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.
About 1.3 billion years ago the first eukaryote (a single cell organism with a complex inner structure) which contained many internal organelles such as mitochondria appeared, having evolved from the prokaryote. From the eukaryote, the multicellular metazoa (shown at left) evolved about 680 million years ago.