Charles Darwin believed that every species must be fertile enough in order to reproduce and extend the population of its own kind. However when asked about the origin of species, he declares that the true indication for this measurement is to first under the natural selection and the survival rate of that the organism could last. In a natural selection process, newly-formed organisms have to attest their endurance for the recurring struggle to exist.
Darwin had found that in ancient Egypt, plants and animals were nurtured in order to produce a selective breeding of the only the best lots. For example, pigeons were bred with careful selection of the strongest groups and the strongest nestlings were retained. This was remarked that the diversity of species was incredible but they were all bred from the same group, the Rock Pigeon.
According to medieval Greek scholar, Genessis, an organism is one of the many creation of nature, which does not have a specific physical form because it will interbreed with others, and a fusion of new categories are born. The uncontrollable and diverse factor of nature intricate the process of identifying a static and fixed species. However a scientist called John Ray stated in his taxonomy that organisms are classified in accuracy and the difference that may occur between the same classifications are due to environmental conditioning. In 1735, Carlos Linneus designed a biological classification which comprises of stratas, families and other significant details of organism which is still applied in modern day biology.
In a journal written by Alfred Russel Wallace in 1885, he mentioned that a close look on newly discovered organisms can reveal the similarity of the new-found species with an existing one. The latest form of organism is far more improved than the previous after re-adjusting its ability to survive better.