Zoology Unit 3: da worms

Phylum Xenacoelmorpha

Two groups: Acoelomorpha and Xenoturbellida

Acoelomorpha

_______ are among the simplest bilaterally symmetrical forms.

Acoelomorpha

are acoelomate triploblastic at the organ-system level of organization.

Acoelomorpha

have very simple nervous and digestive systems; some lack a gut entirely.

Xenoturbellida

phylogenetic placement has varied: with mollusca; with deuterostomes; and now with acoelomorphs worms outside the Bilateria.

Xenoturbellida

comprised of six species of worm-like animals with a blind gut

Xenoturbellida

_____ bodies have an external ciliated ring furrow, and a second longitudinal side furrow.

Spiralia

have spiral cleavage, a protostome feature; also have a lophophore feeding device or a trochophore larva.

Trocophore

free-swimming planktonic marine larvae with several bands of cilia

flat

A Platyhelmenthes is a ______ worm.

segmented

An Annelida is a ________ worm.

Platyhelminthes

Turbellaria, Trematoda, Monogenea, and Cestoda make up Phylum ______.

Turbellaria

body surface is usually a cellular epithelium, at least in part ciliated, containing rod-shaped rhabdites as well as mucous cells that function in locomotion

Turbellaria

Platyhelminthes other than __________ are covered by a no ciliated, syncytial tegument with cell bodies beneath superficial muscle layers.

Platyhelminthes

In most ________, digestion is extracellular and intracellular.

Cestodes

________, class of Platyhelminthes, must absorb predigested nutrients across their tegument because they have no digestive track.

Osmoregulation

____________ is accomplished by flame-cell protonephridia, and removal of metabolic wastes and respiration occur by diffusion across the body wall.

ladder-type

flatworms have a _______-_________ nervous system with motor, sensory, and association neurons.

hermaphrodites

Most flatworms (platyhelminthes) are __________, and asexual reproduction occurs in some groups.

Turbellaria

Class _________ is a paraphyletic group that includes mostly free-living and carnivorous members.

Flukes

Digenean Trematodes are also known as

Digenean trematodes

_________ _________ have a mollusca intermediate host. The extensive asexual reproduction that occurs in their intermediate host helps to increase the chances that some of their offspring will reach a definitive host. Aside from the tegument, they share many basic structural characteristics with terbellarians.

monogeneans

___________ are important ectoparasites of fishes with a direct life cycle (no intermediate host).

Cestoda

Tapeworms are of the class ______________.

Cestoda

What class have a scolex at their posterior end, followed by a long chain of proglottids, each of which contains a complete set of reproductive organs of both sexes. The anterior end of the body has been lost evolutionarily.

Cestoda

This class live as adults in the digestive tracts of vertebrates.

Cestoda

This class has shelled larvae are passed in the feces, and juveniles develop in a vertebrate or invertebrate intermediate host.

Tapeworms

Humans get this parasite from ingesting pork, beef, or fleas (the intermediate hosts)

Pork

_____ tapeworms go for the nervous tissue in our brains and/or spinal cords,

Gastrotrichs

_______________ are tiny aquatic animals. They have ventrally flattened bodies with bristles or scales. They move by cilia or adhesive glands.

Gnathifera

This clade contains five phyla whose common ancestor is hypothesized to possess cuticular jaws with a unique microstructure.

Gnathifera

Gnathostomulida, Chaetognatha, Micrognathozoa, Rotifera, and Acanthocephala make up this clade.

Gnathostomulida

a curious phylum containing tiny worm-like animals living among sand grains and silt. The animals do not have an anus.

Chaetognatha

Commonly called arrow worms. Important and effective predators of zooplankton. They capture prey with jaws and chitinous spines that surround the mouth.

Micrognathozoa

this phylum contains a single species of tiny animals living between sand grains. Similar to rotifers and gnathostomulids, these animals have three pairs of complex jaws.

Rotifera

This phylum is composed of small, mostly freshwater species with a ciliated corona, which creates currents of water to draw planktonic food toward the mouth. This mouth opens into a muscular pharynx, or mastax, which is equipped with jaws. It is possible that they have no males.

Parthogenisis

an asexual reproduction in which a female can produce an embryo without fertilizing an egg with sperm

Acanthocephalans

This phylum are all parasitic in the intestine of vertebrates as adults, and their juvenile stages develop in arthropods.

Acanthocephala

This phylum has an anterior, invaginable proboscis (sucking organ) armed with spines, which they embed in the intestinal wall of their host. They do not have a digestive tract and so must absorb all nutrients across their tegument.

Mesozoa

Members of this phylum are very simply organized animals that are parasitic in kidneys of cephalopod molluscs and in several other invertebrate groups.

Mesozoa

They have only two cell layers, but these are not homologous to the germ layers of other animals. They have a complicated life history that is still incompletely known. Their simple organization may have been derived from a more complex platyhelminth-like ancestor.

