Vertebrate

Fishes Three distinct groups Adaptations Jawless fishes Cartilaginous fishes Bony fishes Adaptations

Mouth at the end of the snout, symmetrical open water feeder angled downward/longer upper jaw feeds on prey below it, bottom feeder angled upward/longer lower jaw feeds on prey above it, surface feeder strong jaws - teeth preys on other fish sucker-shaped eats small plants and animals barbels feeds off bottom, senses food in murky water duckbill jaws grasps its prey no teeth eats plankton very large mouth surrounds prey Fins Large, forked caudal fin strong, fast swimmer spines on fins protection, more difficult to swallow, can be poisonous large pelvic fins bottom dweller small pelvic fins open water swimmer

Eyes both on the same side of the head lies flat on the bottom of the ocean small shallow water fish large usually deep water fish Scales large uses its scales for protection small fast swimmer Coloration no markings swims in the open water stripes hides in seaweeds and grasses mottled hides in rocks or on the bottom countershading – dark on top, light on bottom less visible to predators above and below stripe through eye helps to camouflage fish by hiding the eye false eye spot predator will attack tail giving fish a greater chance to escape

Body shape round difficult to swallow, slow swimmer flat bottomed feeds on the bottom long, eel-like hides in rocks and weeds torpedo shaped high speed swimmer flat from side to side almost invisible from the front and rear, feeds above and below flat from top to bottom hides on the bottom hump backed stable in fast moving water

Jawless fishes Hagfishes Lamprey Do not have a vertebrae Live only in the ocean Lamprey Half are free-living Half are parasites as adults

Cartilaginous fishes Skeletons composed of cartilage Lightweight, flexible tissue Sharks, skates, rays Fertilization occurs inside the body Internal fertilization

Bony Fishes 95% of fishes Characteristics Bone Lungs or swim bladder (buoyancy) Scales Protection; reduce friction Reproduction Fertilization takes place externally

Amphibians Aquatic larval stage – terrestrial adult Skin: moist & thin respiration & protection Pros: rapid diffusion of oxygen, CO2, & water Cons: vulnerable to dehydration; pollution Feet are usually webbed; no claws Reproduction: eggs laid in water or moist places; fertilized externally Adaptations: Vocal cords: frogs use to communicate Poison Color: salamanders can hide from predators

Reptiles Reptiles Metabolism: ectotherm Scales: prevent from water loss, protection Adaptations Tails: swimming Jaws: capture food Shells: protection Fangs: protection Rattles: warning

Nostrils. The nostrils of fish do not open into the back of the mouth as do those of mammals, and are not, therefore, for breathing. They lead into organs of smell which are as a rule, very sensitive, so that a fish can detect the presence of food in the water at considerable distances. Eyes. The eyes of a fish have large round pupils which do not vary in size. Hearing. Although fish have no ears visible externally they can hear by transmission of vibrations through the body to sensitive regions of the inner ear. Mouth. The mouth serves for taking in food; also for the breathing current of water. Some fish have a wide gape, and filter microscopic plants and animals out of the surface waters as they swim along, trapping them in gill rakers before the water is expelled from the operculum. The operculum is a bony structure covering and protecting the gills in teleosts; it plays an important part in the breathing mechanism. Elasmobranchs do not have an operculum but there are separate gill slits for each gill. The lateral line is a jelly-filled tube or canal just below the skin. It opens to the water outside by a series of tiny pores. Its function is to detect movements in the water. A disturbance set up, for example, by a person's hand moving in the water, will cause the jelly in the tube to vibrate. The canal is lined with nerve endings which are stimulated by vibrations and send impulses to the brain. In this way the fish is made aware of the direction and intensity of water movements. The sensitivity of this system makes even a blind fish very difficult to catch by hand. Fins give stability, and control the direction of movement during swimming, as explained later.