Invertebrate Characteristics

Arthropods

• Have a waterproof exoskeleton made mainly of chitin
• Have a segmented body
• Have several pairs of jointed legs

Pisces (Fish)

• Have a waterproof skin covered with scales
• Have gills for breathing
• Have fins for swimming
• Examples: barracuda, flying fish, shark

Paraphrasing Molluscs

• Have a soft, moist, unsegmented body
• Have a muscular foot
• Many have shells
• Examples: slug, snail, octopus

Echinoderms

• Have a body based on a radial pattern of five parts
• Body wall contains calcium carbonate plates, often with projecting spines
• Have tube feet with suction pads for movement
• Examples: starfish, sand dollar, sea urchin

Amphibians

• Have a soft, moist, non-waterproof skin without scales
• Eggs are laid in water, larvae live in water, adults live on land
• Larvae have gills, adults have lungs
• Examples: frog, toad, newt

Reptiles

• Have a dry, waterproof skin with scales
• Lay eggs with a rubbery shell on land
• Examples: barrel sponge, vase sponge

Arachnids

• Have no antennae
• Have four pairs of legs
• Body is divided into cephalothorax and abdomen
• Examples: spider, tick, scorpion

Cnidaria

• Have a bag- or umbrella-shaped body
• Gut has only one opening, the mouth
• Have a ring of tentacles around the mouth
• Examples: sea anemone, coral, jellyfish

Platyhelminthes (Flatworms)

• Have a long, flat, unsegmented body
• Examples: tapeworm, liver fluke

Nematodes (Roundworms)

• Have an elongated, round, unsegmented body with pointed ends
• Examples: hookworm, threadworm

Annelids (Segmented Worms)

• Have an elongated body divided into segments
• Examples: earthworm

Chordates

• Have a notochord (rod) running down the body
• Most have a backbone
• Have a dorsal nerve cord with the anterior end usually enlarged forming the brain
• Most have an internal skeleton of bone and cartilage

Aves (Birds)

• Have a waterproof skin with feathers
• Have a beak and no teeth
• Forelimbs are modified to form wings
• Lay eggs with a hard shell
• Are homeothermic (warm-blooded)
• Examples: sparrow, cattle egret, hawk

Mammals

• Have a waterproof skin with hair and sweat glands
• Have different types of teeth
• Young feed on milk from their mother
• Are homeothermic
• Examples: mouse, whale, human