Evolution of the Brain?

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My understanding is the first multicellular colonies formed tubulars designed to direct a flow of nutrient rich seawater through it and over time appendages formed for mobility but the tube remained and is the our ancestral intestinal tract. As this tube formed, communication between cells required another means and so the enteric nervous system was born, which seems to me to our first primordial brain. I don't have research to back this up and wonder what the established view it is.

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@jerlands,

What I find interesting about the intestinal tract is that everything form the mouth to the anus is considered outside the body. Nothing enters the body until it passes through the epithelial lining which is one cell thick. It seems the human body evolved around this tube.

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@jerlands,

you know what the entire process is called dont you ?

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@farmerman,

Quote:

you know what the entire process is called dont you ?

farmerman? is that you?

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The biggest factor explaining the emergence of the brain is locomotion. When you can move around, it pays to scan your environment to know where to go. This leads to a long-term evolutionary process called cephalization: the concentration of many senses and neuronal networks towards the front of the animal, in the direction where it moves.

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@Olivier5,

Olivier5 wrote:

The biggest factor explaining the emergence of the brain is locomotion. When you can move around, it pays to scan your environment to know where to go. This leads to a long-term evolutionary process called cephalization: the concentration of many senses and neuronal networks towards the front of the animal, in the direction where it moves.

Yes, thanks for that but it just seems the enteric nervous system was principal in the development of the brain?

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@Olivier5,

Olivier5 wrote:

The biggest factor explaining the emergence of the brain is locomotion.

I don't know locomotion is the right word.. I'm thinking more along the lines of undulation.

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@jerlands,

Principal?

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@Olivier5,

Yes, principal being the first and primary means of creating a unified response.

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@Olivier5,

You're thinking of development in response to the need to move from point a to point b. I'm thinking it may have been to do with the need to 'roll' (undulate) from in to out.

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@jerlands,

Locomotion. Movement. The capacity to move around. Animals are different fromp plants in that they can go from point A to point B. This is why (many) animals have a brain of sorts, and plants don't.

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@Olivier5,

see prior post..

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@Olivier5,

I should have said post(s)

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@Olivier5,

my guess is the earliest formations were subject to and reflected the most predominant forces in their environment. Day and night, expansion and contraction, in and out, these just seem to me to be those forces.

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@jerlands,

More nutrients can be extracted (absorbed) if the absorbing surface surrounds the water (a tube) than if the cell is simply surrounded by seawater. The first development must've been a means to move the water through the tube. The tube must expand and contract, or close at one end or have many cilia to push the water through. This coordination of movement would have been the first driver of nervous system formation.

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@TomTomBinks,

TomTomBinks wrote:

More nutrients can be extracted (absorbed) if the absorbing surface surrounds the water (a tube) than if the cell is simply surrounded by seawater. The first development must've been a means to move the water through the tube. The tube must expand and contract, or close at one end or have many cilia to push the water through. This coordination of movement would have been the first driver of nervous system formation.

That's along the lines I was thinking... However, a single cell has more surface area alone than joined. The question arises why would cells join? There must be some benefit to both... similar to bacteria becoming mitochondria.

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@jerlands,

jerlands wrote:

The question arises why would cells join?

Strength in number? I think once the cell developed an identity (RNA) it had encoded the action of "uniting" and building became an inherent or innate response.

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@jerlands,

On land, at least, more surface area means more rapid desiccation. I'm thinking of cyanobacteria around here, the terrestrial form. They're filamentous, one cell in diameter, but they're joined together with other filaments and held together by some kind of gelatinous material. In the summer they dry up and look like little pieces of scat, but after a rain they absorb water and look like seaweed. If they were mono-filamentous they'd have a hard time surviving even more so if they were unicellular.

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@coluber2001,

coluber2001 wrote:

On land, at least, more surface area means more rapid desiccation

I don't understand this? Does one droplet dissipate more rapidly than a puddle?

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@jerlands,

Yes. The smaller the size the more surface area. That's one of the biggest problems of insects, how to keep from drying out.

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Evolution of the Brain?

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