Final answer:
A group of organisms that can only reproduce successfully with others of the same type are members of a species, defined as a group capable of interbreeding and producing fertile offspring.
Step-by-step explanation:
Groups of organisms that can only reproduce successfully with others of the same type are members of a species. A species is a group of individual organisms that interbreed and produce fertile, viable offspring. According to the biological definition, one species is distinguished from another when it is not possible, in nature, for matings between individuals from each species to produce fertile offspring. This concept emphasises the importance of reproductive isolation in the definition of a species. For example, in the species name Homo sapiens, sapiens is the species name, indicating that all humans belong to the same species capable of reproducing with one another.