PHYLUM CHORDATA

PHYLUM CHORDATAPHYLUM CHORDATA

Phylum Chordata CharacteristicsAll chordates at some

point in their life cycle have:

-dorsal hollow nerve cord (just above the notochord)

-notochord (Strong, Strong, flexible, rodlike structure flexible, rodlike structure called a called a notochordnotochord at some at some point in their lives usually point in their lives usually replaced by a backbone in replaced by a backbone in adults))adults))

-pharyngeal pouches

-tail extending beyond the anus

-bilateral symmetry

Invertebrate ancestor

Phylogeny of ChordatesPhylogeny of Chordates

Phylum ChordataPhylum Chordata

Divided into 3 subphylum:Divided into 3 subphylum: Subphylum Vertebrata Subphylum Vertebrata

• VertebratesVertebrates Subphylum TunicataSubphylum Tunicata

• Tunicates, ex. Sea squirtsTunicates, ex. Sea squirts Subphylum CephalochordataSubphylum Cephalochordata

• Lancelets – small fish-like creatures that live at the Lancelets – small fish-like creatures that live at the bottom of the oceanbottom of the ocean

Phylum ChordataSubphylum: Vertebrata

-About 96% of chordate species are vertebrates.

-Vertebrates have a strong supporting structure called the backbone, made of segments called vertebrae. Besides support, the backbone protects the spinal cord.

-The top of the spinal cord grows into a brain.

- Have a skull that protects the brain

- Vertebrates have an endoskeleton made of living cells that grows with the organism (internal skeleton made of cartilage and bone)

7 Classes of Subphylum 7 Classes of Subphylum Vertebrata:Vertebrata:

1.1. Class Agnatha [Class Agnatha [ag-nuh-thuh]ag-nuh-thuh] – jawless fish ex: – jawless fish ex: lamprey *minimal skeleton only a few cartilage plateslamprey *minimal skeleton only a few cartilage plates

2.2. Class Chondrichthyes (con-drik-thee-eez]Class Chondrichthyes (con-drik-thee-eez] – – cartilage fish ex: shark *entire skeleton is cartilagecartilage fish ex: shark *entire skeleton is cartilage

3.3. Class Osteichthyes Class Osteichthyes [os-tee-ik-thee-eez][os-tee-ik-thee-eez] – bony fish – bony fish *most fish belong to this group and their skeleton is *most fish belong to this group and their skeleton is made largely of bonemade largely of bone

4.4. Class Amphibia Class Amphibia [am-fib-ee-uh][am-fib-ee-uh] – amphibians ex: – amphibians ex: frogs *most have an aquatic larval stagefrogs *most have an aquatic larval stage

5.5. Class Reptilia Class Reptilia [rep-til-ee-uh][rep-til-ee-uh] – reptiles ex: snakes – reptiles ex: snakes *reproduce on land*reproduce on land

6.6. Class Aves Class Aves [ey-veez][ey-veez] – birds *have feathers and fly – birds *have feathers and fly7.7. Class MammaliaClass Mammalia [ma-ma-leea][ma-ma-leea] – mammals *hair or – mammals *hair or

fur and develop internally and nurse off milk after birthfur and develop internally and nurse off milk after birth

Fish Agnatha: jawless fish

Chondrichthyes: cartilage fish

Osteichthyes: Bony fish

AmphibiansFrogsToadsNewts

SalamandersCaecilians

ReptilesSnakes

Lizards

Crocodilians

Turtles

Tortoises

Tuatara

Aves:The Birds

Mammalia: the mammals

•These animals have no backbone, but do have a notochord.

•Also have a dorsal hollow nerve cord, pharyngeal pouches and a tail.

•Soft bodied marine organisms

•Although very different from vertebrates, they are distant relatives

Subphylum Tunicata / Subphylum Cephalochordata Subphylum Tunicata / Subphylum Cephalochordata (Nonvertebrate Chordates)

Urochordata: The Tunicates -Filter-feeders (larval

and adult)

-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.