Characteristics of the Kingdom Animalia - Essay Example

Characteristics of the Kingdom Animalia The kingdom Animalia consists of over thirty different major phyla including Mollusca, Arthropoda,Cnidaria, and Chordata. The Chordates are the ones that are most popularly thought of as animals, but insects and mollusk-like creatures are just as much an animal as a koala bear and giraffe. Interestingly, the insects make up 87% of all the animal species on the planet. Members of the group Chordata are indeed special within the Animal kingdom though. They have in common five unique characteristics which distinguish them from other animals.

At some point during their development Chordates have the following body structures: a notochord, gills, a hollow nerve cord, a tail past the anus, and a digestive tube behind the mouth. All animals have the ability to move around at a relatively rapid pace because of the presence of muscle tissue within their anatomy. In contrast members of the plant kingdom are generally rooted to one spot during their entire adult life. The Animal kingdom contains more members than any other kingdom with likely over a million different species on the planet.

They range in size from just a few cells to whale-sized. Most of the animals on the earth live in the sea, some live in fresh water, and the smallest percentage of the Animal kingdom live on land. The Animal kingdom includes all amphibians, birds, bugs, fish, invertebrates, mammals, reptiles, and even prehistoric creatures such as dinosaurs and mammoths. There is an incredible amount of diversity within the Animal kingdom.Some traits that all members of the kingdom Animalia share in common are that they are eukaryotic, multi-cellular, and heterotrophic.

They all have mitochondria within their cells which serve as producers of cellular energy. Because they are eukaryotic, their cells have a true nucleus as well as many other discrete membrane-bound organelles which are the organizing centers of all cellular activity. All animals are composed of many cells and the cells do not produce their own food the way that plant cells do. Members of the Animal kingdom have specialized tissues and organ systems. They all have an internal digestive tract where they obtain nutrition by breaking down ingested foodstuff.

Animal cells are arranged within the organisms into different tissues, each with a specific function. Many animals have discrete organs which are aggregates of tissues. Most animals reproduce sexually, by the joining of an egg from one member and a sperm from a different member to produce a new organism. Though it is also possible for some animals to reproduce asexually through a process called artificial parthenogenesis where only one parent is required. Most animals have two copies of each gene.

The cells of animals are different from plants in that they do not have a cell wall. The most primitive animals have bodies that are asymmetric, while the complex animals are either radially symmetric or bilaterally symmetric. The animals which have bilateral symmetry, i.e. a right side that is closely identical to the left side, also have the specialized feature of cephalization which is a head containing sensory organs.ReferencesKingdom Animalia (2009).angelfire.com. Referenced 23 April 2009 Kingdom Animalia, Characteristics of Animals (2009).

Characteristics_of_animals.pdf. Referenced 23 April 2009 Animals (2009).nationalgeographic.com. Referenced 23 April 2009< http://animals.nationalgeographic.com/animals >