Phylum Chordata

1. Phylum Chordata

2. Phylum Chordata They have 4 main characteristics that they must have at some time in their development. dorsal, hollow nerve cord notochord- long supporting rod runs near nerve cord pharyngeal pouches- paired structures in the throat region a tail that extends beyond the anus

3. Sub-Phylum Vertebrata • A chordate that has a strong supporting structure – Vertebral Column or Backbone. • Dorsal hollow nerve cord -aka Spinal cord • The front of the spinal cord grows into the brain • Backbone made of individual segments called vertebrae. • Endoskeleton-supports and protects the animals body. • Major groups-Fishes, Amphibians, Reptiles, Birds, and Mammals

4. Fishes • Aquatic vertebrates • fresh and marine waters • Fish were the first vertebrates to evolve • About 510 million years ago • Not like the fish we see today. • Characteristics (there are some exceptions) • Paired fins -movement • Scales –protection • Gills –gas exchange • Ectotherms

5. Fishes • Three groups of fish • Agnathans • Jawless fishes (Lampreys and Hagfish) • Lack true teeth and jaws • Chondrichthyes • Cartilaginous fishes (Sharks, rays, etc.) • Skeletons are built entirely of cartilage, not bone. • Osteichthyes • Bony fishes • Skeletons are made of hard, calcified tissue called bone.

6. Fishes • Feeding • Herbivores, carnivores, parasites, filter feeders, and detritus feeders. • They have a 2-opening digestive track with: • Mouth, esophagus, stomach, pyloric ceca, intestine, anus, also have a liver, and pancreas • Respiration • Most fishes exchange gas through gills located on either side of the pharynx • Water passes over the gills and O2 and CO2 are exchanged between the water and blood • A few fishes have “lungs”

7. Fishes • Circulation • Closed circulatory system with a four-chambered heart that pumps blood in a single loop: • Heart Gills Body Heart • Excretion • Waste in the form of ammonia • Some wastes diffuse through gills (CO2) and others are removed by the kidneys • Response • Well-developed nervous system • Highly developed sense organs • Lateral line system • Sensitive receptor system that enables fish to detect gentle currents and vibrations in the water

8. Fishes • Movement • Move by alternately contracting paired sets of muscles on either side of the backbone. • Creates a series of S-shaped curves • Use of fins for direction • Swim bladder –gas-filled organ that helps fish stay afloat. • Reproduction • External and internal fertilization –depends on the species

9. Amphibians • About 4000 living species • First seen about 360 million years ago • Gave rise to all other land vertebrates • Amphibian means “Double Life” • Live in water and on land • Must return to water to reproduce • Characteristics • Lives in water as a larva • Lives on land as an adult • Moist skin that contains mucus glands • Lacks scales and claws • Ectotherms

10. Amphibians • Three groups of Amphibians • Salamanders • Long bodies and tails • Most have 4 legs • Carnivores • Found in moist woods • Tunnel under rocks and rotting logs • some keep their gills • Frogs and Toads • They can jump • Frogs have longer legs than toads • Frogs found more in water areas and toads in moist woods and deserts • Adults lack tails • Caecilians • Legless animals that live in water or moist soil • Feed on small invertebrates

11. Amphibians • Feeding • Tadpoles are filter feeders or herbivores • Adults are carnivores • Complete 2-opening digestive track • Mouth, esophagus, stomach, small intestine, large intestine, cloaca, also have a liver, gallbladder and pancreas • Respiration • Larval forms- gas exchange through skin and gills • Adults- gas exchange through lungs and skin • Salamanders do not have well developed lungs • Gas exchange through linings in mouth • Circulation • Closed circulatory system with a heart that pumps blood in a double loop: • Heart Lungs/Skin Heart Body Heart

12. Amphibians • Excretion • Kidneys that filter waste from the blood and pass out the cloaca: • Kidneys Ureters Urinary bladder Cloaca Outside • Response • Well developed nervous system and sensory systems • Large and moveable eyes • Hear through tympanic membranes • Membrane vibrates sending sound to the brain • Many larva and adult forms have lateral line system to detect water movement

13. Amphibians • Movement • Larvae often move like fish “wiggling” their bodies and using their tail • Adults use front and back legs for walking, running, jumping • Reproduction • Internal and external fertilization • Shell less eggs • Eggs are laid in water—as many as 200

14. Reptiles • About 7000 living species • First seen about 350 million years ago • More common around 300 million years ago • Found all over earth, except very cold places • Characteristics • Dry, scaly skin • The tough skin does not grow, it needs to be shed periodically • Lungs • Terrestrial eggs • Well developed skull • Backbone and tail • Four limbs (except snakes) • Ectotherms

15. Reptiles • Four surviving groups of reptiles • Lizards and snakes • Lizards • Legs, clawed toes, external ears, movable eyelids • Snakes • Lack limbs • Crocodilians • Alligators, Crocodiles, etc. • Fierce carnivores • Only freshwater, except crocodiles that may live in either salt water or freshwater • Turtles and tortoises • Turtles live in water • Tortoises live on land • Have a shell that is built into their skeleton • Lack teeth—have bony ridges that cover upper and lower jaws • Tuatara • Found only on a few small islands off of New Zealand • Resemble lizards, except they lack external ears, and retain primitive scales • Have a “third eye” on top of head….function is still unknown

16. Reptiles • Feeding • Herbivores, and carnivores • They have a two-opening digestive track • Respiration • Lungs for respiration • Lungs are “spongy” providing more gas exchange than amphibians • Circulation • Have a closed circulatory system • Efficient double-loop • Heart lungs heart body heart • Have two atria and either one or two ventricles • Most reptiles have one ventricle, however crocodiles and alligators have the most developed hearts with two ventricles.

