Figure 33.25a Free-living nematode

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1 Figure 33.25a Free-living nematode Bilateraly symmetrical Pseudocoelomates Body covered with secreated, flexible cuticle. No cilia Only longitudinal muscles. No protonephridia Muscular pharynx Gonochoristic

2 Caenorhabditis elegans

3 Structure of cuticle

8 Free-living marine Soil nematode Endoparasite Predator detritivore

9 Lymphatic Filariasis or Elephantiasis Anopheles sp. 120 million people in 73 countries in the tropics.

10 Filariasis Wuchereria bancrofti -a filarid

14 Figure 32.7 A comparison of early development in protostomes and deuterostomes

15 Asteroidea Ophiuroidea Crinoidea Echinoidea Holothuroidea P. 673

16 Figure Anatomy of a sea star Pentaradial Symmetry Exoskeleton of calcareous ossicles Water vascular system Ciliated peritoneum lines the coelom

17 Asteroid water-vascular system Tubular outpocketings of body wall System opens to exterior through madreporite Tiedemann s bodies connect water vascular system to coelom Muscular contraction of ampulla forces water into podium

18 Fast and agile Arms composed of vertebral ossicles Podia reduced Ophiuroids

19 Relationships of Chordate Subphyla : Origin of Vertebrates UROCHORDATES CEPHALOCHORDATES VERTEBRATES Greatly expanded pharynx Reduction of nervous system Sessile Anteriorly extended notochord Oral cirri (tentacles) Burrowing Distinct head & brain (cephalization) Muscularization of pharynx Special paired sensory organs (eyes, nose, ears) Neural crest tissue & neurogenetic placodes in embryo Somites; segmented trunk muscles Axial skeleton & postanal tail retained in adult Notochord Dorsal, hollow nerve cord Pharyngeal slits Postanal tail

20 Postanal Tail Segmentation of Trunk Muscles Cephalochordate Notochord Mechanics Myotomes Hydostatic Skeletal Structure Notochord replaced by vertebral column

Extended notochord Cephalochordates: Structure, Function, Lifestyle Muscularized Notochord Atrium Text Fig. 34.

21 Extended notochord Cephalochordates: Structure, Function, Lifestyle Muscularized Notochord Atrium Text Fig Specialized Features Anteriorly extended notochord Muscularized notochord Specialized nephridia (solenocytes) Relatively inactive burrowers (as adults)

22 Relationships of Chordate Subphyla : Origin of Vertebrates UROCHORDATES CEPHALOCHORDATES VERTEBRATES Greatly expanded pharynx Reduction of nervous system Sessile Anteriorly extended notochord Oral cirri (tentacles) Burrowing Distinct head & brain (cephalization) Muscularization of pharynx Special paired sensory organs (eyes, nose, ears) Neural crest tissue & neurogenetic placodes in embryo Development of New Head Somites; segmented trunk muscles Notochord & postanal tail retained in adult Notochord Dorsal, hollow nerve cord Pharyngeal slits Postanal tail

23 Neural Crest Tissue & Neurogenic Placodes Key Innovation in Vertebrate History Text Fig. 34-6

24 Gill Ventilation

25 Feeding Strategies & Vertebrate Evolution Large Prey Now Possible Become Dominant Predators Neural crest structures Suction feeding Muscularized Pharynx & Supportive Skeleton Suction Feeding Begins Ciliary Driven Food Restricted to Zooplankton

26 Figure Hox mutations and the origin of vertebrates 520 mya 425 mya

27 Relationships Among The Classes of Fishes MYXINI CEPHALASPIDOMORPHA PLACODERMI CHONDRICTHYES OSTEICHTHYES LAMPREYS OSTRACODERMS Oral tentacles Slime glands Scavenging lifestyle Loss of bone Parasitic lifestyle Extensive bony armor Extensive, jointed armor Loss of bone Distinctive tooth-like scales Gills slits exposed externally Gills covered by bony operculum Tendency for tail to become symmetrical Lungs or swim bladder Bony internal skeleton Vertebral column Circular sucking mouth Jaws Paired appendages Lateral line sensory system Bone (dermal) Basic Ancestral Vertebrate Features

