Dog Fish Shark Lesson Plan
Anticipatory Set:
Day 1:
The anticipatory set to be used is a video from Eye-Witness termed Shark.
This video gives students an overview of information about sharks and gets
them ready to zero in on the Dog Fish shark.
Day 2:
BellworkList 3 things you learned about external features yesterday in class.
Day3:
BellworkWhat is the name of the external organ only present in dogfish males?
Day4:
BellworkWhat structure does food enter first after passing through the esophagus?
Day5:
BellworkList the 5 types of fins located on the dogfish shark.
What is the function of the nictitating membrane?
What is the function and location of the pyloric sphincter?
Objectives:
 Students will be able to identify the following structures on the external
surface of the Dog Fish Shark.
o Claspers
o Nostrils
o Caudal Fin
o Spiracles
o Pelvic Fins
o Pectoral Fins
o Ampullae of Lorenzini
o Lateral Line
o Dorsal Fins
o Nictitating Membrane
o Gills /Gill Slits
o Dermal Denticles
o Mouth
o Cloaca
o Rostrum
o Dorsal Spine
 Students will be able to identify the following structures in the inside of the
dogfish shark:
o Esophagus
o Cloaca
o Spiral Valve Intestine
o Brain
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Dog Fish Shark Lesson Plan
o Stomach
o Rectal Gland
o Pyloric Sphincter
o Testes
o Kidneys
o Gall Bladder
o Duodenum
o Rugae
o Ovary
o Spleen
o Pharynx
o Heart
o Liver
o Pancreas
o Cartilage Skeleton
o Gill Rakers
Safety Notes:
Today we will be in the lab and will be using dissecting instruments. Everyone must
be on their best behavior and must be very careful with the materials. All students
must stay at their own stations and use their own materials. This will help to
prevent accidents that may be initiated by students acting out.
Materials:
 Sharks (one for set of students)
 Dissection materials
 Baggy for shark
 Permanent marker
 iPads
 Gloves
 Lab Notes on eBackPack or printed out
Instructional Input:
Days 1 &2:
Today we are going to go through the external structures on your shark and get
them prepared for dissection. I am going to have you watch a video of a dissection
of external features of the dogfish shark to begin. Please, devices down during the
video. http://www.animalearn.org/links.php#.UvULYEJdW99
Now we will go through the structures on a PPT. Please pay close attention and be
sure to answer the questions during the PPT.
The first structure that we are going to discuss is called the External Nares or
Nostrils. These structures are located on each side of the head of the shark right in
front of the eyes. The purpose or function of these nares is to take up water in the
two smaller openings expel it through the larger opening. During this movement,
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Dog Fish Shark Lesson Plan
the water passes by a sensory membrane, which allows the sharks to detect
chemicals in the water.
The second structure we are going to discuss is called the spiracles. The spiracles
are small holes located directly behind the eyes. The purpose or function of the
spiracles is to provide oxygenated blood directly to the eye and brain through a
separate blood vessel.
The third structure we are going to discuss is called the mouth. The mouth is located
at the front of the head. The purpose of the mouth is obviously to eat, but it is also
used for the intake of water that passes through the gills.
The fourth structure we are going to discuss is called the gill slits. There are 5
vertical slits located right in front of the pectoral fin. The function of the gill slits is
to take the oxygen from the water passing over the gills and discharge carbon
dioxide into it.
The fifth structure we are going to discuss is called the lateral line. The lateral line is
a pale line that extends noticeably from the pectoral fin past the pelvic fin. The
lateral line senses tiny pressure disturbances in the water. The lateral line is a line of
pores that run along each side of the shark that help the shark orient to movement &
sound.
The sixth structure we are going to discuss is called the cloaca. The cloaca opening is
located between the pelvic fins/claspers. The Cloaca is the opening for the sex
organs as well as being used for excretory waste.
The seventh structure we are going to discuss is called the clasper. Claspers are only
present in males and are located down the middle of each pelvic fin. Claspers are
used to introduce the sperm into the cloaca of the female.
The eighth structure we are going to discuss is called the fins. There are 5 fins in
total. These are the 1st & 2nd dorsal fins, pectoral fin, pelvic fin & caudal fin. The
dorsal fins are anti-roll stabilizing fins. The pectoral fins are the steering fins. The
pelvic fins are the stabilizing fins. The caudal fin has an upper lobe and lower lobe
that provides thrust.
The rostum is the pointed snout located at the front of the head.
The dorsal spines are just in front of each dorsal fin. They are used defensively by
the shark (each has a poison gland associated with it.)
The Denticles are tooth-like scales on the surface of the sharks skin. They reduce
drag and allow sharks to swim more silently and more smooth.
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Dog Fish Shark Lesson Plan
The Ampullae of Lorenzini are small vesicles and pores that form part of an
extensive subcutaneous sensory network system. These pores are found around the
head of the shark. These pores detect weak magnetic fields produced by other
fishes, at least over short ranges. This enables the shark to locate prey that are
buried in the sand, or orient to nearby movement. They may also allow the shark to
detect changes in water temperature.
The nictitating membrane is a membrane that is present over the eyes that covers &
protects the eyes during feeding.
