Animals are multi-cellular, eukaryotic living organisms in the Kingdom Animalia. With few exceptions, all animals breathe air, eat organic matter, can move, reproduce sexually, and eat other animals. The word ‘animal’ refers to any of these organisms. Birds, amphibians, insects, mammals, and fishes are some examples of animals.
The Order of mammals (here on referred to as the Multituberculata) includes all of the remaining species of the class mentioned above with some exceptions. The Class of reptiles (the Phylum reptiles) includes all of the remainder of the animals in this order. The Class of fishes (the Subclass of Mussels and Aquatics) consists of the living bodies of freshwater and saltwater animals. The Subclass of birds is made up of all of the bird species in this order.
The Family Allidae includes all members of the Order of mammals as well as many bird and mammal species that are closely related to birds and some of the larger mammals. The Class of invertebrates (the Phylum Annelidae) includes all members of the insect Kingdom, including bees, caterpillars, wasps, and certain forms of parasites. The Class of vertebrates (the Class Trichoptera) includes all the classes of vertebrates, which includes all bony fish, sharks, and even some reptile ancestors. The Class of crustaceans (the Class Cetacea) includes all of the terrestrial animals like crayfish and conch.
The Subclass of sea urchins is made up of two subspecies of the genus Uraria, both of which are marine hermit crabs. The first subspecies is classified as S. acroderma, while the second is classified as S. gemmata. The first subspecies has been found only in the Indo Pacific while the second subspecies has been found in the waters of the southern oceans. The Class of land reptiles (the Class Saurischia) includes all of the reptiles that are not amphibians, and all land-based reptiles. One exception to this is the egg thief salamander, which is actually a salamandua, a reptile with both an egg-laying organ and a salamander shell. Finally, there is the Class Copeitians, which includes alligators, sloths, tortoises, and various other crocodiles.
Most animal experiments are performed with non-living materials, but in some cases, live animals are used in research. For example, researchers sometimes use living fish in tissue culture, where they induce the fish to grow under laboratory conditions and keep the cells dividing. Some animal experiments are performed with cephalopods, which are lab-developed animals that have been cloned from a specific species. Other animal species can be used in tissue culture or in research if they are of a reproductive nature, such as dogs, cats, birds, and guinea pigs. In a famous experiment by vertebrate researcher Aristotle Prusapidae, a group of fish were given the human version of obesity, by allowing them to be fed with a piece of bread soaked in fish oil.
Almost all animals have a series of root structure layers, which are trunks, branches, caudal tunnelling bones, osteoblasts, germ layers, and exoskeletons, forming a multicellular body structure. The body plan of an animal can be well described by a single, more general description known as a phylum, or even a metagenome, which consists of all the DNA that codes for the different traits of an animal. This general approach treats all animal bodies as one, but it is very useful when investigating whether two organisms are truly unique. In most cases, however, taxonomy must be applied to distinguish among species.