1. (biology) a scientific theory of the origin of species of plants and animals
   - theory of evolution, evolutionism

Type of: scientific theory

• order Struthioniformes
• order Synentognathi
• order Taxales
• order Temnospondyli
• order Testacea
• order Testudinata
• order Testudines
• order Tetraodontiformes
• order Thecodontia
• order Therapsida
• order Thymelaeales
• order Thysanoptera
• order Thysanura
• order Tinamiformes
• order Torpediniformes
• order Tremellales
• order Trichoptera
• order Trogoniformes
• order Tuberales
• order Tubulidentata
• order Tulostomatales
• order Ulvales
• order Umbellales
• order Uredinales
• order Urodella