No, not quite. Reptiles are (in) the Class Reptilia and amphibians are (in) the Class Amphibia. Each class contains orders and each order contains families. Reptiles and amphibians are not closely related to each other, yet many scientists study both. The field of study is called herpetology, and reptiles and amphibians collectively (and informally) are known as "herptiles" or simply "herps" for convenience. To complicate matters further, many modern scientists regard birds as reptiles, yet the study of birds is called ornithology. Traditional classes often reflect inaccurate and outdated ideas about relationships.