The things that intrigue me most about the human body.

[JohnPBailey]

1. THE BRAIN, the seat of the mind and conscious existence. Without a conscious mind, human or otherwise, nothing matters, nothing in the universe is relevent, what does the beauty of a songbird or rose mean without the means to perceive such beauty in the first place? Consciousness is the single most beautiful thing of Mother Nature, the single greatest natural miracle, and the paradox of this is that consciousness is also the ugliest thing of nature: consciousness means pleasure but it also means misery: the brain is a true case for "mind over matter", without a mind, nothing matters

2. REPRODUCTIVE ORGANS, the single greatest feeling in nature, sex, would not be possible without these and I would not be here typing this right now if it weren't for working male and female parts, of course the conscious brain and some nerve endings are also required to experience the greatest feeling in nature, the BRAIN is the number one sex organ after all 

 

What are the things that fascinate YOU the most about our bodies?  

 

 

Edited December 15, 2022 by JohnPBailey

[iNow]

21 minutes ago, JohnPBailey said:

What are the things that fascinate YOU the most about our bodies? 

The way they interact with nature. How dry winter air pulls moisture from our skin and orifices and dries them out. How the cold tile floor sucks warmth through our feet so much faster than carpet. How the clarity of my ideas depends on my blood sugar levels and how much rest I’ve had the night before. 

Said another way, how they tend toward balance and homeostasis almost regardless of the environment in which we find ourselves. 

But ask me again tomorrow… my answer will surely be different. 

[Genady]

The thing that intrigues me most about human body is its evolution.

[Phi for All]

8 hours ago, Genady said:

The thing that intrigues me most about human body is its evolution.

I completely agree. It's not any single organ. It's the fact that we started cooking our food with fire, which shrank our guts, which shrank our jaws, which made room for bigger brains, but at the same time made it easier to walk upright, which led to using our opposable thumbs to make tools and discover even more things (to oversimplify). The evolution of our body is an amazing story.

[TheVat]

Going from a seven pound helpless blob to an intelligent being that can walk on two legs and plumb the ocean depths, outer space, and a dizzying range of hostile environments.  Our capacity to get used to anything.  Self-repairing tissues.  Epigenetic mechanisms. The thermogenesis of brown fat cells in January.  Why overbites are sexy.  The versatility of the larynx.  Dependence of the mind's operations (per @iNow) on subtle interactions with environment and physiology.  Hand/eye coordination that allows virtuoso musicians and surgeons and other fine-motor miracles.  The generation of consciousness from unconscious matter.

So, yes, evolution.

 

[Peterkin]

most intriguing: hormones and the working of this complex chemical factory.

Prettiest microscopic structure : kidney.

[Arete]

There are about as many bacterial cells in a human body as human cells, and, to quote: 

“The numbers are similar enough that each defecation event may flip the ratio to favour human cells over bacteria,”

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002533

[Ken Fabian]

The false perception that we are perceiving and thinking and acting in the present when there is actually a significant time lag has intrigued me - a little bit, or maybe a lot of predictive power needs to be involved in doing that.

[Sensei]

Man is where is, because of the transmission of knowledge to the next generation.

[JohnPBailey]

14 hours ago, Phi for All said:

I completely agree. It's not any single organ. It's the fact that we started cooking our food with fire, which shrank our guts, which shrank our jaws, which made room for bigger brains, but at the same time made it easier to walk upright, which led to using our opposable thumbs to make tools and discover even more things (to oversimplify). The evolution of our body is an amazing story.

 

When some primates started to eat meat by using tapir leg bones as weapons, the dawn of man had arrived. See Stanley Kubrick's 2001: A Space Odyssey for details. Human enlarged brain size and intelligence came about from animal protein consumption. The carnivoires/flesh-eaters are the smartest and keenest of the animal kindom.  Making fire then would follow making weapons to hunt game. 

[zapatos]

27 minutes ago, JohnPBailey said:

The carnivoires/flesh-eaters are the smartest and keenest of the animal kindom.

Yes, those botflies and leaches always best me at chess.