Precambrian

evidence from sequence analysis of ribosomal genes suggests that ancestral protostomes split from ancestral deuterostomes in the _________

Polyzoa

Clade _______ comprises three phyla (cyclophorans, entoprocts, and ectoprocts) of small animals that use cilia or ciliated tentacles to feed.

Cycliophora

Phylum __________ are very tiny animals living on the setae of mouthparts of lobsters or other marine decapod crustaceans. They also have complex

Entoprocta

This phylum are small, sessile aquatic animals with a cup-shaped body on a small stalk. They have a single crown of ciliated solid feeding tentacles that encircle both the mouth and the anus.

Bryozoa

Phylum _______ possesses a lophophore: a crown of hollow ciliated tentacles surrounding the mouth, but not the anus, and containing an extension of the mesocoel.

lophophore

The _________ functions as both a respiratory and a feeding structure, its cilia creating water currents from which food particles are filtered. There is a U-shaped digestive tract.

Bryozoa

Phylum _______ are sessile as adults, but they have free-swimming larvae. They also are colonial. Each individual lies in a chamber (zoecium), which is a secreted exoskeleton of chitinous, calcium carbonate, or gelatinous material. While abundant in marine habitats, a number of species are also common in freshwater.

Trochozoa

Clade _________ are animals with a trochophore larval stage in their development. This contains five phyla, where 3 (Brachiopoda, Phoronida, and Nemertea) are discussed in chapter 15 of the textbook.

Brachiopoda

This phylum are shelled animals with an internal lophophore: a crown of ciliated tentacles surrounding the mouth, but not the anus.

Brachiopoda

This phylum was very abundant in the Paleozic era but have been declining in numbers and species since the early Mesozoic era.

Phoronida

This phylum are wormlike animals that feed via a lophophore: a crown of ciliated tentacles surrounding the mouth, but not the anus.

Phoronida

The majority of this phylum are tube-dwellers in shallow coastal waters. The lophophore can be retracted into the tube and thrust out for feeding. They are also the least common of the lophophorate taxa.

Nemertea

This phylum are free-living long, thin, extensible worms found predominantly in marine habitats.

Nemertea

This phylum ensnare prey with a long reversible proboscis and also produce a neurotoxin. They have a complete digestive system and a closed circulatory system. They posses a true coelom, but this cavity lies above the digestive tract, not surrounding it as in all other coelomate animals.

Mollusca

This is the largest phylum of this unit, and the most diverse of all phyla. They range in size from microscopic organisms to the largest invertebrates.

Mollusca

This phylum occupy a wide variety of niches. Most are marine, but some are freshwater, and a few are terrestrial. Ocean acidification are a serious threat to them.

Mollusca

This phylum have a body division that is head-foot and visceral mass, which is usually covered by a shell.

foot

In Molluscs, the _____ is usually a ventral, sole-like, locomotory organ, but it may be various modified, as in cephalopods, where it has become arms and a funnel.

mantle

The _______ secretes the shell and overlies a part of the visceral mass to form a cavity housing the gills. It’s cavity has been modified into a lung in some.

radula

The ______ is a protrusible, tonguelike organ with teeth used in feeding. It occurs in all molluscs except bivalves and many solenogasters.

open

The circulatory system of molluscs is _____, with a heart and blood sinuses, except in cephalopods, which have a closed circulatory system.

trocophore

The primary larva of molluscs is the ________; in most marine molluscs, the ________ develops into a second larval stage, the veliger.

Mollusca

This phylum have a complex nervous system with a variety of sense organs. The also typically have a pair of nephridia connecting to the coelom.

Mollusca

This phylum are coelomate, although their coelom is limited to the area around the hear, the gonads, and occasionally part of the intestine. In many animals, the coelom cushions and protects the visceral organs and may serve as a hydrostatic skeleton for locomotion. However, the hard, external sheel of most members of this phylum precludes use of the coelom for cushioning, shape change, or locomotion.

Mollusca

Classes Caudofoveta and Solenogastres are small groups of worm-like members of this phylum.

Monoplacophora

Class ____________ is a tiny, univalve marine group showing pseudometamerism.

Polyplacophora

Class ____________ is a group of common marine grazers with a series of seven or eight plates that form the shell and multiple gills on each side of the foot.

Gastropoda

Class _________ comprises the largest and most diverse group of molluscs. All of them exhibit torsion, a stage in development where the anus is directly over the head. Most have coiling, and elongation and spiraling of the visceral mass.

Bivalvia

In members of Class _________, the shell is divided into two valves joined by a dorsal ligament and held together by an adductor muscle. Most are marine or freshwater filter feeders, drawing water through their gills by ciliary action. A radula is not present.

Cephalopoda

Members of class _________ are all predators and many can swim rapidly. Their arms or tentacles, derivatives of the foot, capture prey by adhesive secretions or by suckers. They swim by forcefully expelling water from their mantle cavity through a funnel.

Mollusca

This phylum contains classes: Cephalopoda, Scaphopoda, Bivalvia, Gastropoda, Polyplacophora, Monoplacophora, Caudofoveata, and Solenogastres.

