1. The Animal Kingdom Chapter 2: Mollusks, Arthropods and Echinoderms

2. Phylum Mollusca: Snails, Clams, Squid
Characteristics:
All have soft bodies and bilateral symmetry.
The Latin word, “mollis” means “soft”.
Most secret hard, calcium carbonate shells to protect themselves.

3. Although they don’t look much alike at first, a snail, a clam, and a squid have the same basic body structures.

4. Basic body pattern of most mollusks:
1. Head: containing the mouth
2. Muscular foot: for crawling, digging, or swimming.
3. Mantle: a thin layer of tissue that surrounds the main body organs. The mantle secretes the shell.
4. Gills: used to breath oxygen from water.

5. Classes of mollusks include:
Gastropoda (stomach-foot) —snails, slugs, and sea slugs.
*One shell (univalve)
*Live in the water or on land *Make beautiful sea shells

6. Attack of the Cone Snail 2:41
*Use a flexible ribbon of
tiny teeth called a
radula to get food.
*Some are herbivores
*Some are carnivores
Mouth
Attack of the Cone Snail 2:41
Radula
Snail Zombies 1:53
Radula Teeth

7. Bivalvia (two-shells)-- clams, oysters, scallops and mussels.
*Filter feeders—most are omnivores
*Economically important as food
*Used in production of pearls.

8. A razor clam digs into the mud by changing the shape of its foot.
- Mollusks
A razor clam digs into the mud by changing the shape of its foot.
Giant Clam Video 1:45

9. 3. Cephalopoda (head-foot) —octopus, squid, cuttlefish, and chambered nautilus.
*Muscular foot is divided into
tentacles for swimming.
*Complex and intelligent.
*Range in size from 1-60 feet.
*Carnivores
*Crawl or swim by jet propulsion

10. Octopus regeneration 2:03
*Not all cephalopods have a shell
Octopus—no shell
Squid—internal shell
Octopus regeneration 2:03
Octopus flexibility
Chambered Nautilus
external shell
Squid video 3:38

11. Phylum Arthropoda: Jointed Legs
Characteristics:
Largest group of animals with over million species known. That number may be as high as 10 million.

12. Exoskeleton made of chitin
Exoskeleton made of chitin. Must be shed from time to time in a process called molting.
Segmented bodies
All have jointed appendages (legs, antenna, pinchers and claws)
Open circulatory system
Bilateral symmetry
One-way digestive tract

13. Five classes: Arachnida, Crustacea, Chilopoda, Diplopoda, Insecta

14. Crustaceans: crabs,
lobsters, crayfish, shrimp and pill bugs.
*Most have two body regions: cephalothorax and abdomen.
*Five pairs of appendages including large pinchers on most.
*Most have two pair of antenna

15. Fiddler crab
Pill Bug
Crayfish

16. 2. Arachnids: spiders, scorpions, mites and ticks.
*Most have two body regions:
abdomen cephalothorax.
*simple eyes
*poison glands, fangs or stingers
*four pair of legs

17. Spiders are found everywhere
Spiders are found everywhere. They spin webs using spinnerets in their abdomen.

18. Scorpions are found in tropical areas and hunt insects and spiders.

19. Ticks are external parasites that feed on the blood of a host
Ticks are external parasites that feed on the blood of a host. Some transmit Lyme Disease and Rocky Mountain Spotted Fever.
Mites are usually found in dust and are mostly harmless.

20. 3. Chilopoda: centipedes
*Long, flat bodies with one pair of legs per body segment.
*Carnivores: eat snails, slugs and worms and can bite humans.

21. 4. Diplopoda: millipedes
Long, rounded bodies with two pairs of legs per body segment.
Plant eaters: will not bite humans

22. 5. Insects: largest group of arthropods
Three body segments: head, thorax and abdomen.
Three pairs of legs attached to the thorax.
One pair of antenna.
Some have one or two pairs of wings; some have no wings.
Large, compound eyes; some also have simple eyes.
Open circulatory system.

23. Wings
Antenna
Thorax
Head
Abdomen
Compound
Eyes
3 Pair of Legs

24. All insects undergo metamorphosis *This is a process in which an
animal’s body undergoes dramatic
changes in its life cycle.
*Two types of metamorphosis:
Complete and Gradual

25. -Stages of Complete Metamorphosis:
*Egg, Larva, Pupa, Adult
(Beetles, bees, butterflies, flies and ants use complete metamorphosis)

26. - Insects
Life Cycle
An insect with complete metamorphosis has four different stages: egg, larva, pupa, and adult.

27. Stages of Gradual Metamorphosis:
*Egg, Nymph, Adult
(Grasshoppers, termites, cockroaches and dragonflies use gradual metamorphosis)

28. - Insects
An insect with gradual metamorphosis has no distinct larval stage. An egg hatches into a stage called a nymph, which usually looks like the adult insect without wings.

29. Phylum Echinodermata: Seastars
6,000 species of spiny-skinned animals
All have radial symmetry.
“Echinoderm” means “spiny-skin”.
Have an internal skeleton made of spines that extend out through the body.

30. All live in the ocean.
Move using a water-vascular system and tube feet.
Most can regenerate lost body parts and can occasionally reproduce this way.

31. Characteristics of Echinoderms
Echinoderms, such as this sea star, have a water vascular system that helps them move and catch food.
Tube Feet
Stomach
Madreporite
Water Vascular
System

32. Examples of echinoderms:
1. Sea stars and brittle stars: have 5 or more arms lined with tube feet. Feed on clams by inserting their stomach into the clam and digesting it inside the shell.

33. 2. Sea urchins and sand dollars: do not have arms
2. Sea urchins and sand dollars: do not have arms. Covered with movable spines used for defense and movement.

34. 3. Sea cucumbers: leathery skin with no spines
3. Sea cucumbers: leathery skin with no spines. Spits out its internal organs to confuse predators.