IB Science Due Date: Wednesday, December 19, 2018 Course: Pre-IB Grade 10 Name: Ryan W, Roger Z, Brandon Y. Spotted Grass Frog Limnodynastes tasmaniensis Habitat: - Lives in urban areas, forests, woodlands, freshwater habitats - Spread across all of New South Wales, Victoria and Southeast Australia, and Tasmania - Native to northern and northeast Australia and parts southern New Guinea - Presence in the Kununurra district in Western Australia believed to be a result of an accidental introduction of the species in that particular region Prey: - Water insects, flying insects and spiders Predators: - Birds, lizards, snakes, turtles and water rats Special Structures: - Has the ability shed several layers of skin, forming a virtually waterproof cocoon that envelopes the body, leaving the nostrils open for breathing - This unique structure allows the frog to go through estivation in the dry seasons Behavior: - Adaptable and well suited to urban environments - Usually the first frog to colonise new dams, ditches and water-covered areas on disturbed ground - Goes through estivation in the dry season due to adverse environmental conditions Sizes: - Males up to 42mm - Females up to 47mm - Tadpoles up to 6mm Reproduction: - Reproduces sexually - Tadpoles are formed from a zygote - Breeding occurs all year round IB Science Due Date: Wednesday, December 19, 2018 Course: Pre-IB Grade 10 Name: Ryan W, Roger Z, Brandon Y. Digestive System: Esophagus: Tube shaped region that connects the mouth to the stomach Stomach: Breaks down the frog’s food into simpler compounds, first major area of chemical digestion Liver: Removes toxins, creates and secretes bile for the digestion of fats Gallbladder: Storage for the bile Pancreas: Produces digestive enzymes; releases those enzymes into the small intestine to help break down food Small Intestine: Absorbs the nutrients broken down from the food into the bloodstream Large Intestine: Transports of waste and the reabsorption of water before it is excreted Cloaca: An opening in the frog’s body that releases feces, urine, and reproductive cells How it works: The digestive process of the frog begins at the mouth where the food is ingested. A spotted frog’s diet usually consists of water insects, spiders and other smaller insects. The food is usually swallowed whole. While doing so, they blink and close their eyes, pushing the food down through the openings in the skull. This helps propel food into the esophagus. While the food sits in the buccal cavity, the tongue of the frog mixes its ingested food with saliva, helping the breakdown of starches into sugars. After the bolus goes through the esophagus and enters the stomach, the food is further broken down into simpler compounds by enzymes secreted by the gastric glands present in the stomach wall. After the food is broken down inside the stomach, it enters the small intestine where the absorption of nutrients begins. The small intestine plays a key role and is an integral part of the digestive tract. Certain enzymes such as trypsin, amylase, and chymotrypsin help with the digestion of carbohydrates and proteins. These enzymes are made in the pancreas. Another fluid that helps with the digestion of food in the small intestine is bile. Bile is made in liver and stored in the gallbladder. It assists with the digestion of fats. Both bile and pancreatic juice flows through a common bile duct into the small intestine from their respective organs. After the absorption of nutrients, the undigested food leaves the small intestine and enters the large intestine. Just like a human’s large intestine, the frog’s intestine performs the task of reabsorbing the leftover water from food residues and to move waste to the cloaca. Liquid waste moves to the urinary bladder while solid waste moves to the cloaca. All waste is then excreted through the cloacal opening. IB Science Due Date: Wednesday, December 19, 2018 Course: Pre-IB Grade 10 Name: Ryan W, Roger Z, Brandon Y. Circulatory System: Heart: Pumps and receives body throughout the entire body Arteries: To transport oxygenated blood throughout its body Veins: To carry poor-oxygen blood back to the heart Spleen: Recycles old blood cell Lungs: Responsible for obtain oxygen and allowing the oxygen to diffuse into the blood and allowing the carbon dioxide waste from the cell to diffuse out How it works: Just like any other animal, the circulatory system all starts with the heart. The heart is the main essential organ that keeps the circulatory system running. The frog’s heart is unlike a human heart and contains 3 chambers: 2 atriums and one ventricle. Deoxygenated body is sent to the atrium from various organs in the body through blood veins. At the same time, oxygenated blood coming from the skin, lungs, and other sites of respiration enters the left atrium. The blood from both atriums is then emptied into a single ventricle. Even though this seems like a wasted opportunity to separate the oxygenated and deoxygenated blood, the ventricle is actually divided into two narrow chambers, where it reduces the mixing of the oxygenated and deoxygenated blood together. The ventricle then contracts, sending oxygenated blood to the brain through carotid arteries from the left ventricle. The deoxygenated blood goes through the right ventricle