Environmental and climatic changes influenced the origin of the genus 'Homo'

Environmental and climate changes influenced the origin of the genus 'Homo'

CENIEH participates in a study on Mille-Logya, a new site located in the emblematic Afar region (Ethiopia), which reinforces the relationship between the origin of the Homo genus and the climatic and environmental changes that took place on the African continent between 2.5 and 3 million years ago
climatic changes Homo Mille-Logya
Hominin remains from the MLP area. Credits: Z. Alemseged et al

Several hypothesis suggest a link between the origin of the genus Homo and the climatic and environmental changes that took place in Africa between 2.5 and 3 million years ago. The geological and paleontological analyses of a new site, Mille-Logya, located in the emblematic region of Afar (Ethiopia) where the species Australopithecus afarensis was found, reinforces with new data these hypothesis.

A new study, published in Nature communication by an international team led by Zeresenay Alemseged from the University of Chicago, and with the participation of the geochronologist from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Mark Jan Sier, reports the finding of four hominin remains (two ulnae fragments, a calvarium fragment and an upper second molar) together with a large sample of faunal remains that include hypopothamus, bovids, giraffes, crocodiles, hyenas and horses.

The fossil samples come from three different areas, Gafura, Seraitu and Uraitele dated from 2.4 to 2.9 million years. “This site represents a unique opportunity to study fossils from an age range that normally is missing in the Afar area”, says Mark Jan Sier, from the Geochronology and Geology Programme of CENIEH and who contributed to the dating of the site with the paleomagnetic analysis.

The comparison of the fauna from the three different areas within Mille-Logya, as well as with that found in the nearby localities of Hadar and Dikika, where famous Australopithecus afarensis samples were found, suggests an important faunal and paleoenvironmental change during this period in this region of Africa.

The faunal and paleoenvironmental reconstructions suggest that the earliest members of Homo were associated with more open environments than Australopithecus was. The in situ faunal change at Mille-logya may be linked to environmental and climatic factors that may have caused Homo to emerge in from Australopithecus or to migrate to the region as part of a fauna adapted to more open habitats.

Full bibliographic information

Alemseged, Z., Wynn, J. G., Geraads, D., Reed, D., Barr, W. A., Bobe, R., McPherron, S. P., Deino, A., Alene, M., Sier, M. J., Roman, D., & Mohan, J. (2020). Fossils from Mille-Logya, Afar, Ethiopia, elucidate the link between Pliocene environmental changes and Homo origins. Nature Communications, 11, 2480. doi: 10.1038/s41467-020-16060-8.
Press release from CENIEH

Egypt pigment Egyptian blue

A pigment from ancient Egypt to modern microscopy

A pigment from ancient Egypt to modern microscopy

Göttingen research team produces new nanosheets for near infrared imaging

Egypt pigment Egyptian blue
Egyptian blue: the researchers obtained the nanosheets from this powder. Credits: University of Göttingen

Egyptian blue is one of the oldest manmade colour pigments. It adorns, for instance, the crown of the world famous bust of Nefertiti. But the pigment can do even more. An international research team led by Dr Sebastian Kruss from the Institute of Physical Chemistry at the University of Göttingen has produced a new nanomaterial based on the Egyptian blue pigment, which is ideally suited for applications in imaging using near infrared spectroscopy and microscopy. The results have been published in the journal Nature Communications.

Microscopy and optical imaging are important tools in basic research and biomedicine. They use substances that can release light when excited. Known as "fluorophores", these substances are used to stain very small structures in samples, enabling clear resolution using modern microscopes. Most fluorophores shine in the range of light visible to humans. When using light in the near infrared spectrum, with a wavelength starting at 800 nanometres, light penetrates even deeper into tissue and there are fewer distortions to the image. So far, however, there are only a few known fluorophores that work in the near infrared spectrum.

The research team has now succeeded in exfoliating extremely thin layers from grains of calcium copper silicate, also known as Egyptian blue. These nanosheets are 100,000 times thinner than a human hair and fluoresce in the near infrared range. "We were able to show that even the smallest nanosheets are extremely stable, shine brightly and do not bleach," says Dr Sebastian Kruss, "making them ideal for optical imaging."

The scientists tested their idea for microscopy in animals and plants. For example, they followed the movement of individual nanosheets in order to visualise mechanical processes and the structure of the tissue around cell nuclei in the fruit fly. In addition, they integrated the nanosheets into plants and were able to identify them even without a microscope, which promises future applications in the agricultural industry. "The potential for state-of-the-art microscopy from this material means that new findings in biomedical research can be expected in the future," says Kruss.

Egypt pigment Egyptian blue
Near-infrared image of nanosheets taken from a plant. Credits: University of Göttingen

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The study involved scientists from the Institute of Physical Chemistry, the Third Institute of Physics, the Department of Developmental Biochemistry and the Institute of Geology as well as the Department of Dermatology, Venereology and Allergology of the University Medical Center Göttingen and the University of California Riverside.

Original publication: Selvaggio et al. "Exfoliated near infrared fluorescent silicate nanosheets for (bio)photonics". Nature Communications, DOI: 10.1038/s41467-020-15299-5

See also - https://www.nature.com/articles/s41467-020-15299-5

 

 

Press release "A pigment from ancient Egypt to modern microscopy" from the University of Göttingen