CategoryHierarchies.com

Kingdom Animalia, also known as the animal kingdom, encompasses all living organisms classified as animals. These are multicellular eukaryotes that lack cell walls and primarily obtain their nutrients by consuming other organisms. They have diverse body forms, from the simple two-part structure of sponges to the complex systems of mammals, birds, reptiles, amphibians, fish, arthropods like arachnids and pseudoscorpions, mollusks, annelids, and others. Animals exhibit mobility during at least part of their life cycle, with various modes of locomotion such as walking, crawling, slithering, flying, or swimming. They possess sensory organs to detect changes in their environment and have a nervous system that allows for response and coordinated movement. Reproduction is primarily sexual, involving the fusion of gametes from two individuals, although some animals can reproduce asexually. The animal kingdom also includes a wide range of sizes, from microscopic organisms like rotifers to large mammals such as elephants and whales.