Climate Change, Genetics or Human Choice: Why Were the Shells of Mankind's Earliest Ornament Larger in the Pleistocene Than in the Holocene?
2007

Why Were the Shells of Mankind's Earliest Ornament Larger in the Pleistocene Than in the Holocene?

Sample size: 1230 publication 10 minutes Evidence: moderate

Author Information

Author(s): Teske Peter R., Papadopoulos Isabelle, McQuaid Christopher D., Newman Brent K., Barker Nigel P.

Primary Institution: Rhodes University, South Africa

Hypothesis

The size difference in shells of Nassarius kraussianus is due to either genetic differences or phenotypic plasticity in response to environmental conditions.

Conclusion

The decrease in fossil shell size from Pleistocene to Holocene was likely due to increased temperatures as a result of climate change.

Supporting Evidence

  • Fossils of N. kraussianus from the Middle Stone Age were significantly larger than those from the Late Stone Age.
  • Genetic analyses revealed two lineages of N. kraussianus, but no genetic basis for size differences was found.
  • Extant individuals from cooler waters had larger shells compared to those from warmer regions.

Takeaway

A long time ago, shells used by humans were bigger, and scientists think this is because it got warmer over time.

Methodology

The study involved genetic analyses and morphological measurements of shell sizes from various populations of Nassarius kraussianus.

Potential Biases

Potential biases may arise from the selection of sampling localities and the methods used for measuring shell sizes.

Limitations

The study's conclusions are based on fossil records and current environmental conditions, which may not fully account for historical variations.

Participant Demographics

The study focused on the southern African population of Nassarius kraussianus.

Statistical Information

P-Value

0.003

Confidence Interval

95% C.I. = 0.94–2.72

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0000614

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