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.
Eukaryotic cells. Unicellular prokaryotic life exists in the fossil record approximately 3.5 billion years ago. The other kind of cell, the eukaryotic cell, does not appear in the record until 1.8 billion years ago. Eukaryotic cells are more complex, with a separate nucleus and organelles, and are usually larger than prokaryotic cells.