1. What is the difference between an invertebrate and a vertebrate animal?

2. Invertebrates do not have a backbone
Examples: jellyfish, earthworm, grasshopper, butterfly, octopus, crab

3. Vertebrates are chordates
Characteristics of chordates (all present at some point during development)
Notochord – flexible, supporting structure. The notochord becomes the backbone in vertebrate chordates.
Dorsal hollow nerve cord (spinal cord)
Post-anal tail – a tail that is posterior to the anus
Pharyngeal pouches (gill slits)

4. A Cladogram of Chordates
Nonvertebrate chordates
Jawless fishes
Cartilaginous fishes
Bony fishes
Amphibians
Reptiles
Birds
Mammals

5. Evolutionary Patterns
Adaptive radiation or divergent evolution – evolutionary lines become less similar
Convergent evolution – unrelated organisms become more similar

6. Body Temperature Control
Ectotherms obtain heat from the environment and rely on behavior to regulate body temperature (fish, amphibian, reptile)
Endotherms generate heat through metabolic activity and rely on physiological mechanisms to regulate body temperature (birds, mammals)
Body Temperature (°C)
Environmental Temperature (°C)

7. Trends in Vertebrate Evolution
As you move from fish to mammals, organ systems become more complex
The heads of vertebrates show many adaptations for feeding (mouthparts, snouts and tongues)

8. Digestive Systems of Vertebrates
Shark
Salamander
Lizard
Pigeon
Cow
Esophagus
Stomach
Intestine
Liver
Gallbladder
Pancreas
Cloaca
Crop
Gizzard
Cecum
Rectum

9. Respiratory Systems of Vertebrates
Nostrils, mouth, and throat
Trachea
Lung
Air sac
Salamander
Lizard
Primate
Pigeon

10. Single-Loop Circulatory System Double-Loop Circulatory System
Circulatory Systems of Vertebrates
Single-Loop Circulatory System
Double-Loop Circulatory System
FISHES
MOST REPTILES
BIRDS & MAMMALS

14. Domestic pigeon Right atrium Left atrium Right ventricle
Left ventricle
Heart
Complete division

15. Section 32-1 Left atrium Right atrium Left ventricle Right ventricle
Complete division

16. Excretory Systems
Fish and aquatic amphibians excrete ammonia through gills
Birds and reptiles excrete uric acid through kidneys
Mammals, land amphibians and cartilaginous fish excrete urea through kidneys

17. Nervous system
The complexity of the cerebrum and cerebellum increases from fish to mammals

18. Movement
Fish, snakes and salamanders move by wiggling side to side; limbs stick out to side

19. Movement
Reptiles (lizards, crocodiles) have limbs bent under body, movement still side to side
Mammals and birds have limbs directly under body; movement involves the backbone flexing up and down

20. Reproduction
Sexual
Fertilization is external in water for fish and amphibians
Fertilization is internal on land for reptiles, birds and mammals
Development of the egg is related to the habitat (oviparous, ovoviviparous or viviparous)