The Evolution of the Human Immune System: The Backstory with Dr. Bill Rawls
By Dr. Bill Rawls Posted 08-12-2021

Ever wondered how the human immune system became what it is today? Discover the surprising ways that life’s first bacteria worked together to eventually create animal and plant defense systems, and learn how we still depend on plants to this day to keep our immune systems in tip-top shape.

Video Transcript

Hello, everybody, Dr. Rawls here. Over the past year I’ve been writing a book on how herbs support the immune system and lower our risk of chronic illness. In that journey I’ve learned a lot of stuff.

There’s just so much interesting information that is out there that’s been scientifically documented, but I don’t have room for all of it in the book. So one of the more interesting stories is the story of the evolution of the human immune system.

And it starts back about three and a half billion years ago with the first bacteria on earth. That’s when we first started seeing fossil records on earth of bacteria. Back then, the earth was a pretty inhospitable environment. It would have been like Mars. Our atmosphere would have been rust-colored instead of the blue sky that we have today because there wasn’t any oxygen in the atmosphere, it was all carbon dioxide and other kinds of gases.

And it took bacteria about a billion years to get a foothold on earth because there wasn’t any food. All food comes from something that was once living. And because there wasn’t any life on earth, there wasn’t anything for bacteria to eat. They basically carved out and existed here and there where they could like volcanic vents under the ocean where there were some organic molecules that came together, and it was really just a bare existence.

So things didn’t start changing until about a billion years into life’s history when certain kinds of bacteria figured out how to photosynthesize, to use energy from the sun to create food in the form of carbohydrates. So, these bacteria kind of floated at the surface of the ocean and any other water surface on the planet and were able to generate food in the form of carbohydrates.

That’s the one thing that changed everything. That’s when life exploded because suddenly there was food. So, it became a bacteria-eat-bacteria world. So bacteria that couldn’t photosynthesize ate bacteria that could and that’s what started everything as far as our whole life cycle.

At that same time, those photosynthesizing bacteria started producing oxygen that started changing the atmosphere and life started flourishing at that point. But bigger is better when it comes to being an early predator. So, certain bacteria became bigger, more advanced, could live longer so they could eat more, and there became a lot of competition.

Eventually, in that game bacteria started coalescing to form multicellular organisms as did the photosynthesizing bacteria. So we started seeing that early representation of the difference between plant and animal. And everything was eating everything with those photosynthesizing bacteria and later plants as the foundation for it all.

So as animals started to evolve in an early stage it was worms. So that animals started evolving in a way that was… They formed a tube so they could eat, they could consume things and pump out the waste at the other end so that cavity was really essential to early animal life.

So interestingly, everything has to eat. So bacteria immediately invaded these multicellular organisms and were invading their cells. So, we first started seeing what we call intracellular bacteria. So there were bacteria inside of the early animals. And very interestingly, the scientists have actually discovered that there was an amoeba, certain kinds of amoeba started patrolling the insides of animals to eat these bacteria that were invading the inside of the animals. And it was beneficial to the animal, that early worm, the early multicellular organisms that we define as animals, it was beneficial. So eventually that became something that the amoeba became part of the animal and that’s where our white blood cells interestingly came from.

So animals developed this white blood cell immune system. Plants, on the other hand don’t have a cavity inside so they did not have the same relationship with these amoeba. So plants instead, they had to protect their cells from being eaten too by bacteria and everything else. So plants started evolving a biochemical defense system that’s pretty analogous to our immune system except it didn’t use cells. So they were producing hundreds and even thousands of different kinds of chemicals to defend themselves against early animals, bacteria, everything else.

So, we end up with systems that are solving the same problem. One, a cellular system that evolved to be our immune system. So over the years, that system became more and more and more complex. It was constantly the immune system and the microbes in this challenging situation of having to one up each other, to move forward to get what they needed, and so the immune system became more and more and more complex.

On the other side of things as plants evolved their biochemical immune system became more and more and more evolved and more and more complex. So getting to the root of the problem and how it relates to the book is that here we’ve got two completely different systems, but are solving the same problem. And because humans have eaten plants since the very beginning or animals have eaten plants since the very beginning, these chemicals that plants produce are very, very similar, are very, very compatible with us. So when we eat those plants, it’s like taking our cellular immune system and getting a boost from a whole different direction to solve this same problem. Which is really kind of cool when you think about it.

But that in a nutshell is why it’s so important for us to eat plants, to do herbs, to gain that chemical protection system that the plants are using to support our immune system. So it protects us against microbes and all kinds of other stress factors that the plant is having to do. So in essence, what we’re doing is getting this huge boost to our immune system when we take herbs and embrace that biochemical defense system that the plants are using.

So I thought that was really one of the more interesting things that has come out of my studies for the book. But yeah, there’s just so much to put in there that that story didn’t quite fit in. So I wanted to share it with you. I hope that was something that might help you makeup your mind of whether to take herbs or not. I think that in itself is a really cool argument. Take care.

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References
1. Emelyanov VV. Rickettsiaceae, rickettsia-like endosymbionts, and the origin of mitochondria. Biosci Rep. 2001 Feb; 21(1):1-17.
2. Janeway CA et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001.
3. Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. Evolution of the innate immune system. Available from: https://www.ncbi.nlm.nih.gov/books/NBK27138/
4. Han GZ. Origin and evolution of the plant immune system. New Phytol. 2019 Apr;222(1):70-83. doi: 10.1111/nph.15596. Epub 2019 Jan 7. PMID: 30575972.
5. Martin WF, Sousa FL. Early Microbial Evolution: The Age of Anaerobes. Cold Spring Harb Perspect Biol. 2015;8(2):a018127. Published 2015 Dec 18. doi:10.1101/cshperspect.a018127
6. Levin PA, Angert ER. Small but Mighty: Cell Size and Bacteria. Cold Spring Harb Perspect Biol. 2015;7(7):a019216. Published 2015 Jun 8. doi:10.1101/cshperspect.a019216
7. Woese CR. Bacterial evolution. Microbiol Rev. 1987;51(2):221-271. doi:10.1128/mr.51.2.221-271.1987

About the Medical Director
Dr. Bill Rawls
Dr. Rawls is a licensed medical doctor in North Carolina and a leading expert in integrative health. He has extensive training in alternative therapies, and is the Medical Director of Vital Plan, a holistic health and herbal supplement company in Raleigh, NC.
  • Dr. Bill Rawls

    ABOUT BILL RAWLS, M.D.

    Dr. Rawls is a licensed medical doctor in North Carolina and a leading expert in integrative health. He has extensive training in alternative therapies, and is the Medical Director of Vital Plan, a holistic health and herbal supplement company in Raleigh, NC.

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