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 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 well- developed 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 O 2 & get rid of CO 2

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 4) Pelvic – 5) Pectoral – Used for stopping and moving up and down (paired fins)

Scales: Protection Prevent loss or gain of water

Internal Anatomy of a Bony Fish

Anus Urogenital Opening Anterior to Anal Fin

Digestive System: Purpose: to break food down into useable molecules Passageway of food: - 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 (2 nd part of digestion- continues what stomach started) - intestines (last part of digestion where food molecules are absorbed into blood) - anus (exit of solid waste) Via blood cells energy & to make new cells

Anus Urogenital Opening 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 stores bile until needed in intestine pancreas makes insulin (insulin helps with carbohydrate digestion) & sends it to the intestine

Anus Urogenital Opening Anterior to Anal Fin

Circulatory System: Closed (1 loop system) Low efficiency Clean & dirty blood mix Purpose: - To deliver O 2 & food -Pick up CO 2 and other wastes

Pathway of Blood: 1. Heart pumps blood thru arteries to capillaries in the gills 2. Blood picks up O 2 & releases CO 2 at gills 3. Gills to body tissues where nutrients & wastes are exchanged veins 4. Blood goes back to heart thru veins

gills brain

Circulatory System

Heart-Circulates Blood 2 Chambers Atrium (upper) Ventricle (lower)

Circulatory System:

Circulatory System

Pathway thru HEART: 1. dO 2 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 O 2 and CO 2 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: ammonia urea blood kidneys (filter blood) (liver converts) urea urea excess H2O excess salt urine urogenital opening urinary bladder Salt H 2 O: urinate very little Fresh H 2 O: urinate in large quantities

Kidneys Filters urea, excess salt, & excess water from the blood

Anus Urogenital Opening

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

Anus Urogenital Opening

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 out urogenital opening Female: eggs

Fertilization: Bony Fish: external fertilization Oviparity ~ lay eggs outside

Cartilaginous Fish: internal fertilization Ovoviviparity ~ eggs hatch inside mother & give birth to live young Fertilization:

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!