Phylum Chordata A.K.A. Chordates

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

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

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

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

Chordate characteristics http://www.biog1105-1106.org/labs/deuts/chordates.html

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

Subphylum Urochordata A.K.A. tunicates SALPS Planktonic Filter feeders Warm water Invertebrates http://www.flickr.com/photos/31124758@N00/165884673/

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

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

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

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

Lampreys

Hagfish

Hagfish

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

Class Chondrichthyes Placoid scales; sandpaper-like

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

Class Osteichthyes Gills covered by an operculum.

Class Osteichthyes Have different scales than sharks: Ctenoid Cycloid Ganoid

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.

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

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

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.

http://dogsbreathdivers.com/marinelife/fish.htm

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

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