Phylum Chordata

What Is A Chordate? 4 characteristics present at some stage of life 1.A dorsal, hollow nerve cord (called spinal cord in vertebrates) 2.N otochord – a supporting rod (develops into a backbone in vertebrates) 3.P haryngeal pouches 4.T ail that extends beyond the anus

General Chordate Structure Notochord Mouth Anus Tail Pharyngeal Pouches Hollow Nerve Cord Muscle Segments

Nonvertebrate Chordates Tunicates - look nothing like other chordatesTunicates - look nothing like other chordates –The larval form has all the chordate characteristics –The adult tunicates have neither a notochord nor a tail Lancelets are more fishlike and have a definite head containing a mouthLancelets are more fishlike and have a definite head containing a mouth

Fish Classes: Agnatha – jawless fish Chondrichthyes – cartilaginous fish Osteichthyes – bony fish

Groups of fish Fish are the first vertebrates to evolve Jawless Fish – have not true teeth or jaws; ex: lampreys & hagfish, parasitic

Cartilage Fish – skeleton made of cartilage; ex: sharks, rays, skates

Bony Fish – skeleton made of hard, calcified tissue  bone; ex: perch, goldfish

Characteristics Integumentary –Scales & paired fins Skeletal/ Muscular –Endoskeleton - made of cartilage or bone Circulation –2-chambered heart; closed-single loop circulation

Reproductive –Internal or external; –Oviparous, Ovoviviparous, Viviparous Eggs house outside the mothers body Born alive after developing eggs inside of mother’s body Bear live young that are nourished by mother Nervous –Brain, lateral lines Respiratory –Gills Characteristics

Digestive –Variety in types of feeding; complete digestive system Excretory –Remove ammonia from gills & kidneys Characteristics

Body Temperature –Ectothermic Habitat –Marine & Fresh Water Characteristics

Bony Fish Structures Mouth Eye Operculum Caudal fin Lateral line Dorsal Fins Anal fin Pectoral fin Pelvic fin

Swim Bladder Gills Brain Spinal Cord Heart Liver Reproductive organ Anus Intestine Stomach Gallbladder

Amphibians Class Amphibia

Amphibians are tetrapod vertebrates (four footed) Include all tetrapod vertebrates that are not amniotes (lay eggs on land) Frogs, toads, salamanders, and newts

Characteristics Integumentary –Moist skin with mucus glands –Found near moist habitats to keep skin damp Skeletal/Muscular –Endoskeleton –Adult: legs for walking or jumping; no legs –Larva: swim

Characteristics Circulatory –Adult: 3 chambered heart, closed- double loop –Larva: 2 chambered heart Reproductive –External fertilization; eggs must stay moist (no shell)

Characteristics Nervous –Brain; eyes w/ nictitating membrane; tympanic membrane (like a drum) for hearing; lateral lines Respiratory –Adult: through lungs, skin, & lining of the mouth –Larva: through skin and gills

Characteristics Digestive –Complete digestive system (mouth --> anus) –Adult: carnivore –Larva: herbivore or filter feeder Excretory –Kidneys filter wastes from blood, urine travels through ureters to urinary bladder and out through cloaca

Characteristics Body Temperature –Ectothermic (cold blooded, find heat from an outside source like the sun) Habitat –Adult: live on land near water –Larva: live in water

Lifecycle of a Frog Adult Frog Young Frog Fertilized Eggs Tadpoles Adults are typically ready to breed in about one to two years. Frog eggs are laid in water and undergo external fertilization. Frog eggs are laid in water and undergo external fertilization. The eggs hatch into tadpoles a few days to several weeks later. Tadpoles gradually grow limbs, lose their tails and gills, and become meat-eaters as they develop into terrestrial adults. Tadpoles gradually grow limbs, lose their tails and gills, and become meat-eaters as they develop into terrestrial adults.

Evolution The first amphibians looked similar to lobe-finned fish

Groups of Amphibians Salamanders – have long bodies & tails, most have 4 legs, usually live in moist woods

Groups of Amphibians Frogs & toads – both jump & lack tails; frogs more closely tied to water

Groups of Amphibians Caecilians – legless animals; live in water or burrow in moist soil; many have fishlike scales,resemble earthworms or snakes