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Ch 27 textbook answers
Sr 27-1
1. Kingdom animalia, phylum molluska: soft bodied organisms with an external or internal shell. Contain foot, shell , mantle cavity,
visceral mass
Class: gastropoda (stomach-foot) ex snail, slug, sea hare, nudibranch
Class: bivalvia: (2 valves) 2 shells: ex: clams, oysters, scallops, muscles
Class: cepahlopoda (head-foot): ex: nautilus, cuttle fish, squid, octopus
2. Positive: food, environmental monitors due to bio-concentration of pollutants while filter feeding, medicine: do not get cancer
Negative: shipworms: drill into wood & destroy
docks, crop & garden damage: slugs & snails
clams & oysters bioconcentrate bacteria, viruses, red tide toxin from protists: humans eat & get sick
3. herbivores: scrape off algae, buds, roots, flowers carnivores: drill through shells of other animals, shoot out poison tipped darts
4. gastropoda: shells, nocturnal, squirt ink, poisonous bad / tasting chemicals, foul-tasting- dark ink, cnidarian nematocysts
Bivalvia: burry in mud, shell,
Cephalopoda: crawl, swim, jet propulsion, ink cloud
5. ↓carnivore abundance in the ecosystem food web:
oysters are eaten by humans: price will go up, pearl prices, jobs
Sr 27-2
1) phylum: annelida: round, wormlike, segmented
Class: polychaeta: (many bristles) ex: p. 598
fanworm, fireworm,
p. 599 sea mouse
Class: oligochaeta: (few bristles) ex: earthworm, tubifex worms
Class: Hirudinea: ex: leaches
2) specialized pharynx:
carnivorous: sharp jaws
Herbivorous: cutting jaws
Detritius feeders:
mucous covered pharynx trap particles
Pumping pharynx
Parasitic: sucking
Filter feeding gill-like pharynx
Tentacle feeding pharynx
3)
detritus ( organic particles) and dirt → mouth → pharynx → esophagous → crop (storage) → gizzard (ground up) → intestine
(extra-cellular digestion) & nutrient absorption → anus → castings (undigested materials & dirt)
4) These are the segments that are the first to penetrate the surface of the earth where the light & heat is. Worms are negatively
phototaxic because if their cuticle (skin) dries out they will be unable to breath by diffusion through the skin.
Ch 27 rev.
Mc
1. D
2. A
3. B
4. C
5. B
Tf
1. F nephridia
2. F Phyla: molluska
F class bivalvia 8. F internal
6. C
7. D
3. F Annelida
8.b
4. F mantle
5. T
6. F gastropods
7.
Wr
1. Class bivalvia
2. Mantle (mantle produces shell) 3. Nudibranchs (type of gastropods) produce for protection 4.
Statocysts
5. Closed circulatory system
6. Annelida
7. Foot
Cm
1.
Phylum: molluska
Radula: herbivore: snails & slugs
Carnivore:
a. drill through shells of other animals
b. hollow darts with poison glands
octopi: sharp jaws
filter feeders: ex: class bivalvia: gills with sticky mucous filter & trap plankton and then pass it to it’s mouth for eating
2. phylum annelida:
class: oligochaeta: soil or fresh water:
underground
respiration: diffusion through skin,
reproduction: hermaphrodites: internal fertilization
class: polychaeta: marine worms (ocean): cracks, tropical reefs, sand, mud, piles of rock
respiration: gills
reproduction: separate sexes: external fertilization
3. use foot to dig its way into the mud, 2 siphons stick up above the mud to allow for respiration and filter feeding
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4. many niches: herbivores, predators, detritus feeders,
symbiotic with algae, parasites, hosts to parasites,
food web, human food
environmental indicators due to bioaccumulation of toxins, bacteria, viruses toxic protists (rd tide)
medicine: no cancer
crop damage, shipworms destroy wood
farmed for food (clams and oysters)
pearls (lacre)
cct1. cross fertilization allows for more genetic diversity by mixing up the DNA, producing more “mutants” which can survive a changing
environment
self fertilization is better in an stable, unchanging environment or when the chances of meeting a member of the opposite sex
is very rare
2. They have evolved in areas that are oxygen poor; such areas are probably deep inside the dirt or mud on the ocean floor
3. many hypothesis will work;
ex:
if octopi eggs release a chemical that stimulates the eye glands to release a hormone that
causes brooding behaviour, then removing the eggs will stop the secretion of the eye glands and non-brooding behaviour will resume
Answers Ws 27-1a p. 585 & 27-1b Mollusks
Name:
Block:
Date:
1)
2)
3)
4)
How many species in this phyla?
