6. Chapter 3A-Fishes(1).ppt - Chapter 3 Diversity and...

This preview shows page 1 - 17 out of 72 pages.

Chapter 3 Diversity and History of the Craniates Part 1: Fishes Diversity of clownfish in New Guinea (left); Diversity of sharks (right).
Deuterostomia Pterobranchia Echinodermata Hemichordata (Enteropneusta) Chordata Urochordata Cephalochordata Craniata (Vertebrates + hagfish)
Craniata Contains ~50,000 living species Phylogenetic relationships among craniates help organize comparative vertebrate anatomy Series of nested subgroups (clades) allows us to study hierarchical patterns of anatomy
Craniate phylogeny and diversity of extant species Fig. 3.1
Vertebrata includes all living craniates except Myxiniformes (hagfishes) Gnathostomata (“jawed” fish) = all living vertebrates except Petromyzontiformes (lampreys) Osteichthyes (bony fish) = all living Gnathostomes except Chondrichthyes (sharks + rays) Sarcopterygii (“fleshy fins”) = all living Osteichthyans except Actinopterygii Rhipidistia = all living Sarcopterygians except Actinistia (Coelocanths) Tetrapoda = all living Rhipidistians except Dipnoi (lungfishes)
Tetrapoda = all living Rhipidistians except Dipnoi Amniota = all living tetrapods except Lissamphibia (frogs and salamanders) Sauropsida = all living amniotes except Mammalia Diapsida = all living sauropsids except Testudines Archosauria = all living diapsids except Lepidosauria Aves = all living archosaurs except Crocodilia Theria = all living mammals except Monotremata Eutheria = all living therians except Metatheria
Craniates = All vertebrates plus the hagfish Cephalized Braincase of cartilage or bone Vertebral column of many vertebrae (stronger than notochord; allows larger animals to swim)
Craniates = All vertebrates plus the hagfish Neural crest (neural crest cells perform many functions; see p. 43) Neurogenic placodes (form neurons and sensory cells)
Craniates cont’d. Complex sense organs Cranial nerves Tripartite brain Complex endocrine system Muscular gut; differentiated digestive system Respiratory gills Heart Hemoglobin
What is a vertebrate? Phylogeny showing the relationship between living members of the Phylum Chordata (in bold, at top), plus the Cambrian fossils Myllokunmingia (12) (a craniate) and
Haikouella (30) (a basal chordate) Shimeld S M, Holland P W H PNAS 2000;97:4449-4452 ©2000 by The National Academy of Sciences
Vertebrate Origins and the Agnathans Agnathans = “jawless fishes”:
Vertebrate Origins and the Agnathans Agnathans = “jawless fishes”: Ostracoderms* Hagfish Lampreys * = extinct
Fossil and Recent Agnathans
Vertebrate Origins and the Agnathans Agnathans = “jawless fishes”: Some of the oldest known vertebrates are the “Ostracoderms” (~500 mya) Armored, jawless fish (over 200 species) Massive head shield Small (most less than 30 cm in length)
Ostracoderms (“Shell skin”) Bony dermal armor, typically covering head Some advanced forms had paired appendages, many didn’t Filter feeders Used muscular gill pouches to suck in prey, a development that previous organisms did not have All extinct
Ostracaderms (extinct armored, jawless fish) Fig. 3.3

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture