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Frog Dissection
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01/02/06 - First Draft
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::Pre-Lab Discussion::
1. The complete classification for the Rana pippens from general to specific is:
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Ranidae
Genus: Rana
Species: pippens
2. The general characterisics of the Amphibians include smooth moist skin, and a usually carnivorous appetite. Amphibians live in wet environments where the climate is usually wet, and the humidity high. Rainforests are an example. They are ectothermic and lay eggs instead of giving live birth. Their larvae usually live in water for a short amount of time. However, amphibians can live in both water and land.
3 The three orders of amphibians are the Urodela, Anura, and Apoda. The Urodela are salamanders and possess tails when they grow into adults. They are carnivorous, usually have four legs, and are aquatic as larvae. The Anura are frogs and toads. The adults have no tails and gain hind legs as adults, made for jumping. Their aquatic larvae are called tadpoles. The Apoda are legless amphibians meaning they are worm-like and they burrow in earth. They have narrow bodies and are viviparous.
An example of the Urodela would be the salamanders or newts. The Anura could be represented by the bullfrog, while the Apoda can be represented by the limacodes. The salamanders and newts are 4 legged creaters who live in warm climates. The bullfrog can be found in the typical rainforest, while the limacode, which is a rare type of moth or butterfly, can be found only in England.
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::Lab Partners::
Elaine O'Neil, Corinne Easter, and Lynda Le(me).
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::Observations::
(External Drawing Attached Last)
Part A: External Anatomy of the Frog
1. The coloring of the ventral surface of the frog can be described as the army camaflouge outfits. They are a yellow-green color with darker, murky green spots. The dorsal surface of the frog is a really dark green, almost brown. Almost like a mud-green.
2. There are 4 digits on each of the frog's hands.
3. There are 5 digits on each of the frog's feet.
4. The nictitating membrane of the frog is attached to the outer eyelid of the frog's eyes at the bottom.
5. The frog's tongue is attached towards the very front and bottom of the jaw. Out tongues are pretty contrasting, being attached at the back instead of the front. (Image of frog's mouth attached).
Part B: Internal Anatomy of the frog
(Image of the frog's heart is attached).
1. The messentary that holds the intestines are thin, web-like tissue. It's purpose is to hold the frog's intestines together and in place. However, the messentary can also be found elsewhere in the body and not only on the intestines.
2. The frog has a closed digestive system which is sac-like, as is ours. However, frogs appear to have more then one liver, which are also much larger in ratio. The frog has a small and large intestine just like us and the general layout is also the same.
We ingest food and the food travels through the stomach; it is then broken down and absorbed. The food then travels through the small and large intestines to sucrete the liquids; leaving waste to be excreted through the anus.
(Exterior and Interior of frog are attached.)
3. When we dissected the frog's stomach, we were confused considering we didn't find anything. That is until we realized that we were to observe the lining of the stomach. The stomach is covered with tiny bristles and ruffles. I think they absorb the nutrients broken down in the stomach.
4. As said before, our frog's stomach was completely bare except for the ruffles on the inside wall of the stomach. It appears they starved the poor thing before they injected it.
5. When we took a medicine dropper and stuck it down the drog's throat and pumped, we were presented with some minor difficulties that made it difficult for us to observe the frog's lungs. However, when pumped properly, the lungs inflate and deflate, no matter how little it was.
6. The walls found in the two atria are not as wide or thick as the ventricle's wall was. Considering there are more of the atria then there are the ventricle; which compared as a 2:1 ratio; it would make sense that the atria would have a thinner wall. They are pressed together and made to look like one another, causing their wall to be thicker.
7. When we lifted the frog's leg, the muscles moved according to how we moved it. Of course when it came to bending and straightening the legs, they would contract and expand. when bent though, the muscles contract so much that it would allow the frog it use it's leg as a spring to leap high up into the air.
(The frog's Urogenital diagram is attached.)
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::Analysis Questions::
1. The feet of the frog are very adapt for swimming. This is because of the web-like structures found on the frog's feet. They extend from one toe curving until it reaches another, making a fan type motion when moved. When the frog moves, it will be fanning water, propelling it forward in order to swim.
2. Frogs are amphibians and will most likely be found in warm and moist environments. A rainforest or tropical forest being one of them, where there are a lot of trees for cover. This particular frog, which is murky green and brown, will blend in perfectly with decayed leaves on the ground or just the trees themselves, giving them the advantage of stealth.