and through the pulmocutaneous arteries to the skin or the lungs where respiration can occur, allowing fresh oxygen to come into the blood. The blood that runs through the aortic arches is fairly mixed up with oxygenated and deoxygenated blood, but it still contains a high amount of oxygen. This is enough to supply the rest of the body with oxygenated blood. This process is continued over and over again to ensure the frog gets the oxygen it needs to function and survive. Respiratory System: Lungs: Responsible for obtaining oxygen and excreting carbon dioxide Trachea: Allows air to travel down into lungs Nose: Allows the intake of oxygen Skin: A vital organ that contributes to the intake of oxygen when the frog is either underwater, in avestivation or hibernation Mouth: Another spot where the frog can take in oxygen How it works: Due to a frog’s amphibian life, it has 3 ways it can intake oxygen. Those 3 ways are cutaneous respiration (through the skin), buccal respiration IB Science Due Date: Wednesday, December 19, 2018 Course: Pre-IB Grade 10 Name: Ryan W, Roger Z, Brandon Y. (through the lining of the buccal-pharyngeal cavity) and pulmonary respiration (through the lungs). Most of the frog’s respiration happens through cutaneous respiration and buccal respiration. Pulmonary respiration is only used when the demand or need of oxygen is great. The main way the frog gets its oxygen is through cutaneous respiration. Due to the amount of time it spends underwater, the only way the frog can get oxygen is through their skin. It serves as an organ for gaseous exchanges. The skin is very-well structured and suited for gaseous exchange as it contains a high amount of blood capillaries and it always stays moist with the water. The oxygen is diffused into the skin due the different concentration levels of oxygen in the blood and the surrounding environment. The carbon dioxide in the blood also diffuses out of the blood and into the water. There is no movement required because the skin is constantly exposed to either water or air, allowing diffusion of oxygen and carbon dioxide to occur. The second way the frog can obtain its oxygen is through buccal respiration. Just like the skin, the buccal cavity also is also rich in blood capillaries so it’s an easy site for oxygen to enter the bloodstream. Buccal respiration occurs by either lowering or raising the floor of the buccal cavity. During that time, air is constantly being sucked into the buccal cavity and drawn out through the internal and external nares. During this type of respiration, no air is going through the lungs. As air enters the buccal cavity when the buccal cavity is lowered, the air gets dissolved in a layer of mucus and then into the blood. At the same time, carbon dioxide is doing the exact opposite. It leaves the bloodstream and out of the buccal cavity when the buccal cavity opens up. When the frog is on land, the frog still uses the other 2 methods of respiration but now they have another way through pulmonary respiration. Air is directly taken in and out via the trachea and through the lungs of the frog. Although the pulmonary respiration isn’t able to act as the primary way of respiration, it still provide a helping hand. The lungs can act as hydrostatic organs. They can be used as floating devices for the frog since all that air in their lungs is enough to keep the frog afloat. All 3 ways of respiration are specifically designed to adapt a frog’s way of life and all play a key role in keeping the frog alive. Excretory System: Kidneys: filters waste materials from the frogs intake of nutrients (ex. excess water) Ureters: ducts that urine passes through from the kidneys to the urinary bladder Urinary Bladder: the place where urine is stored before being removed from the frog's body Cloaca: an opening in the frog's body that allows fluids such as urine and sperm to be released How it Works: Frogs are unique in the fact that their reproductive and excretory systems are interconnected and associated with each other and as such are named as the urogenital system. The excretory system of a front consist mainly of a pair of kidneys, a pair of IB Science Due Date: Wednesday, December 19, 2018 Course: Pre-IB Grade 10 Name: Ryan W, Roger Z, Brandon Y. ureters, a urinary bladder and a cloaca. The excretory system begins with the kidneys, which filters liquid waste and excess water from the frog into urine, which is then sent into the urinary bladder through the ureters, which are tubes that carry urine throughout the excretory system. From this point, urine and feces are removed through the cloaca. During times when the frog doesn’t receive enough water, water in urine present in the bladder is reabsorbed and used in bodily functions. Another process that frogs undergo is the absorption of water from urine in order to hydrate their blood, which prevents evaporation of water from their skin, which can cause death if not addressed. The excretory system of frogs is specifically made this way in order to fit their niche, like those of fellow amphibians. The urogenital system is called this name because many parts of the frogs excretory system share common ducts with the reproductive system, where sperm will also come out of the cloaca. 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