LAMPREYS Lateral line Common Ancestor in Cambrian

28 Myxini AGNATHAN FISHES No jaws No true paired appendages No vertebrae Cephalaspidomorpha HAGFISH LAMPREYS Lateral line Common Ancestor in Cambrian OSTRACODERMS mya Bony armor (calcium phosphate) Not homologous

29 Feeding Strategies in Jawless Fishes Feeding tactics of Lamprey Knotting behavior in Hagfish Keratinaceous teeth

30 Lateral line - line of mechanoreceptors on body surface that detect movement of water.

31 Relationships Among The Classes of Fishes MYXINI CEPHALASPIDOMORPHA PLACODERMI CHONDRICTHYES OSTEICHTHYES LAMPREYS OSTRACODERMS Oral tentacles Slime glands Scavenging lifestyle Loss of bone Parasitic lifestyle Extensive bony armor Extensive, jointed armor Loss of bone Distinctive tooth-like scales Gill slits exposed externally Gills covered by bony operculum Tendency for tail to become symmetrical Lungs or swim bladder AGNATHA = Jawless Fishes Bony internal skeleton Vertebral column Circular sucking mouth Jaws Paired appendages Lateral line sensory system Key Sensory System Bone (dermal) Unique Skeletal Material Basic Ancestral Vertebrate Features

32 Evolution of Jaws Text Fig

33 PLACODERMS Jaws Paired appendages Persistent notochord Great size range Jointed armor First fresh water fishes

34 Dunkleosteus 370 mya

35 Relationships Among The Classes of Fishes MYXINI CEPHALASPIDOMORPHA PLACODERMI CHONDRICTHYES OSTEICHTHYES LAMPREYS OSTRACODERMS Oral tentacles Slime glands Scavenging lifestyle Loss of bone Parasitic lifestyle Extensive bony armor Extensive, jointed armor Loss of bone Distinctive tooth-like scales Gills covered by bony operculum Tendency for tail to become symmetrical Lungs or swim bladder Bony internal skeleton Vertebral column Circular sucking mouth Jaws Paired appendages Major Shift in Feeding & Maneuverability Lateral line sensory system Bone (dermal) Basic Ancestral Vertebrate Features

36 Representative Chondrichthyes Cartilage skeleton Tooth-like scales Multiple external gill slits No lungs or swimbladder Sharks Chimaera / ratfish Shark Placoid Scale Ray

37 Relationships Among The Classes of Fishes MYXINI CEPHALASPIDOMORPHA PLACODERMI CHONDRICTHYES OSTEICHTHYES LAMPREYS OSTRACODERMS Oral tentacles Slime glands Scavenging lifestyle Loss of bone Parasitic lifestyle Extensive bony armor Extensive, jointed armor Loss of bone Distinctive tooth-like scales Gills covered by bony operculum Tendency for tail to become symmetrical Lungs or swim bladder Bony internal skeleton Vertebral column Circular sucking mouth Jaws Paired appendages Faster, Sustained Swimming Lateral line sensory system Craniates Bone (dermal) Basic Ancestral Vertebrate Features

38 Relationships Among The Classes of Fishes MYXINI CEPHALASPIDOMORPHA PLACODERMI CHONDRICTHYES OSTEICHTHYES LAMPREYS OSTRACODERMS Oral tentacles Slime glands Scavenging lifestyle Loss of bone Parasitic lifestyle Extensive bony armor Extensive, jointed armor Loss of bone Distinctive tooth-like scales Gills covered by bony operculum Tendency for tail to become symmetrical Lungs or swim bladder Bony internal skeleton Circular sucking mouth Jaws Vertebral column Faster Swimming & Buoyancy Control, Air Breathing Paired appendages Lateral line sensory system Bone (dermal) Basic Ancestral Vertebrate Features

39 Evolution of lungs Basal vertebrate Basal fish Lung fish

Climate Researchers Feeling Heat. By Juliet Eilperin Washington Post Staff Writer Thursday, April 6, 2006; A27

Biology 2010 April 19, 2006 Readings - From Text (Campbell et al. Biology, 7 th ed.) Chapter 34 pp. 671-707. Climate Researchers Feeling Heat. By Juliet Eilperin Washington Post Staff Writer Thursday,