1. Kindom Animalia, Phylum Chordata pgs 448- 479
R. Pushie
CHS 2011

2. What characteristics set chordates apart from other phyla?
At some point in their development all chordates have these 4 structural characteristics:
A notochord – becomes the vertebral column in humans
A muscular pharynx with gill slits
A post-anal tail – the coccyx in humans
A hollow dorsal nerve chord – later modified into a brain and spinal cord
These attributes are always found in the larval forms or early embryo, although they may be absent in the adult.

3. Phylum Chordata is divided into three subphyla
Subphylum Urochordata
Example: tinucates
Subphylum Cephalochordata
Example: Lancelets
Subphylum Vertebrata
Examples: fish, amphibians, reptiles, birds, mammals

4. Subphylum Urochordata & Subphylum Cephalochordata
Represent 5% of chordates
Aquatic animals that possess the 4 characteristics of chordates.
No backbone or vertebral column
Perhaps represent a transient step between invertebrates and vertebrates

5. Subphyum Vertebrata 95% of all chordates
All possess vertebrae, which are hollow cartilaginous or bony structures that surround the dorsal nerve cord.
Body plan includes (pg 449):
Endoskeleton
Large brain with a protective skull
Advanced nervous system
Complex heart and circulatory system
Special outer body cover
One to two pairs of appendages
Large coelom

6. Subphylum Vetebrata Terminology
Endotherm – warm blooded animals. Internal temperature remains constant regardless of environment. Ex: mammals and birds.
Ectotherms – cold blooded animals. Body temperature and metabolic rate change with the surroundings. Ex: all other vertebrates including fish, frogs, snakes etc.

7. 12.2 Fish pg 452 Divided into 3 groups: Organ/Structure Function
Jawless –Class Agnatha. Ex: lampreys, hagfish
Cartilaginous – Class Chondrictheys. Ex: Sharks, skates, rays
Bony fish - Class Osteichthyes. Ex: Salmon, trout, tuna.
Organ/Structure
Function
Heart
2 chambered heart.
Circulatory System
Blood vessels circulate oxygenated blood
Respiration
Blood travel to Gills to be oxygenated
Nervous System
Brain, spinal cord and peripheral nervous system.
Reproduction
Separate sexes. Internal and external fertilization.
Digestion
One way, developed system.

8. Fish Circulatory System

9. Lobe-finned fish Amphibians
Lobe-finned fish, have a fleshy lobe at the base of their fins that is leg-like in appearance. Scientists believe that this fish is the ancestor of amphibians! Amphibians first appeared 350 million years ago.
*Figure 6, pg 454
Lobe-finned fish, were thought to be extinct until 1938, when a coelacanth Latimeria was first captured by chance, they were known only from the fossil record. Since then several dozen have been captured and some of their behavior has been filmed using robotic cameras.
Latimeria is important because it provides an opportunity to compare observations from the fossil record with a living animal.

10. 12.3 Amphibians pg 455 Reproduction external fertilization which only
occurs in aquatic environments.
Gas exchange
Young amphibians use gills as they live in aquatic environments.
Adult amphibians perform gas exchange through moist skin, (cutaneous respiration), and poorly developed lungs with little internal folding and a small surface area as they are mostly terrestrial.
Nervous and Digestion Systems – highly developed nervous and digestive systems.

11. 12.3 Amphibians pg 455 Circulatory System –
Inefficient 3 chambered heart where oxygenated blood and deoxygenated blood are mixed and then pumped to the body.

12. 12.4 Reptiles pg 457 Reptiles are the first fully terrestrial animals.
Reptiles first appeared 350 million years ago.
3 subclasses:
Anapsida – turtles, tortoises
Lepidosaura – lizards, snakes, tuatara
Archosaura – crocodiles, aligators and dinosaurs
Body plan includes:
Thick skin with protective with surface scales to prevent water loss (gas exchange)
Highly developed lungs with much internal folding
More developed 3 chambered heart
The amniotic egg
Lightweight skeleton
Different joint positions allowing for more efficient movement

13. 12.4 Reptiles pg 457

14. 12.5 Birds pg 461 Class Aves Characteristics of birds:
Descendant of reptiles, similarities retained include skull structure, and presence of scales on beak, legs and feet.
The first endotherms
Only animal with feathers (evolved from reptilian scales)
Their anterior limbs are modified as wings for flight, while the posterior pair is adapted for walking, swimming, or perching.

15. 12.5 Birds pg 461 Class Aves Characteristics for Flight
Circulatory System –4 chambered heart. No mixing of oxygenated and deoxygenated blood.
Respiratory System – Highly developed lungs and the presence of air sacs which provide continuous oxygen as well as buoyancy.
Limbs – lighter, hollow bones.
Excretion – purely semi solid, no urinary bladder
Digestion – rapid and efficient
Senses – excellent hearing and acute colour vision. Superior sight during the day and night.

16. 12.6 Mammals pg 465
Monotremes: mammals that reproduce by laying eggs. Descendant of a different reptilian ancestor than other mammals.
Example – duck billed platypus.
Marsupials: mammals that give birth to partially developed embryo that continue further development in the mother’s pouch.
Example – kangaroos, wallabies, and koalas
Placental Mammals: a type of mammal that has all of the embryo development within the uterus of the female. Includes 95% of all mammals.
Example – humans, dogs, horses etc

17. 12.6 Mammals pg 465 Mammalian Characteristics include: Hair
Sweat glands
Teeth
Fleshy lips
A diaphragm
A four chambered heart
A middle ear
Mammary glands that produce milk (females)
Endoskeleton
A complex brain and nervous system

18. 4 chambered heart

19. Application Questions
Phylum Chordata
Read pgs , do questions pg 449, questions #1, 4, pg 452 #3, 4
Class Fish
Read pgs , do questions pg 454, questions #1, 5, pg 455 #4,
Class Amphibian
Read pgs , do questions pg 460, questions #1, 2

20. Application Questions
Class Reptilia
Read pgs , do questions pg 460, questions #3, pg 461 #2,4,5
Class Aves
Read pgs , do questions pg 465, questions #1, 2
Class Mammalia
Read pgs , do questions pg 478, questions #6, pg 481 # 5, 7, 9