Dual inheritance theory: Difference between revisions

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Revision as of 15:36, 23 August 2023

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'''Lactase persistence'''

One of the best known examples is the prevalence of the genotype for adult lactose absorption in human populations, such as Northern Europeans and some African societies, with a long history of raising cattle for milk. Until around 7,500 years ago,<ref name=":0">{{Cite journal|last1=Itan|first1=Yuval|last2=Powell|first2=Adam|last3=Beaumont|first3=Mark A.|last4=Burger|first4=Joachim|last5=Thomas|first5=Mark G.|date=2009-08-28|title=The Origins of Lactase Persistence in Europe|journal=PLOS Computational Biology|volume=5|issue=8|pages=e1000491|doi=10.1371/journal.pcbi.1000491|issn=1553-7358| pmc=2722739 |pmid=19714206|bibcode=2009PLSCB...5E0491I |doi-access=free }}</ref> lactase production stopped shortly after weaning,<ref>{{Cite journal|last1=Malmström|first1=Helena|last2=Linderholm|first2=Anna|last3=Lidén|first3=Kerstin|last4=Storå|first4=Jan|last5=Molnar|first5=Petra|last6=Holmlund|first6=Gunilla|last7=Jakobsson|first7=Mattias|last8=Götherström|first8=Anders|date=2010-01-01|title=High frequency of lactose intolerance in a prehistoric hunter-gatherer population in northern Europe|journal=BMC Evolutionary Biology|volume=10|pages=89|doi=10.1186/1471-2148-10-89|issn=1471-2148| pmc=2862036 |pmid=20353605 |doi-access=free }}</ref> and in societies which did not develop dairying, such as East Asians and Amerindians, this is still true today.<ref>{{Cite web|url=http://www.ucl.ac.uk/mace-lab/resources/glad/LP_maps|title=Maps|website=www.ucl.ac.uk|language=en|access-date=2017-03-27|archive-url=https://web.archive.org/web/20170328105300/http://www.ucl.ac.uk/mace-lab/resources/glad/LP_maps|archive-date=2017-03-28|url-status=dead}}</ref><ref>{{Cite journal|last1=Gerbault|first1=Pascale|last2=Roffet-Salque|first2=Mélanie|last3=Evershed|first3=Richard P.|last4=Thomas|first4=Mark G.|date=2013-12-01|title=How long have adult humans been consuming milk?|journal=IUBMB Life|language=en|volume=65|issue=12|pages=983–990|doi=10.1002/iub.1227|pmid=24339181|s2cid=34564411|issn=1521-6551|doi-access=free}}</ref> In areas with lactase persistence, it is believed that by domesticating animals, a source of milk became available while an adult and thus strong selection for lactase persistence could occur,<ref name=":0" /><ref name=":1">{{Cite journal|last1=Bersaglieri|first1=Todd|last2=Sabeti|first2=Pardis C.|last3=Patterson|first3=Nick|last4=Vanderploeg|first4=Trisha|last5=Schaffner|first5=Steve F.|last6=Drake|first6=Jared A.|last7=Rhodes|first7=Matthew|last8=Reich|first8=David E.|last9=Hirschhorn|first9=Joel N.|date=2017-03-27|title=Genetic Signatures of Strong Recent Positive Selection at the Lactase Gene|journal=American Journal of Human Genetics|volume=74|issue=6|pages=1111–1120|doi=10.1086/421051|issn=0002-9297| pmc=1182075 |pmid=15114531}}</ref> in a Scandinavian population the estimated [[selection coefficient]] was 0.09-0.19.<ref name=":1" /> This implies that the cultural practice of raising cattle first for meat and later for milk led to [[Lactose intolerence#Evolutionary history|selection for genetic traits for lactose digestion]].<ref>Laland, K. N. and G. R. Brown. 2002. ''Sense & Nonsense: Evolutionary Perspectives on Human Behavior.'' Oxford: Oxford University Press. p. 260</ref> Recently, analysis of natural selection on the human genome suggests that civilization has accelerated genetic change in humans over the past 10,000 years.<ref>Cochran, G. and H. Harpending. 2009. ''The 10,000 Year Explosion: How Civilization Accelerated Human Evolution.'' Basic Books.</ref>

'''Food processing'''

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==Social learning and cumulative cultural evolution==

In DIT, the evolution of culture is dependent on the evolution of social learning. Analytic models show that social learning becomes evolutionarily beneficial when the environment changes with enough frequency that genetic inheritance can not track the changes, but not fast enough that individual learning is more efficient.<ref>Richerson, P.J. and R. Boyd. 2000. Climate, culture, and the evolution of cognition. In C.M. Heyes and L. Huber, (Eds), ''The Evolution of Cognition.'' Massachusetts: MIT Press.</ref> For environments that have very little variability, social learning is not needed since genes can adapt fast enough to the changes that occur, and innate behaviour is able to deal with the constant environment.<ref>{{Cite journal|title=Carving the Cognitive Niche: Optimal Learning Strategies in Homogeneous and Heterogeneous Environments - ScienceDirect|journal=Journal of Theoretical Biology|volume=220|issue=2|pages=169–188|language=en|doi=10.1006/jtbi.2003.3146|year=2003|last1=Kerr|first1=Benjamin|last2=Feldman|first2=Marcus W.|pmid=12468290}}</ref> In fast changing environments cultural learning would not be useful because what the previous generation knew is now outdated and will provide no benefit in the changed environment, and hence individual learning is more beneficial. It is only in the moderately changing environment where cultural learning becomes useful since each generation shares a mostly similar environment but genes have insufficient time to change to changes in the environment.<ref name=":7" /> While other species have social learning, and thus some level of culture, only humans, some birds and chimpanzees are known to have cumulative culture.<ref>Tomasello, M. 1999. ''The Cultural Origins of Human Cognition.'' Cambridge, Massachusetts: Cambridge University Press.</ref> Boyd and Richerson argue that the evolution of cumulative culture depends on observational learning and is uncommon in other species because it is ineffective when it is rare in a population. They propose that the environmental changes occurring in the [[Pleistocene]] may have provided the right environmental conditions.<ref name=":7">{{cite book | last1 = Richerson | first1 = P. J. | last2 = Boyd | first2 = R. | yeartitle = 2000Perspectives in Ethology | titlechapter = TheBuilt for Speed: Pleistocene Climate Variation and the originsOrigin of humanHuman culture: built for speedCulture | journalyear = Perspectives in Ethology2000 | volume = 13 | pages = 1–45 | doi=10.1007/978-1-4615-1221-9_1| isbn = 978-1-4613-5447-5 }}</ref> Michael Tomasello argues that cumulative cultural evolution results from a [[ratchet effect]] that began when humans developed the cognitive architecture to understand others as mental agents.<ref>Tomasello, M. 1999. ''The Cultural Origins of Human Cognition''. Cambridge, MA: Harvard University Press.</ref> Furthermore, Tomasello proposed in the 80s that there are some disparities between the observational learning mechanisms found in humans and great apes - which go some way to explain the observable difference between great ape traditions and human types of culture (see [[Emulation (observational learning)]]).

==Cultural group selection==