ex. Humans, cats, horses, fish, frogs…only about 5% of known species

Phylum Chordata

Characteristics of Phylum Chordata:• Have a notochord = a stiff

rod of cartilage running down the back of the animal. – Later the notochord is

replaced by the backbone.

• Hollow dorsal nerve tube

• Gill slits (pharyngeal slits)

• Tail that extends past the anus.

Post-anal tail

Phylum ChordataSubphylum HemichordataSubphylum UrochordataSubphylum CephalochordataSubphylum Vertebrata

Class Agnatha

Class Chondrichthyes

Class Osteichthyes

Class Amphibia

Class Reptilia

Class Aves

Class Mammalia Order Placentals

Order Monotremes

Order Marsupials

Subphylum HemichordataThe “Half Chordates”

• All are marine worm-like animals

• Adults are benthic – live on the sea floor

• Smallest species are only a few mm long and the largest, Balanoglossus gigas, can reach lengths of 1.5m

• Tripartite (3 section) body plan– protostome– collar– trunk

Subphylum Urochordata: ex) Tunicates• “Sea Squirts”• Spend most of their

lives attached to docks, rocks or the underside of boats

• Firm flexible body covering called a tunic composed of a substance that is similar to cellulose

Subphylum Cephalochordata: ex) Amphioxus

AMPHIOXUS or LANCELETAMPHIOXUS or LANCELET

LARVAELARVAE

ADULTADULT

Amphioxus• From Greek for “both [ends] pointed”, aka lancelets• Small, eel-like animals that spend much their time buried

in the sand• Have over 100 pharyngeal slits or gill slits which are

used to strain food particles out of the water• Are eaten by humans or domestic animals and are

commercially harvested for food in some parts of Asia

http://www.picturesof.net/_people/people_index.html

Subphylum Vertebrata Characteristics:• Bilateral symmetry

• Coelom

• Have vertebrae = hollow, cartilaginous or bony structures that surrounds & protects the dorsal nerve cord

• Endoskeleton

• Large brain protected by a skull

• Complex heart, closed circulatory system

• 1 or 2 pairs of appendages

• Gills or lungs for breathing

• Special outer covering = “skin” (fur, scales, fat, hair….)

Ecological roles of vertebrates:• Food source

• Control animal and plant populations

• Pollinators (birds, bats)

• Seed dispersal

• Aerate soil (moles, squirrels)

• Create ponds - beavers

There are 7 classes of vertebrates:

• Class Agnatha

• Class Chondrichthyes

• Class Osteichthyes

• Class Amphibia

• Class Reptilia

• Class Aves

• Class Mammalia

**DO NOT COPY**

The Shape of Life

• Bones, Brains and Brawn: http://www.dailymotion.com/video/x1ft0rl_pbs-the-shape-of-life-8-of-8-bones-brawn-and-brains_tv