User:Avela057/Homininae

Evolution of Homininae:
As mentioned in the previous section "wikipedia page" Taxonomic classification we can see the lineage of Homininae. Going further into detail of the lineage...

Evolution of Bipedalism:
The evolution of bipedalism encouraged multiple changes among hominins especially when it came to bipedalism in humans as they were now able to do many other things now that they began to walk with their feet. These changes included the ability to now use their hands to create tools or carry things with their hands, the ability to travel longer distances at a faster speed, and the ability to hunt for food. According to researchers, humans were able to be bipedalists due to Darwin’s Principle of natural selection.

The first every theory that introduced the origins of bipedalism was the Savanna- Based theory ( Dart 1925). This theory hypothesized that hominids became bipedalists due to the environment of the Savanna such as the tall grass. This was later proven to be incorrect due to fossil records that showed that hominins were still climbing trees.

The most recent and most accurate theory is the provisioning model that was established by Owen Lovejoy. He suggested that bipedalism was a result of sexual dimorphism in efforts to help with the collecting of food and for women to be able to care for their offspring better as they can now use their hands to hold them. In this model men were the providers whereas the women were the care takers.

Brain Size Evolution:
The current size of the human brain is a big distinguishing factor that separates humans from other primates. Recent examination of the human brain shows that the brain of a human is about more than four times the size of great apes and 20 times larger than the brain size of old world monkeys. A study was conducted to help determine the evolution of the brain size with in the sub family Homininae that tested the genes ASPM (abnormal spindle-like microcephaly associated) and MCHP1 ( microcephalin-1) especially its accosiation with the human brain. In this study researchers discovered that the increase in brain size is correlated to the increase of both ASP and MCPH1. MCPH1 is very polymorphic in humans compared to lesser apes, old world monkeys, great apes, etc which helps encourage the growth of the brain. Further research indicated that the MCPH1 gene in humans could have also been an encouraging factor of population expansion.

References:
Andrews, P., & Harrison, T. (2005). "7 The Last Common Ancestor of Apes and Humans". In Interpreting the Past. Leiden, The Netherlands: Brill. doi: https://doi.org/10.1163/9789047416616_013

Goodman, Morris, et al. “Primate Evolution at the DNA Level and a Classification of Hominoids - Journal of Molecular Evolution.” SpringerLink, Springer-Verlag, https://link.springer.com/article/10.1007/BF02099995.

Ko, Kwang HyunOrigins of Bipedalism. Brazilian Archives of Biology and Technology [online]. 2015, v. 58, n. 6 [Accessed 2 March 2022], pp. 929-934. Available from: < https://doi.org/10.1590/S1516-89132015060399 >. Epub Nov-Dec 2015. ISSN 1678-4324. https://doi.org/10.1590/S1516-89132015060399.

Leyva-Hernández, S. ., Fong-Zazueta, R. ., Medrano-González, L. ., & Aguirre-Samudio, A. J.. (2021). The evolution of brain size among the Homininae and selection at ASPM and MCPH1 genes. Biosis: Biological Systems, 2(2), 293-310. https://doi.org/10.37819/biosis.002.02.0104

Yin-qiu Wang, Bing Su, Molecular evolution of microcephalin, a gene determining human brain size, Human Molecular Genetics, Volume 13, Issue 11, 1 June 2004, Pages 1131–1137, https://doi.org/10.1093/hmg/ddh127

Haile-Selassie. (2021). From trees to the ground: the significance of Australopithecus anamensis in human evolution. Journal of Anthropological Research., 77(4), 457–482.