1. Vertebrate Animals Chapter 17b
Characteristics of Phylum Chordata
Major Evolutionary Novelties in the Chordates/Vertebrates
Fishes
Jawless Fish (Class Agnatha)
Cartilaginous Fish (Class Chondricthyes)
Bony Fish (Class Osteichthyes)
Amphibians (Class Amphibia)
Reptiles (Class Reptilia)
Birds (Class Aves)
Mammals (Class Mammalia)
Primate Evolution (Order Primata)

2. Chordates (Vertebrates) Are All In One Phylum
Figure 17.6

3. Survey of Living Things Grid

4. The Vertebrate Genealogy
Vertebrates
Are represented by mammals, reptiles, amphibians, and fishes.
Have unique features, including the cranium and backbone.

5. Nearly All Chordates are Vertebrates with a Skull and Spinal Vertebrae
Figure 17.29

6. Characteristics of All Chordates At Some Point During Their Lifetimes
Figure 17.30

7. Evolutionary Novelties/Landmarks of Phylum Chordata
Development of hinged jaws
Bony (calcium phosphate) skeleton instead of cartilaginous skeleton
Terrestrial Adaptations
Internal lungs instead of external gills
Four legs for walking on land
Amniotic egg to avoid dehydration of embryo
Endothermy instead of ectothermy
Feathers or fur to maintain constant body temp.

8. Evolutionary Tree of the Chordates
Figure 17.32

9. Jawless Fish (Class Agnatha)
The first vertebrates probably evolved about 542 million years ago.
Cylindrical and elongated like eels
Retention of all 7 gill slits as adults, breathes using gills
No paired fins
Mouth is locked in a circular sucker-shape (no jaws)
Skeleton made of cartilage
Parasitic on other fish
Includes the lampreys and hagfish

10. Evolutionary Tree of the Chordates
Figure 17.32

11. Cartilaginous Fish (Class Chondrichthyes)
True hinged jaws
Predatory or filter feeding carnivores
Skeleton of cartilage
5-7 gills slits (slightly fewer than agnathans)
Paired pectoral fins used for steering
Heterocercal (asymmetrical) tail
Mouth behind nose on ventral surface
Lateral line system of pores that detect water currents and vibrations
Placoid scales (skin feels like sandpaper) migrate anteriorly into mouth
Includes the sharks, skates, and rays
Skate
Manta Ray
Shark Eating a Seal

12. Evolutionary Tree of the Chordates
Figure 17.32

13. Bony Fish (Class Osteichthyes)
Bony skeleton reinforced by hard calcium salts
Flexible paired pectoral and pelvic fins
Homocercal (symmetrical) tail
Single gill slit covered by operculum (gill cover)
Swim bladder to maintain buoyancy (forerunner of a lung?)
Terminal mouth (at very end)
Rounded scales (ctenoid or cycloid)
Lateral line sensing system, keen sense of smell and good eyesight
Clownfish and Anemone

14. Transition To Land and the Development of Legs
Figure 17.35

15. Evolutionary Tree of the Chordates
Figure 17.32

16. Amphibians (Class Amphibia)
A mixture of aquatic and terrestrial adaptations
Semi-functional lungs to extract oxygen out of air
Wet, slimy skin for diffusion of oxygen from air
Four legs (a tetrapod) but relatively weak pectoral and pelvic girdles
Metamorphosis from legless, vegetarian with tail to four-legged, carnivorous adult
Usually needs water for reproduction to and to keep growing embryos hydrated
Includes frogs, toads, newts, and salamanders

17. Evolutionary Tree of the Chordates
Figure 17.32

18. Reptiles (Class Reptilia)
Dry, scaly skin to prevent water loss
Stronger pelvic and pectoral girdles to facilitate walking
Fully-functional lungs
Internal fertilization (no need for water to reproduce)
Amniotic egg to keep growing embryo wet
Ectothermic, as with previous vertebrates
Most have bony teeth for carnivorous diet
Includes snakes, lizards, turtles, crocodiles, and alligators
Snake Ritual Wrestling
Galápagos Tortoise

19. Age of Reptiles: Mesozoic
Dinosaurs included the largest animals ever to live on land.

20. Evolutionary Tree of the Chordates
Figure 17.32

21. Birds (Class Aves)
Birds evolved from a lineage of small, two-legged dinosaurs
Hollow, air-filled bones to reduce weight
Horny beak replaces teeth to reduce weight
Feathers for flight and staying warm (evolved from scales)
Scaly feet are remnants of reptilian ancestry
Highly efficient, specialized lungs
Endothermic (maintain constant internal body temp.)
Hard-shelled calcium eggs
Greatly enlarged sternum to anchor flight muscles

22. Bird wings Are Airfoils Giving Them Lift When They Fly Forward
Flapping Geese
Soaring Hawk
Swans Taking Flight

23. Evolutionary Tree of the Chordates
Figure 17.32

24. Vertebrate Animals Chapter 17b
Characteristics of Phylum Chordata
Major Evolutionary Novelties in the Chordates/Vertebrates
Fishes
Jawless Fish (Class Agnatha)
Cartilaginous Fish (Class Chondricthyes)
Bony Fish (Class Osteichthyes)
Amphibians (Class Amphibia)
Reptiles (Class Reptilia)
Birds (Class Aves)
Mammals (Class Mammalia)
Primate Evolution (Order Primata)

25. Mammals (Class Mammalia)
Arose about 200 million years ago and were probably small, nocturnal insect-eaters.
Most mammals are terrestrial
Fur or hair (endothermic)
Nearly all give birth to live young (no egg-laying)
Suckle the young with breast milk from mammary glands
Most have special filtration organ in uterus called a placenta

26. Class Mammalia, Order Primata
Early primates were arboreal insectivores
Opposable thumbs
Stereoscopic vision
Limber shoulder joints
Eyes in front of the face
Excellent eye-hand coordination
Extensive parental care

27. Evolution of Order Primata
Figure 17.41

28. Order Primata, The Old World and New World Monkeys
Figure 17.42c

29. Order Primata: The Apes or Hominids
Chimp Agonistic Behavior
Chimp Cracking Nut
Gibbons Brachiating

30. Vertebrate Animals Chapter 17b
Characteristics of Phylum Chordata
Major Evolutionary Novelties in the Chordates/Vertebrates
Fishes
Jawless Fish (Class Agnatha)
Cartilaginous Fish (Class Chondricthyes)
Bony Fish (Class Osteichthyes)
Amphibians (Class Amphibia)
Reptiles (Class Reptilia)
Birds (Class Aves)
Mammals (Class Mammalia)
Primate Evolution (Order Primata)