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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) Slide 2 Figure 17.6 Chordates (Vertebrates) Are All In One Phylum Slide 3 Survey of Living Things Grid Slide 4 The Vertebrate Genealogy Vertebrates Are represented by mammals, reptiles, amphibians, and fishes. Have unique features, including the cranium and backbone. Slide 5 Figure 17.29 Nearly All Chordates are Vertebrates with a Skull and Spinal Vertebrae Slide 6 Figure 17.30 Characteristics of All Chordates At Some Point During Their Lifetimes Slide 7 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. Evolutionary Novelties/Landmarks of Phylum Chordata Slide 8 Figure 17.32 Evolutionary Tree of the Chordates Slide 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 Slide 10 Figure 17.32 Evolutionary Tree of the Chordates Slide 11 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 Cartilaginous Fish (Class Chondrichthyes) Skate 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 Shark Eating a Seal Manta Ray Slide 12 Figure 17.32 Evolutionary Tree of the Chordates Slide 13 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 Bony Fish (Class Osteichthyes) Slide 14 Figure 17.35 Transition To Land and the Development of Legs Slide 15 Figure 17.32 Evolutionary Tree of the Chordates Slide 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 Slide 17 Figure 17.32 Evolutionary Tree of the Chordates Slide 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 Galpagos Tortoise Snake Ritual Wrestling Slide 19 Dinosaurs included the largest animals ever to live on land. Age of Reptiles: Mesozoic Slide 20 Figure 17.32 Evolutionary Tree of the Chordates Slide 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 Slide 22 Swans Taking Flight Soaring Hawk Flapping Geese Bird wings Are Airfoils Giving Them Lift When They Fly Forward Slide 23 Figure 17.32 Evolutionary Tree of the Chordates Slide 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) Slide 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 Slide 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 Slide 27 Figure 17.41 Evolution of Order Primata Slide 28 Figure 17.42c Order Primata, The Old World and New World Monkeys Slide 29 Gibbons Brachiating Chimp Cracking Nut Chimp Agonistic Behavior Order Primata: The Apes or Hominids Slide 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)