1. Unit 3: Grow a Backbone!
Outcome: Identify and describe the characteristics of chordates.
Vertebrates represent less than 5% of the animal species on earth, yet we are most familiar with vertebrates because “they are us” as Pogo said.
The vertebrates possess a backbone consisting of a string of cylinders of bone called vertebrae surrounding a spinal protecting cord. They have an internal skeleton (endoskeleton) which starts as cartilage in the embryo and is replaced by bone in most groups as the animal matures. Bone consists of a mixture of living cells and calcium phosphate salts and is unique to the vertebrates. Calcium in invertebrates’ skeletal structures is usually calcium carbonate.
The vertebrates share their phylum – Chordata – with one odd group of invertebrates, tunicates. Tunicates are soft, squishy blobs most commonly seen growing on pier pilings and floating docks. They do not appear to be related to vertebrates, but a careful study of the embryological development of both groups reveals the common characteristics that result in their placement in the same phylum.
Fish comprise the most numerous members of the vertebrates, both in terms of species numbers (48%) and numbers of individuals.  
Drill Questions:
What is a vertebrate?
What are some characteristics that connect us all together?
What Phylum are vertebrates in?
What are tunicates?

2. Classifications Kingdom Phylum Class Order Family Genus Species
For now you will only need to
know these three for the fishes
Know that when Genus and Species
are written that the “genus” is capitalized and the “species” is lower case
EXAMPLE:
Homo sapiens

3. Chordates Kingdom Animalia Phylum Chordata
Organisms that possess at one point in life or another:
Notochord
Hollow dorsal nerve cord
Pharyngeal gill slits
Post anal tail

4. Chordates Kingdom Animalia Phylum Chordata Hollow Dorsal Nerve Cord:
- Nerve cord that is modified into the brain and spinal nerve cord
- Runs dorsal (above) the notochord

5. Chordates Kingdom Animalia Phylum Chordata Notochord:
-Flexible rod is replaced by the vertebrae (backbone)
- Runs below (ventral) the hollow dorsal nerve cord

6. Chordates Kingdom Animalia Phylum Chordata Pharyngeal Gill Slits:
-Slits after the mouth that allow water to pass over
but not go into the stomach
- In mammals these disappear prior to birth, but in fishes they persist through adulthood.

7. Chordates Kingdom Animalia Phylum Chordata Post Anal Tail:
-Muscular region of the body that extends passed the anus
- Present in Homo sapiens when in the embryonic stage and in fish during adulthood

8. Above is Amphioxus, Lancelet, a primative marine chordate.
Today you will be viewing amphioxus under the microscope and drawing the image
making sure to label the:
Hollow Dorsal Nerve Cord
Notocord
Pharyngeal Gill Slits
Post Anal Tail
When completed turn in the notes and lab.

9. Fish Classification Kingdom Animalia Phylum Chordata Class:
Agnatha: Jawless Fish
EX: Hagfish/Lampreys
Chondrichthyes: Cartilaginous, Jaw Fish
EX: Sharks/Rays/Skates/Sawfish
Osteichthyes: Bony, Jaw Fish
EX: Coelacanth/ Salmon/Parrot fish/Puffer fish

10. Class Agnatha Hagfish Lamprey Jaws Jawless Fins No Paired Fins
Juvenile life
Marine water – scavenger
Fresh water –
Filter feeder
Adult life
Marine water – Parasite
Defense Mechanism
Slime glands

12. Class Chondrichthyes Sharks Cartilaginous skeletons
Fins: Dorsal, Caudal, Pectoral, Pelvic, and Anal
Senses: Lateral Line, Ampullae of Lorenzini, and one drop of blood in one million parts water
No swim bladders – Nitrogenous livers

13. Class Chondrichthyes Rays VS Skates Both have cartilaginous skeletons
Both have enlarged pectoral/reduced dorsal & pelvic fins
Breathing adaptation: Spiracles
No swim bladders – Continuously Swim
Rays: Fins flap like wings on a bird
Skates: Fins move like waves
Defenses:
Rays: 220V shock and poison barbs on spine tail

14. Class Osteichthyes Bony Fish Bone skeleton
Fins: Dorsal, Caudal, Pectoral, Pelvic, and Anal
Senses: Lateral Line
Swim bladders
Defenses vary widely: inflation to spined tails

15. Pigments
The use of specialized cells in the skin that contain pigment granules, called chromatophores, to blend with their environment, like the flounder or the squid/octopus/cuttlefish.

16. Countershading
Blending in with the open ocean by having a dark green or blue-gray colored dorsal side and a white colored ventral side

17. Cryptic Colors
Coloration or body features that mimic the environment around them, like sea horses.

18. Poster Colors Bright showy color patterns
Show territorial ownership, sexual displays, or to show they are poisonous as

19. Reproduction Internal External Without direct maternal nourishment
Shark egg case (nourishment inside case)
With direct maternal nourishment
Pregnant Shark (direct nourishment)
External
Lays eggs
External to
the parent

20. Hermaphrodites Sequential Hermaphrodites Synchronous Hermaphrodites
Protogyny: Females change to Males
EX: Parrot Fish
Protandry: Males change to Females
EX: Clown Fish
Synchronous Hermaphrodites
Functional male and female sex organs
Hamlets