Royal jelly, a thick, milky substance secreted by young nurse honeybees to feed a bee colonyâs larvae, most notably the queen larvae, is a rich source of nutrients, as well as acetycholine, a neurotransmitter that plays a critical role in cognitive function.
The origin of the eukaryotic cell is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The timing of this series of events is hard to determine; Knoll (2006) suggests they developed approximately 1.6â2.1 billion years ago.
Also coming from this time are the first abundant fossils of living organisms, mostly bacteria and archaeans, but by about 1.8 billion years ago eukaryotic cells appear as fossils too. With the beginning of the Mesoproterozoic comes the first evidence of oxygen build-up in the atmosphere.