Final answer:
Charles Darwin's recognition of variation within species is a central aspect of his evolutionary theory, making the statement that he thought organisms of the same species are identical false.
Step-by-step explanation:
The statement that Charles Darwin came to realize that organisms of the same species are identical is false. Darwin's evolutionary theory is based on the idea that there is variation within species. This variation is essential for natural selection, where traits that are advantageous for survival and reproduction are more likely to be passed on to future generations. Moreover, Darwin's observations that organisms fall into 'natural' groupings due to common evolutionary ancestry contradict the idea that members of the same species are identical.
It's the differences, and not the similarities, that drive the process of evolution by natural selection, which he meticulously explained in his work titled 'On the Origin of Species'. Therefore, the importance of variation within species is a fundamental aspect of Darwin's explanation of how evolution shapes the diversity of life.