All About the Little Fish

Vertebrate Cladogram Jawless fish Jaws Sharks Boney Skeleton Ray Finned Bones in Pectoral Fins (Appendages) Lobe finned Paired appendages Amphibians Amniotic egg Reptiles Endotherms Birds Hair/fur Mammals Shared Derived Characteristics: The trait that separates one group from the others.

Fish Classification Kingdom: Animal Phylum: Chordates Subphylum: Vertebrates Classes: 1) Jawless Fish (Agnatha) 2) Cartilaginous Fish (Chondrichthyes) 3) Bony Fish (Osteichthyes)

3 Classes of Fish

1.Class Agnatha Lack jaws – attach to prey with a disk-shaped sucker mouth Elongated eel-like bodies Lack paired fins & bones Lack scales Cartilaginous skeleton Nickname: Jawless Fish Examples: Lamprey, Hagfish

Hagfish traits: Bottom dwellers Salt water No jaws have a plate-like tongue to rip flesh off organism Tie themselves into knots so they can’t be preyed upon Hagfish Video

Lamprey traits: Lack jaws Sucker mouth feed off the body fluids of prey In salt or fresh water Lamprey Video

2.Class Chondrichthyes Nickname: Cartilaginous fish Examples: Sharks, rays, skates Skeleton made up of cartilage Jaws Paired fins Predators carnivores

Scales – PLACOID SCALES like sand paper Internal fertilization Claspers Mating sharks

Shark traits: 6-20 rows of teeth Pointed inward Immediate replacement 20,000 teeth in a lifetime Extremely well- developed sense organs to detect prey Constantly swim Or they will sink lack air bladder Store excess lipids So they are less dense.

Ray traits: Flat bodies Bottom dwellers Give birth to live young Diamond shaped body Live in fresh and salt water Has a venom apparatus or sting at base of tail. -contains toxin that causes great pain and may alter heart rate and respiration of stung mammal (Killed Steve Irwin)

Skate traits: Flat bodies Bottom dwellers Long, whip-like tails No venomous barb Lay eggs “Mermaid Purses” Triangular body Live only in salt water

3.Class Osteichthyes Nicknames: Bony Fish Examples: Trout, bass, etc.. Jaws Bony skeleton Paired fins Have lungs or swim bladders -fill with air for buoyancy “Little Nemo” living in his Cnidarian home.

Two major groups of Osteichthyes: 1. Ray Finned Fish Common fish Trout, perch,etc.. Fins supported by long flexible, bony rays Contains an air bladder Scales – CYCLOID camouflaging for protection in the water similar to rings in trees

The “Penis” Fish (Candiru)“Penis” Fish

2. Lobe-finned Fish: Lunged fish Lunged fish and Coelacanth fish: have gills and lungs live in shallow ponds ~ ponds dry up, buries self in mud ~ uses lungs -Have fleshy fins with no rays

Coelacanth fish thought to be extinct but recently viewed Lack rays Has fleshy skin

Evolution from water to land:

Fish adaptations for life in water

1. Stream-Lined body Allows them to move without resistance

2. Muscular Tail Rapid Movement

3. Paired Fins Maneuver through water

4. Gills Take in O 2 & get rid of CO 2 because scales enable diffusion through the skin.

5. Dorsal Fin Increases stability

6. Secrete Mucus Reduces friction as they swim

7. Lateral Line Row of sensory structures that runs length of body and are connected to the brain. Used to detect vibrations

External Anatomy of a Bony Fish: Adipose fin

Fins: 1) Caudal – for forward movement of fish 2) Dorsal – keep the fish upright and stable 3) Anal – keeps fish moving in a straight line 4) Pelvic – 5) Pectoral – 6) Adipose - only in certain types of fish, unknown function Used for stopping and moving up and down (paired fins)

Dorsal fins: -one -two -joined -separated

Operculum:Operculum: Hyperlink - hard cover that protects the gills CLOSED when water enters the mouth OPEN when water comes out the gills Barbel: -slender whisker like appendages near the mouths of certain fish - notably members of the carp and catfish families - have a sensory function

Scales: Protection Prevent loss or gain of water

Other Fun Bionerdy Facts Fish = pets since 1853 ~12M households July 2005 ~646lb Mekong catfish in Thailand Goldfish = ~ 20 year life span Dental offices to reduce stress

That’s All Folks!