ABSTRACT
The classes of the Chordata, for instance, include cartilaginous fishes, bony fishes, amphibians, reptiles, birds, mammals. Each of these may be divided still further into groups known as orders, the order into families, the family into genera, and the genus into species. Sometimes from a single specimen, or a very small series, a taxonomist will describe a new species, designating one specimen as his “type”--that is, as representing his best concept of the characteristics of the species he is describing. If there is going to be any change in the species it must come through a change in the genetic make-up of the organisms which are further produced. This is the reason there is a great deal of emphasis being given to the particular concept at the present time. Evolution is defined by some as any change in plants or animals which can be passed on to their offspring.
