Perch Fish Dissection

Here are some facts about the Perch Fish before we begin the dissection process:

• They are carnivorous
• They feed on smaller fish, shellfish, and insect larvae
• They are found in bodies of water such as ponds or streams
• They are most commonly found in the Great Lakes
• Therefore they are a freshwater fish
• They breathe by using their gills. Gills take in water where it flows through the blood. The blood then proceeds to take out the oxygen from the water.

Fun Fact: There are over 6,000 species in the Percidae family.

External Anatomy

Nares on the front of the fish help in the breathing process.
Gills take in water to filter out the oxygen
the pectoral, pelvic, anal, and dorsal fins help the fish swim
while the caudal fin helps it change direction.  

Internal Anatomy

The heart can be difficult to find at first due to it being
underneath the liver. It pumps blood to the body.

The gills are the breathing mechanism for the fish.

They help with the urinary system by removing waste.

 Swim Bladder-helps the fish stay where it needs to be, no sinking or floating.
Stomach- breaks down ingested food.
Liver-aids in the digestion of food by secreting bile.
Muscle- helps in the movement of limbs.
Spleen- filters the blood.
Intestine- takes nutrients from digested food.

Incision Guide

Cut, in a rectangle, just below the dorsal fin,
right before the anal fin, just above the pelvic fin,
past the pectoral fin.

https://www.youtube.com/watch?v=6jwjqhhxjoU

Crayfish Dissection

Crayfish are found in fresh water like streams, ponds, and ditches. This organism prefers to live in non-polluted water. They can be found under rocks of small streams and creeks. Crayfish eat both plants and animals. They will also eat dead organisms that are relatively fresh. Examples of their diet include worms, insects, insect larvae, and eggs of other organisms. Crayfish are able to live despite hostile conditions due to the wide range of food they are able to consume. Also their ability to consume detritus allows energy transfer of organisms. Crayfish have gills that allows them to retrieve oxygen from water. Crayfish may breathe outside of water if and only if their gills remain moist. In other words, crayfish living in humid environments are able to spend time outside of water. Crayfish can live up to 20-30 years if they hide in holes and do nothing. They reach maturity after 4 years.

Major External Anatomy

Eyes- capture light for vision
Antenna- sensory appendages used to sense food and surroundings
Cheliped- 1st pair of walking legs used for grasping and defense
Walking legs- appendages used for movement
Abdomen- segmented region used to swim backwards
Swimmeret- used for reproduction
Rostrum- protects the sensory appendages of the face
Telson- central swimming paddle
Uropod- small swimming paddles

Green Gland- excretes waste products and balances water in blood
1st-2nd maxilliped- holds food
Mandible- crushes food

We are able to determine the sex of our crayfish by looking at the first set of swimmerets. Males have larger 1st swimmerets to hold the female during mating. They are labeled in blue on the image.

Incision Guide

Begin by cutting along the carapace as shown in the top image. Start from the sides closest to the abdomen and cut towards the head of the cray fish following the curves depicted. Try to cut along the indentations already present on the carapace. Extend the cut closer to the cephalic region. The bottom image shows the cuts made when the crayfish is on its side. Cut from the abdomen towards the cephalic region from the top side first. Then perform the same cut along the bottom side. The image uses highlighted blue markings to demonstrate that this bottom cut should occur without cutting the walking legs.  These legs should be pushed aside to perform this cut.

Major Internal Anatomy
The picture below is kind of blurry. Red highlights are the gills which are used for breathing. The green highlight is the stomach which is used to digest food. The blue highlight is the digestive gland which produces digestive enzymes. The purple is the midgut which is part of the intestines and absorbs nutrients. the yellow is the ventral nerve cord which connects the brain to the rest of the body. The intestines prepare food for secretion. The tail muscles are used for swimming.

Dissection Video

https://www.youtube.com/watch?v=D4gdFtXlvG4

Earthworm Dissection

Earthworms can live in tress, in bark, under rocks, along the river, springs and ponds, they prefer to live in the earth’s rich soil. They get their nutrition from things in the soil such as decaying roots and leaves. Earthworms don’t have lungs, but they breathe through their skin.  

