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Tracing Vegetation Changes through Carbon Isotopes. Implication for ecosystems and human evolution. C 3 and C 4 plants have photosynthetic pathways that fractionate stable carbon isotopes to different degrees d values between -36.5 ‰(VPDB) and -22‰ for C 3
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Tracing Vegetation Changes through Carbon Isotopes Implication for ecosystems and human evolution
C3 and C4 plants have photosynthetic pathways that fractionate stable carbon isotopes to different degrees • d values between -36.5‰(VPDB) and -22‰ for C3 • d values between -15‰ and -11‰ for C4 • ~14‰ enrichment factor in large mammals compared to their diet [Cerling et al., 1997]
Extant d13C values for herbivore tooth enamel [Levin et al., 2008]
d13C values in ‰ of tooth enamel for fossil herbivores from: As Duma Member SegalaNoumou Member Gona Western Margin South Adu-Asa Formation Gray bars represent d13C values for averages expected of strict C3 diet from closed-canopy, C3 from forest/bushland, and C4 grassland. [Levin et al., 2008]
What type of environment did early man evolve in? • These fossil herbivore teeth were found in situ with Ardipithecus kadabba and Ardipithecus ramidus. • Most similar to isotopic values from extant herbivores living in bushland and grassland Ardipithecus ramidus