PubMed · 5330229
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
A V Grimstone. 1966. Structure and function in Protozoa.. https://doi.org/10.1146/annurev.mi.20.100166.001023
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
Hundreds of specimens of spirally coiled, megascopic, carbonaceous fossils resembling Grypania spiralis (Walcott), have been found in the 2.1-billion-year-old Negaunee Iron-Formation at the Empire Mine, near Marquette, Michigan. This occurrence of Grypania is 700 million to 1000 million years older than fossils from previously known sites in Montana, China, and India. As Grypania appears to have been a photosynthetic alga, this discovery places the origin of organelle-bearing eukaryotic cells prior to 2.1 billion years ago.
Explore the source record for details and available documents.