The lack of well - preserved spines from other human ancestors has prevented anthropologists from father a clear picture of how our backs develop . A new discovery has changed that , as much as any individual fossil can .
Backpain is so vernacular because our spines are ill - suit to the New modus vivendi , but where did we go improper ? Is the job that we pass too much time model down , or have our spines not caught up with our new - fangled drill of walking erect ? Although anatomists accept the job has more to do with the former , we ’d still care to fuck more about how our spines have adapt to us coming down from the tree diagram .
The uncovering of a 3.3 - million - yr - old skeleton from Dikika , Ethiopia , has filled in a little of this missing knowledge . The fossil of the 2.5 - twelvemonth - old tiddler , depict inProceedings of the National Academy of Sciences , has been diagnose Selam , mean peace in Amharic .
Selam was found in 2000 , but removing the encasing sandstone without damage the precious bones has been a irksome process . The author note Selam correspond “ the only fuck perfect hominin cervical and thoracic vertebral pillar before 60,000 long time ago . ” That ’s a fate of human development to be represented by one specimen . Moreover , Professor Zeresenay Alemsegedof the University of Chicago , who find Selam , said in astatement : " This type of preservation is unprecedented , particularly in a young individual whose vertebrae are not yet fully fused . "
world have 12 thoracic vertebrae , which shape the middle discussion section of the spinal chromatography column . Most African apes have 13 . We compensate with redundant vertebrae in the lower back , assisting our in full upright stance . One of the swelled question about spinal organic evolution was which categoryAustralopithecinesfell into as they made theawkward shiftfrom tree - dwellers . Selam , anAustralopithecus afarensis , had 12 thoracic vertebra , indicating this feature of human anatomy is very honest-to-god .
Likewise Selam had an drawn-out waist and more depressed back vertebrae for easier running . " This structure and its modification through time is one of the key events in the account of human phylogeny , " Alemseged said .
Even today , humans depart in our changeover between the vertebrae of the lower and middle spine . In most people , it come about over 2 - 3 vertebrae , while a minority have a more sudden change . see this , a single specimen may not expose the full diversity of our ancestors ' spine . Nevertheless , three other fossilAustralopithecusspines and a 1.6 - million - year - oldHomo erectusskeleton , while incomplete , show single vertebrae transitions , higher up than in most New human spine . Salem fit this radiation diagram , reassert that what is now a infrequency evolved at least 3.3 million years ago , and was once widespread .
