1. What are the four major phyla of marine worms? (in order from least to most complex) Worm Essential Questions Marine Biology Platyhelminthes - flatworms Nemertea ribbon worms or proboscis worms Nematoda - roundworms Annelida segmented worms 2. What is a coelom? What is the difference between a coelomate, pseudocoelomate and an acoelomate? A coelom is a fluid filled cavity surrounded by cells (mesoderm) that forms in development The coelom cavity gives room for organs to develop Coelomate is an organism that has a coelom; segmented worms (all vertebrates) Pseudocoelomate is an organism that has a fluid filled cavity partially surrounded by cells (mesoderm); roundworms Acoelomates are organisms without a coelom; no body cavity for internal organs; flatworms 3. Flatworms make up what marine worm phylum? Platyhelminthes 4. What kind of digestive system do worms in phylum Platyhelminthes have? Simple digestive system with one opening that is both a mouth and an anus 5. How do most Platyhelminthes get their food? What is one exception? Most are parasites. (tapeworms and flukes) One exception is Tubellaria (planarians = free- living flatworms) 1
6. How do parasitic tapeworms live in a host? Tapeworms have a head (called a scolex) scolex) that has hooks and suckers that latch on to a host and repeating units called proglottids 7. Tapeworms each proglottid is detachable and has muscles, nerves, and reproductive organs each proglottid can have 100,000 eggs (some worms have 2,000 proglotids) proglotids) What is the lifecycle of parasitic flatworms called flukes? What disease is commonly caused by blood flukes? Fluke enters organs of vertebrate (ex. Human) feeds on cells, blood, or nutrients lays eggs that pass out in waste larvae infect intermediate host (snail) new larvae leave intermediate host and infect final host (ex. human) Schistosomiasis 2
8. How do Platyhelminthes reproduce? Sexually most are hermaphrodites that send sperm down tubes to reach eggs Asexually by regeneration Ex. If one is cut in half, the head grows a new tail and the tail grows a new head 9. Which marine worm phylum consists of ribbon worms? Nemertea 10. What kind of digestive system do Nemerteans and Nematodes have? One-way digestive system with one mouth and one anus 11.How do most Nemerteans get their food? Carniverous hunters that search in the sand for prey Also called proboscis worms 12.What is the longest animal in the world? Lineus longissimus (a type of ribbon worm) 60 meters long longer than Siphonophores and Blue Whales 13.Which marine worm phylum consists of roundworms? Nematoda 3
14.How do most Nematodes get their food? RELEASE OF NEMATODES FROM INFESTED CATERPILLAR Most are free- living and are carnivores or herbivores Many are parasitic worms that live in the digestive system of a host 15.How many species of roundworms infect human beings? About 50 16. What are some of the methods roundworms use to invade and infect humans? Ascaris swallow eggs from dirty hands; eggs hatch in intestine, move to lungs through the bloodstream and are coughed up and swallowed causing reinfection Hookworms people walk on contaminated soil with bare feet; worm crawls in and infects Pinworms most common in children; kids eat something that is contaminated with eggs; females lay eggs near anus; kids scratch, eat and reinfect themselves Trichinella undercooked pork; causes Trichinellosis Ascaris Hookworm lifecycle 4
Hookworms Pinworms A nine year-old Brazilian boy, displaying the hookworms and tapeworms he expelled when treated by the Rockefeller Foundation staff Trichinella lifecycle 17. How are segmented worms different from other marine worms? They are more anatomically complex They have nephridia, nephridia, a heart/circulatory system, and sometimes even jaws, complete digestive tract, They have metamerism = body segments Trichinella 18. Which marine worm phylum consists of segmented worms? Which class has the most marine worm species? Annelida Class Polychaeta has the most marine species 5
19.What 19.What are some specific types of Polychaete worms? Tubeworms live on coral reefs Bristleworms live on coral reefs and sting and burn when touched Spongeworms live on sponges Fireworms live on the top of fire coral 20. What are some of the characteristics of annelids called leeches? Most live in freshwater streams or rivers Parasites that suck blood from hosts (ducks, turtles, fishes, people) Bite doesn t hurt because they release an anesthetic Also release a chemical the prevents blood from clotting can be used in medicine 6