Post on 03-Jan-2016
Phylum Chordata
Section 30-1
Nonvertebratechordates
FishesAmphibians
ReptilesBirds
Mammals
Invertebrate ancestor
Chordate Cladogram
Chordate Characteristics
All chordates at some point in their life cycle have:
-dorsal hollow nerve cord (brain/spinal cord)
-notochord (vertebral column)
-pharyngeal pouches (pharynx)
-tail extending beyond the anus
Subphylum: VERTEBRATAAbout 96% of chordates are vertebratesApprox. what % of all animals are vertebrates?Internal framework called an endoskeleton
made of cartilage or boneHave a skull that protects the brainVertebral column or backbone that protects the
spinal cord Rib cage to protect internal organsMost have two pairs of limbsMost taxonomists divide vertebrates into seven
classes.
7 Classes of Vertebrates:1. Class Agnatha – jawless fish ex: lamprey, hagfish *minimal
skeleton, no true teeth2. Class Chondrichthyes – cartilage fish ex: shark, skates &
rays*entire skeleton is cartilage3. Class Osteichthyes – bony fish *most fish belong to this group
and their skeleton is made largely of bone ex: perch, carp, seahorse.
4. Class Amphibia – amphibians ex: frogs, toad, salemander *most have an aquatic larval stage (breath through skin/gills) and adults have lungs
5. Class Reptilia – reptiles ex: snakes, lizards, crocs *lay eggs on land
6. Class Aves – birds *have feathers, most fly, beaks/bills ex: hawk, heron, crow, emu
7. Class Mammalia – mammals *hair or fur and develop internally and nurse off milk after birth, 4 chambered heart ex: shrews, whales, bats, horses, tigers, elephants, rabbits, humans
Fish Agnatha: jawless fish
Chondrichthyes: cartilage fish
Osteichthyes: Bony fish
AmphibiansFrogsToads
Salamanders
ReptilesSnakes
Lizards
Crocodilians
Turtles
Aves:The Birds
Mammalia: the mammals
Nonvertebrate Chordates
-These animals have no backbone, but do have a notochord.
-Also have a dorsal hollow nerve cord, pharyngeal pouches and a tail.
-Two sub-phyla: Urochordata and Cephalochordata
-Although very different from vertebrates, they are distant relatives
Urochordata: The Tunicates -Filter-feeders
-Name comes from the tough covering called a tunic
-Called sea squirts
-Larvae have all four chordate characteristics
-Adult tunicates have no notochord or tail
Tunicate Larva
-Notochord
-Hollow dorsal nerve cord
-Pharyngeal pouches
-Tail
Cephalochordata: Lancelets
- Small fish-like animals that live in the sandy bottom.
-Have a head region with a mouth.-Lancelets take water into their pharynx and pick out food.
-Pharynx has up to 100 pairs of gill slits
-Have a circulatory system but no heart. Blood is moved by the vessels.