Animal Kingdom

Phylum Nematoda (roundworms)

Feeding/ Digestion:

The feeding of phylum Nematoda is interesting because the oral cavity is lined with a cuticle, which is usually strengthened with ridges and other structures. The mouth usually has a sharp stylet which always the worm to bite down on its prey to make it easier for it to swallow. There is no stomach which allows the food to go straight down to its intestine, that forms the main length of gut. The intestine has valves which makes it easier to make the food move throughout the intestine.

Reproduction:

Nematoda can reproduce in one of two (known) ways. The first is that Nematoda are self-fertilizing organisms and simply replicate themselves. However, there are male and female nematoda that reproduce by mating.

Respiration:

A roundworm has no formal respiratory system.

Circulation:

They do not have circulation systems.

Nervous System:

A roundworm has two nerve cords that transmit impulses. At the anterior end of the animal, the nerves branch from a dense, circular nerve ring surrounding the pharynx, and serving as the brain. Smaller nerves run forward from the ring to supply the sensory organs of the head.

Phylum Annelida (earthworm)

Feeding/ Digestion:

The digestive system is partitioned into many regions, each with a certain function. The digestive system consists of the pharynx, the esophagus, the crop, the intestine and the gizzard. Food such as soil enters the earthworm’s mouth where it is swallowed by the pharynx. Then the soil passes through the esophagus, which has calciferous glands that release calcium carbonate to rid the earthworm’s body of excess calcium. 

Reproduction:

Earthworms are hermaphrodites where each earthworm contains both male and female sex organs. The male and female sex organs can produce sperm and egg respectively in each earthworm. Although earthworms are hermaphrodites, most need a mate to reproduce. During mating, two worms line up inverted from each other so sperm can be exchanged. The earthworms each have two male openings and two sperm receptacles, which take in the sperm from another mate.

Respiration:

Earthworms do not have lungs. They breathe through their skin. Oxygen and carbon dioxide pass through the earthworm’s skin by diffusion. For diffusion to occur, the earthworm’s skin must be kept moist. Body fluid and mucous is released to keep its skin moist. 

Circulation:

The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels. There are three main vessels that supply the blood to organs within the earthworm. These vessels are the aortic arches, dorsal blood vessels, and ventral blood vessels.

Nervous System:

The earthworm is made of about 100-150 segments. The segmented body parts provide important structural functions. Segmentation can help the earthworm move. Each segment or section has muscles and bristles called setae. The bristles or setae help anchor and control the worm when moving through soil. The bristles hold a section of the worm firmly into the ground while the other part of the body protrudes forward. 

Phylum Arthropoda (grasshopper)

Feeding/ Digestion:

The grasshopper has a tubular digestive system. Food enters the mouth and is mechanically broken down, and then mixed with saliva by salivary glands. Food is then transported from esophagus to the crop. Chitinous teeth-like plates, which grind food, are seen in the muscular gizzards. Chemical digestion takes place in the stomach. Gastric caeca surround stomach.

Reproduction:

 Grasshoppers reproduce sexually. Only full grown grasshoppers have reproductive organs. Eggs are produced in the ovaries and sperm in the testicles. When sperm enters the female body it is stored in the seminal receptacle. Eggs are fertilized in the oviduct, then leave the females body. 

Respiration:

The grasshoppers respitory system is the same as many other insects, but the grasshoppers respitory system is called the tracheal system. As the abdomen expands, air pressure drops within the trachea, at the same time the anterior four pairs of spiracle open.

Circulation:

A grasshopper has an open circulatory system which means the blood flows into open spaces or sinuses. The blood is colorless because it contains no hemoglobin. The blood transports food and waste but not oxygen or carbon dioxide. Along the dorsal surface of the grasshopper is the aorta and a tubular heart as well as a large pericardial sinus and a large sternal sinus. Contractions of the heart pump da blood through the aorta to the head. In most open systems the blood moves slowly but systems are efficient enough to meet the needs of the organisms.

Nervous System:

Grasshoppers have a peripheral nervous system, this system consists of the sensory system. While the central nervous system consists of the ventral nerve cord. Since the grasshopper is a segmented insect each segment has its own interganglionic.

Phylum Echinodermata (starfish)

Feeding/ Digestion:

The mouth of the starfish is found on the under side of the starfish creature. Food enters the mouth and into the first stomach. Then it is passed onto the secondary stomach and then into the many digestive glands that are located within each of the arms of the starfish. These digestive glands secrete enzymes and absorb the much needed nutrients from food.

Reproduction:

Starfish reproduce through sexual and asexual reproduction, with the starfish being male or female. They can't, however, be both male and female at once. They also can not change sexes. Fertilization takes place outside the starfish in their environment through the gonopore. Both male and females release their gametes into the water.

Respiration:

Gas exchange in sea starfish occurs over their surface: they have neither gills nor lungs. Folds of skin on their dorsal surface permit gas exchange, as do the tube feet on their ventral surface. Also, they have a water-based vascular system, which also performs gas exchange.

Circulation:

A starfish's circulatory system has a central ring and five radial vessels. The type of circulatory system a startfish has is open and reduced, this is called the Hemal system.

Nervous System:

The central nervous system of a starfish consists of a radial nerve running the length of each ray and a circumoral nerve ring that connects the radial nerves. All the sensory information must go to the radial nerves, any memories must be stored in the radial nerves, and any decisions about what to do must be made in the radial nerves. And somehow, the five different radial nerves must coordinate those decisions if the starfish is going to get anywhere.

Phylum Vertebrata (grass frog)

Feeding/ Digestion: 

Food is captured by the bilobed tongue. Digestion of food takes place by the action of HCl and gastric juices secreted from the walls of the stomach. Partially digested food called chyme is passed from stomach to the first part of the intestine, the duodenum. The duodenum receives bile from gall bladder and pancreatic juices from the pancreas through a common bile duct. Bile emulsifies fat and pancreatic juices digest carbohydrates and proteins. 

Reproduction:

Common frogs become sexually mature at around three years of age. During February and March they begin to emerge from hibernation and make their way to the breeding grounds. Common frogs have been seen to return annually to the sites where they originally developed from spawn into adult frogs. The males arrive first and attempt to attract a mate by producing a low purring croak. A successful male will wrap his forelimbs around the female in a mating embrace known as 'amplexus'. Each female lays 1000-4000 eggs at a time, which are fertilised by the male as they are released. Frogs can spawn as early as December and as late as April, depending on how warm the weather is. They prefer to lay their eggs in shallow, still water. Frogspawn is surrounded with a clear jelly-like substance, which swells up in the water to protect the fragile embryos.

Respiration:

The frogs respitory system is made up of three respitory systems that is used to exchnges gases with the surrounding. These are the mouth lining, the skin, and the lungs.

Circulation:

The skin of a frog is permeable to oxygen and carbon dioxide, as well as to water. There are blood vessels near the surface of the skin and when a frog is underwater, oxygen diffuses directly into the blood. When not submerged, a frog breathes by a process known as buccal pumping. Its lungs are similar to those of humans but the chest muscles are not involved in respiration, and there are no ribs. or diaphragm to help move air in and out.

Nervous System:

The frog has a highly developed nervous system that consists of a brain, spinal cord and nerves. Many parts of the frog's brain correspond with those of humans. It consists of two olfactory lobes, two cerebral hemispheres, a pineal body, two optic lobes, a cerebellum and a medulla oblongata.