1. Phylum Chordata
A.K.A. Chordates

2. Four Distinguishing Features
Single, hollow, dorsal nerve cord
Gill or pharyngeal slits (or pouches)--small openings along anterior part of body or pharynx
Notochord: flexible rod for support that lies between the nerve cord and gut
Post-anal tail: tail that extends beyond the anus

3. Nerve Cord Runs along the dorsal or back side of a chordate
Connects nerves to internal organs, muscles and sense organs

4. Notochord
A long supporting rod located just below the nerve cord (ventral to the nerve cord)
All chordates begin life with the notochord, but do not always retain it when they reach adulthood (like the human post-anal tail)
Notochord is usually replaced with backbone in most vertebrates

5. Pharyngeal Pouch
Series of paired structures that develop into gills in some vertebrates like lancelets and tunicates.
In humans they develop into the internal ear organs and some throat organs like the parathyroid

6. Chordate characteristics

7. Subphylum Urochordata A.K.A. tunicates
SEA SQUIRTS
3,000 species; all marine
Invertebrates
Sessile
Filter feeders
Larval form has all four characteristics of chordates; adults do not

8. Subphylum Urochordata A.K.A. tunicates
SALPS
Planktonic
Filter feeders
Warm water
Invertebrates

9. Subphylum Cephalochordata A.K.A. Lancelets (amphioxis)
23 species
7 cm long, similar in shape to a fish
Retains chordate characteristics entire life
Invertebrate (lack a backbone)
Filter feeders using its pharynx with pharyngeal slits; inhabit soft bottoms

10. Subphylum Vertebrata A.K.A. Vertebrates
Have a backbone; usually made of bony segments called vertebrae
Bilateral symmetry
Endoskeleton
Complete digestive system
Closed circulatory system
96% of all chordates are in this phylum
Include: fish, reptiles, birds and mammals

11. Types of Fishes
1) Class Agnatha: Jawless fish 2) Class Chondrichthyes: cartilaginous fish 3) Class Osteichthyes: bony fish

12. Class Agnatha A.k.a. Jawless fish
Lack jaws
Elongated like an eel
Lack paired fins
Lack scales
Mostly parasitic
Examples: hagfish and lampreys

13. Lampreys

14. Hagfish

15. Hagfish

16. Class Chondrichthyes A.k.a. Cartilaginous Fish
Skeleton of cartilage
Movable jaws with teeth
Paired lateral fins for efficient swimming
Placoid scales: similar shape to teeth embedded into the skin
Spiracle and gill slits are not covered
Includes: Sharks, Rays, Skates, and Ratfish

20. Class Chondrichthyes
Placoid scales; sandpaper-like

21. Class Osteichthyes A.k.a. Bony fish
Skeleton made of bone
Cycloid, ganoid or ctenoid scales which are thin flexible and overlapping
Scales are made of bone and covered by a thin layer of tissue and mucus
Operculum that covers and protects the gills
Swim bladder: fills with air to control buoyancy

22. Class Osteichthyes
Gills covered by an operculum.

23. Class Osteichthyes Have different scales than sharks: Ctenoid Cycloid
Ganoid

25. Fertilization
Internal: sperm is transferred to female through the act of copulation; mainly Chondrichthyes (claspers)
External: (Broadcast spawning) release gametes into the water; most common in Agnatha and Osteichthyes.

26. Development
Oviparous: eggs develop outside of the mother’s body; embryo receives nutrients from the yolk sac
Ovoviviparous: retain the eggs within the mother’s body for protection; embyo receives nutrients from the yolk sac (a.k.a. aplacental viviparous)
Viviparous: embryo absorbs nutrients from the wall of the mother’s reproductive tract

28. Parthenogenesis
The development of an egg into a normal embryo without fertilization by sperm.
Rare but does happen in sharks and some bony fish
A.k.a. virgin birth

29. Reproductive Oddities
Sex reversal: individuals begin as one sex and switch to the opposite sex.
Example: anemone fish
Sea anemone is inhabited by one large female that mates with a large dominant male. Others living in the anemone are small, non-breeding males. When female dies or is removed the male becomes female and the largest non breeding male becomes the new dominant male.

31. Fish Adaptations You will work in pairs.
Each pair will have one sheet of paper and each person should have a different color pen.
Each person in the pair will answer every other question in their color pen.
Answer the following questions:
Part I: 1, 2, 3, 4, 5, 7 8, 10, 11, 12(read),14, 15, 16, 17 (your fish only)
PartII: 1, 2 a-c, 3, 5, 7
Part III: 1, 2, 3, 4, 6

32. Things you need to take the test
Chordate notes
Fish Notes: Class Agnatha, Osteichthyes, Chondrichthyes
Fish Word Scramble (half sheet)
Fish Reproduction Notes
Lamprey Lab (half sheet)
Perch Dissection Lab
Shark Dissection Lab
Phylum Chart