Tunicates “Tail Cords” – over 2,000 species Adults sessile Free swimming larvae; only larvae have a 4 defining characteristics

Lancelets “Head-Cords” tiny marine animals retain all 4 characteristics into adulthood Notochord, pharyngeal slits, dorsal hollow nerve cord, post anal tail led to vertebrates Filter Feeders

5 Classes 1st vertebrates, aquatic Generally characterized by scales, fins and pharyngeal gills Exothermic (Ectothermic) – no internal body temperature regulation

Circulation closed circulatory system with a 2 chambered heart. Reproduction  reproduce through external fertilization - spawning

Jawless Fish Hagfish (Class Myxini) and Lampreys (Cephalaspidomorphi) Lack vertebrae (hagfish) or have incomplete vertebral column (lamprey) Predators that attach to the side of a fish with modified mouth Have no scales

Class Chondrichthyes Cartilage fish Sharks, skate, rays and sawfish Primitive Older fish Most have to swim to breathe

Bony Fish Ray finned fish ( Class Actinopterygii ) - - most common fish - have jaws and paired fins - fins supported by rays fanning our from central bone Lobe finned fish (Class Sarcopterygii) - fins supported by central axis bone - ancestors of amphibians

Walking Fish - Grunion

Class Amphibia Frogs and salemanders Aquatic as larvae, after metamorphosis, live on land as adults. Have moist skin with many glands must be moist to breathe; respirate through skin evolved from fish 360 mya exothermic

Circulation Amphibians have a double-loop circulatory system with three-chambered heart. Reproduction Fertilization is external Shell-less eggs must be laid and fertilized in water

Class Reptilia Include 3 groups: snakes, turtles, crocodiles Fully adapted to life on land  Amniotic egg  scaly skin (prevents loss of moisture)  Exothermic - regulate their body temperatures by basking in the sun, burrowing in the ground. Soaking in water etc…

Circulation more efficient circulatory and respiratory systems (lungs, 3 chambered heart). Reproduction internal fertilization Lay fluid filled amniotic egg covered with a protective shell

Class Aves Most are adapted for flight Covered with feathers hollow bones 2 legs for walking, 2 modified for wings Birds are endothermic - generate body heat internally by their own metabolism.

Circulation 4 chambered heart; allows for efficient delivery of O 2 to cells. Reproduction  internal fertilization.  incubate eggs and feed young  have amniotic eggs (keeps eggs moist)

Fossil evidence shows that birds evolved from the same line as crocodiles and dinosaurs.

Class Mammalia Characteristics: hair - insulation, camouflage, sensory device, waterproofing, signaling and defense mammary glands Endothermic

Circulation  4 Chambered heart  Require a constant supply of nutrients and oxygen to maintain homeostasis and metabolism  Keeping blood separate makes the delivery of nutrients and oxygen more efficient. Reproduction  Internal fertilization

1.Monotremes - young develop in shelled eggs; Ex. spiny anteater and duck-billed platypus 2. Marsupial - young leave mother’s body to pouch before development is complete. Ex. kangaroo and opossum 3. Placental - young develop completely within the uterus of the female Ex. Human, whales, giraffe etc… 3 Types