Skeletal SystemThe skeletal system provides important functions for support (giving the animal protection and structure), movement, the bones help produce blood cells, and they store calcium.Lamprey- Lamprey do not have any true bone. Their skeletal system consists of of cartilage which provides the framework for the body. Perch-The perch skeletal system is made up of both bone and cartilage in order to give structure and protection to its body.It consists of the vertebral column, cranium, jaw, ribs, and intramuscular bones. Frog-The skeletal system of a bullfrog contains bone, hyaline cartilage and calcified cartilage. The bones provide the structure and framework of the body. Frogs do not have scapula or suprascapula which is why they are able to jump very well.Rat-The rat skeleton is similar to that of a cat. It consists of primarily bone but also has cartilage on the surfaces of bones. It is divided into the axial and appendicular skeleton. The axial contains the skull, mandible, hyoid, ribs, sternum, and vertebrae.The appendicular skeleton consists of the appendages, and girdle. Bird-The skeleton of the American robin has been adapted for flight. The skeleton of all birds are generally the same except for some extreme specialization. Many bones in the skeleton have a hollow interior which contain inner struts to provide extra support. The bone structure of the wing is similar to the arm of a human containing a humerus, radius, ulna, and scapula. Instead of having multiple metacarpals it has a single carpometacarpus. The bird has 3 sections of the leg opposed to 2 in most animals. What most think to be the knees are actually the ankles.Muscular SystemThe muscular system has two preliminary functions, movement, and maintaining posture as well as position. Lamprey- The myomeres that formed from subunits contain muscle fibers. They have simple striated muscles and W shaped myomeres. Myotomes, groups of muscle bundles are unique to lampreys. Perch- their heads contain muscles that move the jaws, and mouth, as well as lateral fins. The contractions in the body of the perch flex the body and allow the fish to swim. The myoseptum separates every myotome. Epaxial muscles separate the myotome into ventral and dorsal sections. Frog- Some major muscles in frogs include: the pectoralis, which flexes the arms of the frog toward the body, the rectus abdominis, which flexes the trunk, triceps femoris, each flexing the thigh and extend the shank (part of leg in between the knee and ankle). Frogs are able to jump because of the gastrocnemius, as this contracts, frogs gain the ability to push and use this while leaping or swimming.Rat- Biceps brachii are located on the anterior surface of the arm, allowing the lower part of the arm to flex. Biceps femoris do the same for the lower leg. On both sides of the abdomen, the external oblique flexes the body wall and the pectoralis major and minor are located in the chest area which allow the arm to be drawn forward (when the rat is walking/ running).Bird- The largest muscles of a bird are their breast (pectoralis) muscles which control the wings. The supracoracoideus raises the wings making it possible for them to beat while the bird is in the air. This muscle as well as the pectoralis make up around 35% of the bird’s body weight. Reproductive SystemThe reproductive system allows animals to produce offspring.Lamprey – In the reproductive system of a lamprey the gonad (testes of ovaries) occupies the majority of the body cavity. Females can hold up to 250,000 eggs in their lifetime. The posterior end of the body has pores where sperm and eggs are discharged. Perch – Alike the lamprey, Perch also have a gonad. Because the female gonad is bulging with eggs, the male gonad is rather small. In the female perch, the gonad takes up quite a bit of space, females also have yellow ovaries that are near the swim bladder and males have two long white testes near the swim bladder and intestine. Frog- Female frogs are filled with eggs when they are ready to breed. Their eggs are black and spongy. Male frogs have testes (that are yellow and shaped like beans) they are attached to the kidneys. Both male and female frogs have fat bodies that store fat (they look like ramen noodles).Rat- Male rats have a scrotal sac where their testes are located. On top of the testes there are coiled tubes (epididymis) these tubes store sperm. Female rats have a vagina which is a grey short tube. They have a duplex uterus which allows the rats to have litters. Bird- The testes of male birds become much larger during breeding season, allowing them to produce sperm. Female birds only have one ovary that functions and the sperm can be kept in the female’s sperm tubules for up to one hundred days.Digestive SystemThe digestive system breaks down fats, proteins, and sugars in order to distribute nutrients throughout the body. Lamprey- The lamprey sucks the blood out of its prey in order to obtain nutrients. Using on their tongue, lingual lamina, they