3. The location of the nares is an adaptation to living in water mainly because it gives easy access to oxygen, being located at the front of the frog's jaw. Of course, naturally frogs navigate towards water but need air to breathe. Its nares are often lifted into the air in order to breathe when it needs to take breathe after a long swim.
4. The reason a frog's tongue is so sticky in the front, is to attach itself to whatever it chooses to eat. The sticky slimy substances sticks to whatever object the frog throws it's tongue at, a fly or mosquito most likely, and brings it into it's mouth. Trapping the insect to be swallowed and digested.
5. The length of the small intestine relates to its function in absorbing digested food because the small intestine does much more work than the other organs and need a long tube in order to function properly. The small instine holds a lot of water and it cannot function with all the water it holds if it is short. The small intestine absorbs the nutrients broken down from the stomach and brings it into the blood stream.
6. The frog's heart has an atrium and ventricle, very much like our heart. However, the ventricle of the frog's heart has a thicker wall than the atrium does. This is because the ventricle is much larger in size compared to it's atrium partnet. The ventricle is due to the fact that it does the hard job of pumping and separating the types of blood apart.
7. As mentioned before, the frog's tongue is advantageous because of the type of food it eats. Insects being the large majority of their diet. Their tongue is short when looked upon, but can be stretched and flung outwards catching prey that are in mid-air. Their tongues are sticky and will trap and insect that was unfortunate enough to have crossed a frog in need of a meal.
8. Frog's are a type of amphibian that can live in both land and water. Some adaptations that permit frogs to live on land successfully include their sprouting of limbs/legs. Other things may include their ability to breathe pure oxygen unhindered by water through the use of newly developed lungs.
9. Frogs spend a majority of their life in water. The reason they are able to do this is because of their ability to swim using their web-like structured feet. Other reasons may include the second eyelid that protects the frog when under water. It allows the frog to see underwater without the water hurting it's eyes. Meaning it is transparent and see-through.
There is also the fact that frogs change in color depending on what stage of life their in. When they are in water, they are tiny/small and hard to see. When they grow up, their skins grow rougher and darker to hide it's bulk of a body. Making it easier to survive.
10. The frog's sensory organs are located on the top of it's head. This is because it helps the frog to detect what is in front of it when it can't see in water. Frogs can live a lot longer because of this fact simply because it would be able to detect oncoming predators according to the movement in the air.
::Additional Questions::
1. Frogs are organisms that use their tongue the majority of the time in order to feed. They are insectavores and therefore need some kind of net in order to catch creatures that are able to fly away. The tongue has a sticky substance on it that is able to snatch the insect out of the air and placing it in it's mouth.
The frog can then chew, swallow, digest, absorb, and excrete the food and waste products. This is done through the esophagus, stomach, small and large intestines, and anus. The process would then be complete.
b. The frog's respiratory system is not unlike ours according to the organs and system used. Oxygen is inhaled from the air using the nares at the top or inside of the frog's jaw, and brought to the lungs. However, that would be for frog's who have lived out their tadpole days. Tadpoles cannot breathe in air because they have gills instead of lungs which filtrate oxygen from water.
c. Frogs are able to move around easily using their legs and/or fins/tails. From the begginning of life, frogs are hatched from eggs that were laid in water, and burst forth as little tadpoles with a tail. This tail allows the tadpole to swim around in water, but it can only survive in water for the time being because of it's lack of limbs. Once the tadpoles move through their stages of infancy, they will grow arms and legs, giving them the ability to move on land.
d. Frogs reproduce using sexual reproduction, and external fertilization. When a female and male get together, the male jumps on the female's back and starts nudging the eggs that are already in her ovaries, out into the open. The male then fertilizes them using his sperm. However, this is only a typical frog, and there are other ways frogs can reproduce.
e. The frog has a heart that contains three chambers. Two are the atriums while the other is the ventricle. The circulatory system also works like ours, or at least for frogs in their adult form. Their circulatory system is looped and therefore will travel the same path over and over again. There are blood vessels that carry the blood containing oxygen throughout the body, trading their space with carbon dioxide to bring back to the heart.
f. Frogs excrete waste through their anus, found at the posterior of the ventral side. However, in order to do so, their large intestine must do it's job to absorb the liquids before it can exit the body, taking the waste products somewhere else. The liquids absorbed are also waste products and are stored in the bladder until they can exit the body through another opening in their body.
g. Frogs are able to respond to their environment because of their sensitve sensory organs that are placed on the frog's head. These sensory organs are able to detect sound and movement near it's location and will either lie and wait or hop away in the case of a predator. Like most animals, they help the world from becoming over populated and take down a large portion of insects that would otherwise be considered pests to us.
