This document provides an introduction to the characteristics of animals in the kingdom Animalia. It discusses their heterotrophic and multicellular nature, as well as their ability to move. It also describes the basic embryonic stages of zygote, embryo, blastula and gastrula. The three germ layers - ectoderm, mesoderm and endoderm - are identified along with the organ systems they give rise to. Diagrams of body plans for protostomes and deuterostomes are included. Finally, the document discusses symmetry in animals from asymmetry to radial and bilateral symmetry.