VERTEBRATE ANIMALS VERTEBRATES ARE ANIMALS WITH ENDOSKELETONS VERTEBRATE ANIMALS HAVE BACKBONES MOST VERTEBRATES ARE FISH FISH CAN BE CLASSIFIED INTO 3 GROUPS MOST YOUNG FISH DEVELOP INSIDE AN EGG AMPHIBIANS AND REPTILES ARE ADAPTED FOR LIFE ON LAND BIRDS MEET THEIR NEEDS ON LAND, IN WATER, AND IN THE AIR MAMMALS LIVE IN MANY ENVIRONMENTS

Vertebrates have backbones Fish, frogs, snakes, birds, dogs, humans are all vertebrates (animals with backbones) Only 5% of animals are vertebrates (rest are invertebrates) they are the most studied. Have muscles, digestive systems, respiratory system, & nervous system with sensory organs. Have endoskeleton-internal support system that grows with the animal; allow for more flexibility & movement. Named for specialized bones-vertebrae (backbones). Supports muscles & surrounds spinal cord (connects brain to nerves).

Most Vertebrates are Fish More than 20,000 species of fish, in nearly every aquatic environment. Get oxygen from water, & move to find food. Muscles & fins push bodies through water & move them quickly. Many have swim bladder to control depth at which they float. Have sensory organs for taste, odor & sound; most have a lateral line (senses vibrations of objects) Gills made of many folds of tissue filled with blood (takes in oxygen from water into blood, and water is forced out through gill slits)

3 Groups of Fish JAWLESS, CARTILGINOUS & BONY FISH Jawless have tube shape bodies (lampreys & hagfish); digestive system with no stomach, but teeth- bite other organisms to attach & suck out flesh & fluids Cartilaginous = sharks, rays & skates; no bone but cartilage skeletons Some sharks pose danger to humans but most don’t & feed on fish, crustaceans & mollusks. Whale sharks feed by filtering small organisms as they swim. Rays have flat bodies, & skim ocean floor to feed on small animals in sand. Has large wing like fins on its side.

Bony Fish Most fish (tuna, flounder, goldfish, eel) are bony (96%) Have bony skeletons, and most fish are covered with scales, have jaws, teeth & several pair of fins. Tropical fish are bright & colorful (may give camaflouge in their environment or help to attract a potential mate.

Most young fish develop in eggs Most reproduce sexually, female makes eggs, male makes sperm Often they select mates (female may only release eggs into water when a certain male is around to fertilize them); then parent fish usually leave eggs to hatch on own, but are some exceptions. Most fish eggs are surrounded by a soft egg case that lets water pass through(giving it oxygen too); the yolk gives the developing fish food- so these eggs don’t need care from adult fish Since many animals eat fish eggs, fish often lay & fertilize many, so a few will survive to maturity.