Could the brain have evolved from a parasitic organism?

[cosmictotem]

The entire vertebrate brain is an outgrowth of the olfactory lobe. The first sensory ability was smell: the detection and categorization of chemicals in the water that might be food, predators, shelter, a mate, etc. This information was used to decide which direction to move in for survival.

Some of the members of the less-advanced phyla, such as the octopus, also have brain-like organs that evolved from more primitive cells. Some insects have surprisingly complex cognitive powers, even though they don't have a central nervous system anything like ours.

The brain is not something that showed up miraculously in its current configuration. It evolved over hundreds of millions of years.

That's surprising that the first sensory ability was smell. I would have thought it would be touch, although I would suspect all senses are ultimately based on the sense of touch or, more precisely, a receptor making contact with stimuli.

Of course, I wasn't suggesting the brain latched onto a body fully evolved. If my hypothesis had any chance of being a possibility (which has already been dismissed), I was suggesting it would have been one brainless species embedding itself into another brainless species as a parasite and then any parasite that had even the smallest ability to influence the movement of its host to avoid or warn of danger would have had a survival advantage over those that couldn't that could have progressively evolved and refined itself over generation after generation. The parasitic protobrain would have lost the ability of outward movement in exchange for a primitive form of "inward movement" or a precursor of perception or thought that could be employed to control its host and improve both their chances of survival and slowly evolving into a brain.

That's where I was trying to go with that but...

 

[Kittamaru]

Has anyone ever tried to explain where the organism of the brain came from?

I'm just speculating here but could the protobrain have started out as an organism that would attach itself to the inside of another organism and feed? And as this organism evolved it lost the ability for self-propelled movement? And is thought in the brain that long lost motive power turned in on itself? So instead of moving itself, it evolved thought and senses to better successfully direct it's host through its environment?

I am going to ask in all seriousness - what level biology/health courses have you taken and passed?

I don't ask to be an ass, but rather I need to know a baseline of your background knowledge.

 

[cosmictotem]

I am going to ask in all seriousness - what level biology/health courses have you taken and passed?

I don't ask to be an ass, but rather I need to know a baseline of your background knowledge.

No, don't think you can't question my background. I have been quite upfront in admitting I am not a scientist or have anywhere near the knowledge base that a lot of you have here. I freely admit I am just slightly above a casual consumer of science but not someone with a academic background. I just throw things out there hoping something might stick with those who have more of a background. Just ignore me if I say ask something stupid.

But to answer your question, yea, I didn't really study biology or health formally any time after high school so...(I went into electronics after high school...)...that's what you're dealing with...Since then I have read and enjoyed some books like "Climbing Mount Improbable" which I loved and was able to follow but perhaps I don't remember it all.

If you feel you can't talk to me based on my level of knowledge or lack thereof I won't be offended at all...that's just the way it is and I understand...There would be too much background info you'd have to impart...But i do have an ability to remain civil in any discussion so I've got that going for me...

 

[Kittamaru]

No, don't think you can't question my background. I have been quite upfront in admitting I am not a scientist or have anywhere near the knowledge base that a lot of you have here. I freely admit I am just slightly above a casual consumer of science but not someone with a academic background. I just throw things out there hoping something might stick with those who have more of a background. Just ignore me if I say ask something stupid.

But to answer your question, yea, I didn't really study biology or health formally any time after high school so...(I went into electronics after high school...)...that's what you're dealing with...Since then I have read and enjoyed some books like "Climbing Mount Improbable" which I loved and was able to follow but perhaps I don't remember it all.

If you feel you can't talk to me based on my level of knowledge or lack thereof I won't be offended at all...that's just the way it is and I understand...There would be too much background info you'd have to impart...But i do have an ability to remain civil in any discussion so I've got that going for me...

*nods* No no, not a problem at all, and I appreciate your candor - it just helps me to know where to start.

First and foremost, you are confusing organism and organ - the brain is a living part of the human body, but it is not an organism unto itself; rather, it is a part of the whole.

The question of when the brain first developed as we know it is one that has many possible answers - generally (and someone feel free to correct me if I'm wrong) it is accepted that the brain started developing into the organ we know it was today as our diet evolved. During the time of the Homo Ergaster, the intestines reduced in size, as well as some other characteristics found in their remains, and indicate a change from a vegetarian diet to one high in animal proteins and fats. These are much denser supplies of calories, fats, proteins, and other essential building blocks required for the large brains we enjoy today.

A good place to start might be here:

http://www.bradshawfoundation.com/origins/origins_overview.php

It will no doubt have a lot of references to material you are unfamiliar with - research the items you do not know and it will greatly expand your knowledge on this and the prerequisite background knowledge.

 

[Fraggle Rocker]

That's surprising that the first sensory ability was smell. I would have thought it would be touch. . . .

Smell is the sense that the more primitive animals use to find food. The first animals were aquatic; living in a three-dimensional environment does not afford as many opportunities to touch things as we terrestrial animals get in our two-dimensional environment.

Of course, I wasn't suggesting the brain latched onto a body fully evolved. If my hypothesis had any chance of being a possibility (which has already been dismissed), I was suggesting it would have been one brainless species embedding itself into another brainless species as a parasite and then any parasite that had even the smallest ability to influence the movement of its host to avoid or warn of danger would have had a survival advantage over those that couldn't that could have progressively evolved and refined itself over generation after generation.

Animals are full of parasites--except for the fact that most of them are symbiotes rather than parasites.

About 95% of the mass of the human body is bacteria. They help us digest our food, fight off infections, etc.

 

[cosmictotem]

*nods* No no, not a problem at all, and I appreciate your candor - it just helps me to know where to start.

First and foremost, you are confusing organism and organ - the brain is a living part of the human body, but it is not an organism unto itself; rather, it is a part of the whole.

The question of when the brain first developed as we know it is one that has many possible answers - generally (and someone feel free to correct me if I'm wrong) it is accepted that the brain started developing into the organ we know it was today as our diet evolved. During the time of the Homo Ergaster, the intestines reduced in size, as well as some other characteristics found in their remains, and indicate a change from a vegetarian diet to one high in animal proteins and fats. These are much denser supplies of calories, fats, proteins, and other essential building blocks required for the large brains we enjoy today.

A good place to start might be here:

http://www.bradshawfoundation.com/origins/origins_overview.php

It will no doubt have a lot of references to material you are unfamiliar with - research the items you do not know and it will greatly expand your knowledge on this and the prerequisite background knowledge.

Thank you that site is awesome. While I am familiar with a lot of the content, it really breaks things down and makes it all easier to remember.

 

[Jake Arave]

Smell is the sense that the more primitive animals use to find food. The first animals were aquatic; living in a three-dimensional environment does not afford as many opportunities to touch things as we terrestrial animals get in our two-dimensional environment.

Animals are full of parasites--except for the fact that most of them are symbiotes rather than parasites.

About 95% of the mass of the human body is bacteria. They help us digest our food, fight off infections, etc.

Incorrect on the mass portion of the comment, citation needed on the smell portion.