Ch 34 - Vertebrates (1 slide per page)-1

E h2o w food enters mouth leaves via slits wo food

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Unformatted text preview: eding or respiration (gills) •i.e. H2O w/ food enters mouth & leaves via slits w/o food (filter) or O2 (gills) •In tetrapod adults, 1st groove becomes outer ear opening & others disappear Pharyngeal slit Figure 34.3 (Campbell et al) 9 Phylum Chordata 3 Subphyla: (1) Lancelets (Cephalochordata) Vertebrata is a group within the subphylum Craniata (2) Tunicates (Urochordata) (3)Craniates Limbs w/ digits Figure 34.2 (Campbell et al) 10 1. Lancelets Larva (Cephalochordata) • ~25 marine species (e.g. lancelet “amphioxus”) • Small (<5cm), translucent, fish-like • Larvae swim vs. most adults sedentary burrowers • Adults have all 5 chordate characters • Gill slits primarily for filter feeding (not respiration) • Unlike vertebrates, notochord extends to tip of snout Adult w/ slits Figure 34.4 (Campbell et al) 12 2. Tunicates (Urochordata) • Tunicates • ~2000 species • Filter-feeders • Free swimming larvae • Most sessile as adults 13 2. Tunicates (Urochordata) ADULT (1) DHNC (2) Endostyle (3) Pharyngeal slits *No notochord or tail LARVA • All 5 chordate charachters Adult Water flow: Incurrent siphon → Pharynx → Gill slits → Atrium → Excurrent siphon Spp w/ free-swimming adults resemble larval form more. Figure 34.5 (Campbell et al) 14 A juvenile of tunicate Oikopleura dioica 15 3. Subphylum Craniata • 1 invertebrate class (Hagfish (Myxini)) • All other classes are vertebrates 3 Subphyla: 1.Lancelets 2.Tunicates 3.Craniates Limbs w/ digits Figure 34.2 (Campbell et al) 16 CRANIATE FEATURES •Cranium to protect brain; •Head extends beyond notochord; •Complex brain and sense organs •Closed circulatory system •Complex multichambered heart •Gills primarily for respiration not feeding; • etc… 19 • • • • Hagfish (Class Myxini ) Cartilaginous skull No jaws and no vertebrae Mouth w/ “toothed” tongue (keratin) Bottom-dwelling scavengers • rip off flesh • eviscerate dead or dying animals from inside 20 Hagfish (Class Myxini ) • Produce slime to aid in movement through animal and as a defen...
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