Fun Facts

Earthworms are androgynous, producing both eggs and sperm.

Function of external structures

• clitellum - produces mucous slime during mating
• mouth- where the food goes in
• anus- releases undigested material
• male genital pore- opening where sperm from that worm is released during mating
• setae- bristle-like structures that help the worm grip surfaces and to move
• Prostomium- is a small projection that hangs over the mouth
• female genital pore- releases eggs
• sperm groove- Carries sperm from male genital pore to clitellum
• seminal receptacles- stores sperm received from other worms
• septum- Divides coelom into compartments
• segment- contract during movement
  
  

  

  
  

  

  
  
  
  
  

Function of internal structures

• pharynx- sucks in food
• gizzard - breaks down and grinds the food
• crop-  stores food
• esophagus-  food goes through here before it goes to the crop and after the pharynx
• intestine- food is broken down and absorbed by the blood
• ventral nerve cord- Relays messages between brain and body
• ganglia( brian)- masses of tissue containing many nerve cells
• ventral blood vessel- Transports blood to posterior end of body
• Dorsal blood vessel- Transports blood to anterior end of body
• septa- dividing wall between segments
• nephrida- expel excess water and metabolic waste from the blood
• testes-produces sperm for fertilization
• ovaries- where eggs are laid and stored until they mature
• buccal cavity - Holds for food and opens to Pharynx
• septum- Divides coelom into compartments
• seminal receptacles- stores sperm received from other worms
• central nerve cord-  helps the worm move and feel
• pseudohearts- pumps blood throughout the body
• sperm duct- openings in which sperm can pass through
• oviduct- a tube connecting the ovaries and the uterus
• typhlosole- provide surface area and increase absorption of nutrients
• seminal vesicles- storms sperm made by this worm to give away
  
  
  
  

  

  
  
  Incision Guide-

Cut a slit in the dorsal surface near the posterior pin

 Dissection video

Starfish Dissection

Starfish Dissection

Starfish live in ocean on the sea bottom. Starfish breathe through their feet. Their feet are made of thin tissue that gases can easily move through. Starfish’s tubed feet and tiny bumps all over their bodies transport the oxygen from the seawater to their tissues. Starfish mainly eat clams, oysters’ sand dollars and mussels.

Fun FACT

A starfish can regenerate lost arms. This is useful if the sea star is threatened by a predator. Starfish house most of their vital organs in their arms, so some can even regenerate an entirely new sea star from just one arm and a portion of the star’s central disc. It takes almost a year for this to happen

function of external structures 

 ring of oral spines- spines around the mouth

Central dics- holds all the arms of the starfish 

arms- help with movement and capture prey

Ambulacral groove-contains the tube feet on the oral side and used to pry open the shells of bivalves

  tube feet-  used for feeding, movement, and a little for respiration

eyespot- Senses Light And Dark

madreporite- where water enters in the water vascular system

Spines-  helps protects the starfish

mouth-stomach that is pushed out to eat food

 

function of internal structures

pyloric ceeca-secretes enzymes for digestion and absorption of nutrients

gonads-  make sperm or eggs

ampulla -Fill up with water and then release to tube feet

ossicles - Plates That Fuse To Form Skeleton

stone canal- a short canal that connects the madreporite to the ring canal around the mouth

ring canal- Circular canal in the center disk

lateral canal-  Branches off of radial canal all the way down the arm and leads into the ampulla

Incision Guide

Dissection video

Grasshopper Dissection

Facts

• Grasshoppers live on all continents besides Antarctica. Most live in dry environments with lots of grass.
• They eat leaves, flowers, stems, and seeds. Occasionally they scavenge dead insects.
• They exchange oxygen and carbon dioxide between their tissues and the atmosphere through air-filled tubes called tracheae. Tracheae open to the environment through small holes called spiracles.
• In Africa and Asia, grasshoppers are known to be crop pests.

