races. The first version stated that "National, religious, geographic, linguistic and cultural groups do not necessarily coincide with racial groups: and the cultural traits of such groups have no demonstrated genetic connection with racial traits. Because serious errors of this kind are habitually committed when the term 'race' is used in popular parlance, it would be better when speaking of human races to drop the term 'race' altogether and speak of ethnic groups." The revised version instead stated that the experts "agreed to reserve race as the word to be used for anthropological classification of groups showing definite combinations of physical (including physiological) traits in characteristic proportions." A revised version of the statement was published in 1951 and accompanied by observations, comments, and criticisms from many of the scientists engaged in the drafting and review of the text. Notably, four scientists are listed as "frankly opposed" to the statement as a whole. Among these, English statistician and biologist R. A. Fisher insisted on racial differences, arguing that evidence and everyday experience showed that human groups differ profoundly "in their innate capacity for intellectual and emotional development" and concluded that the "practical international problem is that of learning to share the resources of this planet amicably with persons of materially different nature", and that "this problem is being obscured by entirely well-intentioned efforts to minimize the real differences that exist." The 1951 revised statement The 1951 revised statement stated that Homo sapiens is one species. "The concept of race is unanimously regarded by anthropologists as a classificatory device providing a zoological frame within which the various groups of mankind may be arranged and by means of which studies of evolutionary processes can be facilitated. In its anthropological sense, the word 'race' should be reserved for groups of mankind possessing well-developed and primarily heritable physical differences from other groups." These differences have been caused in part by partial isolation preventing intermingling, geography an important explanation for the major races, often cultural for the minor races. National, religious, geographical, linguistic and cultural groups do not necessarily coincide with racial groups. There is no evidence for the existence of so-called "pure races" and no scientific justification exists for discouraging reproduction between persons of different races. Legacy and other UNESCO statements The UNESCO later published other similar statements on racism. In 1978, the UNESCO Declaration on Race and Racial Prejudice stated that "All peoples of