WormsWormsCh.7 – Marine Bio BookCh.7 – Marine Bio BookCh.34/35 – Biology BookCh.34/35 – Biology Book

Developed by Dave WernerDeveloped by Dave Werner

MATESMATES

Bilateral SymmetryBilateral Symmetry

Cut body one way = 2 Cut body one way = 2 identical halves identical halves (fig7.12b, p.120)(fig7.12b, p.120)

((bibi = two, = two, latuslatus = = side). side).

Orientation includes:Orientation includes:– AnteriorAnterior– PosteriorPosterior– Dorsal Dorsal – VentralVentral

Symmetry ComparisonSymmetry Comparison

FlatwormsFlatwormsPhylum PlatyhelminthesPhylum Platyhelminthes

Simplest – dorsoventrally flattened Simplest – dorsoventrally flattened (flat backs & bellies)(flat backs & bellies)

triploblastictriploblastic (composed of three (composed of three fundamental cell layers) fundamental cell layers)

Real organs & organ systemsReal organs & organ systems no body cavity other than the gut no body cavity other than the gut Central nervous system = simple Central nervous system = simple

brain (aggregation of nerve cells)brain (aggregation of nerve cells) lack an anus; the same pharyngeal lack an anus; the same pharyngeal

opening both takes in food and opening both takes in food and expels waste expels waste

must respire by must respire by diffusiondiffusion, and no , and no cell can be too far from the outside, cell can be too far from the outside, making a flattened shape necessarymaking a flattened shape necessary

PlatyhelminthesPlatyhelminthes

Life without a coelom :Life without a coelom : The image at left is a fluke (possibly a species of The image at left is a fluke (possibly a species of ProbolitremaProbolitrema). Flukes, ). Flukes, like other parasitic flatworms, have complex life cycles often involving two or more host like other parasitic flatworms, have complex life cycles often involving two or more host organisms. At right, a planarian (organisms. At right, a planarian (DugesiaDugesia). Planarians are free-living flatworms, and have a much ). Planarians are free-living flatworms, and have a much simpler life history. They inhabit freshwater, and are carnivores (even without teeth) or simpler life history. They inhabit freshwater, and are carnivores (even without teeth) or scavengers. Most are less than a centimeter long. scavengers. Most are less than a centimeter long.

Marine FlatwormsMarine Flatworms

Marine flatworms :Marine flatworms : The marine flatworms ( The marine flatworms (polycladidspolycladids) are ) are the largest of the free-living flatworms, sometimes reaching the largest of the free-living flatworms, sometimes reaching lengths of 15 centimeters. Polycladids get their name from lengths of 15 centimeters. Polycladids get their name from their highly branched digestive cavity. These individuals were their highly branched digestive cavity. These individuals were photographed on a reef near the island of Guam.photographed on a reef near the island of Guam.

3 Groups of Flatworms3 Groups of Flatworms(Turbellaria, Trematoda, Cestoda)(Turbellaria, Trematoda, Cestoda)

1. Class 1. Class TurbellariaTurbellaria--free-living, include free-living, include the planarian, the planarian, DugesiaDugesia, found in , found in the oceans, fresh the oceans, fresh water, & in moist water, & in moist terrestrial habitats, terrestrial habitats, a few are parasitic a few are parasitic

Parisitic Video ClipParisitic Video Clip Body InvadersBody Invaders ParisitesParisites

2. Class 2. Class TrematodaTrematoda, or flukes, all parasitic, have complex life , or flukes, all parasitic, have complex life cycles specialized for parasitism in animal tissues. Members of cycles specialized for parasitism in animal tissues. Members of one major taxon of flukes, the Digenea -- which includes the one major taxon of flukes, the Digenea -- which includes the human lung fluke -- pass through a number of juvenile stages human lung fluke -- pass through a number of juvenile stages that are parasitic in one, two, or more that are parasitic in one, two, or more intermediate hostsintermediate hosts before reaching adulthood, at which time they parasitize a before reaching adulthood, at which time they parasitize a definitive hostdefinitive host..