[JohnPBailey]

24 minutes ago, zapatos said:

Yes, those botflies and leaches always best me at chess.

German shepherd dogs and wolves (carnvoires) are smart. Sheep and cows (herbavoires) are stupid.  Adolf Hitler was a vegetarian and a complete idiot. Animal proteins make for smart brains.

 

Edited December 16, 2022 by JohnPBailey

[zapatos]

16 minutes ago, JohnPBailey said:

German shepherd dogs and wolves (carnvoires) are smart. Sheep and cows (herbavoires) are stupid. 

Botflies and leaches (carnivores) are stupid. Elephants (herbivores) are one of the smartest animals in the animal kingdom. Orangutans are almost complete fruit eaters.

German shepherds are not carnivores. They are omnivores.

Edited December 16, 2022 by zapatos

[Phi for All]

8 hours ago, JohnPBailey said:

Human enlarged brain size and intelligence came about from animal protein consumption.

Our skulls wouldn't have had the room if our jaws hadn't shrunk due to eating cooked meat.

8 hours ago, JohnPBailey said:

The carnivoires/flesh-eaters are the smartest and keenest of the animal kindom. 

You'd have to define "smart" and "keen" first. Also carnivore usually refers to obligate carnivores, which are different from animals that can eat meat. Humans are omnivores, not carnivores, and we can be pretty smart and keen, by my definitions.

[mistermack]

Humans became fully upright millions of years before the use of fire. They also started evolving big brains millions of years before. The jaws were also shrinking long before they cooked anything. Fire is a comparatively recent tool for humans, dating back only about a million years, and the ability to light a fire much more recent than that. 

Richard Wrangham has pushed the hypothesis that "cooking made us human" but the evidence so far is wafer thin. If you restrict the definition of "human" to the last couple of million years years then cooking played a part. But human history obviously goes back six million years or more. It's just that looking back, we call earlier ancestors pre-human. But they were the humans of their day. 

So the idea that cooking made us human is a bit contrived. Most of what made us human happened long before.

[CharonY]

28 minutes ago, mistermack said:

They also started evolving big brains millions of years before.

In human fossils significant bran growth was seen around 2 million years ago. While cooking would be difficult to pinpoint as the relevant factor, a study in 2004 (Stedman, H., Kozyak, B., Nelson, A. et al. Myosin gene mutation correlates with anatomical changes in the human lineage. Nature 428, 415–418 (2004)  https://doi.org/10.1038/nature0235) has found a mutation in a gene that leads to weaker jaw muscles, estimated to have occurred about 2.4 million years ago. In related primates, the jaw muscles are connected to large skull crests, which are absent from modern humans. Thus, the author speculate that when our jaw muscles stopped putting stress on the skull, the crests were not important anymore and might have opened the way to further skull growth. However, it has also been argued that some fossils still showed small brain sizes as recent as 1.8 million years ago (early Homo erectus). 

Now I don't know much about the consensus in terms of first fire use, but using wiki a range of 1.7 - 2 million years ago are mentioned. While the evidence from that time does not seem definite, it would line up with the fossil data for brain growth and myosin gene mutation. It does appear that fire use 1 million years ago is rather certain, so if we used this time point the largest discrepancy between fire use and brain growth would be around 1 million years ago (though certainly not millions).

I have also read that folks speculate that beyond cooking meat, the simple act of pre-processing food (e.g. mashing and cutting) could have contributed to the lack of need of large jaw muscles and such tools were around since at least 2.6 million years. 

