Among the things which are generally taken to change, historically, are ideas, theories, social systems, technologies, customs, beliefs. Biological evolutionary changes or developments are often distinguished from and sometimes compared with these historical changes: Thus, species-change, or the evolution of particular organs or traits, or even geological change are taken to be processes of natural transformation, as distinct from those post-natural or cultural changes which may be characterized as historical, and which involve human action and human history distinctively. Thus, for example, cultural evolution is contrasted with natural or biological evolution, the "noösphere' is contrasted with the "biosphere', and transhistorical species-specific traints, such as erect posture, or speech are contrasted with culturally variant features, such as particular natural languages, or even more differentially, styles or customs or political systems.