By 124 1st Edition Lecture 11 Outline of Last Lecture Chapter 33Coelomates (cont.)I. Phylum NemerteaII. Phylum LophophoraIII. Phylum Mollusca IV. Phylum AnnelidaV. Phylum Tardigrada VI. Phylum ArthropodaOutline of Current Lecture Chapter 33Coelomates (cont.)I. Phylum CrustaceaDeuterostomesI. Phylum BrachiopodaII. Phylum Echinodermata III. Phylum Hemichordata Chapter 34I. Phylum Chordataa. 4 key characteristics of all chordatesb. Subphylum CraniataCurrent LectureThese 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 partsi. cephalothoraxb. Antennae c. Chewing mouthpartsd. 3 or more pairs of legse. Have some swimming appendages f. MoltDEUTEROSTOMESI. Phylum Brachiopodaa. Lophophore – bears tentacles which surround mouthII. Phylum Echinodermata i. “spine- skin”ii. Looks like it could be radially symmetrical but it isn’t truly radial. It is bilateral1. Look at larva – bilateraliii. Usually marineiv. Can move but not a whole lotv. Water vascular system1. Involved in feeding, locomotion, respiration, and in sensory perception2. 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 isvi. Nerrvous system = nerve ring around central cavityvii. Small, stiff, porous skeletal-like plates called ossiclesviii. Separate sexesix. External sexesx. Test (body)xi. segmentedb. Class Asteroidea (sea stars)i. Figure 33.40ii. Can regenerate – cut it a certain way and they can regrow from piecesc. Class Ophiuroidea (brittle stars)i. body is more slender than sea starsd. Class Echinodea (sea urchins)i. Figure 33.43ii. Test (body) is made of a bunch of plates that are fused togethere. Class Crinoidea (sea lilies)i. Feathered arms surrounding upward-pointing mouthii. Don’t really movef. 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 marineb. Have paired sets of gill slitsi. Openings through lateral wall of interior gutii. Water comes in mouth and exits through slitsiii. Can sort out food c. Have a dorsally situated nerve cord that forms like human nerve cordsChapter 34: The Origin and Evolution of VertebratesVERTEBRATES a. Have a vertebra – series of backbones I. Phylum Chordatai. Bilateral symmetryii. Deuterostomesiii. Two groups are invertebrates1. Subphylum Cephalochordata (lancelets)a. Blade-like shapeb. Suspension feedersc. Figure 34.4i. Adult lancelet has all 4 below characteristics1. Segmented muscles arise from blocks of segmented mesoderm called somites2. Subphylum Urochordata (tunicates)a. More closely related to chordatesb. Draws in water through siphonc. “sea squirts”d. Only characteristic that it keeps from below list is the pharyngeal slitsi. Loses hollow nerve cord, notochord and tail from embryonic stagee. Bilateral symmetry as larvaiv. 4 key characteristics:a. Some of these traits will only be seen during embryonic stage2. Notochord – present in all chordate embryosa. A longitudinal flexible rod that is located between nerve cord and guti. All we have left of ours is intervertebral disc3. Dorsal hollow nerve corda. Invertebrates have ventral solid nerve cordb. Develops from ectoderm4. Pharyngeal slits or cleftsa. Feeding structureb. Gas exchangec. Develops into parts of neck and head5. Muscular, post-anal taila. We had these as embryosv. Early chordate evolution1. Hox genes2. Genome sequencing suggest that genes for nerve impulses are unique to vertebrates but genes for heart and thyroid are common to all chordates3. Figure 34.6vi. Figure 34.2 will be important for studyingb. Subphylum Craniata1. Skull, brain, eyes, and other sensory organs2. 2 clusters of Hox genesa. Lancelets and tunicates only have 13. Neural tube cellsa. Ectoderm becomes brain and spinal cord i. Figure 34.7b. Become teeth, bones and cartilage in skull, dermis of face, several types of neurons, and sensory capsules on eyes and other sense organs4. More active than all previous animals5. 2 chambered hearts6. Red blood cells (RBCs) and can transport Hemoglobin7. Kidneys8. True gill slits (no longer pharyngeal slits)9. Higher metabolismii. Grouping: Pisces1. Class Myxini (hagfish)a. Agnatha – “no jaw”b. More advanced nervous systemc. Transcription factor gene duplicated to make this creatured. Cartilaginous skeletone. 2 chambered heartf. Produces tons of slime as defensei. Slime glands2. Class Cephalospidomorphi (lamprey)a. Cartilaginous skeletonb. ONLY vertebrate parasitec. Have a cartilaginous pipe around notochord with stiff projection that act to latch onto things3. Class Conodonta (Conodonts)a. 1st vertebrates with mineralized skeletal elements in mouthand pharynx (teeth)i. Used for feedingb. All extinctc. Bone plates4. Gnathostomatai. When jaws aroseii. Jaws may have arisen from skeletal rods of gill slits1. A gill slit cannot become a jaw, the rods thatare associated with those doiii. 4 sets of Hox genes iv. Lateral line system – sensitive to vibration down sides of animals v. Can fall into many different classesb. Class Placodermi (placoderms)i. Huge jaw = predatorii. Paired fins1. Can swim betteriii. Appeared at end of Devonian period1. “age of fishes”iv. All