Invertebrates Vs. Vertebrates Classifying Animals

What are Invertebrates like? Nearly 95 out of every 100 animals are invertebrates. 8 invertebrate phyla Mollusks Sponges Cnidarians Echinoderms Flatworms Roundworms Segmented worms Arthropods

Arthropods- largest invertebrate phylum Scientist think there are more than a million arthropod species! Characteristics: Arthropods have…. Jointed legs Body parts divided into sections Breath with gills or an open-tube breathing system. hard exoskeleton for protection

4 Main Arthropod Classes Arachnids 4 pairs of legs 2-section body up to 8 eyes Crustaceans Centipedes and millipedes Insects 3 pairs of legs 3 body parts: (head, thorax, abdomen)

Classifying Vertebrates Vertebrates can be classified into two groups using this characteristic: Cold-blooded Warm-blooded These animals get heat from outside their bodies. The body temperature changes with the temperature of its surroundings. **If the outside temps change, so does its body temperature. **Cold air temperature means cold body temperature. The body temperature does not change much. They use energy from food to keep a constant temperature. **If body temp changes much, this could mean sickness (like a fever for humans).

Reptiles cold-blooded vertebrate dry, scaly skin lays eggs many have four legs, but some have none strong, waterproof skin breathes with lungs can live in many environments, both dry and wet

Amphibians frog breathe through lungs, skin, and gills during different parts of life vertebrate most have 4 legs toad life cycle includes larva stage (tadpoles) salamander cold-blooded moist skin All amphibians live near water so their skin won’t dry out. Frogs spend half their lives in water and half on land. lays eggs; usually in a jelly-like mass in water

Fish cold-blooded vertebrate covered by scales some species only live in freshwater (rivers, lakes) and some only live in saltwater (ocean) lays eggs in water eyes usually on side of head life cycle includes larva stage breathes through gills have fins and streamlined bodies to help them glide through water

Birds warm-blooded vertebrate have waterproof feathers live on land; found in all environments lay hard-shelled eggs hollow bones allow birds to fly breathe with lungs and have air sacs not all birds can fly all birds have wings and beaks

Mammals warm-blooded vertebrate most have body hair or fur breathe through lungs large, well-developed brains most live on land reproduce by live birth nurse their young with milk different kinds of teeth for eating different foods

Some Tricky Classifications to Think About A fish? A bird? Really? A mammal? How can whales, dolphins, bats, and the famous duckbill platypus be classified as mammals?