Chordates An Introduction

Kingdom Animalia- All inverts & verts 1.Phylum Chordata: All have nerve cords. 3 subphyla : A- Urochordata (tunicates aka sea squirts). Only larvae have notochord B-Cephalochordata (lancelets aka Amphioxus). Retain notochord throughout adulthood, but “muscle- like” for burrowing C-Vertebrata- Notochord becomes backbone. 7 Classes

Section 33-1 have the following key features which is Concept Map Chordates A flexible supporting structure Notochord Dorsal hollow nerve cord Pharyngeal gill slits/ pouches Postanal tail

4 Chordates

5 Phylum Chordata

6 Notochord Gill slits or pharyngeal pouches Dorsal hollow nerve cord Postanal tail Segmented muscles Deuterostome

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11 Evolutionary Adaptations of Chordates From filter feeding ancestors to active predators –Mobility –Oxygen capture –Digestion –Circulation –Nervous system

12 Skeletal Changes Skeleton becomes stronger to work with bigger muscles Allows more rapid movement

13 Oxygen Capture Gill slit and muscular pharynx will move more water over gills –More oxygen is extracted from water

14 Circulation Stronger heart to circulate blood faster

15 Digestion Digest more food –Muscularized gut –Digestive glands Liver Pancreas

16 Nervous System More complex for better –Motor control of body to capture food –Sensory detection of the animals environment –Integration centers (brain)

17 Brain With Three Parts Forebrain Midbrain Hindbrain

Section 33-1 Nonvertebrate chordates Jawless fishes Cartilaginous fishes Bony fishes Amphibians Reptiles Birds Mammals Figure 33–2 A Cladogram of Chordates

Mammals Birds Reptiles Amphibians Fishes Nonvertebrate chordates Invertebrate ancestor Chordate Cladogram

Section 33-1 Fishes (47%) Nonvertebrate chordates (4%) Mammals (8%) Birds (18%) Reptiles (14%) Amphibians (9%) Figure 33–4 Diversity of Chordates

21 Chordate Subphyla Phylum. Chordata Subphylum. Urochordata Subphylum. Cephalochordata Subphylum. Vertebrata Phylum. Chordata Subphylum. Urochordata Subphylum. Cephalochordata Subphylum. Vertebrata

22 Sea Squirts

23 Subphylum Urochordata Sea squirts Gill slits (pharyngeal slits) Notochord –Only in larva Adult has tunic- made of cellulose, sessile ss.com/2010/03/14/1-2- behold-the-tunicates/ ss.com/2010/03/14/1-2- behold-the-tunicates/

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27 Subphylum Cephalochordata Amphioxus Notochord length of body Dorsal hollow nerve cord Gill slits Segmented muscles Maintain all chordate characteristics as adult

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29 Amphioxus

Subphylum Vertebrata: All Vertebrates have: Closed circulatory system Bilateral symmetry True coelom 3 germ layers Endoskeleton- backbone Sexual reproduction- internal or external

Homeostasis Endothermic (warm-blooded)- internal temp. regulation that must be maintained Ex. Birds & Mammals Ectothermic (cold-blooded)- external temp. regulation/ regulated by environment Ex. Nonvertebrate chordates, Fish, Amphibians, Reptiles

Section 33-2 Environmental Temperature (°C) Body Temperature (°C) Temperature Control in Chordates 98.6 F- avg human temp

Animal GroupEndo/ectothermBehavior/structure FishEctothermSwim bladder: Cold/move up Hot/move down AmphibianEctothermCool/go in sun Hot/go to water ReptileEctothermCool/bask Hot/go to water BirdsEndothermCool/fluff feather Hot/raise wings MammalsEndothermSweat, pant, shiver How vertebrates maintain their temperature

Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Agnatha “Jawless” Fish (most primitive) : Traits: -Sucker like mouth(no jaws) -No fins or paired appendages -Cartilage skeleton w/ notochord Ex: lamprey & hagfish

Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Chondrichthyes-Cartilage Fish Traits: Cartilage skeleton; 2 chambered heart Lateral line system –detect vibrations (movement & sense) Paired appendages- pectoral and pelvic girdles Poor eyesight, great olfactory Carnivorous or scavenger, no swim bladder Ex: sharks, skates, rays

Fish Scales ScalesTails

Sharks and rays lungfish Bony fish

Fish Tail Cladogram

Kingdom Animalia Phylum Chordata Class Osteichthyes- Bony Fish Traits: Bony skeleton; 2 chambered heart Lateral line system/movement & sense Swim bladder-control depth (buoyancy) Have operculum over gills Good smell (olfactory) and eyesight Ex: perch, bass, flounder