Download All About the Little Fish

All About the Little Fish
Vertebrate Cladogram
Mammals
Birds
Reptiles
Hair/fur
Amphibians
Lobe finned
Ray Finned
Sharks
Jawless
fish
Jaws
Boney
Skeleton
Endotherms
Amniotic egg
Paired appendages
Bones in Pectoral
Fins (Appendages)
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
Nickname: Jawless Fish
Examples: Lamprey, Hagfish
Lack jaws – attach to prey with a
disk-shaped sucker mouth
Elongated eel-like bodies
Lack paired fins & bones
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 on
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
Chondrichthyes continued…
Scales – PLACOID SCALES
• like sand paper
Internal fertilization
Claspers
Shark traits:
6-20 rows of teeth
• 20,000 teeth in a
lifetime
Extremely welldeveloped sense
organs
Lots of lipids
Constantly swim
• lack air bladder
Ray traits:
Flat bodies
Bottom dwellers
Long, whip-like
tails
Live young
Diamond shaped
body
Skate traits:
Flat bodies
Bottom dwellers
Long, whip-like tails
Lay eggs
• “Mermaid Purses”
Triangular body
3. Class Osteichthyes
Nicknames: Bony Fish
Examples: Trout, bass
Jaws
Bony skeleton
Paired fins
(“Little Nemo”)
Two major groups of Osteichthyes:
1. Ray Finned Fish
Traits
Common fish
Air bladder
Scales – CYCLOID
• camouflaging for
protection in the water
• similar to rings in trees
The “Penis” Fish (Candiru)
Two major groups of Osteichthyes:
2. Lobe Finned
Fish Traits
Lunged fish
• gills and lungs
• shallow ponds
Two major groups of Osteichthyes:
Coelacanth fish
• thought to be extinct
Lack rays
Fleshy skin
Fish adaptations
for life in water
Stream-Lined body
Allows them to move without resistance
Muscular Tail
Rapid Movement
Paired Fins
Maneuver through water
Gills
Take in O2 & get rid of CO2
Dorsal Fin
Increases stability
Secrete Mucus
Reduces friction
Lateral Line
Runs length of body of sensory nerves
to detect vibrations
External Anatomy of a Bony Fish:
Operculum:
- hard gill cover that protects the gills
• CLOSED when water enters the mouth
• OPEN when water comes out the gills
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
Used for stopping and
4) Pelvic –
moving up and down
5) Pectoral –
(paired fins)
Scales:
Protection
Prevent loss or
gain of water
Internal Anatomy of a Bony Fish
Urogenital
Opening
Anus
Anterior to Anal Fin
Digestive System:
Purpose: to break food down into useable molecules
Passageway of food:
Via blood cells
energy &
to make new cells
- mouth (entrance for food)
- pharynx (back of throat-connects
mouth to esophagus)
- esophagus (passageway for food
that leads to stomach)
- stomach (starts digestion of all
food by acids and enzymes)
- pyloric ceca (2nd part of digestioncontinues what stomach started)
- intestines (last part of digestion
where food molecules are absorbed
into blood)
- anus (exit of solid waste)
Urogenital
Opening
Anus
Anterior to Anal Fin
Digestive System:
Accessory Organs
Additional organs of digestion:
- help
with digestion, but food does not pass
through them
• liver
makes bile
(bile digests fats in intestine)
• gall bladder
intestine
stores bile until needed in
• pancreas
makes insulin (insulin helps with
carbohydrate digestion) & sends it to the
intestine
Urogenital
Opening
Anus
Anterior to Anal Fin
Circulatory System:
Closed (1 loop system)
Low efficiency
Clean & dirty blood mix
Purpose:
- To deliver O2 & food
-Pick up CO2 and other
wastes
Pathway of Blood:
1. Heart pumps blood thru arteries to
capillaries in the gills
2. Blood picks up O2 & releases CO2 at
gills
3. Gills to body tissues where nutrients &
wastes are exchanged
4. Blood goes back to heart thru veins
gills
brain
Circulatory System
Heart-Circulates Blood
2 Chambers
Atrium
(upper)
Ventricle
(lower)
Circulatory System:
6.
5.
4.
3.
2.
1.
Circulatory System
Pathway thru HEART:
1. dO2 blood returns from body to Sinus
Venosus
2. To large Atrium
3. To muscular Ventricle (PUMP)
4. To Conus/Bulbus Arteriosus
~ saturated with blood vessels
-has valves to decrease backflow
5. To Aorta (large artery) to body
Respiratory System:
Purpose:
- exchange O2 and CO2 with environment
• DO NOT USE NOSTRILS TO BREATHE!!!!
Respiratory System: Gills
• Gills that have a large surface area
• Each gill (2) is composed of 4 gill arches
- cartilaginous structures with
gill filaments projecting off of them
- gill rakers ~ filters out food from gills
Excretory System:
Purpose: to remove nitrogenous
waste (ammonia) from the blood
which is created by the cells going
through metabolism
Excretory System:
Salt H2O: urinate
very little
ammonia
urea
Fresh H2O: urinate in
large quantities
blood
kidneys (filter blood)
(liver converts)
urea
excess H2O excess salt
urine
urogenital opening
urinary bladder
Kidneys
Filters urea, excess salt, & excess water
from the blood
Urogenital
Opening
Anus
Swim Bladder:
Purpose: provides BUOYANCY & helps it
FLOAT when not swimming
- Allows fish to adjust its DENSITY in
order to raise and lower itself to a
different depth
Urogenital
Opening
Anus
Nervous System:
Purpose

-
-
To transmit electrical impulses from brain to
the rest of the body
Brain
Spinal cord
Nerves
Sense organs
• lateral line
• eyes
• nose
Bony Fish Nervous System
1) Olfactory lobe (scent)
-connects to nostrils (draws
in odors from water) by
nerves
2) Cerebrum
- reasoning
- maternal care
- controls higher brain
functions
3) Optic lobe
- sight (lens, optic nerve)
- hearing
4) Cerebellum
- coordinates
balance/movement
5) Medulla
- controls internal organs
6) Spinal cord
- nerves transmitted
Reproductive System:
(spawning)
Purpose: to produce viable sex cells
Male: sperm
Female: eggs
out urogenital opening
Fertilization:
Bony Fish:
• external fertilization
Oviparity ~ lay eggs outside
Fertilization:
Cartilaginous
Fish:
• internal
fertilization
Ovoviviparity ~
eggs hatch inside
mother & give
birth to live
young
Chondrichthyes: Live Birth Video
Sea Horse
Mangrove Fish
Stingray
Shell Brooding Cichlids
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!