100 000
List the habitats of mollusks.
Ocean trenches to mountain brooks, trees
Give the size range of this phylum grain of sand-20m
2 characteristics that unify mollusks in the same phyla are ? fg 27-2 p. 586
similar development (trochophore
larva), similar body plan
5)
Define Mollusk. Soft-bodied, internal or external shell
6)
List the 4 basic body parts of a mollusk. Fg 27-3 p 586
foot, shell, mantle cavity, visceral mass
7)
What is the difference between the visceral mass and the mantle?
Mantle covers most of the body (including the guts /
internal organs (visceral mass)) and produces the shell
8)
What 2 characteristics are used to group members of this phyla into different classes?
Type of foot and kind of shell
9)
Describe 2 different ways some mollusks feed using a radula. Fg 27-4 p. 587
herbivores scrape plant matter off, carnivores
drill through shells
10)
Describe the different way an octopus feeds as compared to a clam.
Octopus uses its sharp beak, clam uses its gills to filter
out food as it breaths
11)
Gills can serve 2 purposes. What are they?
Breath and feed
12)
Explain the difference in the way a land snail breaths compared to an aquatic mollusks?
Aquatic use gills, land snails use a
folded mantle with many blood vessels around it
13)
Why do most land snails and slugs live in moist dark places?
To prevent the mantle cavity from drying out so that gasses can
be easily exchanged from the air to the blood
14)
This phylum has a major evolutionary advancement in the development of an advanced respiratory and circulatory system. What
is the main function of these systems?
Respiratory system brings in and out of the body carbon dioxide and oxygen,
circulatory system delivers it and picks it up from the cells
15)
What is the difference between an open and a closed circulatory system? Blood is not always inside a blood vessel but instead
passes into a sinus in and open system,
in closed systems, the blood is always inside a blood vessel
16)
What is a sinus? Open spaces that fill with blood inside the body where certain organs rest
17)
Why do some organisms require a closed circulatory system only?
To move faster, longer
18)
Where does undigested food go and what is this waste called? Solid waste (feces), out the anus
19)
Where does ammonia come from and why must it be eliminated?
From cellular metabolism, very poisonous
20)
What is the function of nephridia? What organ does this resemble in humans? (not in book) to remove poisonous ammonia,
similar to the liver or kidney
21)
Describe the nervous system of mollusks that live inactive life styles.
Simple, few ganglia by their mouths, few nerve cords,
some sensory cells (chemical, touch, statocysts, ocelli
22)
Which are the smartest mollusks? What can they be compared to intelligence wise?
Octopus and other tentacle mollusks,
smarter then some vertebrates
23)
What part of there nervous system is advanced?
brain
24)
Explain separate sexes.
Male or female
25)
Explain external fertilization.
Eggs and sperm are released outside the body, random fertilization occurs
26)
Define hermaphrodite.
Has both male and female sexes
27)
Define internal fertilization.
Sperm is delivered inside the female
28)
What unusual thing can oysters do? Switch between being male and female
Answers Ws 27-1b p590
Mollusks and Annelids Note Equivalent Name:
Block:
Date:
1) Class name of snails, slugs and their relatives?
Gastropoda
2) What phylum does this class belong to?
Molluska
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3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
17)
18)
19)
20)
21)
22)
23)
24)
25)
26)
27)
Lesser known (exotics) gastropods examples are (4) abalones, sea butterflies, sea hares, nudibranchs
What does “gastro” “pod” mean? Stomach
foot
Why are the organisms in this class called gastropods?
Foot is located on their ventral (stomach) side
Give 2 examples of how shell-less gastropods protect themselves.
