1. Animalia
Vertebrates

2. Animals Animals are spilt into two major groups: Vertebrates
Invertebrates

4. Vertebrates Agnatha Chondrichthyes Osteichthyes Tetrapoda Aves
These are animals with a backbone.
There are six groups of vertebrates:
Agnatha
Chondrichthyes
Osteichthyes
Tetrapoda
Amphibians
Reptiles
Aves
Mammalia

5. Agnatha Jaws are absent. Paired fins are generally absent.
In most cases the skeleton is cartilaginous.
The digestive system lacks a stomach.
Includes:
Lampreys
Hagfishes

6. Chondrichthyes Lack true bone Have a skeleton made of cartilage
May have calcified teeth and bone but these are structurally different to true bone
Have jaws with teeth
Lays eggs (oviparous) or give birth to live young (viviparous)
Have paired fins
Live in water
Mostly marine, 5% live in freshwater
Includes:
Sharks
Skates
rays

7. Rays vs skates Rays One lobed pelvic fin Usually have dorsal fins
Stinging spine
Skates
Two lobed pelvic fin
No dorsal fins
No stinging spine

8. Osteichthyes Bony fishes Have true ossified bone
Usually have some form of skull
Wet scales
Most have swim bladders
Two major groups:
Ray finned & lobe finned

9. Wet vs dry scales Wet scales Dry scales Aquatic organisms: fish
Are derived from skin
May contain bone and enamel
May grow in concentric layers
Are “designed” to reduce drag through water
Dry scales
On reptiles, arthropods and birds
Are generally ridged
Can be derived from hair
Are usually keratinous
Are to prevent wear from friction

10. Tetrapoda Includes amphibia and reptilia Are four legged vertebrates
have evolved into mammals
Pentadactyl limb

11. Commonality in Tetrapods

12. Amphibia Have moist skin Lay jelly coated eggs in water
Lives on land and water
Evolution of lungs
Two circuit circulatory system
Undergo metamorphosis
Includes:
Frogs & toads
Salamanders
newts

13. Frogs vs Toads Order Anura Longer jumping legs Eggs in clusters
Moist, smooth skin
Prefer moist environments
Have vomerine teeth in upper jaw
Eyes bulge
Order Anura
Shorter walking or hopping legs
Eggs in chains
Some give birth to live young
Dry bumpy skin
Dryer environments
No teeth
Eyes don’t bulge

14. Mexican Walking fish (axolotl)
Is not a fish but an amphibian
Undergoes a condition called Neoteny
Is a reduced rate of development to the point where the juvenile doesn’t develop into an adult
The adult stage retains the form of the juvenile. The axolotl is a large tadpole.
In some cases the axolotl will metamorphose into an adult version similar to a tiger salamander

15. Reptilia Have dry scales
Lay leathery shelled eggs (some species give birth to live young)
Some have a form of placenta
All have lungs
Cold blooded
Includes:
Turtles & tortoises
Crocodilians
Lizards
Tuatara (NZ)

16. Evolution of Bipedalism
Graviportal Mediportal Cursorial

17. Aves Have feathers and hollow bones Lay hard shelled eggs Warm blooded
Skeleton approximately 5% of total weight (humans approx. 15%)
Feathers weigh approximately 6% of total weight
Lay hard shelled eggs
Warm blooded
No teeth*
Highly advanced respiratory system
Includes:

19. Mammalia Hair Mammary glands teeth Auditory ossicles Neocortex
Four chambered heart
Sweat glands
Most give birth to live offspring (vivparous)
Warm blooded

21. Kangaroos vs Wallabies
Are both macropods (f. macropodidae)
Primarily size-based
Kangaroos – longer legs for speed
Wallabies – shorter legs for manoeuvrability
Different dentition and head shape
Kangaroos tend to have dull coats

22. Summary of Vertebrates (Chordata)