Lecture 5- Chordate Evolution & Vertebrate Anatomy (Fall 2024) PDF

LECTURE 5: Chordate Evolution & Vertebrate Anatomy From Chapters 4, p. 66-79 from Dinosaurs (4th Ed.) Tiktaalik by Tyler Keillor LECTURE 5: Chordate Evolution & Vertebrate Anatomy From Chapters 4, p. 66-79 from Dinosa...

LECTURE 5: Chordate Evolution & Vertebrate Anatomy From Chapters 4, p. 66-79 from Dinosaurs (4th Ed.) Tiktaalik by Tyler Keillor LECTURE 5: Chordate Evolution & Vertebrate Anatomy From Chapters 4, p. 66-79 from Dinosaurs (4th Ed.) Lecture Outline Part 1: Chordate evolution to Diapsida Part 2: Vertebrate Anatomy LECTURE 5: Chordate Evolution & Vertebrate Anatomy From Chapters 4, p. 66-79 from Dinosaurs (4th Ed.) Objectives Know & understand the defining features of the major clades of Chordata Know & understand the anatomy of the vertebrate skeleton  The cladogram tells the story Life is monophyletic united by the unique possession of DNA), RNA, cell membranes, and all kinds of chemical pathways Skipping ~3.7 Ga (billion years!) to 510 Ma we meet the oldest clade, Chordata Fig. 4.3  Chordata (1) Chordata Diagnostic Characters: Pharyngeal gill slits Notochord Fig. 4.3 Nerve cord urgess Shale, BC Pikaia graciens. ~510 MA , Middle Cambrian, Burgess Shale Fig. 4.1  Chordata (1) Chordata Diagnostic Characters: Pharyngeal gill slits Notochord Fig. 4.3 Nerve cord Univ. of Hawaii Generalized chordate anatomy  Urochordata Primate chordates: Urochordata Cephalochordata Fig. 4.3 Fig. 4.1 Fig. 4.2 A. Amphioxus. B. Ciona (sea squirt). C. Ciona  Cephalochordata Primate chordates: Urochordata Cephalochordata Fig. 4.3 Fig. 4.1 Fig. 4.2 A. Amphioxus. B. Ciona (sea squirt). C. Ciona la  Cephalochordata Primate chordates: Cephalochordata Muscle segmentation Upper & lower nerve & blo vessel branches Hormone & enzyme system Fig. 4.3 Amphioxous OpenEd CUNY  Vertebrata (3) Vertebrata bone organized into elements neural crest cells diff. of cranial nerves Fig. 4.3 eyes, kidneys, new hormonal systems mouthparts  Vertebrata: Agnatha Agnatha Agnatha Primitive jawless fish that first appeared in the Cambrian and were common in the early Paleozoic Fig. 4.3 Sister group to all vertebrates with jaws (Gnathostomata) Extinct groups include conodonts and ostracoderms Living agnathans are Register/Getty Images Arsty | Dreamstime.com the lampreys and Hagfish Lamprey hagfish Creative Commons  Vertebrata: Agnatha Agnatha Cephalaspis – an ostracoderm bony- armored, jawless fish (mid Silurian to Late Devonian) Fig. 4.3 Creative Commons  Gnathostomata (4) Gnathostomata are vertebrates with true jaws Fig. 4.3 Live Science BB Creative Commons C  How Did Jaws Evolve? tebrates are derived from modifications of the anterior gill arches of jaw Image: MacMillianHIgherLearning.com  Chondrichthyes Chrondrichthyes Cartilaginous fish (sharks and chimaeras) Evolved from primitive acanthodians (extinct group of jawed fish) Earliest unequivocal Fig. 4.3 fossils are Silurian (430 Ma). Creative Commons Acanthodes, an acanthodian from the Carboniferous Creative Commons  Vertebrate Skeleton Composition Lampreys and hagfishes (Agnatha) lack mineralized tissues Cartilaginous fishes produce extensive Credit: BluePlanetArchive / Michael Patrick O'Neill dermal bone such as teeth, dermal denticles and fin spines Only Osteichthyes (bony vertebrates) make Credit: RenderHub.com endochondral bone (cartilage replaced by Great White Shark bone)  Osteichthyes (5) Osteichthyes “bony fishes” bony endochondral skeleton First appear in the Late Silurian Fig. 4.3 Osteichthyes = Actinopterygii + Sarcopterygii All gnathostomes more derived than Chondrichthyes Actinoptergyii Osteichthyes You are a member of Creative Commons Osteichthyes Sarcopterygii Creative Commons Timeline of key features in vertebrate evolution  Osteichthyes: Actinopterygii Actinopterygii Ray finned fishes Fins are supported by th spines of bone 99% of the >30,000 fish Creative Commons Fig. 4.3 Creative Commons mages: Creative Commons Understanding Evolution  Sarcopterygii (8) Sarcopterygii “Lobe-finned fishes” Distinctive boney elements 1st appear in pectoral & pelvic fins Image:Collins Coelacanth ulna Fig. 4.3 radius Image: Live Science Understanding Evolution Understanding Evolution Sarcopterygii: Transition from Water to Land  Sarcopterygii: Transition from Water to Land scapula Homologous bones indicated in colour humerus ulna radius Fig. 4.4 Eusthenopteron Tiktaalik Early Tetrapod Sarcopterygii Tetrapoda Are you a fish? Read Box 4.1, page 70 Early tetrapods: Tiktaalik & the Transition from Water to Land Image:NSF Tiktaali  k Late Devonian (~375 Ma); discovered in Nunavut, 2004  Lived in oxygen-poor, shallow-water habitats  Transitional fossil with a mixture of both fish and tetrapod characteristics Fish-like: gills & scales “Fishapod”: half-fish, half-tetrapod limb bones and joints; functional Early tetrapods: Qikiqtania – back to the water! Qikiqtania  Late Devonian (~385 Ma); slightly older than Tiktaalik; discovered close to Tiktaalik quarry Tiktaalik  Jaws with teeth, designed to suck in & hold prey Qikiqtania  Very similar to Tiktaalik, except its limbs appear to be secondary adapted from land to back to water!  