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 ClassificationKingdom: 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 mouthElongated eel-like bodiesLack paired fins & bonesLack scalesCartilaginous skeleton

Nickname: Jawless Fish

Examples: Lamprey, Hagfish

Hagfish traits:

Bottom dwellersSalt waterNo jaws• have a plate-like tongue to rip flesh off organismTie themselves into knots so they can’t be preyed upon

                                        

                   

                                     

Hagfish Video

Lamprey traits:

Lack jawsSucker mouth• feed off the body fluids of preyIn salt or fresh water

Lamprey Video

2. Class Chondrichthyes

Nickname: Cartilaginous fish Examples: Sharks, rays, skates

Skeleton made up of cartilageJawsPaired finsPredators 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 lifetimeExtremely well-developed sense organs to detect preyConstantly swim Or they will sink lack air bladder Store excess lipidsSo they are less dense.

Ray traits:

Flat bodiesBottom dwellersGive birth to live youngDiamond shaped bodyLive 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 bodiesBottom dwellersLong, whip-like tails No venomous barb

Lay eggs• “Mermaid Purses”Triangular bodyLive only in salt water

3. Class OsteichthyesNicknames: Bony FishExamples: Trout, bass, etc..

Jaws Bony skeletonPaired finsHave lungs or swim

bladders-fill with air for buoyancy

“Little Nemo”

living in his Cnidarian

home.

Two major groups of Osteichthyes:

1. Ray Finned FishCommon fish

Trout, perch,etc..

Fins supported by long flexible, bony rays

Contains an air bladderScales – CYCLOID• camouflaging for protection in the water • similar to rings in trees

The “Penis” Fish (Candiru)

2. Lobe-finned 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 O2 & get rid of CO2

because scales enable diffusion

through the skin.

5. Dorsal Fin

Increases stability

6. Secrete Mucus

Reduces friction as they swim

7. Lateral LineRow 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

fish2) Dorsal – keep the fish upright and

stable3) Anal – keeps fish moving in a

straight line4) 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: 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:

ProtectionPrevent loss or gain of water

Other Fun Bionerdy Facts

Fish = pets since 1853~12M householdsJuly 2005 ~646lb Mekong catfish in Thailand

Goldfish = ~ 20 year life spanDental offices to reduce stress

That’s All Folks!