Chordates

Vertebrate Animals

Vertebrate Classes

●Jawless Fish (lamprey, hagfish)●Cartilage Fish (sharks, rays…)●Bony Fish (salmon, catfish, goldfish…)●Amphibians (frogs, salamanders…)●Reptiles (lizards, turtles…)●Birds (sparrows, hawks…)●Mammals (humans, whales, cats..)

Lancelet

What is a vertebrate?-Animals with a backbone (and endoskeleton)

-Have spinal cord (dorsal, hollow nerve cord)

-Front end of spinal cord develops a brain

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

●1st Fish were jawless●Devonian Period - "Age of Fishes“

Fossil of a devonian fish with jaws and armored plates

B. FINS

Other Fish Adaptations

A. Swim Bladder – maintains buoyancy (like a balloon)

Sharks do not have a swim bladder, if they stop swimming, they sink.

AMPHIBIANS

What is an amphibian?❏Vertebrate❏Leads a “double life”❏Moist skin❏Metamorphosis

Evolution of Amphibians●Bones became stronger●Lungs to breath air●Limbs to walk on land

Paleontologists have discovered fossils of a species that provides the missing evolutionary link between fish and the first animals that walked out of water onto land about 375 million years ago. The newly found species, Tiktaalik roseae, has a skull, a neck, ribs and parts of the limbs that are similar to four-legged animals known as tetrapods, as well as fish-like features such as a primitive jaw, fins and scales.

METAMORPHOSISSeries of changes that occur as an organism grows

Amphibian GroupsKingdom Animalia…..Phylum Chordata……...Subphylum Vertebrata………….Class Amphibia

Order UrodelaOrder AnuraOrder Apoda

http://www.britannica.com/EBchecked/media/117744/Representative-amphibians

REPTILES

Order Testudines

Sphenodonta

Characteristics of Reptiles

1. Strong, bony skeletons and feet with claws2. Ectothermic (cold-blooded)3. Dry scaley skin4. Amniote eggs5. Respiration with lungs6. Ventricle partially divided7. Internal fertilization

The Amniote EggContains a water and food supply for the

embryo and can be laid on land. 

Must be fertilized internally, has a shell

Snakes Hatching

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

What's this famous turtle's name?

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

Alligators are found mainly in North and South America and only live in freshwater

Alligators only show their upper teeth when their mouth is closed, and their snouts are rounder (u-shaped)

Extinct Reptiles

31-2 Birds

*Ornithology is the study of birds

Characteristics

1. Forelimbs modified into wings 2. Feathers 3. Hollow, lightweight bones 4. Endothermic5. Efficient respiration 6. Heart with a completely divided ventricle (4 chambers) 7. Scaley feet (birds are related to reptiles) 8. Furculum (wishbone)

Evolution of Birds (from reptiles)

●Archaeopteryx - “ancient wing” ●Reptile like - Had teeth, bony tail,

claws on wings ●Bird like = Had feathers,

& fused collarbone (wishbone)

Adaptations for flight:●Efficient digestive, respiratory, and circulatory

systems●Aerodynamic feathers and wings●Strong, lightweight bones●Strong chest muscles

MovementForelimbs modified for flight = wings

Collarbones are fused making a strong base for flight muscles - fused bone is the furculum

Many baby birds are born helpless and without feathers. These baby birds require lots of care from their parents.

Some babies hatch with feathers and can follow their mom around, swim and eat on their own.