Caesarian births helping humans evolve?

[Brian G Turner]

If humans' evolutionary past reflects our future, then our next stages should be expected to have even more enlarged brains - but that's a problem because of the mechanics of giving birth.

Now it's being suggested that the more common and routine ceasarean births become, the most likely this could already be happening:

Are caesareans really making us evolve to have bigger babies?

In which case - and here's a mind-bending moment - does this mean that the process of evolution already accounts for technical innovation to allow for continued development?

 

[Parson]

Logical if unconfirmed. But I do think a case could be made for diabetes. With modern advances even people with type 1 diabetes usually survive and often have children which keeps the gene pool viable.

 

[HareBrain]

then our next stages should be expected to have even more enlarged brains

Hopefully it'll do us more good than it did the Boskops, who had brains substantially larger than our current ones, but who still died out, possibly (unsubstantiated) because they became too self-reflective.

Anyway, I'm not sure it could be called a helpful evolutionary step to make a higher proportion of births dependent on surgery, especially since we don't know if we'll still have antibiotics in a few years' time.

 

[Aquilonian]

Head size doesn't correlate that closely with brain size, most people with severe "learning disabilities" have normal size heads, likewise all geniuses. Most common reason for excessively big head is hydrocephaly, which often goes along with learning disability.

Personally I'm certain that human evolution is now reversed in civilised countries, i.e. the average intelligence of the species must be declining, due to less intelligent people, and people with less impulse control (not entirely the same thing) having more children. I have read that British men with a criminal record father about twice as many kids (on average) as men without a criminal record. I've also occasionally heard evolutionary biologists asked about this, they always manage to deny that evolution has reversed, but never at all convincingly- an example of wishful thinking in my opinion.

I suspect that this may set a limit on the progress of many intelligent species, and partly accounts for the Fermi Paradox.

 

[RX-79G]

We are "breeding" people that can't get through life without corrective lenses, and any number of other changes that aren't "better" or "more fit". It is a mistake to view evolution as a process that creates species of increasing fitness, unless the fitness is understood to just be a greater chance of breeding another generation.

 

[SilentRoamer]

I think humanity in terms of physical and mental prowess may have already had their peak. There are currently very few of the limiting factors that shaped modern humans evolution. Arguably the primary reason humans became smart was all about survival, once you have no driving evolutionary restrictions for the gene pool then it can only become weaker and allow traits that previously would have been clipped to develop. So smarter humans lived longer and gave birth to more smarter humans, if you weren't smart enough to survive then you died and your genes with you.

Its wrong to view evolution as something that evolves towards an environment, it's the other way around - the environment shapes the course of evolution. Richard Dawkins in one of his lectures on evolutionary Biology compares it to tiny chisel strokes chipping away at bits of the genetic code we don't need (the chisels being the environmental factors that end their gene continuation).

This of course has to be balanced with other factors which have resulted from human exploitation - we are able to sustain high protein diets which are important for development and perhaps soon will be able to shape genes in ways we see fit - whether this is a good thing or not I will leave to others to decide.

Interesting topic Brian.

 

[Vertigo]

Hopefully it'll do us more good than it did the Boskops, who had brains substantially larger than our current ones, but who still died out, possibly (unsubstantiated) because they became too self-reflective.

Anyway, I'm not sure it could be called a helpful evolutionary step to make a higher proportion of births dependent on surgery, especially since we don't know if we'll still have antibiotics in a few years' time.

I thought the 'Boskop hominid' had now been discredited as being based on false assumptions and that they now consider it (and other similar finds) to be within the normal range of cranium size. However I may be wrong.

 

[HareBrain]

@Vertigo, you could be right. I'm afraid my research wasn't spectacularly thorough.