Over time people have discovered more than one and one-half million species of animals.

Scientists divide all of these animals into two groups based on an important difference-

-whether or not the animals have backbones.

Invertebrates & Vertebrates

Invertebrates (Animals without backbones) Most animal species are invertebrates. In fact 96 out of every hundred animal species are invertebrates!

Invertebrates can be divided into smaller groups. Sponges Coelenterates Flatworms Roundworms Segmented worms Mollusks Echinoderms Arthropods

Sponges No mouth No stomach or other organs Cannot move Have a bad smell or taste (This prevents other animals from eating them) Most sponges live in the ocean. Some live in freshwater.

Examples of Sponges Pale Pink Subtidal Sponge Cloud Sponge

Coelenterates Stinging cells Body like a bag One opening Have tentacles growing around the opening. Stinging cells cover each tentacle. (a slender,flexible body part used to touch, hold, or to move.)

Examples of Coelenterates Saddle sea anemone Jelly fish Coral

Flatworms Flatbodies One body opening Most are parasites (an organism that harms another organism by living on or taking nutrients from it)

Examples of Flatworms Planarian Fluke Tapeworm (no organs to digest food)

Roundworms Tubelike body Opening at each end Organs that digest food Live in soil, water, or other organisms Most eat dead plants and animals

Examples of Roundworms Vinegar Eel Hook Worm Trichnia Worm

Segmented Worms (made up of many similar sections) Many special organs in each segment.

Examples of Segmented Worms Clam worm Earthworm Leech

Mollusks (Invertebrates with unsegmented soft bodies, often covered by a shell) Soft bodies Live in the ocean, in fresh water, and on land Organs that digest food, pump blood, and take oxygen from water. Eyes

Examples of Mollusks Clam Squid Octopus Snail

Echinoderms Tough skins & spines Most have bodies with five sections Many tube feet

Examples of Echinoderms Star fish or sea star (can regenerate or regrow lost parts) Sea urchins Sand dollars

Arthropods (Invertebrates with jointed feet and a segmented body.) Jointed feet Exoskeleton (a hard covering that supports the body) Body has 2 or 3 segments Two main body openings Keen sense organs Move quickly

Arthropods (Most of the animals on earth are arthropods.) Arthropods can be classified into several main groups: Crustaceans Arachnids Insects Millipedes and Centipedes

Crustaceans (Arthropods with 5 pairs of legs, 2 pairs of antennae, and 2 main body segments.) Live on or near the ocean Tiny drift near the surface of the ocean Some live in fresh water Few live on land

Crab Lobster Examples of Crustaceans

Arachnids (Arthropods with 4 pairs of walking legs, no attenae, and 2 body segments) Four pairs of walking legs Two body segments No antennae Most live on land Few spiders live in fresh water

Examples of Arachnids Garden Orb Spiders Mites Ticks

Antennae - (feelers on the heads of arthropods) 3 pairs of legs Head Thorax - (the middle section of an insect’s body) Abdomen - ( the rear section of an insect’s body) Most have wings 2 kinds of eyes (simple & compound) Insects (Biggest group of Arthropods)

Examples of Insects Horsefly Beetle Dragonfly Butterfly

Millipedes & Centipedes Many body segments These animals have less than 100 legs.

Millipede (means “thousand feet”) Many body segments 4 legs on each segment Live under rocks and other dark places Eat plants Protects itself by curling up

Centipede (means “ hundred feet”) Many body segments 2 legs on each segment Claws with poison glands Catch and eat earthworms and insects Live under rocks and other dark places

Vertebrates (Animals with backbones)

Vertebrates can be divided into five main groups. Fish Amphibians Reptiles Birds Mammals

Fish Make up the largest group of vertebrates!

Fish ( make up the largest group of vertebrates) cold-blooded (body temperature changes when the temperature of the air or water around it changes) a vertebrate that has fins breathes with gills all its life lives in water

Fish Live in oceans, streams, and lakes all over the world scales protect its body lateral line ( a row of tiny holes with nerve endings that feel changes in water pressure)

Examples of Fish Porcupine Fish Sharpnosed Puffer Stonefish Frogfish

Amphibians (vertebrates that begin life with gills and later develop lungs) Coldblooded Begin lives in water Breathe with gills Later grow lungs And eventually can move to land

Examples of Amphibians Frog Salamander

Reptiles Cold blooded Breathe with lungs all through their lives Lay eggs with shells Most covered with hard, dry rough scales

Example of Reptiles Turtles Lizards Alligators and Crocidiles Snakes

Birds Warm blooded ( body temperature that stay the same even when the temperature of the air or water around them changes) Lay eggs with shells Only animals with feathers Most bodies shaped for flying Strong bones, but very light

Examples of Birds Flamingo Duck Penguin

Mammals Warm blooded Only animals that make milk to feed their young Hair or fur Lungs and breathe air Most live on land Some live in the water (whales)

Examples of Mammals lion elephant whale