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Complex behaviors of organisms, such as learning and memory, as well as aggression, feeding, and sleep, are governed by neurotransmitters in the brain. These neurotransmitters (serotonin, adrenaline, dopamine, etc) characteristically contain a single nitrogen capable of acting chemically as a base. A compound that contains a basic nitrogen bonded to an organic molecule is called an amine. As such, these neurotransmitters are called monoamines (since they contain only one such nitrogen).
Researchers at the University of Leicester (UK) and the University of Fribourg (Switzerland) searched for the genes responsible for the production, detection, and degradation of these neurotransmitters, and then, using a computational techniques, studied how these genes likely evolved. Their conclusion is that the use of monoamine neurotransmitters in organisms originated 650 million years ago. Considering what is known about the history of biological evolution on Earth, the development of monoamine neurotransmitters predates an event called the Cambrian explosion, which happened 538.8 million years ago. This event marks a point where a large number of diverse species rapidly appear, including all classes of fauna known to exist presently; no new classes have appeared since. Given the fact that the development of monoamine neurotransmitters for brain signaling evolved before the Cambrian explosion, it seems likely that this kind of brain signaling made the Cambrian explosion possible. Indeed, it has been observed that among the fossils of pre-Cambrian animals, there are no apparent predators, and the evolution of predators may have sparked the Cambrian explosion. Given that aggression is one of the complex behaviors associated with monoamine neurotransmitters, it seems likely that the development of these neurotransmitters was at least in part responsible for the Cambrian explosion. The presence of these neurotransmitters gave organisms the flexibility to adapt to changing and challenging environments, permitting them to survive and evolve.
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This comment by The Idiot in a comment thread replying to a comment posted by The Geogre bringing attention to a Pro Publica report about how just 6 people were responsible for 100,000 challenges to voter registrations in Georgia in the 2022 election. All of this was posted to Greg Dworkin’s Saturday Abbreviated Pundit Roundup.
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