Animals: Platyhelminthes, Annelida, Nematoda

Question 1

Lophotrochozoa (Annelids, Mollusks, Flatworms)
-Trocophore: specialized free-swimming ______________
-common to ________ lophotochozoans
-_____ in all terrestrial groups

Answer 1

-larval stage
-aquatic
-lost

Question 2

Phylum: Platyhelminthes
-_____________
- Platy “_____”
-Helminthe “worm”
-include: free living flatworms, parasitic flukes, and tapeworms

Answer 2

-flatworms
-flat

Question 3

Phylum: Platyhelminthes
Traits shared by all Platyhelminthes:
1. ___________ body
2. ____________
-cells are near enough to body surface to _________________ with environment

Answer 3

-flattened
-no coelom
-exchange gas directly

Question 4

Phylum: Platyhelminthes
Free living flatworms
-usually predators or scavengers
-_______ opens to muscular, tubelike pharynx at body _________
-delivers food to ________ digestive tract
-highly branched gut
-undigested food ejected through pharynx and mouth

Answer 4

-mouth
-midpoint
-incomplete

Question 5

Phylum: Platyhelminthes
Free living flatworms
-________ system can sense stimuli and ________ movements
-Planarian has ladderlike arrangement of ______________ running the length of its body
-Head end features a simple brain, sensory structures that detect _____, chemicals, and ______ intensity

Answer 5

-nervous
-coordinate
-nerve cords
-touch
-light

Question 6

Phylum: Platyhelminthes
Reproduction
-many reproduce ____________
-free living species may simply pinch in half and _________ missing parts
-sexual reproduction also common
-Hermaphrodites produce sperm and egg cells
-in a mating pair, each animal fertilizes the eggs of __________

Answer 6

-asexually
-regenerate
-its partners

Question 7

Phylum: Platyhelminthes
Flukes and Tapeworms
-___________
-tough, _____ layer protect against host’s digestive enzymes and ___________
-have ________ hosts
-produce ______ numbers of offspring
-__________ chance a few will encounter a suitable host

Answer 7

-parasites
-outer
-immune system
-multiple
-huge
-maximize

Fluke: infects snails(intermediate host), larva infects humans through skin(final host)

Question 8

Phylum: Platyhelminthes
Tapeworm:
-___________ and digestive system
-hook onto host’s _________
-consist of repeated organs called proglottids (contain ______________)
-Proglottids break off, leave host in _______
-When intermediate host (ex. ____) swallows proglottids, eggs hatch
-Larvae can migrate to host’s ______
-_______ acquire tapeworm by eating infected fish, beef, or pork

Answer 8

-lacks mouth
-intestines
-fertilized eggs
-feces
-pig
-muscles
-humans

Question 9

Phylum: Annelida
-______________
-annulus (“little ring”
Main classes:
1. earthworms
2. leeches
3. polychaetes
Shared features:
-___________
-saddlelike thickening near _________
-_________
-secretes a protective “cocoon” for fertilized eggs when the animal reproduces

Answer 9

-segmented worms
-segmentation
-head-end
-coelom

Question 10

Phylum: Annelida
Earthworms
-ingest ______
-digest ______ matter
-eliminate indigestible particles as _________
-each segment of the body sports a few ________
-Provide ________ while burrowing through soil

Answer 10

-soil
-organic
-castings
-bristles
-traction

Question 11

Phylum: Annelida
Leeches
-most live in __________
-_____ bristles
-some _________ of vertebrates (including humans)
-but most eat small animals such as arthropods, snails, or other annelids
-each _____ has a _______ to attach itself to a surface or to its prey

Answer 11

-freshwater
-no
-suck blood
-end
-sucker

Question 12

Phylum: Annelida
Polychaetes
-________ segmented worms
-most have pairs of fleshy, paddlelike appendages used for ___________
-name comes from the ________ (chaetae) in each appendage

Answer 12

-marine
-locomotion
-bristles

Question 13

Phylum: Annelida
Annelida Characteristics
-_____ specialized respiratory system
-exchange gases by diffusion across the ________ (some polychaetes have _______)
-gas exchange can occur only across a ______ surface
-leeches and polychaetes live in water
-earthworms are vulnerable to ___________

Answer 13

-lack
-bodywall
-gills
-moist
-drying out

Question 14

Phylum: Annelida
Annelida Characteristics
-leeches and earthworms are ______________
-two individuals copulate, each discharging sperm for the other’s eggs
-after fertilization, secrete fluid to form protective “________” into which they lay eggs

Answer 14

-hermaphrodites
-cocoon

Question 15

Phylum: Annelida
How do humans benefit from annelids?
-earthworms aerate and _________ soil
-used as __________ or soil conditioners
-_____________ chemical from leeches can stimulate circulation in surgically _____________ digits and ears
-leeches can remove ________ blood that accumulates other damage to nervous system

Answer 15

-fertilize soil
-fishing bait
-blood-thinning
-reattached
-excess

Question 16

Phylum: Nematoda
-__________
-Nema “thread”
-unsegmented, cylindrical worms
-Pseudocoelom
->80,000 species
-_______ with naked eye
-____________ (land, freshwater, oceans)
-small scoop of _____ can yield thousands of nematodes

Answer 16

-roundworms
-hard to see
-very abundant
-mud

Question 17

Phylum: Nematoda
-Pseudocoelom
-distributes nutrients, O2, and CO2 throughout body
-lack specialized circulatory or respiratory organs
-________ to back-and-forth, thrashing motions
-only __________________
-can neither _______ nor lift its body above its substrate

Answer 17

-limited
-longitudinal muscles
-crawl

Question 18

Phylum: Nematoda
Closest Relatives: ____________
-both nematodes and ________________ and replace their tough external covering several times during development
(ecdysis)

Answer 18

-arthropods
-arthropods shed

Question 19

Phylum: Nematoda
-free living nematodes live in soil or the __________ of aquatic ecosystems
-ability to survive ________ heat, cold, or drying
-enter state of ________________; life resumes when favorable conditions return
-eat bacteria, protists, fungi, plants, insect larvae, or decomposing organic matter
-playing essential roles in _________ cycling

Answer 19

-sediments
-extreme
-suspended animation
-nutrient

Question 20

Phylum: Nematoda
-can also parasitize _______
-spearlike mouthparts to pierce _______ or shoots
-suck out contents, reduce yields of crops such as ________ and _________

Answer 20

-plants
-roots
-cotton
-soybeans

Question 21

Phylum: Nematoda
-most familiar nematodes _______ humans, animals
-_________ parasites (pinworms, hookworms)
-Trichinella, live in _______ tissue of humans and pigs
-transmitted by eating undercooked pork
-others cause elephantiasis or African river blindness
-insects transmit the worms
-__________ are nematodes that infect the heart, lungs, and blood vessels of dogs and cats

Answer 21

-infect
-intestinal
-muscle
-heartworms

Question 22

Phylums, examples, characteristics
Platyhelminthes(flatworms); planeria, tapeworms, flukes; unsegmented, symmetrical, no coelom, digestive cavity, 1 opening; marine, freshwater, parasitic

Nematoda (roundworms); pinworms, hookworms; pseudocoelomate, unsegmented, bilaterally symmetrical worms, tubular digestive tract from mouth to anus; tiny; without cilia, live in great numbers in soil and aquatic sediments; some are important animal parasites

Annelida(segmented worms); earthworms, marine worms, leeches; coelomate, serially segmented, bilaterally symmetrical worms; complete digestive tract; most have bristles called setae on each segment that can anchor them during crawling; marine, freshwater, and terrestrial