Download - Chordate Evolution (Chapter 30.1, and 33 )
Chordate Evolution (Chapter 30.1, and 33)Please set up your notebook for Cornell Notes
Phylum ChordataChordate an animal that has 4 characteristics for at least part of it’s life cycle
Dorsal hollow nerve cord – hollow tube running on the dorsal side of the animalNotochord a rigid supporting rod running below the dorsal hollow nerve cordPharyngeal pouch paired structures in the throat regionTail that extends beyond the anus
Most chordates are vertebrates animals with a backbone
Vertebrates have an endoskeleton that grows as the organism grows
Maintaining homeostasisEctotherm body temp controlled by the environment
Fish, amphibians, reptilesLow metabolism
Endotherm generate heat and maintain body temperature
Birds, MammalsHigh metabolism
Form and FunctionFeeding
Nonvertebrate chordates – tunicates and lancelets
Filter feedersVertebrates
Skull and teeth are adapted to a wide range of foodHave well developed digestive systems adapted for different eating habits
RespirationGills tunicates, fish, amphibian larvaLungs adult amphibians, reptiles, birds, mammals
Alveoli bubble-like structures in the lings
Thin membranes so that oxygen and carbon dioxide can diffuse across
CirculationSingle loop blood travels from heart, to gills, to body and back to heartDouble loop oxygen poor blood to lungs, oxygen rich blood to heart and then to bodyHearts have chambers
Fish and larval amphibians – 2 chambersAdult amphibians and most reptiles – 3 chambersCrocodiles, birds, mammals – 4 chambers
ExcretionNonvertebrate chordates and fish use gills to diffuse ammonia waste out of bodyOther vertebrates use kidneys
Kidneys also help maintain homeostasis by maintaining balance of water and salt in body
ResponseNonvertebrate chordates have simple nervous systems with a mass of nerve cells forming brainsVertebrates have more complex brains with regions that have specialized functions
MovementSkeletal and muscular systems support body and make a wide range of motion possible
ReproductionAlmost all chordates reproduce sexually
ExternalNonvertebrate chordates, fish, amphibians
InternalReptiles, birds, mammals
After fertilizationOviparous eggs develop outside of female body
Most fishes and amphibians, reptiles and all birds
Ovoviviparous eggs develop inside of mothers body and are nourished from yolk inside the egg
SharksViviparous develop in mothers body and get nutrients directly from mother
Mammals
Nonvertebrate ChordatesSubphylum Urochordata tunicates (sea squirts)
Marine, filter feeder, adults are sessileSubphylum Cephalochordata lancelets
Marine, filter feeder, live in sand with head region above sandClosed circulatory system but no true heart
Subphylum Cephalochordata lanceletsMarine, filter feeder, live in sand with head region above sand