FlatwormsFlatworms include non-parasitic worms such as planaria, which live in water, and include non-parasitic worms such as planaria, which live in water, and parasitic flukes and tapeworms. The human liver fluke infects over 75% of the parasitic flukes and tapeworms. The human liver fluke infects over 75% of the people in parts of Japan, China, and South Asia. The adult fluke, about 3/4 inch people in parts of Japan, China, and South Asia. The adult fluke, about 3/4 inch long, lives in the bile ducts of the liver; its eggs (1) pass from the body in the long, lives in the bile ducts of the liver; its eggs (1) pass from the body in the feces. The eggs, containing larvae, are eaten by water snails (2) and then develop feces. The eggs, containing larvae, are eaten by water snails (2) and then develop into another form, which passes into the water. They then bore into the bodies of into another form, which passes into the water. They then bore into the bodies of fishes (3). When raw fish is eaten (4) - as is common in the Orient - the young fishes (3). When raw fish is eaten (4) - as is common in the Orient - the young worms swim from the intestine into the fine branches of the bile duct and grow to worms swim from the intestine into the fine branches of the bile duct and grow to maturity. maturity.

3.3. Class Cestoda Class Cestoda, , or tapeworms, or tapeworms, are intestinal are intestinal parasites in parasites in vertebrates, and vertebrates, and they also show they also show anatomical & life anatomical & life history history modifications for modifications for parasitism.parasitism.

Use suckers or Use suckers or hooks to latch onhooks to latch on

50 ft worm found 50 ft worm found in Sperm Whalein Sperm Whale

Beef Beef Tapeworm - TheTapeworm - The cestodes (tapeworms) cestodes (tapeworms) Taenia saginataTaenia saginata (beef tapeworm) (beef tapeworm)

andand T. solium T. solium (pork tapeworm).  (pork tapeworm).  Taenia soliumTaenia solium can also cause cysticercosis can also cause cysticercosis. . Life Cycle:Life Cycle:

Ribbon WormsRibbon WormsPhylum NemerteaPhylum Nemertea

about 900 known species (fig.7.14, p.128, 121)about 900 known species (fig.7.14, p.128, 121) the European nemertine the European nemertine Lineus longissimusLineus longissimus has been known to has been known to

reach 30 meters (nearly 100 ft) in length, reach 30 meters (nearly 100 ft) in length, Most nemertines are marine Most nemertines are marine ProboscisProboscis-wraps around the prey, and toxic secretions immobilize -wraps around the prey, and toxic secretions immobilize

the prey the prey StyletStylet-piercing barb -piercing barb nemertines are carnivorous; most feed on small invertebrates like nemertines are carnivorous; most feed on small invertebrates like

crustaceans and annelids, but some feed on the eggs of other crustaceans and annelids, but some feed on the eggs of other invertebrates, and a few live inside the mantle cavity of molluscs invertebrates, and a few live inside the mantle cavity of molluscs and feed on microbes filtered out by the host. and feed on microbes filtered out by the host.

nemertines have major features that flatworms lack, nemertines have major features that flatworms lack, notably a complete gut with an anus, and a system of blood notably a complete gut with an anus, and a system of blood vessels. This vessel system may in fact be homologous with vessels. This vessel system may in fact be homologous with the the coelomcoelom, or fluid-filled lined body cavity , or fluid-filled lined body cavity

True organsw/ organ system & central nervous systemTrue organsw/ organ system & central nervous system

Here Here Parborlasia corrugatusParborlasia corrugatus worms are eating fish eggs. worms are eating fish eggs. P. corrugatusP. corrugatus has a one-way has a one-way gut with a large mouth and a gut with a large mouth and a closed circulatory system; closed circulatory system; nemertean worms are the nemertean worms are the simplest animals with a simplest animals with a circulatory system. Like other circulatory system. Like other proboscis or nemertean proboscis or nemertean worms, the wedge-shaped worms, the wedge-shaped head of head of P. corrugatusP. corrugatus has a has a fluid-filled cavity used to fluid-filled cavity used to rapidly shoot a barbed rapidly shoot a barbed proboscis which the worm proboscis which the worm uses to capture prey and uses to capture prey and defend itself [1]. This defend itself [1]. This harpoon-like proboscis has harpoon-like proboscis has adhesive secretions which adhesive secretions which secure prey. secure prey. P. corrugatusP. corrugatus is is chemically defended by an chemically defended by an acidic mucus (pH 3.5) which acidic mucus (pH 3.5) which potential predators avoid [4]. potential predators avoid [4].

