User:Skoud001/sandbox

(The page I am editing: Mosaic Evolution)

Will add a Sub-header: "Mosaic Evolution in hominin"
Outline:

Explain what mosaic evolution means in terms of in hominin

Show the pattern of transitions

End with example of canine teeth showing this type of evolution

Finalized Draft:

Although mosaic evolution is usually seen in terms of animals such as Darwin's finches, it can also be seen in the evolutionary process of hominin. To help further explain the meaning of mosaic evolution in hominin, mosaicism will get broken down into three subgroups. Group 1 includes related species developing independently, of which carry deep variability in their own morphological structure. Examples of this can be seen within comparisons of Au. sediba, H. naledi, and H. floresiensis. Group 2 relies on the different environmental impacts on the changes of a species. An example of this is the variability of bipedalism forming independently within all related species of hominin. Lastly, Group 3 involves the presence of behavior such as the human vernacular. Language is a mosaic composite of various elements working together for one specific attribute, and this is not a single trait an offspring can inherit directly. In addition, it has been shown that an increase in social interactions corresponds to the evolution of human intelligence or in other words, an increase in brain size. This is provided and shown by Robin Dunbar’s social brain hypothesis. Moreover, this can be used as a level of transition in human evolution; of which also includes dental shapes.

Brain size has shown intra-specific mosaic variability within its own development, as these differences are a result of environmental limitations. In other words, independent variability of brain structure is seen more when brain regions are unassociated from one another, ultimately, giving rise to perceptible features. When comparing current brain size and capacity between humans and chimpanzees, the ability to predict the evolutionary change between their ancestors was incredibly insightful. This granted the discovery that “local spatial interactions” were the main effect of the limitations. Furthermore, alongside the cranial capacity and structure of the brain, dental shape provides another example of mosaicism.

Using fossil record, dental shape showed mosaic evolution within the canine teeth found in early hominin. Reduction of canine sizes are seen as an authentication mark of human ancestor evolution. However, A. anamensis, discovered in Kenya, was found to have the largest mandibular canine root as part of Australopithecus evolution. This alters the authentication mark because the dimorphism between root and crown reduction has not been assessed. Although canine reduction has probably occurred prior to the evolution of Australopithecus, “changes in canine shape, in both crowns and roots, occurred in a mosaic fashion throughout the A. anamensis–afarensis lineage”.