The Animal Kingdom – A Quick Look At The Differences Between All The Fish And Other Kinds Of Animals
Animals are multicellular, anukaryotic organisms in the microbial kingdom. The majority of animals are land animals. With a few exceptions, animals breathe oxygen, eat organic matter, can move, reproduce sexually, and do not require a digestive system. Some eukaryotes, however, such as certain algae and protozoa, are symbiotic in nature and use their hosts’ muscles to move about and breathe atmospheric oxygen. In some respects, all animals are members of the Kingdom Protista.
All animals have a nervous system, but not all animals are alike. Every chord is composed of a pair of nerve cells, each connected to a pair of other nerve cells. The nerves deliver messages from one animal to the other, directing the body to walk, move to eat, take water or air, and many other actions. When the chord breaks, a malfunction occurs, thus resulting in the death of the animal. However, some animals have more complex nervous systems, which allow them to perceive, think, control body temperature and regulate gland size and shape, among other things.
An animal’s primary diet consists of foodstuffs obtained from vegetation and animal origin. Plants provide the calories that the animal needs to survive, while animal products such as meat, eggs, fur, and feathers provide the proteins and the energy needed to develop and perform well. Animals can acquire these nutrients from both plant and animal origin foods, though plants may contain more calories and other nutrients than animals. Animals can also derive energy from the sun. Plants only derive energy from the sun through photosynthesis, while animals derive energy from food sources that include meat, fats, carbohydrates, and other forms of biomass.
All living organisms belong to the Kingdom Animalia, the most general division of the Kingdom Multentextra where all animals are placed. Each animal species belong to a separate genus or class. For example, all land animals belong to the genus Acacia. All vertebrates (the class consisting of all mammals) and all reptiles (the class consisting of reptiles, mollusks and amphibians) belong to the class reptile. The class arboreal vertebrates (alligators, sloths and crocodiles) fall into the class of the terrestrial animals.
Every animal has a skeleton, which provides the basic structure and parts of the animal’s nervous system and composed of a single cell. The cell wall of an animal cell is surrounded by the cellular membrane, which serves as a protective outer membrane. The cell wall is made up of numerous protein fibers and sometimes mucus-like cells. The term “animal” is used to designate any vertebrate having the capacity to move about on two legs. The word “plant” is used to designate any large animal having the capacity to move about on four limbs, while vertebrates and reptiles are used to designate different classifications or kinds of mammals and reptiles.
An animal’s lifespan may be measured in years, months, days or decades. A year is the most common lifetime for most creatures in nature. There are two exceptions: marine reptiles are not extinct but have been so far from the surface of the earth that they have not been observed for millions of years; and some cetaceans have been known to live up to one hundred years or more. Some specialists believe that dinosaurs became extinct when the supercontinent broke up, but others believe that it was a gradual process.