The Animal Body Parts and Functions
The classification of animals is diverse. Although some classifications are universally accepted, many others remain controversial. Animals share basic features and behaviors that enable them to be grouped into categories. These classifications are used to help people identify different types of animals.
The first classification is Eutherians, which includes all land animals and all freshwater habitats. The second classification is reptile and amphibians, which include all vertebrates, including humans and all salamanders. Multicellular organisms are eukaryotic, a type of organism with cells that produce both protein and DNA. With few exceptions, all animals breathe air, eat protein, can multiply, move, and reproduce by cell division, are capable of moving about by swimming, have nerve centers that allow them to detect changes in physical structure, and have some ability to regenerate tissue parts.
An animal that is neither a vertebrate nor an invertebrate belongs to an organism that is part of the Kingdom Protista. Kingdom Protista is a subcategory of the Classialevacea, which includes the classes amphibians and vertebrates. Animals in this subclass are not classified as true vertebrates. The main article on this subclass is Animals of the Subclassialevacea.
The classification of animals including insects begins with the class Copeceae, which consists of bees, certain wasps and certain flies. Bees produce honey and queen bees are classified as the main source of food for other insects. Major insectivores include cats, dogs, horses, porcupines, rabbits, rats, birds, and insects that feed on these animals. Major predators of animals include snakes, hyenas, sharks, and scavengers.
The classification of animals also includes protozoa, which are microscopic unicellular organisms that are parasitic. These animals have an exoskeleton and a digestive system but do not have a muscular skeletal structure. The three main orders of the kingdom Animalia are: Prototheria, Dermatophytes and Eutherians.
All animal groups are categorized according to the order they derive from. Cetacea is the first order of animals to be classified according to their skeletal arrangements. A few of the animal groups that belong to the order Cetacea are the elodeons, cephalopods, mollusks, snails, trilobites and the eels. Insects are classified according to the Kingdom Protista and they are further divided into the Kingdom Insecta, which includes all crustaceans and insects that belong to the class insects. The order Orthoptera consists of the butterflies, caterpillars, moths, dragonflies, wasps and beetles.
The digestive tract in animals is divided into two different classes: animal cells and cell contents. Animal cells include the intestinal tracts of all animal species. In the case of plants, these cells are called fascia. Cells content are present in all tissues of animals including the brain, heart, lungs, gall bladder, liver and small intestine. The digestive enzymes that digest the proteins are manufactured in the stomach and these are transferred to the intestines through the excretion. Digestive enzymes are present in all animal cells except in the case of fibrin, which is manufactured by the liver.
The animals possess a set of organs called the exoskeleton, which provides protection to the internal organs. Most animals have only one set of exoskeletons, whereas some groups have two or more exoskeletons. The remainder of the animal skeleton is composed of soft tissues like the muscles and internal organs. All living beings, though covered with a thin membrane called mucus, possess an exoskeleton in which the major digestive organs are located. Mucus prevents the bacteria that cause infection from invading the interior. The gastrointestinal tract of the platypus is lined with glandular tissue.