ProboscisProboscis

Prostoma rubrum,Prostoma rubrum,

an example of the an example of the phylum Nemertea, phylum Nemertea, with its long with its long proboscis everted.proboscis everted.

Fig 7.14, p. 121Fig 7.14, p. 121

Nematodes - RoundwormsNematodes - RoundwormsPhylum NematodaPhylum Nematoda

Nematodes are the most numerous multicellular animals on Nematodes are the most numerous multicellular animals on earth earth

Most common in soil & marine sedimentsMost common in soil & marine sediments nearly 20,000 described species (>500,000 total)nearly 20,000 described species (>500,000 total) 1,000 somatic cells 1,000 somatic cells possess digestive, nervous, excretory, and reproductive possess digestive, nervous, excretory, and reproductive

systems, but lack a discrete circulatory or respiratory system systems, but lack a discrete circulatory or respiratory system range from 0.3 mm to over 8 meters range from 0.3 mm to over 8 meters The largest nematode ever observed isThe largest nematode ever observed is Placentonema Placentonema

gigantismagigantisma, discovered in the placenta of a sperm whale w/ , discovered in the placenta of a sperm whale w/ 32 ovaries32 ovaries

Found inhabit intestines of seals & dolphins & flesh of fish Found inhabit intestines of seals & dolphins & flesh of fish (sashimi)(sashimi)

Humans - hookworm, trichinosis and elephantiasisHumans - hookworm, trichinosis and elephantiasis

Intestinal RoundwormsIntestinal Roundworms, of which Ascaris is a , of which Ascaris is a common form, infect wild and domestic animals common form, infect wild and domestic animals and man. Eggs drop to the ground in animal feces. and man. Eggs drop to the ground in animal feces. Humans are infected by eating contaminated Humans are infected by eating contaminated food. The diagram at right shows the life history of food. The diagram at right shows the life history of Ascaris. Eggs hatch into larvae in the intestinal Ascaris. Eggs hatch into larvae in the intestinal tract and bore through intestine wall (1). Blood tract and bore through intestine wall (1). Blood carries larvae to lungs (2), where they grow. They carries larvae to lungs (2), where they grow. They are then coughed up or crawl up windpipe to back are then coughed up or crawl up windpipe to back of mouth (3), are swallowed (4), and mature in of mouth (3), are swallowed (4), and mature in intestine (5). A female worm living in the intestine intestine (5). A female worm living in the intestine may have millions of eggs in its body. These pass may have millions of eggs in its body. These pass out in feces (6) and, if eaten by other animals, out in feces (6) and, if eaten by other animals, start the life cycle over again.start the life cycle over again.

Pinworm – lay eggs around the anus of Pinworm – lay eggs around the anus of childern at night. Most common childern at night. Most common parasite in humans in the US.parasite in humans in the US.

HookwormHookworm, once a serious disease in the , once a serious disease in the southern U.S., is still common in the warm southern U.S., is still common in the warm areas of the world. Infected people lack areas of the world. Infected people lack energy. The hook-worm life cycle is like that energy. The hook-worm life cycle is like that of intestinal roundworms except that of intestinal roundworms except that infection occurs as larvae hatched in the infection occurs as larvae hatched in the warm soil bore through the skin, usually on warm soil bore through the skin, usually on the soles of the feet, to enter the blood.the soles of the feet, to enter the blood.

