
Sense organs that respond to changes in water current directions are the
rheoreceptors
Which of the following groups includes ectoparasites of fish and amphibians?
Monogenea
The animals that are leaf-shaped endoparasites, have a tegument, and have complex life cycles are members of the class
Trematoda
Cestodes are monoecious and lack a digestive tract. The reproductive units of the cestodes are called
proglottids
The chain of proglottids is collectively called the ________, and the holdfast or attachment organ is called the
strobila, scolex.
Which of the following organisms is a blood fluke?
Worms of the genus Schistosoma.
The rhynchocoel is a cavity that contains the
heart
In the digenetic trematodes, the first or invertebrate host is called the _________ and the second or final host, which is usually a vertebrate, is called the _________ host.
intermediate, definitive
The members of phylum Rotifera are cosmopolitan, which means they are found in many different habitats, and the body is made of three parts. These three parts are the
head, trunk, and foot.
The members of phylum Rotifera feed by the circular motion of the
corona
The rotifers reproduce sexually by ________ eggs and asexually by ________ eggs.
mictic, amictic
Which of the pseudocoelomate phyla has a two-part head, dorsal plates, and a ventral ciliary
Kinorhyncha
Recent evidence suggests that Rotifera and Acanothocephala are closely related to the ____.
Gnathostomulida
Several pseudocoelomate phyla are characterized by having a constant number of cells or nuclei, a condition referred to as ____.
eutely
Most of the species of phylum Gnathostomulida have been found living between grains of sand or silt.
true
The members of the phylum Gnathostomulida share a characteristic with rotifers because they both have grinding jaws.
true
The jaw and pharynx of the Gnathostomulida are quite similar to those of the ____.
rotifera
The pork tapeworm is Fasciolopsis hepatica.
false
The human liver fluke, Clonorchis sinensis, is common in China, and can cause cirrhosis of the liver and death.
true
The fact that some parasites have a first or intermediate host, and a final or definitive host, is reflected in the class name Digenea.
true
The best-known turbellarian is the planarian, which is often used in the laboratory. The generic name of this organism is Clonorchis.
false
The sense organs of the flatworm that help the organism maintain its equilibrium are called rheoreceptors.
false
Of the phyla discussed in this chapter, all are primarily bilaterally symmetrical.
true
Of the phyla discussed in this chapter, only the gnathostomulids have a circulatory system.
false
The term proglottid is only used when referring to the cestodes.
true
The parenchyma is different from mesoglea, as it is cellular, and is mesodermal in origin. But, because there is no cavity in this area around the gut, these worms are considered to be acoelomate.
true
Neodermata is a taxonomic name proposed for the trematodes, monogeneans, and cestodes, as they have a unique tegument.
true
In some turbellarians, the yolk that provides nutrition for the developing embryo is contained within the egg cell, a condition known as ectolecithal.
false
Turbellarians are the only flatworms that may be both terrestrial and free-living.
true
Cladistic analysis indicates that the class _____ is paraphyletic and will therefore probably be further divided into many more taxa.
Turbellaria