External Anatomy:

• head, thorax, abdomen: top, middle, bottom regions of grasshopper
• tympanic membrane: transmit sound from the air to the organism
• spiracle: hole used by grasshoppers for respiration; air is taken in through them and filtered by hairs in tracheae.
• ovipositor: tube that delivers eggs
• antenna: odours, touch, humidity, vibration, wind velocity and direction.
• compound eyes: can see shape, colour, movement, and tell the distance.
• mouthpieces: cut and grind food
• trochanter: attachment point for muscles
• femur: supports weight of body
• tarsus: forms ankle joint
• tibia: connects femur to tarsal segments

Internal Anatomy:

• heart (not pictured): pumps the fluid to the head from where it filters past the tissues and organs on its way back to the abdomen.
• crop: stores food
• gastric caecae: pockets of the stomach that secrete enzymes that break down food
• intestine: transports waste through the digestive system
• rectum: passageway for digested waste from the intestine to the anus

Incision Guide:

• for internal organs

• for appendages
  

Dissection Video:

Clam Dissection

Facts

• Clams live in both freshwater and marine environments.
• They eat plankton.
• They take in oxygen through the surrounding water to breathe.
• “Clams do not have any sense. They cannot smell, hear or even see because they have no noses, ears and eyes.”

External Anatomy:

• umbo: highest, most prominent part of the shell
• growth rings: age markers
• hinge ligament: located near umbo, hinges valves together

Internal Anatomy:

• gonad: reproductive organ, produces egg or sperm
• gills:respiratory structures responsible for obtaining water and food
• digestive gland: used for digestion after passing mouth
• foot: used to burrow into mud and sand
• mantle: tissue that lines valve and covers soft body of clam
• posterior/anterior adductors:on the sides of the clams, used to close shell.
• exhalant siphon:expels water and waste out of the clam
• inhalant siphon:brings in oxygen, food, and water into the clam
• teeth: ridges near anterior end of hinge that interlock when shell is closed

Incision Guide:

• cut along ventral side
  

Dissection video:

Frog Dissection

Frogs are amphibians. This means that they are born in water, but are able to live near and away from water once they become adults. Most frogs are found in areas with warm temperatures. Frogs eat small invertebrates, but some frogs species can be omnivorous. Small frogs eat insects. In the water, frogs breathe through their skin which is a thin membranous tissue that allows gas exchange to occur. Frogs can also breathe through their nostrils using their lungs. Since frogs don't have diaphragms, they must use the bottom of their mouths to push air in and out of the lungs. At rest, frogs use a respiratory surface in their mouth to breathe. Large declines in frog populations have occurred in the past 50 years due to habitat destruction, chemical pollution, climate changes, and many other human activities.

Fun Facts

Frogs’ long legs allow them to leap more than 20 times their body length.

Vocal cords first developed in frogs. Males have vocal cords that fill up with air.

Incision Guide

                               

External Anatomy 

External Nares allow air to enter.
Nictitating Membrane protects the eye.
The tympanum is the eardrum.

Vomerine and Maxillary teeth used to hold prey.
Internal nostrils used for respiration.
Eustachian Tubes provide pressure in the inner ear.
Tongue used to capture prey.
Gullet Opening is the beginning of the digestive tract.

Internal Anatomy

When we opened our frog, we didn't find eggs scattered throughout the internal cavity. However, our frog is a female because we were able to locate the oviducts which produce eggs in female frogs. In male frogs, this structure may be present but it has no vital function (vestigial structure). 

 Function of structures:
Fat Bodies- Like humans, adipose tissue insulates internal organs and protects them.
Heart- Pumps blood to the entire body.
Lungs- Used for respiration and gas exchange.
Peritoneum- Covers internal organs and holds them in place.
Oviducts- Produce eggs in females. Vestigial structure in males.
Liver- Secretes bile and helps digest food.
Stomach- Storage for food. Food digested.
Small Intestine- Most digestion and absorption of nutrients occurs here. Enzyme from the pancreas enter the duodenum.
Large Intestine- Absorbs most fluids. Prepares food for secretion.