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The evolution of Homo neanderthalensis to Homo sapiens

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Presentation on theme: "The evolution of Homo neanderthalensis to Homo sapiens"— Presentation transcript:

1 The evolution of Homo neanderthalensis to Homo sapiens
Alex Noble Bradley Weiss Brittany Wike

2 Anatomy differences between the two species

3 Questions to be answered: braincase
Could a lower braincase with higher bone density of Homo neanderthalensis give them an advantage in protection from head trauma?

4 Brain case: frontal view

5 Brain case: side view

6 Brain case: back view

7 Brain case Image G shows Guattari, or a “classic” Homo neanderthalensis skull. Image H shows Homo sapiens

8 Bone density Left: Thick walled bones are characteristic of Homo neanderthalensis; indicating a higher bone density. Right: Thin walled bones are characteristic of Homo sapiens; indicating less bone density.

9 Questions to be answered: bone density
Were Homo neanderthalensis exposed to more traumatic environments?

10 Bone Density Percentage distributions of traumatic lesions by anatomical region for Neanderthals without DJD vs. Recent human clinical samples

11 Bone Density Figure shows the combined cortical thickness of the humerus; anteroposterior and mediolateral views of Homo neanderthals, early Homo sapiens, and modern Homo sapiens.

12 Mandible Homo neanderthalensis skull and mandible from the Smithsonian

13 Why the Mandible? In modern H. sapiens, the ascending mandibular ramus are in two processes, the coronoid and condylar process, and separated by a deep notch. In Neanderthals, the coronoid appears larger and more elevated than the condylar process, with a shallow notch in between.

14 Methods Traced the mandibular notch of each specimen.
While using the Condylar and Coronoid Processes as fixed points.

15 Mandibular Tracing Outline of mandibular notch in the Neanderthal, top arrow. Mean outline of 250 modern human specimens, bottom arrow.

16 Discussion Mandibular ramus is a truly diagnostic character for Neanderthals. Analysis shows Neanderthals face and braincase clearly indicate the species’ unique taxonomic status.

17 Rak et al concluded that based on the mandibular ramus, Homo neanderthalensis forms a side branch that evolved differently from the modern human. Led to the conclusion that Neanderthals do not play a role in our biological ancestry.

18 Thoracic Cavity Neanderthals have a longer and wider sternum
Longer and curved clavicles giving them a deeper and wider chest

19 Case Study Weinstein: used results found by other researchers
2 Neanderthals, 2 early modern humans, and 4 human skeletons from the Andes. Comparing the thorax of human fossils to Neanderthals Also to see if higher altitudes made a difference

20 Significance of the hyper-barrel-shaped thorax of the Neanderthal
Two main factors: Enhanced respiratory volume and aerobic capacities that function as adaptations to elevated activity levels Adaptations to cold climates

21 Comparisons to the Andes
Rib length and respiratory area are larger in the Neanderthal sample than the human fossils found in the Andes Early human fossils had reduced rib measurements and a narrower thoracic cavity


23 Results The large thorax was an advantage to both factors
Large thorax reduced surface area to body mass, which reduces body heat lost to the environment Large thorax also allowed for great lung capacity and ventilation which was needed for high physical activity and high metabolic rates

24 Difficulties in the Study?
Finding full or near full ribcages to do studies on Low sample sizes More data will allow for a better understanding

25 Daily Energy Requirements
Sorenson and Leonard Estimated their total energy expenditure by calculating their basal metabolic rates Neanderthals ranged from kcal/day Modern human populations ranged from /- 607 kcal/day Neanderthals had higher energy requirements daily

26 Future Research Comparing the thickness of the braincase for both species. The head trauma that H. neanderthalensis’ displayed may increase the density of the skull. Comparing rib measurements: including lengths, cross sections, muscle rigidity, and degree of curvature

27 Works Cited Howells W. (1975) Neanderthal man: facts and figures. Paleoanthropology: morphology and paleoecology. Paris: Mouton. 389–407. Rak, Y. et al. (2002) Does Homo neanderthalensis Play a Role in Modern Human Ancestry? The Mandibular Evidence. Am J Phys Anthropol 119: Humphrey, L.T., M.C. Dean, C.B. Stringer. (1999) Morphological variation in great ape and modern human mandibles. J. Anat. 195: Itzhak-Ben, S., Smith, P., Bloom, R.A. (1988) Radiographic Study of the Humerus in Neanderthals and Homo sapiens sapiens. American Journal of Physical Anthropology. 77: Berger, T.D., Trinkaus, E. (1995) Patterns of Trauma among the Neanderthals. Journal of Archaeological Science. 22: Bookstein, F., Schafer, K., Prossinger, H., Seidler, H., Fieder, M., Stringer, C., Weber, G.W., Arsuaga, J.L., Slice, D.E., Rohlf, F.J., Recheis, W., Mariam, A,J., Marcus, L.F. (1999) Comparing Frontal Cranial Profiles in Archaic and Modern Homo by Morphometric Analysis. The Anatomical Record (New Anat.) 257: Folger, T. (1997) Strong Bones, and Thus Dim-witted? Discover Magazine. Denning, K. (2006, November 6). Humanity’s Journeys. Retrieved April from Weinstein, K. (2008) Thoracic morphology in Near Eastern Neandertals and early modern humans compared with recent modern humans from high and low altitudes. Journal of Human Evolution. 54:

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