1. Vertebrates

2. Phylum Chordata 4 basic characteristics:
Notochord – supporting rod dorsally located, below the nerve cord, replaced by vertebral column in most chordates
Nerve cord – anterior portion becomes brain, rest spinal cord
Pharyngeal pouches – only seen during embryonic development, gills in aquatic vertebrates. In humans, 1st pair = auditory tubes, 2nd = tonsils, 3 and 4th pair = thyroid and parathyroid
Postanal tail – in embryo if not in adult

3. Nonvertebrate chordates
Notochord persists in adults
Lancelets
marine, few centimeters long
retain 4 chordate characteristics as adult
Sea squirts (tunicates)
live on ocean floor
squirt water in defense
Retain gills as adult

4. Vertebrates
At some stage in life history, have all four chordate characteristics
Living endoskeleton with vertebral column
Closed circulatory system
Paired appendages
Efficient respiration and excretory
High degree of cephalization

5. Fishes Evolution Jawless – agnathans, lamprey jaws
Cartilaginous – sharks, stingrays
Bony -
Lobe finned – coelacanths, thought to give rise to amphibians
Ray finned – soldier fish, lionfish, seahorse, swordfish

6. Fish Characteristics
Aquatic ectotherms – depend on environment to regulate body temp
Skin covered with scales
Fins for swimming
Single loop cardiovascular pathway, 2 chambered heart
Breath with gills
Lay eggs
Swim bladder seen in bony fish, buoyancy

7. Amphibians Live on both land and water 3 main groups
Salamanders and newts –elongated bodies, long tails
Frogs and toads - tailless
Caecilians – legless, sometimes sightless, worm shaped

8. Amphibian characteristics
Usually tetrapod – 4 legged
Usually lungs in adults
Metamorphosis
Smooth and moist skin
3 chambered heart
Ectothermy
Most lay eggs in water

9. Reptiles Amniotic egg evolves
Extraembryonic membranes – protect the embryo, remove nitrogenous wastes and provide the embryo with oxygen, food and water
Crocodiles and alligators, turtles, lizards, snakes, amphisbaenians (worm lizards) and tuataras

10. Reptile characteristics
Usually tetrapods
Lungs with expandable rib cage
Leathery-sheled amniotic egg – allows for movement to land
Dry, scaly skin that is impermeable to water
Ectotherms – can lay in sun to maintain a warm body temperature

11. Birds - Aves Some fly, some do not
Usually classified according to beak and foot type
Efficient nervous, respiratory, and circulatory systems.

12. Bird characteristics Feathers Hard shelled amniotic egg
4 chambered heart
Usually wings for flying
Air sac
endothermy

13. Mammals - development
Monotremes – mammals have a cloaca and lay hard shelled amniote eggs
Duckbill platypus and spiny anteater
Marsupials – begin development inside the female body and born in a very immature condition, move to pouch and attach to nipple
Kangaroo, koala, wombat
Placental mammals – Eutherians - dependent on the placenta (organ of exchange between maternal blood and fetal blood)
Long dependency on the parents

14. Mammal characteristics
Body hair
Differentiated teeth
Well-developed brain
Usually live births and newborn dependency
Mammary glands
Endothermy
Internal development