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.
All these events appear to have preceded the oldest fossil stromatolites. So the eukaryotic lineage appears to be very ancient, about as ancient as the two prokaryotic lineages. The key unanswered question here concerns when on the eukaryotic line the eukaryotic type of cell formed. Eukaryotic cells seem structurally far more complex than their prokaryotic counterparts (from which they arose), so biologists generally believe that many evolutionary steps must have separated the two.