Chapter 18

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Suggested answers to questions from the textbook

1. What is a totem?

Ans. A person who is given a name from the living world takes on a responsibilityto care for that animal or plant and that animal or plant becomes that person'stotem.

2. Who are elders and what is their role?

Ans. Senior members of a community who amongst many other things, teachchildren about the living world.

3. What is a heterotroph and how is it different from a omnivore?

Ans. Animals are heterotrophs because they obtain their food from otherorganisms. Animals that eat both plants and animals are called omnivores.

4. What are the levels of classification of animals?

Ans. All living things can be classified on the basis of their similaritieswith other organisms. The animal kingdom can be divided into phyla, eachphylum into classes, each class into orders, each order into families, eachfamily into genera, and each genus into species

5. What is the major difference between animal and plant cells?

Ans. Another major difference between plants and animals is the cellstructure. Plant cells contain chloroplasts, the cell components used forphotosynthesis, and are surrounded by a rigid cell wall containing cellulose.This structure gives plant cells a more regular shape than animal cells(see Figure 181.1). In general, marine animals can move around, they respondmore rapidly to stimuli than plants do, and they have a more flexible cellwall.

6. Name the five kingdoms of marine life.

Ans. See Figure 181.3. Animals, plants, fungi, protists and monerans.

7. Name the structural characteristics of Protozoa.

Ans. Microscopic, single-celled animals.

8. How are sponges different from protozoans?

Ans. Animals with many pores and many cells but no organs or tissue,attached to the sea floor. Adult sponges grow attached to rocks, sea plants,the shells of marine animals, and to artificial structures. They can befound at all depths from the inter-tidal zone to the deepest parts of thesea. Live sponges are often brightly coloured.

9. Name the structural characteristics of Cnidarians.

Ans. Sac-like animals with body plan arranged in a circle and a sac atone end, two cell layers, stinging cells.

10. All marine worms have one thing in common. What is it?

Ans. Segments

11. Why have insects failed to conquer the marine world?

Ans. Possibly due to their inability to cope with the high levels ofsalt in sea water.

12. What are tubed feet and what of phylum are they a structural characteristic?

Ans. Tubed feet help Echinoderms move and feed.

13. An animal has a spiny skin, radial symmetry, a gill membrane, nosegmentation and most types are protected by a shell. To what phylum doesit belong?

Ans. An Echinoderm

14. What do divers like about tube worms?

Ans. When they snap their fingers they retract into their burrows veryquickly.

15. What do crustaceans do when they moult?

Ans. Mate, loose their shell, grow bigger.

16. Why are sharks important in the food chain?

Ans. Sharks are important because they help control population sizesin the food chain. They also weed out the sick and injured as well as scavengingfor food.

17. Give an example of one animal that uses regeneration as part of itsadaptation to underwater life.

Ans. A starfish

18. What is the largest invertebrate animal?

Ans. Giant squid

19. What is a radula and how is it used by molluscs to get food fromrocks?

Ans. Molluscs also have a modified mouth piece called a radula whichscrapes food off rocks.

20. Name any four characteristics of the phylum Chordata.

Ans. Skeleton made of cartilage or bone, gill slits in the throat atsome stage of its life cycle, dorsal nerve cord that extends the lengthof the animal and a posterior tail.

21. Draw a diagram of a shark, naming all the fins.

Ans. See Figure 190.3

22. Do sharks have scales?

Ans. No

23. What is cartilage?

Ans. Cartilage is a type of gristle similar to that found in your nose.

24. What is an operculum?

Ans. Bony fish have true scales, a bony skeleton, a single pair of gillopenings and an operculum which covers the gills

25. How are reptile eggs different from fish eggs?

Ans. Most reptiles lay eggs which, unlike the eggs of fish and amphibians,resist drying out.

26. What are salt glands and how do they help reptiles?

Ans. Marine reptiles are equipped with salt glands which remove excesssalts.

27. Why are plastic bags dangerous to turtles?

Ans. Turtles are also threatened by litter such as plastic bags thatare thrown into the sea. Turtles eat jellyfish and often mistake plasticbags for food. When they eat plastic bags they die a slow, painful death

28. Which animals have a four-chambered heart?

Ans. Sea birds and marine mammals

29. What in greek mythology, was a siren?

Ans. A singing mermaid of Greek mythology who lured sailors to theirdoom on rocks and reefs.

Diving deeper - some suggested answers

1 Visit a fish shop and buy a selection of local crustaceans such asprawns or crabs. Find out where they live and how to cook them.

Suggestion. Visit a fish shop or fish monger. See also Chapter 22 TeachersGuide.

2. Visit a fishing boat and ask the skipper to describe how crustaceansare caught.

Suggestion. Find a parent who fishes and ask the question.

3. Use the library to compare drawings of fish scales and shark teeth.

Suggestions.

See your librarian

4. How do sharks reproduce?

Suggestions. Use your library.

5. What impacts have humans had on shark numbers worldwide?

Suggestions. Locate a fisheries officer, shark contractor or search theinternet for sharks.

6. Arrange an excursion to a rocky shore to identify the different zonesand identify some of the animals that live there. The aim is to see theanimals, so do not collect any and be careful as rocks are slippery.

Suggestions. Make sure you plan the excursion around the tide. Low tidesare best for excursions.

Check out the excursions in the Wet Paper Marine Environment Manuals.

7. Many videos describe animal marine life. Visit your library and borrowfour. Make a report on some of the animals discussed in the video.

Suggestions. See your librarian for advice.

8. Make a fibreglass fish. Instructions are in the Wet Paper Marine EnvironmentManual.

Suggestions: See Page 174.

9. Set up an aquarium as discussed in Chapter 15 and keep some fish fora term.

Suggestions: See Chapter 15.

10. Visit a local marine aquarium or zoo and study marine life there.

Suggestions: Make the trip.

11. Write a poem or song about life in the sea.

Suggestions: Read the Rhyme of the ancient mariner. Download the Simpsonsunder the sea song from the internet.

12. Invite a marine scientist to your class. Ask for a discussion onthe research he or she is doing into the marine world.

Suggestions: Ask parents for help or your local aquarium, sea life park,education advisor.

13. Run a marine photographic competition. Use a digital camera to captureimages and make a web page.

Suggestions: Email your results to wet paper and we will put a link toyour page.

14. Ask your computer to find web pages about squid.

Suggestions: Type squid into your favourite engine

Chapter summary questions answers

1. totem

2. autotrophs

3. heterotrophs

4. coelenteron

5. segmented

6. anterior

7. posterior

8. dorsal

9. ventral

10. chitin

11. bilaterally

12. mate

13. moult

14. sperm

15. bundle

16. packet

17. chamber

18. Molluscs

19. foot

20. cartilage

21. scales

22. operculum

23. four-chambered heart

24. eggs

25. reptiles

26. insulate

27. teeth

28. baleen plates