The Kingdom of Animals
General characteristics of animals:
Heterotrophs: need organic carbon as food
Multicellular: complex body forms and anatomies
No cell walls: cells flexible, held together within tissues by strings of proteins (collagen)
Active movement: related is the evolution of muscle and nerve tissues to coordinate movements
Sexual reproduction occurs in most animals
Embryonic development shows similar patterns
Unique tissues: complexes of cells with special form and function (except sponges)