Characteristics of Animal Groups

What makes a crustacean a crustacean?

• Ten or more jointed legs

• Abdomen often has segments (usually 19)

• No wings

• Two pairs of antennae (one may be very small)

• Two body parts (head and abdomen) protected by a hard outer shell

What makes an insect an insect?

• Three body parts (head, thorax and abdomen)

• Usually, one or two pairs of wings

• Six jointed legs

• One pair of antennae

What makes a myriapod a myriapod?

• Abdomen has many segments

• Two body parts (head and abdomen)

• Each segment has one or two pairs of legs

• One pair of antennae

• No wings

What makes a mollusc a mollusc?

• Soft-bodied

• Muscular foot

• Most have tentacles for feeding and sensing

• Most have shells

• No segments

What makes an arachnid an arachnid?

• No antennae

• Two body parts (head and abdomen)

• No wings

• Eight jointed legs

What makes an annelid an annelid?

• No wings

• Segmented body

• No legs

• Usually have bristles, although these may be too small to see

• No antenna

What makes a flatworm a flatworm?

• Simple, flattened bodies

• No blood vessels

• Soft-bodied

• No segments

What makes an echinoderm an echinoderm?

• Tube feet operated by fluid pressure

• Body usually in five segments

• Usually live in water

• Calcium skeleton