Nocturnal, squirt ink from glands, poisonous or bad
tasting bodies, swim fast, nematocysts from cnidarians, warning colours
Match each of the 4 pictures on pg 590-91 with the appropriate gastropod.
Ringed snail, banana slug, nudibranchs
Class bivalvia: list the common organisms. Clams, oysters, scallops
Give 2 characteristics of this class. 2 shells that are hinged together
All bivalves start their life out as a motile________________ larva. P. 586
free swimming
Which bivalve has the giant penis? (aquarium)
the arthropod oyster
The 2 most important functions of the mantle is to produce which 2 substances?
Shells, mother of pearl (smoothness)
How does a pearl form? A sand grain gets in between the mantel and the shell
List the 14 basic structures of a typical bivalve from fg 27-10. Foot, ganglion, mouth, adductor muscle, stomach, nephridium,
heart, adductor muscle, anus, excurrent siphon, incurrent siphon, gills, intestine, gonad
Class Cephalopoda: list 4 most common organisms in this class.
Octopi, squid, cuttlefish, nautilus
Why are these creatures called cephalopods?
Head is located attached to their foot
The common characteristic in the cephalopods are? tentacles
How are the nautilus and squid similar to each other?
2 long slender arms in addition to tentacles
2 ways the nautilus are different form the other cephalopods are?
Many tentacles, no suckers, slimy mucous covered
tentacles
What structure have most cephalopods lost through evolution?
shell
Which cephalopod has completely lost its shell?
octopus
3 possible methods of cephalopod locomotion are? Craw, swim, jet propulsion
2 methods of protection are?
Foul-tasting ink, swim away, camouflage (change colour to match their environment)
Bivalves are environmental indicators (index species). How do these organisms accomplish this task for us?
As many
mollusks filter feed, they begin to concentrate many pollutants in their bodies. Tells us of future poisonous environments
What disease does the phylum Molluska never seem to get? Why is this important to us? No cancer, find out why, maybe
humans can get cured
List 3 problems that some humans have with some organisms in the phylum Molluska. Crop eaters, shipworms eat wood in
water, clams and oysters can bio-accumulate toxins allowing humans to get sick when they eat them
Define what you think “bio-concentration” might mean based on the reading from the last part of the last paragraph on p. 593.
On organism higher up the food chain eats many smaller organisms that have a small amount of poison. As this food is
constantly eaten, the higher predators slowly start to poison themselves as they bio=concentrate the bad stuff
Answers Ws 27-2a Annelids p. 594
1. Where do the 9000 sp of segmented worms live?
Moist soil, fresh water and sea
2. What is another name for segmented worms?
Annelids
3. Where do most annelids live?
Sea
4. Give the phylum name for segmented worms
Annelida
5. List 3 characteristics of the phylum Annelida
round, wormlike, long, segmented body
6. What does the Latin word annellus mean? Little ring
7. The range of sizes are….
½ mm to 3m
8. What separates the annelid’s body segments?
Septa
9. Define pharynx. Muscular front end of the digestive tube
10. What can some annelids do with their pharynx?
Extend it out its mouth
11. What are often attached to the front pharynx of a carnivorous annelid?
Sharp jaws
12. Fg 27-13 shows….
Polychaete annelid with jaws extended on the pharynx
13. Why is the front of the pharynx coated with mucous in detritus feeding annelids?
Food particles stick to it
when extended
14. What does an earthworm pharynx do?
Act like a pump sucking in detritus in the soil
15. The function of the pharynx in a leech is to…
suck blood
16. Fg 27-15 left. How does the spaghetti worm feed?
Tentacles pick up bits of debris from the ocean floor
17. Fg 27-15 right. How does the plume worm feed and breath?
Brush shaped structures filter out food (plankton and
debris) and act as gills
18. Fg 27-14. List the parts of the digestive tract.
Mouth, pharynx esophagus, crop, gizzard, intestine anus
19. Where does the feather duster live?
Inside a burrow or tube.
