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Wire rider, the reason you are unaware of the evolutionary changes which took place in human evolution is because you have not been acquainted with the facts. If you were a Saharan nomad, you would not require fifty words to describe different types of snow.
The study of early man (paleoanthropology) could be a dry or obscure science to the outsider, partly because it is dependent on the understanding and integration of many other disciplines. To grasp the subject, firstly the concept of geological time and the pattern of climate changes including temperature, humidity, polar ice volumes and sea-level changes are keys to dating the hominin (early human) fossils which must be well understood. Secondly the geological markers including volcanic events and earth magnetic polarity reversals as well as the reading of the earth movements and sediment layers where the artefacts and or bones are found. Then there is the comparison of anatomical information to find the place within the evolutionary tree (phylogeny) built up from the record of thousands of skeletal finds from other sites. Dating the context and objects is yet another science involving radiometric analysis; the ratio of isotopes of a particular element to the standard atomic number. There are many scientific tests by different methods useful for different periods of pre-history and too technical to describe here. Other key markers of the date are the known animal, insect plant and pollen assemblages evidence of which are found in the context or matrix materials.
I think people living in North America are at a disadvantage in learning about these matters. for two reasons. one, a historically blind insistence on asserting that the Bible must be true and two, the absence of the Old World pre-history. American history is hard to discover before the Clovis culture around 12,000 BCE whereas In Europe the place is awash with paleolithic find sites. These include the Neanderthals and the early contemporaries of them Homo heidelburgensis and not forgetting the cave art of the Cro-magnons.
So to understand the history of early man you do have to wade through this sort of stuff to get there.