3 ms·

Where Did the Brain Come From?

3 points by rolph 3y ago

bediger4000 3y ago
Paywalled, so I'm probably speaking through my hat... This one seems obvious: moving around requires senses and at least some degree of central control over moving parts. There's selective pressure to not consume much energy. This leads quickly to a front end, with a brain in it.
- rolph 3y ago
  from article: Before our evolutionary ancestors had a brain—before they had any organs—18 different cell types got together to make a sea sponge. Remarkably, some of these cells had many of the genes needed to make a brain, even though the sponge has neither neurons nor a brain. In my neuroscience lab at the University of California, Santa Barbara, my colleagues and collaborators discovered this large repository of brain genes in the sponge. Ever since, we have asked ourselves why this ancient, porous blob of cells would contain a set of neural genes in the absence of a nervous system? What was evolution up to? The sea sponge first shows up in the fossil record about 600 million years ago. They live at the bottom of the ocean and are immobile, passive feeders. In fact, early biologists thought they were plants. Often encased by a hard exterior, a row of cells borders a watery center. Each cell has a tiny cilium that gently circulates a rich flow of microorganisms on which they feed. This seemingly simple organization belies a giant step in evolution. For the previous 3 billion years, single-celled creatures inhabited the planet. In one of evolution’s most creative acts, independent cells joined together, first into a colony and later into a truly inseparable multicellular organism. Why did this porous blob of cells contain neural genes? What was evolution up to?
rolph 3y ago
related articles concerning early aquisition of conserved core neurogenetic features of Animalia. https://www.nature.com/articles/d41586-021-03015-2 https://www.nature.com/articles/d41586-021-03015-2 https://www.science.org/content/article/sponge-innards-suggest-how-nerve-cells-evolved https://www.science.org/content/article/sponge-innards-sugge... https://answersingenesis.org/genetics/dna-similarities/sponge-synapses/ https://answersingenesis.org/genetics/dna-similarities/spong... https://www.wired.com/story/sponge-genes-hint-at-the-origins-of-neurons-and-other-cells/ https://www.wired.com/story/sponge-genes-hint-at-the-origins... https://pubmed.ncbi.nlm.nih.gov/28647138/ https://pubmed.ncbi.nlm.nih.gov/28647138/

3 points by rolph 3y ago

Paywalled, so I'm probably speaking through my hat... This one seems obvious: moving around requires senses and at least some degree of central control over moving parts. There's selective pressure to not consume much energy. This leads quickly to a front end, with a brain in it.

rolph 3y ago
from article: Before our evolutionary ancestors had a brain—before they had any organs—18 different cell types got together to make a sea sponge. Remarkably, some of these cells had many of the genes needed to make a brain, even though the sponge has neither neurons nor a brain. In my neuroscience lab at the University of California, Santa Barbara, my colleagues and collaborators discovered this large repository of brain genes in the sponge. Ever since, we have asked ourselves why this ancient, porous blob of cells would contain a set of neural genes in the absence of a nervous system? What was evolution up to? The sea sponge first shows up in the fossil record about 600 million years ago. They live at the bottom of the ocean and are immobile, passive feeders. In fact, early biologists thought they were plants. Often encased by a hard exterior, a row of cells borders a watery center. Each cell has a tiny cilium that gently circulates a rich flow of microorganisms on which they feed. This seemingly simple organization belies a giant step in evolution. For the previous 3 billion years, single-celled creatures inhabited the planet. In one of evolution’s most creative acts, independent cells joined together, first into a colony and later into a truly inseparable multicellular organism. Why did this porous blob of cells contain neural genes? What was evolution up to?

rolph 3y ago

related articles concerning early aquisition of conserved core neurogenetic features of Animalia. https://www.nature.com/articles/d41586-021-03015-2 https://www.nature.com/articles/d41586-021-03015-2 https://www.science.org/content/article/sponge-innards-suggest-how-nerve-cells-evolved https://www.science.org/content/article/sponge-innards-sugge... https://answersingenesis.org/genetics/dna-similarities/sponge-synapses/ https://answersingenesis.org/genetics/dna-similarities/spong... https://www.wired.com/story/sponge-genes-hint-at-the-origins-of-neurons-and-other-cells/ https://www.wired.com/story/sponge-genes-hint-at-the-origins... https://pubmed.ncbi.nlm.nih.gov/28647138/ https://pubmed.ncbi.nlm.nih.gov/28647138/