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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 Concept Map Chordates have the following key features Notochord which is Dorsal hollow nerve cord Muscular tail Pharyngeal pouches The Generalized Structure of a Chordate: Section 30-1 A flexible supporting structure We even start out this way in the womb! Notochord Muscle segments Tail Hollow nerve cord Anus Mouth Pharyngeal pouches Section 33-1 Nonvertebrate chordates Jawless fishes Cartilaginous fishes Bony fishes Amphibians Reptiles Birds Mammals Figure 33–2 A Cladogram of Chordates Chordate Cladogram Mammals Birds Amphibians Fishes Nonvertebrate chordates Invertebrate ancestor Reptiles Figure 33–4 Diversity of Chordates Section 33-1 Nonvertebrate chordates (4%) Mammals (8%) Birds (18%) Reptiles (14%) Amphibians (9%) Fishes (47%) All Vertebrates have: • • • • • • Closed circulatory system Bilateral symmetry True coelom 3 germ layers Endoskeleton 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 Temperature Control in Chordates Body Temperature (°C) Section 33-2 Environmental Temperature (°C) 98.6 F- avg human temp How animals maintain their temperature Animal Group Endo/ectotherm Behavior/structure Fish Ectotherm Swim bladder: Cold/move up Hot/move down Amphibian Ectotherm Cool/go in sun Hot/go to water Reptile Ectotherm Cool/bask Hot/go to water Birds Endotherm Cool/fluff feather Hot/raise wings Mammals Endotherm Sweat, pant, shiver Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Agnatha Jawless Fish (most primitive): Traits: -Sucker like mouth(no jaws) -No fins -Cartilage skeleton Ex: lamprey & hagfish Kingdom Animalia Phylum Chordata (Sub-Vert) Class ChondrichthyesCartilage Fish Traits: Cartilage skeleton; 2 chambered heart Lateral line system –detect vibrations (movement & sense) Poor eyesight, great olfactory Carnivorous or scavenger Ex: sharks, skates, rays Kingdom Animalia Phylum Chordata Class OsteichthyesBony Fish Traits: Bony skeleton; 2 chambered heart Lateral line system/movement & sense Swim bladder-control depth (buoyancy) Have operculum over gills Good smell and eyesight Kingdom Animalia Phylum Chordata Class Amphibia Traits: 1st land vertebrates 3 chambered heart Breath with skin/lungs Need water to breed Aquatic larvae; terrestrial adult No scales or claws Ex: frogs, toads, & salamanders Kingdom Animalia Phylum Chordata Class Reptilia Traits: Imperfect 4 chambered heart Dry, scaly skin Breathe with lungs Lay amniotic eggs Ex: snake, turtle, lizards crocodile, dinosaurs Kingdom Animalia Phylum Chordata Class Aves-birds Traits: Down feathers for insulation Air sacs/hollow bones make bird lighter Lungs to breathe 4 chambered heart Beak & feet adapted for food/habitat Internal fert.,Lay amniotic eggs Kingdom Animalia Phylum Chordata Class Mammalia 1. Have fur/hair 2. mammary glands 3. Length of time in uterus - gestation period 4. Give birth to live young (except monotremes) 5. 4 chambered heart 6. Diaphragm 7. Specialized teeth Placental Mammals: *Develop inside uterus *Ex: people(primates), cats, dogs (carnivores) Marsupials: pouch *Develop inside *Ex: kangaroos, opossums Monotremes: *Lay eggs Ex: platypus,echidna Other placental orders • Chiroptera-bats; only mammals that can fly; nocturnal • Rodentia-gnawing mammals with long incisor teeth. Ex: rats, squirrels, porcupines, rabbits • Insectivora-long snout. Ex: shrews, moles • Cetacea-Whales, dolphins Terms to know • • • • • • • Imprinting Migration Hibernation Estivation Oviparous Viviporous Oviviviporous Evolution • Change over time michael was here • Which Chordate class do you think has more advantages/adaptations to survive changing times? • Which classes have disadvantages? • Which Chordate classes can you see evolutionary similarities in so far?