17. Reptiles • Excretion • Kidneys filter blood and produce urine • Some reptiles have a urinary bladder • Urine contains either ammonia or uric acid • Response • Similar brain to that of an amphibian • Except cerebrum and cerebellum are larger compared to the rest of the brain • Complex eyes that can see color well • Good sense of smell • Most have a pair of sensory organs in the roof of the mouth that can detect chemicals • Simple ears with external ear drums • Some snakes can detect body heat

18. Reptiles • Movement • Reptiles with legs have larger and stronger limbs that enable them to walk, run, burrow, swim, or climb • Limbs are rotated further under the body allowing them to carry more body weight • Legs and feet of many aquatic turtles have developed into flippers • Reproduction • All reproduce by internal fertilization • Male deposits sperm inside the female • Most lay eggs that develop out side the body • The shell and membranes of the egg help create a protected environment for the embryo to develop with out drying out • Called an amniotic egg

19. Birds • Nearly 10,000 bird species today • Reptile like animals • First seen 150 million years ago • Archaeopteryx • Characteristics • Endotherms • Maintain a constant body temperature • Hollow bones • Outer covering of feathers • Made mostly of protein • Help birds to fly and maintain temp. • Two legs that are covered with scales • Used for walking or perching • Modified front limbs for flying

20. Birds • Over 30 different groups • Largest group is the Passerines • Over 5,000 species • Perching birds • Larks, sparrows, finches • Some other groups • Pelicans and their relatives • Pelicans, boobies, etc. • Parrots • Macaws, lovebirds, cockatoos, etc. • Birds of prey • Condors, hawks, owls, eagles, etc. • Cavity-nesting birds • Woodpeckers, toucans, etc. • Herons and their relatives • Storks, spoonbills, cranes, herons, etc. • Ostriches and their relatives • Ostriches, emus, etc.

21. Birds • Feeding • The beak is adapted to the type of food they eat. • Complete two-opening digestive track from mouth to cloaca • Lack teeth • Respiration • One-way flow of air • Allows for constant exposure of the lungs to oxygen-rich air • Have air sacs in the body cavity and bones • Circulation • Closed circulatory system with a double loop system • Four-chambered heart • Two atria and two ventricles • Complete separation of oxygen-rich and oxygen-poor blood

22. Birds • Excretion • Similar to reptiles • Nitrogenous waste is removed from blood by the kidney, converted to uric acid and deposited in the cloaca • Most water is reabsorbed in the cloaca leaving uric acid crystals in a white pasty form • Response • Well developed sense organs • Well developed eyes • See color very well • Hear very well • Brain that can quickly interpret and respond to a lot of incoming signals

23. Birds • Movement • Some birds cannot fly • They walk, run, or swim • Large chest muscles that aid in flying • Reproduction • Both male and female reproductive tracks open into the cloaca • Organs often shrink in size when not breeding • Amniotic eggs • Similar to reptiles, but have a hard outer shell

24. Mammals • Nearly 4500 species today • First seen 220 million years ago • Characteristics • Endotherms • Maintain a constant body temperature • Have hair • Nourish their young with milk • Breath air • Four-chambered heart

25. Mammals • Three main groups of mammals • Differ in means of reproduction and development • Monotremes • Three species exist (duckbill platypus, and two species spiny ant eaters) • Lay eggs • Have cloaca • Marsupials • Bear live young that complete their development in a pouch • Kangaroos, koalas, wombats • Placentals • Nutrients, oxygen, carbon dioxide, and wastes are exchanged between embryo and mother through the placenta • Humans, dogs, cats, elephants, etc…

26. Mammals • Feeding • As mammals evolved, the form and function of their jaws and teeth became adapted to eat different types of food • Herbivores • Jaws move from side to side • Carnivores • Jaws move up and down • Respiration • Lungs • Diaphragm • Muscle that pulls the bottom of the chest cavity downward which increases volume • Circulation • Closed, double-loop circulatory system • Four-chambered heart

27. Mammals • Excretion • Highly developed kidneys that extract nitrogenous waste from the blood in the form of urea • Urea, with other wastes, and water combine to form urine (Pee) • Urine is stored in a urinary bladder until it is eliminated • Response • Have the most highly developed brain of any other animal • Highly developed senses • Taste • Smell • Touch • Hearing • Sight

28. Mammals • Movement • Evolved a variety of adaptations that aid in movement: • Backbone that flexes both vertically and side to side • Shoulders and pelvic bones became more streamlined and flexible • Allows them to: • Run, walk, climb, burrow, hop, pounce, swing, fly, leap, and swim • Reproduction • Internal fertilization • Males deposit sperm inside the female reproductive track • Three types of development and birth • Monotremes, Marsupials, and Placentals • Young depend on mother for food and protecting