20. Why does the skin of annelids need to be moist?
21. What is the purpose of a cuticle for terrestrial annelids?
To keep the body moist
22. Which direction does blood flow in the blood vessels?
Dorsal goes to the head, ventral goes to the back of
worm
23. What are ring vessels?
Connect dorsal with ventral blood vessels and feed the organs
24. The 2 ways blood moves through an annelid are: hearts (pumping ring vessels, and muscle contractions while moving)
25. Where does solid waste leave the animal?
Anus
26. Where does the liquid waste that is removed by the nephridia originate?
liquid waste formed during cellular metabolism
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27. The location of the brain is….
On top of the gut at the anterior end
28. Give the function of each pair of small ganglia located at each segment.
Carry nerve messages from sense organs and
coordinate the movement of muscles
29. List 4 sense organs commonly found in free-living marine annelids.
Sensory tentacles, statocysts, chemical
receptors and 2 or more pairs of eyes.
30. Tube dwelling annelids do what when there light detectors detect a shadow?
Retreat into their tube for avoidance of
predators
31. What do earthworms do when they are threatened? Grab onto the walls of their burrows
32. How do marine fanworms avoid predators?
Secrete a calcium carbonate tube (shell) that they live in
33. What do marine fireworms do when attached?
Poisonous bristles break off and penetrate the predators skin
34. Why do u think the organism in fg 27-17 is called a paddleworm?
Appendages act as paddles?
Ws 27-2b p. 597 Annelids
Name:
B:
D:
1. What type of muscles make the worm shorter?
Longitudinal
2. What type of muscles make the worm skinnier?
Circular
3. How do most annelids reproduce?
Sexually
4. Explain separate sexes and external fertilization.
Each worm is a male or a female only. Eggs and sperm are
released outside the body
5. What behavior helps palolo worms reproduce?
During a phase of the moon these worms surface and
simultaneously release eggs and sperm into the water. This helps ensure that eggs will be fertilized by sperm
6. What do hermaphrodites rarely do?
Fertilize their own eggs
7. What is the function of the clitellum?
It secretes a layer of mucous that allows the sperm stored by the worm to
fertilize the worms eggs.
8. What happens to this mucous ring?
It slips off the worms body with the fertilized eggs and turns into a
cocoon that helps protect the eggs
9. p. 596 fg 27-16 Where is the clitellum located?
1/3 from the anterior end
10. How many hearts / ring vessels are there?
7
11. Which organ system does the nephridia belong to? EXCRETORY
12. What does the brain connect to?
Ventral nerve cord
13. p. 598 Give the meaning for the class Polychaeta.
Poly = many
chaeta = bristles
14. Where do most polychaetes live
ocean
15. What is at the end of each Polychaete appendage?
Bristles
16. Why is a sea mouse called a sea mouse?
Its long bristles look like hairs or fur
17. Fg 27-18 How does a fanworm eat?
It filters the water for food with its bristles
18. List some of the environments that the class polychaeta typically live in.
coral reefs, sand, mud, piles of rocks,
tubes they build
19. List 2 common organisms in the class oligochaeta.
Earthworms, tubifex worms
20. What are common human uses for tubifex worms? Tropical-fish food.
21. Where do most oligochaetes live? Soil or fresh water
22. What does oligo mean?
Few
23. What is the main difference between an oligochaete and a Polychaete?
Oligochaetes have fewer hairs
24. What are castings?
Sand grains, clay particles and indigestible organic matter that pass out of the anus
25. Name the 3rd class of annelids.
Class Hirudinea
26. What organisms mostly make up this class? Leeches
27. Where do most leeches exist?
Freshwater
28. How do most leeches feed?
They are mostly external parasites and drink the blood and body fluids of their
host
29. ¼ of all leaches are…
carnivorous rather than parasites
30. What is the posterior sucker used for?
Anchor the leech to rocks, leaves, and other objects
31. Give the function of the 2 substances many leeches inject into its host.
Anti blood clotting agent and an anesthetic to
prevent the host from feeling the leech
32. How often must a leech feed?
Once a year
33. What so small polychaetes and their larvae make up in the ocean?
Plankton
34. 2 essential functions of oligchaetes (earthworms) in the soil are……1) aerate the soil (allow air to pass through tunnels made
by the worms), 2) return nitrogen and other nutrients into the soil so that plants may get access to these nutrients
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