Phylum Chordata (The Chordates)

What is a chordate?• Classification: Kingdom Animalia,

Phylum Chordata• Four Phylum Characteristics

• Notochord: supportive rod (replaced by cartilage or bone in vertebrates)

• Tubular nerve cord: single, dorsal; anterior end enlarged into brain (develops into brain and spinal chord in higher vertebrates)

• Pharyngeal gill slits/pouches/folds (controversial) mostly embryonic in higher vertebrates

• Post anal tail: generally supported by notochord or vertebral column • provides method of locomotion in aquatic chordates• present in humans as coccyx; in most other mammals as

wagging tail.

Chordate Anatomy

Invertebrate Chordates (NO vertebrae): Sea Squirts or Tunicates

Lancelet

What is a vertebrate?

Characteristics:

•Animals with a backbone or vertebral column (endoskeleton)

•Presence of a Spinal Cord - dorsal, hollow nerve cord

•Anterior end of spinal cord develops a brain

Vertebrate Classes

• Class Agnatha: Jawless Fish (lamprey, hagfish)• Class Chondrichthyes Cartilage Fish (sharks,

rays, skates, catfish…)• Class Osteichthyes: Bony Fish (salmon, bass,

goldfish, etc…)• Class Amphibia: Amphibians (frogs,

salamanders…)• Class Reptilia: Reptiles (lizards, turtles…)• Class Aves: Birds (sparrows, hawks…)• Class Mammalia: Mammals (humans, whales,

cats…)

What are Fish?* Anything with gills, scales, and fins…

TYPES OF FISH

Jawless fish (Agnatha): lamprey and hagfish

•Lamprey is a parasite, it attaches to other fish and sucks their blood

•Hagfish is a scavenger, it lives in the ocean and is known for its slimy secretions

Cartilage Fish

•Kingdom Animalia, •Phylum Chordata, •Subphylum Vertebrata•CLASS CHONDRICHTHYES

Sharks and Rays

SHARKS

*The pectoral fins of sharks do not move* Sharks do not have an operculum or a swim bladder*sharks will sink if they stop swimming

BONY FISH

•Class OSTEICHTHYES•Bony skeleton•75% of vertebrates•Most have swim bladder to regulate density•Operculum = bone covering the gills•Two chambered heart

External Anatomy: Bony Fish

Coelacanth: living fossil, lobe-finned

Clown Fish (Nemo)

Kissing Fish…Awww…

Other Vertebrate ClassesClass Amphibia: Amphibians

• Live in and out of water• Need water for soft skin and for

reproduction (external fertilization)• Respiration by gills, lungs, and skin• 3-chambered heart: 2 atria, 1

ventricle• Poikilotherms

Amphibian Groups

Kingdom AnimaliaPhylum ChordataSubphylum VertebrataClass Amphibia

3 Orders:Order Urodela (Salamander/Newts)Order Anura (Frogs/Toads)Order Apoda (Cecilians)

METAMORPHOSIS• Series of changes that occur as an

organism grows

Feeding• Larva (tadpoles) are usually herbivores• Adults are usually carnivores

Respiration• Larva (tadpoles) breath with gills• Adult frogs have lungs

Some amphibians keep gills all their life, mudpuppy

See videos at

http://video.nationalgeographic.com/video/player/animals/index.html

Class Reptilia: Reptiles

• Link between sea and land??• Adapted to land:

– Dry scaly skin- aids in conserving moisture– Internal fertilization- improves egg survival– Amniotic egg- embryo enclosed in fluid-filled sac covered

by shell– Lungs for gas exchange– Excretes uric acid - insoluble solid, nitrogenous waste– Poikilotherm– 3-chambered heart: 2 atria, partly divided ventricle

(exception: alligators have 4)

Types of Reptiles

4 Main Groups (ORDERS) Crocodilia = crocodiles, alligators Testudines = turtles and tortoises Sphenodonta = tuatara Squamata = lizards,  snakes ( largest group )

Order Sphenodonta

Only found in New Zealand, they have no external ears and a 3rd eye

Order Testudines

Tortoises usually live on the land, turtles in the water

Snapping turtles can be very aggressive

The top of a turtle's shell is the carapace, the bottom is the plastron

Is this a turtle or a tortoise?

Order Crocodilia

*Ornithology is the study of birds

Classification

Kingdom Animalia---Phylum Chordata------Subphylum Vertebrata---------Class Aves

Aviation = flight

Characteristics

1. Forelimbs modified into wings 2. Feathers 3. Hollow, lightweight bones 4. Endothermic (a.k.a. Homeotherm)5. Efficient respiration 6. Heart with a completely divided ventricle (4 chambers) 7. Scaley feet (birds are related to reptiles) 8. Furculum (wishbone)

Types of Feathers

Down feathers - provide insulation* birds are endothermic (homeotherms)

Contour feathers - cover head and body, provide coloration

Flight feathers - on wings and tail, provide lift