Humerus shows adaptations for Tiktaalik supporting body weight, but it has lost the necessary processes for muscle attachment A new elpistostegalian sites from the Late Devonian of the Canadian Arctic. Nature, July 20, 2022; DOI: 10.1038/s41586-022-04990-w  Tetrapoda (9) Tetrapoda Four limbs capable of supporting body weight for mobility on land Fig. 4.3 Understanding Evolution Understanding Evolution Vertebrate Anatomy Velociraptor by Dr. Scott Hartman  Vertebrate Anatomy SKULL Velociraptor by Dr. Scott Hartman  Vertebrate Anatomy SKULL MANDIBLE (lower jaw) Velociraptor by Dr. Scott Hartman  Vertebrate Anatomy Cranial (skull) Post-cranial (body) Velociraptor by Dr. Scott Hartman Anatomical Terms of Orientation Axial: of the midline or the vertebral skelet Appendicular: of the limbs Image: Medicina Genérica  PECTORAL GIRDLE: Pectoral Gridle Clavicle Scapula, Coracoid, Scapula Coracoid Clavicle (‘wishbone’; not visible)  Pelvic Gridle PECTORAL GIRDLE: Scapula, Coracoid, Clavicle Ilium Ischium Pubis  The Vertebrate Skeleton Fig. 4.5 Plateosaurus, Late Triassic, Europe, Greenland & NA  Cranium = bones surrounding the brain Fig. 4.5 Plateosaurus, Late Triassic, Europe, Greenland & NA  Pluralization of Anatomical Terms Astragalus Astragali CalcaneumCalcanei Centrum Centra Dentary Dentaries Fenestra Fenestrae Femur Femora Fibula Fibulae Humerus Humeri Ilium Ilia Ischium Ischia Maxilla Maxillae Phalanx Phalanges Premaxilla Premaxillae Pubis Pubes Radius Radii Sacrum Sacra Scapula Scapulae Ulna Ulnae Vertebra Vertebrae https://www.skeletaldrawing.com/anatomy  TETRAPODA (1) Tetrapoda Four limbs capable of supporting body weight f mobility on land Fig. 4.7 https://www.artstation.com/artwork/6eQGN  Amniota (3) Amniota Amniote egg with amnion, a membrane that blocks moisture loss, but allows gasses to diffuse. Eggs could thus be laid on land without water loss Land colonization Fig. 4.7 Fig. 4.8  Synapsida (2) Synapsida Lower temporal fenestra on Includes Mammalia Fig. 4.7 Fig. 4.8  Synapsida Synapsida (stem mammals) Amniota Diapsida (including Sauropsida) Synapsids have been historically called “mammal-like reptiles, but they are outside of Reptilia. Sauropsids include non-synapsid amniotes for the purposes of this course. Earliest fossils from the Pennsylvanian; common in the Early Permian; up to 6m in length. Pelycosaur-like synapsids (e.g., Dimetrodon) replaced by more advanced Therapsida in mid-Permian.  Synapsida Only the therapsid dicynodonts and eutheriodonts (Therocephalia + Cynodontia) survived into the Triassic period. Only the cynodont group Probainognathia (includes mammals) survives beyond the Triassic. In mammalian evolution the bones of the lower jaw are reduced to only the dentary. The articular & quadrate form the inner ear bones of modern mammals rinaxodon, a cynodont from the Early Triassic of South Africa UC Berkeley By Nobu Tamura CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=19459918  Diapsida (4) Diapsida lower & upper temporal fenestrae Fig. 4.7 Fig. Fig. 4.8 4.9  Anapsida Anapsida (Chelonia = Anapsida turtles) No temporal fenestrae The ancestral vertebrate skull was likely anaspid & is seen in many early quadrupeds Turtles are likely highly derived diapsids that have lost the temporal Fig. 4.7 skull openings For more info on turtle evolution watch the video: Fig. 4.9 ‘How the Turtle Got Its Shell’  Lepidosauromorpha Lepidosauromorpha includes living lizards, snakes tuataras Fig. 4.7 Tuatara (Sphenodon punctatus) is endemic to New Z Only surviving member of the Order Rhynchocephal Fig. 4.8  What Is A Reptile? Reptilia? Reptilia? Reptilia? Fig. 4.7 Image: Sierra Club Books for Children Fig. 4.8  What Is A Reptile? Read Box 4.2, p. 78 Fig. B4.2.1 Reptilia (reptere – to crawl); originally defined as scaly, four-legged critters that crawl Reptilia is defined based on relationships, not characters (it has no diagnostic characters) Next Lecture: Archosauromorpha to The Earliest Dinosaurs