The phylum Chordata consists of six groups: five groups of vertebrates: fish, amphibians, reptiles, birds, and mammals, and non-vertebrate chordates. Most of all modern chordate species are vertebrates. Chordates are animals that contain a notochord, are bilaterally symmetric, and display segmentation. To obtain food, Chordates have specialized features adapted to their diets. Chordates digest extracellularly in a digestive tract which means that food enters in one direction and waste exits from the anus. Food enters through the mouth from which it enters the esophagus and then to the stomach. In the stomach, digestive enzymes are released to break down the food. From the stomach, food enters the intestines where nutrients are absorbed from the food and waste is formed. From the intestines, wastes are expelled from the anus.
Gorilla beringei beringei (Mountain Gorilla) The gorilla obtains its food by feeding on foliage and vegetation such as leaves, stems, and shoots; gorillas also feed on ants and fruits. Gorillas contain front teeth and muscular lips that are adapted to grab and pull leaves. Its flattened molars grind leaves to a pulp. To digest its food, the gorilla contains a digestive tract where food enters from the mouth and exits through the anus. From the mouth, the food goes through the esophagus and to the stomach where it is stored and broken down by digestive enzymes. From the stomach the food enters the small intestine where bile further facilitates the breaking down of food. Nutrients from the food are absorbed in the small intestine and waste moves through the large intestine where water is removed and the waste exits from the anus.
Litoria caerulea (Australian green tree frog) The green tree frog obtains its food by eating small prey such as insects, snails, spiders, and worms. The green tree frog uses its sticky tongue to catch its prey where its then brought into its mouth. To assist in swallowing food, the green tree frog can retract its eyes to push the food into the esophagus. From the mouth, its food moves through the esophagus and into the stomach. When inside the stomach, the food is broken down and churned with the help of digestive enzymes. The broken down food then moves to the small intestine where it is digested. Bile and pancreatic fluid are secreted to break down the food further. The nutrients from the food are then absorbed in the small intestine. The waste moves into the large intestine where water is removed and it is expelled from the cloaca.
Carcharodon carcharias (Great White Shark) The carnivorous Great White Shark obtains its food by using its sharp rows of teeth to hunt and rip flesh from marine animals. To digest its food, it moves from the mouth to its J-shaped stomach where it is then stored. Unnecessary items that were ingested, are expelled from the shark by vomiting. Once the food is stored in the stomach, digestive enzymes are released to break down the food. From the stomach, the food moves to the shark's short intestine. The short intestine contains a spiral valve which increases the surface area for the absorption of nutrients in the intestine. The broken down food is kept in the intestine for extended periods of time to allow for the maximum absorption of nutrients. Once the food is fully digested, it exits through its cloaca or universal opening.