What Are the Main Characteristics of the Kingdom Animalia?

Almost 1,000,000 species of animals exist on Earth. The meaning of the word animal comes from the Latin "anima" for "with soul." The animal kingdom includes creatures as small as insects and large ones like elephants. All members of the ancient animal kingdom share common characteristics that distinguish them from other life forms.

  1. Cells

    • An animal has millions of cells in its body, and each performs a different function vital to life. A red blood cell that carries oxygen is different from a reproductive cell. Animals that are visible to the naked eye are multi-cellular. Animal life developed from single cell organisms 2,000,000,000 years ago.

    Eukaryotic

    • Animal cells have no walls but instead have a membrane that surrounds the complex nucleus. It contains all the animal's genetic material and DNA. Eukaryotic is a Greek word that means "good nut or kernel." Animals inhale oxygen and exhale carbon dioxide.

    Food

    • All animals must survive by consuming their food source, either live or dead, from life forms such as other animals, plants or both. Animals digest and metabolize their food into energy and waste byproducts. Bears store food as layers of fat for months of hibernation.

    Reproduction

    • Mature animals reproduce sexually with a mate of the same species. Some species have one mate for life, such as the elephant. Other species like lions or tigers mate with multiple partners to pass on their particular genes. Some animal species can reproduce asexually, without mating.

    Motion

    • Animals move from place to place for various reasons, to seek shelter from weather or enemies, to find food or for mating. Animals move throughout their life, but as they age, their movement slows or stops as they adapt to their environment until they die.