Vertebrates Pre-reading Assignment PDF

Chptr 11 34 THE ORIGIN AND EVOLUTION OF VERTEBRATES Pre-reading assignment What are gnathostomes? What does oviparous mean? How is the cloaca different from an anus? Are Caecilians snakes? Give reasons for your answer Where does the term “mammals” come from? DIFFERENCES BETWEEN CHORDATES...

Chptr 11 34 THE ORIGIN AND EVOLUTION OF VERTEBRATES Pre-reading assignment What are gnathostomes? What does oviparous mean? How is the cloaca different from an anus? Are Caecilians snakes? Give reasons for your answer Where does the term “mammals” come from? DIFFERENCES BETWEEN CHORDATES AND ECHINODERMS CHORDATES ECHINODERMS Bilateral symmetry Adults pentaradial True endoskeleton to Calcareous plates which muscles are embedded in skin to attached which muscles are attached Locomotion by muscles Locomotion by tube attached to bones feet Nerve cord, notochord, Not present pharyngeal gill slits, post anal tail Phylogeny of living chordates Echinodermata ANCESTRAL Cephalochordata Chordates DEUTEROSTOME Urochordata Notochord Myxini Vertebrates Cyclostomes Common ancestor of chordates Petromyzontida Vertebrae Chondrichthyes Gnathostomes Actinopterygii Osteichthyans Jaws, mineralized skeleton Actinistia Lobe-fins Lungs or lung derivatives Dipnoi Lobed fins Amphibia Tetrapods Reptilia Amniotes Limbs with digits Amniotic egg Mammalia Milk © 2017 Pearson Education, Inc.  Eumetazoa, Bilateria, Triploblastic, Coelomate, PHY CHORDATA Eucoelomate, Deuterostomes Notochord Dorsal, hollow nerve cord Muscle segments Mouth Anus Post-anal tail Pharyngeal slits or clefts © 2017 Pearson Education, Inc.  PHY CHORDATES SUB PHY SUB PHY SUB PHY UROCHORDATA CEPHALOCHORDATA VERTEBRATA Notochord retained Notochord retained Notochord become in adult; seen only in in adult; extends vertebral column tail region from head to tail in adult The lancelet Branchiostoma, a cephalochordate 1 cm Cirri Mouth Notochord Pharyngeal slits Dorsal, hollow nerve cord Atrium Digestive tract Atriopore Segmental muscles Anus Tail © 2017 Pearson Education, Inc. A tunicate- Sub Phy Urochordata Incurrent Water flow siphon Notochord to mouth Excurrent Dorsal, hollow siphon nerve cord Tail Excurrent Excurrent siphon siphon Atrium Muscle Incurrent segments siphon Pharynx Intestine with numerous Anus Stomach slits Intestine Atrium Tunic Esophagus Pharynx with slits Stomach (a) A tunicate larva (b) An adult tunicate (c) An adult tunicate © 2017 Pearson Education, Inc. Evolution of Vertebrates VERTEBRATES MAJOR CHARACTERISTICS OF VERTEBRATES 2. HEAD WITH BRAIN 1.VERTEBRAL COLUMN 3. HEART POWERED CLOSED CIRCULATORY SYSTEM EVOLUTION OF THE JAW 1st vertebrates were jawless fish (Extant classes: Myxini and Cephalaspidomorphi) Jawed fish evolved from the jawless fish FISHES 1. Vertebral column 2. Jaws and paired appendages 5 classes 3. Internal gills Cl Myxini 4. Efficient blood circulation Cl Petromyzontida (Cephalaspidomorp hi) Cl Chondrichthyes Cl Actinopterygii Cl Actinistia (Sarcopterygii) Cl Dipnoi HAGFISH Cl: Myxini LAMPREY Cl: Petromyzontida Slime glands © 2017 Pearson Education, Inc. Cl: CHONDRICHTHYES Improved jaws Cartilaginous skeleton Stream lined body Teeth Lateral line sense organs OSTEICHTHYES CL ACTINOPTERYGII CL SARCOPTERYGII CL: Ray-finned fishes Lobe-finned fishes ACTINISTIA Fin has parallel thin bony rays. No muscle Fin has a long muscular lobe supported by bones Cannot move fins independently of one Can move fins independently of one another another so can “walk” EG: COELACANTH S AND LUNG FISH EVOLUTION OF AMPHIBIANS: Discovery of a “fishapod”: Tiktaalik Shoulder bones Ribs Neck Scales Head Eyes on top of skull Humerus Flat skull “Wrist” Elbow Ulna Radius Fin Fin skeleton Fish Tetrapod Characters Characters Scales Neck Fins Ribs Gills and lungs Fin skeleton Flat skull Eyes on top of skull © 2017 Pearson Education, Inc. COMMON CHARACTERISTICS OF AMPHIBIANS Legs Lungs Cutaneous respiration Pulmonary veins present Divided heart and two circuits (pulmonary and systemic) Frogs and toads Salamanders Caecilians Smooth, moist skin Smooth, moist skin Smooth, moist skin or dry skin Long hind legs 4 legs No legs No tail Long tail Small or absent tail Teeth present Teeth present Teeth present Ext. fertilization Int. fertilization Int. fertilization Tadpole larva Axolotl larva Most are viviparous Common characteristics of Reptiles 1. Dry skin 2. Thoracic breathing 3. Amniotic egg 4. Internal fertilization 5. More efficient circulatory system  Extraembryonic membranes Allantois Chorion The amniotic egg Embryo Amniotic cavity with amniotic fluid Yolk (nutrients) Albumen Shell Amnion Yolk sac Extraembryonic membranes © 2017 Pearson Education, Inc. CL: AVES Archaeopteryx. Closely related to its ancestors among the bipedal dinosaurs, the crow-sized Archaeopteryx lived in the forests of central Europe 150 MYA. MISSING LINK BETWEEN REPTILES AND BIRDS CAUDIPTERYX MISSING LINK BETWEEN DINOSAURS AND COMMON CHARACTERISTICS OF BIRDS Feathers Skeleton Air sacs Efficient circulation SHAFT VANE Endothermy BARBS BARBUL ES COMMON CHARACTERISTICS OF MAMMALS Hair Mammary glands Endothermy Efficient circulation Efficient respiration Placenta Specialized teeth Hooves and horns FLYING MAMMALS: BATS