By 124 1st Edition Lecture 11 Outline of Last Lecture Chapter 33 Coelomates cont I Phylum Nemertea II Phylum Lophophora III Phylum Mollusca IV Phylum Annelida V Phylum Tardigrada VI Phylum Arthropoda Outline of Current Lecture Chapter 33 Coelomates cont I Phylum Crustacea Deuterostomes I II III Phylum Brachiopoda Phylum Echinodermata Phylum Hemichordata Chapter 34 I Phylum Chordata a 4 key characteristics of all chordates b Subphylum Craniata Current Lecture These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Chapter 33 cont COELOMATES cont I Phylum Crustacea crabs lobsters crayfishes shrimps a Body has 2 or 3 parts i cephalothorax b Antennae c Chewing mouthparts d 3 or more pairs of legs e Have some swimming appendages f Molt DEUTEROSTOMES I II Phylum Brachiopoda a Lophophore bears tentacles which surround mouth Phylum Echinodermata i spine skin ii Looks like it could be radially symmetrical but it isn t truly radial It is bilateral 1 Look at larva bilateral iii Usually marine iv Can move but not a whole lot v Water vascular system 1 Involved in feeding locomotion respiration and in sensory perception 2 A modifies portion of coelom 3 Extends into structures called tube feet and water is sucked up into bulbs that can hold sea star where it is vi Nerrvous system nerve ring around central cavity vii Small stiff porous skeletal like plates called ossicles viii Separate sexes ix External sexes x Test body xi segmented b Class Asteroidea sea stars i Figure 33 40 ii Can regenerate cut it a certain way and they can regrow from pieces c Class Ophiuroidea brittle stars i body is more slender than sea stars d Class Echinodea sea urchins i Figure 33 43 ii Test body is made of a bunch of plates that are fused together e Class Crinoidea sea lilies i Feathered arms surrounding upward pointing mouth ii Don t really move f Class Holothuroidea sea cucumbers g Class Concentricycloidea sea daisies i Found on wood of old shipwrecks Hints Segmentation is governed by regulatory genes Hox genes o Sponges do not have true Hox genes Mezozoans and parazoans have true Hox genes III Phylum Hemichordata acorn worm a All marine b Have paired sets of gill slits i Openings through lateral wall of interior gut ii Water comes in mouth and exits through slits iii Can sort out food c Have a dorsally situated nerve cord that forms like human nerve cords Chapter 34 The Origin and Evolution of Vertebrates VERTEBRATES I a Have a vertebra series of backbones Phylum Chordata i Bilateral symmetry ii Deuterostomes iii Two groups are invertebrates 1 Subphylum Cephalochordata lancelets a Blade like shape b Suspension feeders c Figure 34 4 i Adult lancelet has all 4 below characteristics 1 Segmented muscles arise from blocks of segmented mesoderm called somites 2 Subphylum Urochordata tunicates a More closely related to chordates b Draws in water through siphon c sea squirts d Only characteristic that it keeps from below list is the pharyngeal slits i Loses hollow nerve cord notochord and tail from embryonic stage e Bilateral symmetry as larva iv 4 key characteristics a Some of these traits will only be seen during embryonic stage 2 Notochord present in all chordate embryos a A longitudinal flexible rod that is located between nerve cord and gut i All we have left of ours is intervertebral disc 3 Dorsal hollow nerve cord a Invertebrates have ventral solid nerve cord b Develops from ectoderm 4 Pharyngeal slits or clefts a Feeding structure b Gas exchange c Develops into parts of neck and head 5 Muscular post anal tail a We had these as embryos v Early chordate evolution 1 Hox genes 2 Genome sequencing suggest that genes for nerve impulses are unique to vertebrates but genes for heart and thyroid are common to all chordates 3 Figure 34 6 vi Figure 34 2 will be important for studying b Subphylum Craniata 1 Skull brain eyes and other sensory organs 2 2 clusters of Hox genes a Lancelets and tunicates only have 1 3 Neural tube cells a Ectoderm becomes brain and spinal cord i Figure 34 7 b Become teeth bones and cartilage in skull dermis of face several types of neurons and sensory capsules on eyes and other sense organs 4 More active than all previous animals 5 2 chambered hearts 6 Red blood cells RBCs and can transport Hemoglobin 7 Kidneys 8 True gill slits no longer pharyngeal slits 9 Higher metabolism ii Grouping Pisces 1 Class Myxini hagfish a Agnatha no jaw b More advanced nervous system c Transcription factor gene duplicated to make this creature d Cartilaginous skeleton e 2 chambered heart f Produces tons of slime as defense i Slime glands 2 Class Cephalospidomorphi lamprey a Cartilaginous skeleton b ONLY vertebrate parasite c Have a cartilaginous pipe around notochord with stiff projection that act to latch onto things 3 Class Conodonta Conodonts a 1st vertebrates with mineralized skeletal elements in mouth and pharynx teeth i Used for feeding b All extinct c Bone plates 4 Gnathostomata i When jaws arose ii Jaws may have arisen from skeletal rods of gill slits 1 A gill slit cannot become a jaw the rods that are associated with those do iii 4 sets of Hox genes iv Lateral line system sensitive to vibration down sides of animals v Can fall into many different classes b Class Placodermi placoderms i Huge jaw predator ii Paired fins 1 Can swim better iii Appeared at end of Devonian period 1 age of fishes iv All extinct