Biology Notes Ch 26

Ch. 26 - Anamalia II - The Chodates Characteristics of Chordates a. Notochord b. Postanal tail c. Dorsal, hollow nerve chord d. Pharyngeal gill pouches or slits Chrodates are divided into 3 subphyla: a. Urochordata (Invertebrates) b. Cephalochordata (Invertebrates) c. Vertebrata A. Urochordata (tunicates) a. Free-swimming larvae b. Sessile adults c. Retain gill slits d. Filter feeders e. Most reproduce sexually (hermaphroditic); asexually via budding B. Cephalochordata (lancelets) a. Free-swimming larvae b. Fish-like adults c. Retains al chordate characteristics d. Filter feeder e. Reproduce sexually (separate sexes C. Vertebrata a. Possess a vertebral column b. Must have: i. Paired limbs ii. Endoskeleton iii. Hinged jaw c. Reproduce sexually (separate sexes) 1. Fishes a. Typically ectothermic b. Gills c. 2-chambered heart d. Well-developed senses e. Most are oviparous A. Jawless Fishes (hagfishes & lampreys) a. Lack jaws, fins, bones & scales b. Cartilaginous skeleton c. Notochord persist in adults B. Jawed Fishes a. Possess hinged jaws (developed from bones that support gills)

b. Notochord replaced by vertebrae in adults • •

• •

Placoderms (extinct) 1st Jawed fishes Cartilaginous fishes (class Chondrichthyes) Cartilaginous skeleton; acute senses, including lateral line system. Ex. Chimaeras, skates, rays & sharks Bony fishes ????????????????????????????????????????????????????? Bony Fishes include: a. Ray-finned fishes b. Lungfishes c. Lobe-finned fishes (coelacanth)

Adaptations to life on land: 1. appendages modified for moving on land 2. denser skeleton 3. improved lungs 4. more complex circulatory system 5. improved hearing and vision 6. development of mechanisms to prevent water loss Class Amphibia • 4015 Species • Smallest class of living vertebrates i. Ectothermic ii. Many have terretrial adults & aquatic larvae iii. Lungs &/or skin to respire; some use gills iv. 3-chambered heart v. most are oviparous A. Caecilians a. Order gymnophoina b. 163 species B. Salamanders and Newts a. Order Urodela b. 358 species C. Frogs and Toads a. Order Anura b. 3494 species Class Reptilia 1. ectothermic

2. 3. 4. 5.

lungs scales composed of keratin majority have a 3-chambered heart most are oviparous, laying an amniote egg

Reptiles Class Reptilia -6547 Species Turtles and Tortoises -order Chelonia -244 species Lizards -order Squamata -3751 species Worm Lizards -order Squamata -144 species Snakes -order Squamata -2389 species Tuatara -order Rhynochocephalia -1 species Crocodilians -order Crocodylia -22 species Bids (Aves) 1. endothermic 2. adapted for flight a. tapered body (streamlined profile) b. feathers (provide lift) c. hollow bones (reduce weight) d. keeled sternum 3. lungs a. 4-chambered heart b. beak shaped adapted to diet c. oviparous, laying an amniote egg d. parental care for young Mammals 1. 2. 3. 4. 5.

endothermic posses hair & mammary lands 4-chambered heart; RBC’s lack nuclei skin contains sweat & oil glands two sets of teeth

6. 7. 8. 9.

diaphragm ventilates lungs complex brains internal fertilization; most viviparous parental care for young

Mammals are divides into 3 groups: 1. Montremes - lay eggs a. Ex. Duck-billed platypus 2. Marsupials - immature young nurse and develop in a pouch a. Ex. Kangaroos and opossums 3. Placenta Mammals - females carry the young in the uterus with the placental to connect material and fetal circulatory systems Characteristics of Primates 1. well-developed cerebral cortex 2. acute vision (color & binocular) 3. five digits on each limb 4. nails instead of claws 5. “opposable” thumbs