Invertebrates

Invertebrates worksheets answers

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Worksheet 1
1 b  jellyfish; 2 e  seabed X; 3 a  backbone X;
4 c  earthworm; 5 d  starfish; 6 f  tapeworm.
echinoderms (starfish); worms (earthworm); molluscs
(snail); arthropods (wasp); cnidaria (jellyfish/polyp);
porifera (sea sponge).
1. Invertebrates are animals with no backbone.
2. Some, like spiders, have an exoskeleton.
3. Sponges are porifera.
4. Cnidaria have radial symmetry and tentacles.
5. Annelids breathe through gills.

Worksheet 2
1c; 2e; 3a; 4g; 5f; 6b; 7d.
1. Insects.
2. Myriapods.
3. Arachnids.
4. Crustaceans.
Individual answers.

Worksheet 3
1. Porifera.
2. Molluscs.
3. Cnidaria.
4. Echinoderms.
5. Worms.
6. Arthropods.
1T; 2T; 3F The largest known invertebrate is the giant
squid.; 4F Jellyfish are cnidaria.; 5T; 6F Leeches are
aquatic annelids.; 7T; 8T; 9F There are five subgroups
of echinoderms.
Individual answers.

Worksheet 4
Individual answers.

Worksheet 5
Palolos reproduce once a year.
Reproduction cycle: Adult male palolo worms have
segments full of sperm. Adult female palolo worms have
segments full of eggs. Once a year, on one night
in October or November, these segments detach
themselves and swim to the surface of the water. Here
they break open, and fertilisation occurs.
Individual answers.

Test 4
1a; 2c; 3a; 4a; 5b; 6c; 7a; 8b; 9c; 10b.
1. Tapeworms live inside human and animal intestines.
2. When they eat meat from animals which were
infected.
3. They absorb nutrients directly from their host.
4. The body of a tapeworm is long, flat and soft.
It has no respiratory or digestive system.