...Looked at this way; if human sperm could drift through the air and impregnate the female, that particular feature of procreation would eliminate one of the two fundamental requirements for mobility, “Love and War”. If humans were capable of self-defence by application of poison or sting for example, that aspect would eliminate another essential need for mobility, defence. This of course, is a crude and shaky argument for the need of a brain, but it’s more a question of how much brain is required for the organism to survive and function successfully.

...We appear to be using metaphors from the sea as an example of the need for a brain. Over many years of being immersed in the ocean, I haven’t noticed an obvious oversupply of intelligence roaming around down there. I can offer some anecdotal evidence from personal experience only yesterday, when I was pinned to the sea-bed by a 4m wobbegong shark that mistook me for one of its own. (I don’t wish to be implicated by OLO posters, with some sort of “bestiality” perversion, or the response may not be all good), it really did happen!

...An interesting and thought provoking article, worthy of the intriguing heading

While it may not appear obvious, you answered your own question within the piece, within another question.

" And why has it not developed a brain in 600 million years? "

"How did we evolve from a brain less sponge you might wonder?"

See? It DID evolve a brain. One just has to think of evolution as branching through time, not linear.

Roger, you ask, “Why does a sponge have most of the genes it needs to make a brain? And why has it not developed a brain in 600 million years?”

If there is no intelligent designer/God, then there is only one possible answer to what are essentially pointless questions.

Everything, including sponge genes, is the way it is because that is simply the way it happens to have happened. End of story.

If materialism is correct then nothing happens intentionally or with any purpose. Things just simply happen and all ‘why’ questions are meaningless.

Are all 'why' questions an inquiry into 'purpose' in a religious world?

Son: "Daddy, why is the sky blue? Why are rainbows different colours?"
Dad: "We live in a materialist universe son, nothing happens intentionally or with any purpose. Things just simply happen and all ‘why’ questions are meaningless."
Son: "Oh, ok"

Christian Dad response: "Because we live in a non-materialist universe son, things happen intentionally and with purpose. The rainbow is there as God's way of reminding us of his promise that He will never send a flood again."
Son: "It was God what done it?"
C Dad: "Yes son, no matter what the scientists say"

Try harder JP.

Very interesting! Invokes a complete re-think on species' relationship, and on the merits and mystery of the so-called 'junk' DNA.

It appears that unravelling the full story of the human genome may be an impossibility, and rightly so. (And with any luck, will put an end to ambitions of human cloning or genetic modification or 'enhancement'.)

Bugsy you seem to be inappropriately substituting the word ‘why’ for the word ‘how’.

Yes, we can investigate how things work, but science can tell us nothing about why things are the way they are. In a materialistic universe, things just ‘are’.