Dissection
Domain Eukarya- Their cells are Eukaryotic cell
Eukaryotic- has a true nucleus because it’s nucleus has a membrane bound
Kingdom Animalia
Vertebrate- Phylum Chordata
Subphylum Vertebrata- Amphibia, mammals, and fish
Class Amphibia
Three different orders in Amphibia
Order Apoda-Caecilian
Caecilians are legless and they look like a segmented worm
Order Urodela- salamanders, newts
These amphibians keep their tails as adults
Order Anura- Frogs, toads
These Amphibians lose their tails as adults
External Anatomy
Tympanic membrane- Frogs have two one on each side of the head behind each eye
Tympanic membranes are round and a different color then the rest of the skin
Tympanic membranes- serve as the frogs eardrum
Nictitating membrane- A third eyelid for the frog
Nictitating membrane- helps to keep the eye moist, clean, and protects the eye
Internal Mouth Parts
Gullet A horizontal opening goes the entire width of the mouth and it’s what the frog swallows its food with. It leads down to the esophagus
Glottis A vertical slit, It's on the floor of the mouth, leads to lungs. It tends to collapse pretty tight in the preserved animal
Tongue Used to grab a hold of prey, It’s long, and it won’t be in the preserved animal. It’s sticky. It’s attached at the front of the mouth and it places the food back at the gullet. The tip of the tongue is split or divided to help pick up food
Eustachian Tube Openings They are in the back of the throat, up in the roof one on each side of the head. Eustachian tube opening regulates air pressure in the ear so it doesn’t burst it’s eardrum
Vocal Sac Openings only in male frogs, they are on the floor of the mouth in the very back and it carries oxygen to the vocal sacs so that the male frog can make the mating call, on a diagram
two different types of teeth
Vomerine Teeth there are two, they are in the front of the mouth on the roof, and their small
Maxillary Teeth line the roof of the mouth. They help to keep the prey in the mouth because the mouth is moist
Internal Eye Sockets When a frog swallows it will blink pushing the eyes down into the sockets which then helps to push the food down into the throat
Internal Nostril Opening They bring oxygen into the mouth,The gas exchange can across the lining of the mouth as long as it’s moist. If the activity level increases then the frog pushes the oxygen through the glottis and it goes to the lungs.
Digestive System
Frogs have a complete digestive system; they have two openings, one to bring food into, and one to take waste products out of. They swallow their food through the gullet, then it goes to the esophagus, and then to the stomach. There are structures in the stomach that produce digestive juice called gastric glands. They make gastric juice. This starts the process of digesting the food. There’s a valve between the stomach and small intestines, and it’s called the pyloric valve. It moves the food from the stomach to the small intestines. The frogs’ small intestine consists of the first part being the duodenum, and the second part being the ileum. The small intestine completes digestion, and absorbs the digested food. There is a clear tissue, called the mesentery, and it helps to support the small intestines. Whatever is left, is moved into the large intestine. The water will be absorbed. From the large intestine, we go to the cloaca, and out the cloacal opening. ( Large intestine→Cloaca→Cloacal Opening ) Frogs have a liver. Digestively, a liver makes bile. Bile breaks apart fat. Bile is stored in the gallbladder. There is a tube, called the bile duct, that carries the bile from the gallbladder to the small intestines. The other organ is the pancreas. It produces pancreatic fluid/pancreatic juice. It helps with the digestion of food. The pancreatic duct will carry the pancreatic fluid/juice to the small intestines. ( Pancreatic Fluid→pancreatic duct→small intestines )
***Tadpoles are herbivores. As adults, they eat meat.***
Excretory System
This system removes the nitrogen waste product ( ammonia ), when the animal makes this waste product. They digest protein, then they give off a nitrogen base.The frog will convert the nitrogen waste to urea acid. Frogs have 2 kidneys to filter the urea out of your blood. There are 2 tubes coming off of each kidney, called the ureter/urinary duct. Then, the urine goes to the urinary bladder, where it can be stored. Then, it goes to the cloaca, and out the cloacal opening. ( Kidney→Ureter/urinary duct→Urinary bladder→Cloaca→Cloacal Opening )
Reproductive System
Male and Female animal
Female: Eggs are produced in the ovaries, when the eggs are ready to be fertilized, matured, they break out of the ovaries, and sit in the body cavity. She uses her muscles of the abdomen to move the eggs into tubes, called the oviducts. The oviducts deposit into the cloaca. Once the eggs are in the cloaca, they will go out the cloacal opening
Male: Sperm are produced in the testes. The sperm is carried from the testes to the vasa efferentia. The vasa efferentia carries sperm to the kidney. Now, the sperm goes through the ureter/urinary duct. The sperm passes through the urinary bladder, to the cloaca, and out the cloacal opening.
Fertilization Of Eggs
All fertilization occurs outside of the animal’s body. The sperm is spread on top of the eggs. The jelly-like coating will form around the eggs, when the eggs hit water.
3 functions For Jelly-Like Coating:
Insulates the eggs to help with temperature changes
It’s food for the tadpole
It might prevent predators from eating all of the fertilized eggs
Amplexus- Where the male frog uses the inside toe on the front legs to push on the sides of the female, to help her work the eggs out of her body.
Respiratory System
In the tadpole stage, they have gills to pick up oxygen and give of carbon dioxide. As an adult, they will use their lungs. From birth on, respiration is across the skin, especially the lining of the mouth. In order for this to occur, the skin must stay moist. If it dried out, you wouldn’t be able to have that gas exchange.
Ectotherm- Cold blooded animals; they get their heat from the environment. All frogs are ectotherms.
Endotherm- Warm blooded animals; their metabolism maintains their body heat for the animal.
Circulatory System
A tadpole has a two-chambered heart. The upper chamber is called the atrium, and the lower chamber is called the ventricle. As an adult frog, it has 3 chambered hearts. They have a left and a right atrium. They have one ventricle. Blood that is rich in oxygen, that comes from the lungs, will be placed in the left atrium. Blood that’s coming back from the body that is lower in oxygen goes into the right atrium.
Pathway Of Blood Away From The Heart:
Arteries carry the blood away from the heart. Veins bring blood back towards the heart. The left and right atrium contract, and the blood goes into the ventricle; that lower chamber. From the ventricle, the blood goes into the conus arteriosus. Then, the blood goes into the left and right truncus arteriosus.
Pathway Of Blood Towards / Back To The Heart:
If you’re coming back from the body, and low on oxygen, it will go into the right atrium. On the back of the heart, there are 3 large veins. They are called Venae Cavae. Any blood coming back from anywhere in the body, goes into one of those 3 veins. The blood goes from the venae cavae, all of the blood will feed into the sinus venosus, in the right atrium. Any blood coming back from the lungs, and then goes into the left atrium.
(Venae Cavae→Sinus Venosus→Right Atrium)
Front Legs and Back legs
Front Legs
Four toes on the front feet - no webbing
3 Functions
They help the animal to walk
They absorb the shock of the jump (So they don’t go face-first into the ground)
They prop up the animal
Back Legs
Five toes between the feet; webbing. The bones in the lower leg are fused together for strength. They have well-developed thigh and calf muscles. Back legs are for jumping and swimming.