Trichina WormTrichina Worm

Round WormRound Worm The trichina worm lives inside the The trichina worm lives inside the

small intestine of a host animal, small intestine of a host animal, where it mates and reproduces. where it mates and reproduces. Once her eggs have been fertilized, Once her eggs have been fertilized, the female burrows into the the female burrows into the intestinal wall and releases her intestinal wall and releases her larvae. The larvae migrate into the larvae. The larvae migrate into the lymph channels of the intestine, lymph channels of the intestine, from which they enter the from which they enter the bloodstream and travel to all parts bloodstream and travel to all parts of the body. When the larvae reach of the body. When the larvae reach the skeletal muscles they burrow the skeletal muscles they burrow into the muscles and form tough into the muscles and form tough cyst-like cocoons. The host secretes cyst-like cocoons. The host secretes lime salts, which are deposited in lime salts, which are deposited in the capsule, eventually the capsule, eventually transforming the capsule into a transforming the capsule into a completely calcified cyst. The completely calcified cyst. The worms may live in the cyst for years worms may live in the cyst for years until they are consumed and until they are consumed and digested by another mammal.digested by another mammal.

Nematode WormsNematode Worms

Marine Nematode - Marine Nematode - DraconemaDraconema

Phylum PogonophoraPhylum Pogonophora

Beard WormsBeard Worms (pogonophorans) – (pogonophorans) – lack a mouth and lack a mouth and gut (fig. 7.17) – use gut (fig. 7.17) – use symbiotic bacteria symbiotic bacteria to manufacture to manufacture food.food.

4in.-7ft. – Read 4in.-7ft. – Read fig.7.17fig.7.17

Vestimentiferans – Vestimentiferans – hydrothermal vent hydrothermal vent wormsworms

Leeches in the eye of an unfortunate soul who Leeches in the eye of an unfortunate soul who drank from the wrong pond in India. Probably drank from the wrong pond in India. Probably

Hirudinaria granulosaHirudinaria granulosa. . - Mark E. Siddall- Mark E. Siddall

Peanut WormsPeanut WormsPhylum SipunculaPhylum Sipuncula

Soft, unsegmented Soft, unsegmented bodies (fig. 7.18, bodies (fig. 7.18, p.124)p.124)

320 known species320 known species .4in.-14in..4in.-14in. Deposit feedersDeposit feeders Peanut shapedPeanut shaped

EchiuransEchiuransPhylum EchiuraPhylum Echiura

MarineMarine Look like soft Look like soft

unsegmented unsegmented sausages buried in sausages buried in mud/sandmud/sand

Spoon-like or Spoon-like or forked proboscis forked proboscis (fig 13.9, p.272)(fig 13.9, p.272)

Deposit feedersDeposit feeders

Segmented WormsSegmented WormsPhylum AnnelidaPhylum Annelida

Everybody's favorite, worms. . .Everybody's favorite, worms. . .

earthworms, earthworms, leeches, leeches, polychaetespolychaetes

about 9000 known about 9000 known species species

SegmentationSegmentation Hydrostatic Hydrostatic

SkeletonSkeleton CoelomCoelom Cerebral GanglionCerebral Ganglion

Polychaete WormsPolychaete WormsClass PolychaetaClass Polychaeta

The most advanced The most advanced wormsworms

Mostly marine- 10,000 Mostly marine- 10,000 speciesspecies

2-4 in.2-4 in. Proboscis w/ jawsProboscis w/ jaws Parapodia – flattened Parapodia – flattened

extensionsextensions Setae – bristles (Fig. 7.15)Setae – bristles (Fig. 7.15) Closed Circulatory SystemClosed Circulatory System Gills w/ capilaries on Gills w/ capilaries on

parapodia & body allow parapodia & body allow respiratory exchangerespiratory exchange

Polychaete External Polychaete External AnatomyAnatomy

NereisNereis species speciesClam or Sand WormClam or Sand Worm

Video ClipVideo Clip

More AnnelidsMore Annelids

Class Oligochaetes Class Oligochaetes – small, live in – small, live in mud/sand mud/sand

Marine relative of Marine relative of earthwormsearthworms

Lack parapodiaLack parapodia

And More PolychaetesAnd More Polychaetes

Leeches (Class Leeches (Class Hirudinea) – mostly Hirudinea) – mostly FW, marine species FW, marine species are found attached are found attached to fish & inverts to fish & inverts ((parasitize)parasitize)

Sucker at each end Sucker at each end w/ no parapodiaw/ no parapodia

hermaphroditichermaphroditic