Now that we have covered the information, let’s go into the lab and take a look at
your sharks.
Days 3 & 4:
Today we are going to go through the internal structures on your shark and get
them prepared for dissection. I am going to have you watch a video of a dissection
of internal features of the dogfish shark to begin. Please, devices down during the
video. http://www.animalearn.org/links.php#.UvULYEJdW99
Now we will go through the structures on a PPT. Please pay close attention and be
sure to answer the questions during the PPT.
The first structure we are looking at is the heart. The heart is two chambered in a
dogfish shark which is made up of an atrium and a ventricle. The atrium pumps
blood to the dorsal ventricle and the ventricle pumps blood through the conus
arteriosus to the gills and the rest of the body.
The second structure is the spleen. The spleen is located at the end of the stomach. It
is triangular in shape and dark in color. The spleen functions in production,
degradation and storage of red blood cells.
The third structure is the gill rakers. The rakers vary in number and spacing
depending on the type of shark you have as well as its maturity. The rakers function
in preventing food particles from entering the gill chambers.
The kidneys are the next structure we are going to discuss. They are located on
either side of the midline. They look quite a bit different then human kidneys. They
function in extracting urea from urine and returning the urea to the blood.
The brain in the shark is much smaller and less complex in comparison to larger
sharks. The brain in the dogfish shark is in charge of body movement and processing
sensory information as well as many other things.
The pyloric sphincter is located at the base of the stomach. It is a contracting ring of
muscle, which guards the entrance of the small intestine. It functions in controlling
the rate and amount of stomach contents being emptied into the spiral intestine and
prevents back flow into the stomach.
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Dog Fish Shark Lesson Plan
The rectal gland is located at eh base of the shark between the spiral intestine and
the rectum. It functions in secreting salt to help the shark maintain osmotic balance
with the seawater.
The spiral valve intestine is located between the duodenum and the rectal gland. It
is an internally coiled organ that functions almost like a spiral staircase. It increases
the surface area across which nutrients can be absorbed. Because of this organ,
sharks have to feed less frequently than species that do not have this organ.
The stomach is a j-shaped organ in the dogfish shark. It has two portions, the cardiac
and the pyloric. The cardiac being located towards the head of the shark and the
pyloric being located towards the caudal fin. It functions in digestion.
The liver occupies most of the sharks body cavity. It has two main functions: it
stores all fatty reserves for energy there and it also serves as a hydrostatic organ.
The pharynx allows passage of food and air from the outside world to flow into the
larynx.
The duodenum is located between the stomach and the spiral intestine. It receives
bile from the liver in order to further digest food.
The rugae are longitudinal folds located in the stomach that help in the churning and
mixing the food with digestive juices.
The ovary is located underneath the liver towards the spine.
The esophagus is the connection between the pharynx and the stomach. It allows
food to move from the pharynx down to the stomach to be digested. It has the same
function in humans.
The gall bladder is located within a smaller lobe of the liver. It functions in the
storage of bile from the liver and also aids in floatation.
The testes are located near the top of the body cavity underneath the liver and next
to the kidneys. The sperm passes from the testes down the vas deferens near the
kidneys.
The pancreas is the last structure we are going to discuss today. It is located on the
duodenum and the lower stomach. It passes secretions from one side of the
pancreas to the duodenum.
Day 5:
I will use the shark review worksheet as well as the post test to go over any
questions the students have about the shark and clarify any information that I may
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Dog Fish Shark Lesson Plan
have not been clear on the first time around. I will then have all students take the
post-test.
Modeling:
The students will watch a short video explaining the dissection tools and how to use
them if necessary. I will also go over this in class.
Check for Understanding:
 What are the names of the 5 fins that are on the Dog Fish shark?
 What is the difference between a lateral line and a dorsal spine?
 What is one characteristic of the Denticles on the surface of the shark’s skin?
 What is the name of the structure located on the surface of the pelvic fin in
males sharks that is not located on female sharks?
 How do the gills function for gas exchange?
Guided Practice:
I will use closing questions each day at the end to sum up what we learned and
discussed.
On the final day, I will review for the first 15 minutes of the class period and then
give the students the remainder of the class to take the post-test.
Independent Practice:
Each set of students will get their shark. They will be instructed to take them out of
the bags, wash them, and write their names on the bag with permanent marker.
Depending on the amount of class-time left, the students will be instructed to begin
dissection using the notes page on their iPads.
Conclusion:
At the conclusion of each class period I will sum up what all we went over during
that class. Using the worksheets previously created, I will ask the students questions
regarding the material covered that day.
Day1:
Why are the spiracles important?
What is the function of the Gill Slits?
How many fins does a dogfish shark have and what are the names of them?
Where are the dorsal spines located?
Day2:
How is the shark’s nose different from our own?
Between what two fins is the lateral line located?
What is the function of the cloaca in both males & females?
Day3:
Where are the testes located in the male shark?
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Dog Fish Shark Lesson Plan
Where are the ovaries located in the female shark?
Describe the Ampullae of Lorenzini.
What is the name of the structure that the heart uses to pump blood through
to get it to the gills and the rest of the body?
Day4:
What are the two chambers of the heart called?
What is the function of the spleen?
What is the function of the rectal gland?
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