What are fish? Aquatic vertebrates Most have Paired fins Scales
Gills Wide range of characteristics Belong to different
classes
Slide 3
Fish Evolution First fishes: armored bodies, no jaws Cambrian
period (510 mya) 505 mya to 410 mya: Adaptive Radiation of fishes
variation increased (no armor v. armor; jaws v. jawless)
Slide 4
Fish Evolution Jaw evolution and paired fins seem to have come
about together Made out of bone or cartilage Paired fins More
control during swimming Tail fins More muscle mass along trunk of
body
Slide 5
Fish Evolution Fish evolved into two groups: Class
Chondrichthyes Superclass Osteichthyes Lobe finned (Class
Sarcopterygii) evolutionary links point to the lobe finned fish
sharing a common ancestor with early amphibians Ray finned (Class
Actinopterygii)
Slide 6
Orders of Bony Fish 1. Anguilliformes Order 2. Salmoniformes
Order 3. Cypriniformes Order 4. Siluriformes Order 5. Perciformes
Order Use your computers to research characteristics of one order
(body layout, habitat, types of food eaten, modes of feeding,
examples). You will present your findings to the class.
Slide 7
Fish Order: Body layout: Habitat Types of food eaten Modes of
feeding Examples:
Slide 8
Fish Form and Function Adaptations for life in water Methods of
feeding Gills Paired fins
Slide 9
Feeding Display all modes of feeding Herbivores, carnivores,
omnivores, parasites, filter feeders, detritus feeders Depending on
type of food available Some fish are highly specialized (barracuda
- carnivore)
Slide 10
External Fish Anatomy Fins: Dorsal Pectoral Pelvic Anal
Caudal
Slide 11
External Structures Fins steering, propulsion through water
Lateral Line Operculum covers/protects gills Nares Nasal
openings
Slide 12
Lateral Line Senses changes in the water Current Electrical
Heat NO external ear Utilizes lateral line for detecting sound
vibrations
Slide 13
Key: External Fish Anatomy Nares Eye Fins: Dorsal Pectoral
Pelvic Anal Caudal Operculum Mouth Lateral Line
Slide 14
Skeletal System Consists of bone and cartilage Skull Vertebrae
Ribs Rays within the fins
Slide 15
Skeletal System
Slide 16
Muscular System Tail and Trunk Muscle Myotomes blocks of muscle
that run up and down the fishs body Separated by myosepta Jaw
Fin
Slide 17
Digestive System Mouth Pharynx Esophagus Short, expandable (to
enable swallowing of large food) Stomach Gastric glands Pyloric
ceca Finger-like projections responsible for most digestion Liver
and pancreas secrete enzymes to help with digestion Intestines
majority of food absorption, length differs in herbivores a
carnivores Gizzard
Respiratory System Gills on either side of the pharynx Made up
of filaments Feathery structures with large number of capillaries
for increased gas exchange Pull water in through the mouth, over
the gills, out the openings on the side of the pharynx
Slide 21
Specialized Respiratory Systems Exception: Lungfish need to go
to surface of water to fill air sac (lung) Oxygen poor water
Also, describe how fish breathe. What happens to the operculum?
What is the purpose of afferent/efferent blood vessels?
Slide 24
Nervous System VERY simplified Brain 3 lobes Forebrain (smell)
Midbrain (vision, learning, motor receptors) Hindbrain (medulla
oblongata and cerebellum) Coordination Movement Balance Spinal cord
serves rest of the body
Slide 25
Nervous System - Brain
Slide 26
Circulatory System Closed circulatory system Single loop around
body 4 part heart: (but considered 2 chambered) Sinus venosus
Atrium Ventricle Bulbus arteriosus
Slide 27
Circulatory System Blood Flow Sinus venosus receives
unoxygenated blood from the body Valve at the end of the sinus
venosus opens into the atrium Atrium has thick, muscular walls
Atrium receives unoxygenated blood and pumps it into the ventricle
Ventricle is the largest and most muscular chamber of the heart
Ventricle fills with blood it constricts and forces the blood
through the bulbus arteriosus
Slide 28
Circulatory System Blood Flow Bulbus arteriosus is a valve or
series of valves that control blood flow out of the ventricle and
into the ventral aorta. Blood passes through the bulbus arteriosus
to the ventral aorta. From the ventral aorta, blood flows to the
gill filaments, where it is oxygenated. Blood flows out of gills
through the dorsal aorta and through the fishs body.
Slide 29
Label the heart of a fish Sinus venosus Atrium Ventricle Bulbus
arteriosus Vein Ventral Aorta Also, draw in direction of blood
flow.
Slide 30
Circulatory System Red blood cell production Spleen Kidney
Bones
Slide 31
Blood Flow
Slide 32
Excretory System Release nitrogenous waste as ammonia Gills
Kidneys filter blood to excrete liquid waste Kidneys allow fish to
maintain salt balance Salt water fish Fresh water fish Cloaca
Slide 33
Reproduction External fertilization Oviparous completely
separate from both parents Females release eggs into water Males
release sperm Ovoviviparous One parent carries fertilized eggs
until they hatch no direct connection to the parent (yolk sac is
nourishment) Viviparous Carry fertilized eggs internally direct
connection between mother and offspring (no yolk sac) Live birth
Sharks
Slide 34
Slide 35
Growth and Development Fish are able to live independently when
hatched Some species build nests, care for young for long periods
of time Aquatic life minimal strain on organs, bone, muscle Can
grow large Limits on circulatory system, brain function
Slide 36
Life Cycle of Bony Fish Egg Larval fish/Alevin Fry Juvenile
Adult Spawning adult
Slide 37
Other Structures Swim Bladder Between the stomach and the spine
Allows for buoyancy Fills with air to keep fish afloat If the fish
does not have a swim bladder, they will sink if they stop
swimming
Slide 38
Slide 39
You will need to sketch and label the following systems:
External fish anatomy Respiratory system Reproductive system
Digestive system Heart I expect these to be turned in with the
dissection packet and questions.
Slide 40
Also You will be removing organs from your perch. Throughout
the dissection I will be circulating to see which organ(s) we will
save for future comparisons. You will be graded on the dissection
as well as the post-dissection packet. I will collect 1 packet from
each person The answers to the questions throughout the procedure
should be on a separate sheet of paper these can be completed after
the dissection Each group will receive a dissection grade.