are able to drill a hole in the skin of their prey. When they become attached to their host, a vacuum is created in the buccal funnel allowing blood to be sucked in. Lampreys do not have a skeleton because it has not separated from their intestine. Perch- The digestive system of perch consists of the mouth, stomach, pylorus, and the pyloric caeca along with the liver, pancreas, and intestines. Their diet consists of smaller fish and insect larvae. The pyloric caeca secretes digestive enzymes to help break down food. Most of the absorption of nutrients is done in the intestines.Frog-Frogs have a three lobed liver which covers the gall bladder that stores bile. Food enters through the esophagus and passes through the stomach to the intestines. Next to the stomach is the pancreas which is an important organ in the digestion process. Rat-The digestive system is composed of the mouth, liver, esophagus, pharynx, stomach, intestines, and the cecum. Food enters through the mouth and goes down the esophagus to the stomach where it is broken down. It then enters the intestines where the nutrients are absorbed. Rats also have a cecum which contains bacteria and proteins to aid in the breakdown of cellulose. Bird- Birds have a unique pouch attached to the esophagus called the crop. This functions to soften the food and is able to regulate its flow by storing it. Females can give it to their young so that it’s partially digested. Circulatory/Cardiovascular SystemThe cardiovascular system is important for transporting oxygen, nutrients and hormones throughout the body. It also functions to remove carbon dioxide and other wastes. Lamprey- In the circulatory system of a lamprey, the blood goes through vessels and supplies oxygen/ nutrients to the body in order to remove carbon dioxide and any other wastes. Arteries are used to carry the blood away from the heart and veins bring it back. Their hearts are an S shape. Perch- This fish only has two sections in their heart, one atrium and one ventricle. The blood containing oxygen leaves the gills in arteries in order to travel to other tissues throughout the perch’s body. Perch’s have two vein systems, the hepatic portal system and the systemic veins.Frog- Frogs only have 3 chambered hearts, one ventricle and two atria. Both of the atria empty out the deoxygenated blood and oxygenated blood into the ventricle. This allows the blood to mix a little bit (there are narrow chambers that partially divide the oxygen rich and poor blood, but this does not completely prevent the mixing of blood). Rat- Alike humans, rats have a four chambered heart. The heart is enclosed in a pericardial sac, and pulmonary circulation has blood travel through the lungs (in order to obtain oxygen) and then back to the heart. The circulatory system in vertebrates is akin to a system of pipes with water flowing through them. WIthin the rat, blood flows through the heart twice in one complete circuit. Bird- Birds need very strong hearts in order for them to maintain a large amount of physical strain for a long time. In order to have this rapid circulation, birds require relatively high metabolism. As their four chambered heart beats, a large quantity of blood travels through their arteries, delivering oxygen and removing toxins. Respiratory SystemThe respiratory system is important for obtaining oxygen and getting rid of carbon dioxide and other wastes.Lamprey-The lamprey respiratory system has 7 pairs of gills. Each gill pouch has many gill lamellae on the inside. They are separated by interbranchial septa. Water passes through the gill pouches and enters the respiratory tube through the gill pores. The gas exchange takes place in the gill lamellae.Perch-Perch gills lie to the side of the mouth and contain fleshy filaments that hold blood vessels. Water is taken in through the mouth and passes through the gill filaments where the gas exchange takes place. Frog-Frogs have three surfaces where they can exchange gas: the lungs, the skin, and the mouth. When underwater, the respiration takes place in the skin. The skin contains a thin membranous tissue that has many blood vessels. Oxygen can diffuse directly into the blood vessels through the water. When on land mucus glands keep the skin moist so this process can continue. Frogs can also breath like humans using their lungs to take in oxygen. There are also respiratory surfaces on the linings of the mouth that allow gas exchanges to occur. Rat-Rats are mammals and have a similar respiratory to most other mammals including humans. Their respiratory system contains lungs, the trachea and the larynx. Air is taken in through the nostrils. The trachea connects the nostril cavity to the lungs where the gas exchange occurs. Bird-Birds have 7 air sacs that act in place of the diaphragm to move air in and out of the respiratory system. In birds the gas exchange occurs in the lungs. But the lungs do not expand and contract like they do in mammals. Birds are more efficient than mammals in their gas exchange.