Exploring the Evolutionary Pathways of Molars in the Genus Homo: Investigating the Relationship Between Enamel Thickness and Brain Shape Evolution

Outline: Exploring the Evolutionary Pathways of Molars in the Genus Homo: Investigating the Relationship Between Enamel Thickness and Brain Shape Evolution

I. Introduction

1. Thesis Statement

• Image being able to bite a tree (something harf a chimp still eats). This investigation/research  is going to through the Exploration of the evolutionary pathways of molars in the genus Homo, with a focus on investigating the relationship between enamel thickness and brain shape evolution. The  hypothesis that evolutionary adaptations in brain shape influenced changes in enamel thickness in Homo molars, potentially reflecting shifts in dietary needs and cognitive demands over time. 

II. Literature Review and Historical Context

1. Early Homo Dentition and Enamel-Dentine Junction Analysis

• Summary of key findings from Smith et al. (2023) on the enamel-dentine junction (EDJ) in postcanine teeth, highlighting the dental traits shared between early Homo habilis and Australopithecus, and the implications for classification and evolutionary history.

2. Processes in Human Evolution

• Overview of relevant book chapters and lectures covering the evolutionary processes influencing human dentition and brain morphology.

3. Brain Shape Evolution and Enamel Thickness Trends

• Discussion of studies on brain shape evolution (Lieberman et al., 2004) and enamel thickness trends in hominin molars (Skinner et al., 2019), linking these to broader evolutionary patterns in the genus Homo.

III. Methods

1. Geometric and Anatomical Analysis

• Description of the 2D geometric morphometrics and other metrics used by Lieberman et al. (2004) to study brain shape evolution in Homo, including the integration of Type I and Type III landmarks.

2. Comparative Methodology

• Explanation of methods used by Skinner et al. (2019) to examine relative enamel thickness (RET) and 2D average enamel thickness (AET) in hominin molars.

3. Supplementary Materials

• Incorporation of examples and images from relevant book chapters and lectures to support the methodological approaches.

IV. Results

1. Comparative Analysis of Findings

• Comparison of the findings from Smith et al. (2023) and Skinner et al. (2019), emphasizing the differences and similarities in enamel thickness trends and their evolutionary significance.

• Discussion on how these findings relate to the changes in brain shape as outlined by Lieberman et al. (2004), and the potential interplay between dental and neurological evolution.

2. Integration of Geometric and Anatomical Data

• Analysis of the methodological advancements highlighted by Lieberman et al. (2004) in the context of the enamel-dentine junction and enamel thickness studies, underscoring the importance of combining geometric and anatomical landmarks for accurate paleoneurological and dental analyses.

V. Conclusion

1. Summary of Key Insights

• Recapitulation of the thesis statement and main findings, emphasizing the proposed relationship between evolutionary adaptations in brain shape and changes in enamel thickness in Homo molars.

2. Implications for Future Research

• Discussion on the broader implications of the study for understanding human evolution, particularly in terms of dietary needs and cognitive demands, and suggestions for future research directions based on the current findings.

References

1. Smith, T. M., Kupczik, K., Thiery, M., Vialet, A., & Olejniczak, A. J. (2023). Early Homo dentition and enamel-dentine junction analysis. Nature Communications, 14, 44375. Link

2. Skinner, M. M., Alemseged, Z., Gauld, S. C., & Frost, S. R. (2019). Trends in enamel thickness of hominin molars. Journal of Human Evolution, 135, 102662. Link

Lieberman, D. E., McBratney, B. M., & Krovitz, G. E. (2004). The evolution of brain shape in the genus Homo. Journal of Human Evolution, 47(4), 292-318. Link