Evolutionary transition in individuality

Evolutionary transition in individuality is the process through which descendants of independent organism become lower level units within a super-organism on a higher hierarchical level. Examples include cells assembling into a multicellular organism, or endosymbiosis of cells into more complex cells.{{cite journal|doi=10.1016/j.tree.2013.10.007 |title=Evolutionary transitions in individuality: Insights from transposable elements |date=2014 |last1=Ågren |first1=J. Arvid |journal=Trends in Ecology & Evolution |volume=29 |issue=2 |pages=90–96 |pmid=24252439 }}{{cite journal|doi=10.1073/pnas.1421402112 |title=Major evolutionary transitions in individuality |date=2015 |last1=West |first1=Stuart A. |last2=Fisher |first2=Roberta M. |last3=Gardner |first3=Andy |last4=Kiers |first4=E. Toby |journal=Proceedings of the National Academy of Sciences |volume=112 |issue=33 |pages=10112–10119 |doi-access=free |pmid=25964342 |pmc=4547252 |bibcode=2015PNAS..11210112W }}{{cite book|title=Evolution of individuality|date=1987|first1=Leo W.|last1=Buss|publisher=Princeton University Press}}