Chordates An Introduction

Kingdom Animalia- All inverts & verts 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

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

Chordates Fig. 23.2a

Phylum Chordata Fig. 23.1

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

Fig. 23.p469a

Fig. 23.p469b

Fig. 23.p472a

Fig. 23.p472c

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

Skeletal Changes Skeleton becomes stronger to work with bigger muscles Allows more rapid movement Fig. 23.p477

Oxygen Capture Gill slit and muscular pharynx will move more water over gills More oxygen is extracted from water Fig. 23.p478a

Circulation Stronger heart to circulate blood faster Fig. 23.p478a

Digestion Digest more food Muscularized gut Digestive glands Liver Pancreas Fig. 23.p478a

Nervous System More complex for better Motor control of body to capture food Sensory detection of the animals environment Integration centers (brain) Fig. 23.p478b

Brain With Three Parts Hindbrain Midbrain Forebrain Fig. 23.14

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

Chordate Cladogram Mammals Birds Reptiles Amphibians Fishes Nonvertebrate chordates Invertebrate ancestor

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

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

Sea Squirts

Subphylum Urochordata Sea squirts Gill slits (pharyngeal slits) Notochord Only in larva Adult has tunic- made of cellulose, sessile http://www.arkive.org/star-ascidian/botryllus-schlosseri/ http://finstofeet.wordpress.com/2010/03/14/1-2-behold-the-tunicates/

Fig. 23.5

Fig. 23.7

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

Amphioxus Fig. 23.CO

Amphioxus

Subphylum Vertebrata: All Vertebrates have: Endoskeleton- backbone Closed circulatory system Bilateral symmetry True coelom Sexual reproduction- internal or external Vertebrate Groups- Fish, Amphibians, Reptiles, Birds, and Mammals

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

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

Animal Group Endo/ectotherm Behavior/structure Fish Ectotherm How vertebrates maintain their temperature Animal Group Endo/ectotherm Behavior/structure Fish Ectotherm Swim bladder: Cold/move up Hot/move down Amphibian Cool/go in sun Hot/go to water Reptile Cool/bask Birds Endotherm Cool/fluff feather Hot/raise wings Mammals Sweat, pant, shiver

“Jawless” Fish (most primitive): 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

Class Chondrichthyes-Cartilage Fish 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

Tails Bony fish Sharks and rays lungfish

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