Mollusca

There is both embryological and molecular evidence that phylum ________ share a common ancestor with Annelida more recently than either of these phyla do with arthropods or deuterostome phyla.

Annelida

Phylum ________ is a large, cosmopolitan group containing marine polychaetes, earthworms and freshwater oligochaetes, and leeches, plus organisms once placed in separate phyla: pogonophorans (siboglinid), echiurans, and sipunculans.

Annelida

The most important structural innovation underlying diversification of phylum ________ is metamerism (segmentation), a division of the body into a series of similar segments, each of which contains a repeated arrangement of many organs and systems.

Annelida

In this phylum, the coelom also is highly developed, and this, together with the septal arrangement of fluid-filled compartments and a well-developed body-wall musculature, is an effective hydrostatic skeleton for burrowing, crawling, and swimming.

Siboglinids

________ live in tubes on the deep-ocean floor, and they are metameric. They have no mouth or digestive tract, absorbing some nutrients by the anterior crown of tentacles. Much of their energy is due to chemoautotrophs of bacteria in their trophosome.

Echiurans

__________ are burrowing marine worms, and most are deposit feeders, with a proboscis anterior to their mouth. Some species bear epidermal setae. They lack segmentation.

Sipunculans

______________ are small, burrowing marine worms with an reversible introvert at their anterior end. The introvert bears tentacles used for deposit feeding. They are not segmented and lack setae.

Pleistoannelida

Most annelids, other than chaetopterids and sipunculans, are placed in a large clade called ________. This is divided into two classes, Errantia and Sedentaria, both of which include animals with a polychaete body plan.

Errantia

Clade _________ contains freely moving polychaetes with diverse forms and habitats.

Sedentaria

Clade _________ contains animals with polychaete body plans that have been modified for life in tubes or burrows, such as siboglinids and echiurans, as well as animals with an Oligochaeta body plan.

Clitellata

Within Sedentaria, annelids with Oligochaeta and leech body plans are placed in this clade. The citellum, which this clade is named after, is important for reproduction: it secretes mucus to surround the worms during copulation and a cocoon to receive eggs and sperm and in which embryonation occurs.

oligochaetes

Earthworms and many freshwater Annelida are ____________; they have a small number of setae per segment (as compared with polychaetes) and no parapodia. They have a closed circulatory system and paired nephridia in most segments, and they are hermaphroditic and practice cross-fertilization.

annelid

Earthworms have the typical ________ nervous system: dorsal cerebral ganglia connected to a double, ventral nerve cord with segmental ganglia running the length of the worm.

Hirudinida

Leeches (class __________) are mostly freshwater animals, but a few are marine or terrestrial. Most feed on fluids; many are predators, some are temporary parasites, and a few are permanent parasites.

coelom

The ________ appears to have evolved independently in protostomes and deuterostomes. The annelid _____ functions as a hydrostatic skeleton and is functionally important in burrowing.

metameric

A ________ or segmented body plan has arisen three times: in annelids, in arthropods, and in chordates.

annelids

Embryological evidence places _______ with molluscs and arthropods in the Protostomia. Molecular evidence suggests that ________ and molluscs are more closely related to each other (in Lophotrochozoa) than either phylum is to arthropods (in Ecdysozoa).

Chaetognatha

Commonly known as arrow worms; all marine; feed on plankton and little crustaceans; inject venom which paralyzes prey; debate about phylogeny; use symbiotic bacteria to produce venom

Mesozoans

Made of Rhombozoa and Orthonectida; marine parasites; all affect different hosts: for example, Rhombozoans affect the kidneys of squids and other cephalopods

Gastrotrichs

These are worms without the corona or specialized jaw; they are common in freshwater and marine environments.

Nemertea

This phylum are all marine; commonly known as “ribbon worms”; typically 5-6 inches, but can grow to be very long in the Arctic; historically thought to be a flatworm, but has mouth on anterior and anus on posterior; we don’t think they’re platyhelminthes; they have a tounge in a separate hole used to eat other worms.

Platyhelminthes

this phylum are flatworms; it is comprised of classes Turbellaria, Trematoda, and Cestoda

gravid

the older segments of a tapeworm; typically at the posterior end

proglottid

an egg mass on a tapeworm; the most posterior gravid ones get broken off into feces, which will get eat to continue the life cycle

beef

_____ tapeworms embed into intestinal wall; grow segments; shed proglottids and shelled larvae into feces; the feces gets eaten (contaminated grass) by cows; cow, as the intermediate host, has oncospheres in its muscle (invaginated cysticerus); muscle is improperly cooked and eaten; juveniles (cysticeri) embed themselves in upper intestine (invaginated cysticerus); cycle repeats.

oncospheres

shelled larvae of beef tapeworms

scolex

the head of a tapeworm which produces the proglottids

cysticeri

This is the juvenille form of a tapeworm. In the beef tapeworm life cycle, the ________ is embedded in muscle, resulting in measly beef.