I have been very impressed with Gemini Advanced, the $20/month subscription version of the more popular free Gemini A.I. chat engine. However, after reading the following, very helpful answer, I was surprised to see the first of two citations at the end, a rather notorious source:
The pancreas, as a distinct organ with both endocrine and exocrine functions, is a feature unique to vertebrates. According to current scientific understanding, it first evolved in jawed vertebrates (gnathostomes).
Jawless Fish (Agnathans): These ancient fish, like lampreys and hagfish, lack a discrete pancreas. However, they possess dispersed cells in their digestive system that perform similar endocrine and exocrine functions. These cells are considered homologous to the pancreatic tissue found in more evolved vertebrates.
Jawed Fish (Gnathostomes): The development of a distinct pancreatic organ occurred in jawed fish. The earliest known vertebrates with a pancreas are thought to be the armored fish called placoderms. These fish had a pancreas with both endocrine (hormone-producing) and exocrine (digestive enzyme-producing) functions, similar to the pancreas found in modern vertebrates.
Evolutionary Significance: The evolution of the pancreas allowed for more efficient digestion and regulation of blood glucose levels, which likely played a crucial role in the diversification and success of vertebrates.
It’s important to note that the exact timeline and evolutionary steps leading to the development of the pancreas are still areas of active research. However, the current evidence suggests that the pancreas first evolved in jawed vertebrates, likely around 450-500 million years ago.
For further information, you can refer to these resources:
- Evolution of the Pancreas: https://answersresearchjournal.org/human-evolution/evolution-pancreas/
- Stages of vertebrate pancreas evolution: https://www.researchgate.net/figure/Stages-of-vertebrate-pancreas-evolution-The-earliest-vertebrates-likely-possessed_fig3_269190477
By the way, my original question was “When did the pancreas first evolve?”
At least in this case Answers in Genesis helped inform their readers of the wonders of pancreatic evolution.