2. There are many types of frogs in the world, but they can be found mainly in warm and wet climates, a rain or tropical forest being the typical choice. However, they can live anywhere that is wet in general, marshes, swamps, and ponds are also typical choices for them.
Frogs fit into this world because of their ability to ingest so many parasites and insects that would probably be considered a nuisance. Such responsibilities that the frog's carry have a large impact on the environment. They also provide a nice meal. ^^
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::Conclusion::
No hypothesis was made during the process of this lab because this lab is based off of learning dissecting skills and observation. However, there was the question of how a frog is structured for survival, and from the knowledge gained, I can conclude that the frog is very well adapt to living in the world and staying alive as well.
Frogs are versatile creatures that can live in many different places whether it be land or water. They can live in water because of their ability to swim. Their feet have flaps of skin that connect each toe to another. This allows their feet to propel the frog forward or upwards using a fan-like motion. It has a somewhat angular face, that allows the frog to push through water. Unlike us, the frogs have a second eyelid that allow them to see underwater without hurting their eyes. This allows them to avoid objects that can harm them or just to find some prey. Frogs also spend the majority of their tadpole life in water.
Frogs usually begin to surface on land when they have developed their arms and legs, making them able to move about. They also trade in some gills for a pair of lungs that allow it to breathe in oxygen without the use of water. On land, they are not protected by the water so it develops a defense.
Other than that, the frogs are able to survive and eat using their sticky tongues to catch food, and they have a body similar to ours that allows them to eat and sucrete waste properly. They have sensory organs that allow them to interact with their environment and serve as pest control. So to say, I believe the frog can very well live on by itself effectively.
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::Reflection::
The competencies I demonstrate in this lab include 8a and b, 11a-c, and 12a-c. These competencies state that I must be able to explain how a variety of organisms accomplish life, which include their energy intake, excretion of waste, their circulatory system, how they reproduce, move, develop, and how they interact with their environment. They also state that I must be careful and be able to use the lab equipment effectively. Meaning now horse play. I was able to use the camera effectively, taking good shots of the frog for my team. By doing so, I was able to contribute to my team positively and earn competency 12. After every lab, we also managed to get everything cleaned up and sanitized. Making things must more tolerable.
The role I played in my lab group was to help with the dissection and removal of organs as well as to take all the pictures used for this lab. I was hesitant to dissect the frog directly so I didn't do so, but once I got to see what the frog was actually like inside, I wasn't so hesitant to help any longer. It looked pretty interesting. I took care of all the pictures considering I'm the only one with a working USB drive.
During the course of this lab I learned many things, one of them being that the frog isn't all too different from us anatomy-wise. The structure of the interior of the frog was similar in the way the muscles were stretched across it's abdomen as well as the placing of it's heart.
They also had a sac-like digestive system that included the stomach, and the small and large intestine. here wasn't much else to learn except how to dissect a frog. I learned the parts of the frog that I was to observe as well as which area I would dissect the frog at.
Next time, and I'm pretty sure I'll be given the chance, I would try and work more efficiently. This was the first time we were able to dissect anything other than the worm and it was fairly new to us. Making us slow in progress. However, I thought we managed our time fairly nice and adequate considering we managed to finish the lab after all.
I thought I contributed to the group well according to the pictures, observations, and removal of organs. I was pretty good at identifying some of the organs found in the frog. Clean up was also pretty well done. We made a pretty nice mess involving water and paper towels,but we managed to get everything in control before we left on both days of the lab. All I can say now is that I had fun!
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::Assessment::
Lab Report Score: 4.5
This lab satisifies the criteria for a 4.5 because it is organized and remains on the task at hand. This lab is also properly checked in grammar and spelling. It has a scientific vocabulary and shows no signs of any immaturity. It basically follows the guidelins for a 4, and a 5, but doesn't exactly deserve a 5 because of the slow progress we made. I was unable to attend to our third hour of dissecting the frog because of an appointment. So I have decided to choose a score right inbetween, being a 4.5.
::Lab Work Self Evaluation::
Procedures - 5
Cooperatively - 5
Productively - 4
Safety - 5
Clean Up - 5
Total - 24
Average - 4.8
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