 

[mistermack]

Most of the claims about fire use more than a million years ago are not supported by firm evidence. That doesn't mean it didn't happen, but the evidence is very weak. 
The thing with fire though, is that it's development is likely to have taken a very long time. 
We're used to things happening very quickly, but go back more than a few hundred years, and development happened at a snails pace. The way stone tools evolved was slower than the way the species evolved. 
Fire would have first been 'controlled' by people throwing sticks onto a natural fire, to keep it going. The most likely reason would be to keep predators and insects away, and to keep warm at night. Finding traces of fire from a million years ago does NOT mean that people were cooking. They might have been, but there's no evidence for it. 
It's very unlikely that they were cooking to such an extent that it influence the evolution of the species, that would surely leave far more evidence behind. 
wiki : 
Archaeological evidence from 300,000 years ago,[10] in the form of ancient hearths, earth ovens, burnt animal bones, and flint, are found across Europe and the Middle East. Anthropologists think that widespread cooking fires began about 250,000 years ago when hearths first appeared.[11]
Lately that's been pushed back to 300,000 years in a cave in Israel. But the use of a hearth doesn't necessarily mean cooking. And certainly doesn't mean cooking to an extent that the species changed as a result.

[Ken Fabian]

An ongoing interest of mine has been what is usually (misleadingly) named human hairlessness - notably smaller hairs that leave human skin exposed and visible over most of the body, which is so different to related apes and primates. But it also comes with a greatly increased follicular nerve supply ie increased sensory sensitivity of those hairs. That is not a visible trait but is something subjectively experienced, presumably by every human barring those that for some reason have no body hairs, or they don't have nerve connections.

How furlessness (I prefer that term) evolved has been an ongoing puzzle that has engaged the minds of many serious contributors to science but the greater puzzle to my mind has been how so many people attempting to explain it could entirely overlook that sensory function - many to the point of claiming our fine body hairs serve no useful function at all, despite living immersed in the sensations they provide. Busy, buzzy insects, puffs of breeze, slide of cloth as we move, close passes by hard objects - sensory awareness of them is a useful function.

I have a picture in my mind of Charles Darwin in short sleeves, deep in thought and unthinkingly swiping at annoying flies tickling the hairs on his arms as he composes the line "No one supposes that the nakedness of the skin is any direct advantage to man: his body, therefore, cannot have been divested of hair through natural selection." Which I think is both false - he admits as much in his response to a naturalist named Belt who did suppose that by suggesting ease of finding and removing skin parasites as an advantage - and an example of "not even wrong" type of wrong; it casts the question as one of the advantages of absence of hairs, when hairs are not absent, but are small with high sensory sensitivity.

That capacity for such deep thought and concentration that we can lose awareness of our senses has to be unusual in the animal kingdom - I do that too - but that so many people who were seriously attempting to understand how human furlessness evolved could have such a big blind spot is intriguing.

[zapatos]

Cell differentiation.

The fact that a particular cell says 'now is the time to do something different', and by following some set of directions, this cell rather than the one next to it, knows it is time for a change.

[CharonY]

5 minutes ago, zapatos said:

Cell differentiation.

The fact that a particular cell says 'now is the time to do something different', and by following some set of directions, this cell rather than the one next to it, knows it is time for a change.

May I interest you in de-differentiation? A process where a differentiated cell decides to try something new and becomes a state that has higher flexibility and then changes again to a new job- but slightly different then those that differentiated directly into the role?

I assume it is a process exclusively developed to annoy the heck out of cell biologists.

[zapatos]

That's news to me. Thank you!

[Ken Fabian]

@mistermack - Fire was also used to drive prey animals towards hunters and burning of dry grass and vegetation around camps was done to make them safe from wildfires. That kind of burning also results in fresh green plant growth as the area recovers and that attracts grazing (prey) animals.

[mistermack]

40 minutes ago, Ken Fabian said:

@mistermack - Fire was also used to drive prey animals towards hunters and burning of dry grass and vegetation around camps was done to make them safe from wildfires. That kind of burning also results in fresh green plant growth as the area recovers and that attracts grazing (prey) animals.

Good point. It was originally probably wildfires that caught their attention for the bounty of food left behind. They could probably see fires from a long way off, and would move towards it like vultures to clean up the goodies left behind. It would progress from that to using smouldering embers to reignite fires on unburned areas to produce more leftover food. Eventually they would learn how to preserve fire for long periods, and how to carry smouldering embers from one place to another so that they could take fire from place to place, and no longer rely on lightning strikes to start fires. 

But that progression would probably take a lot of time, probably millions of years. And right at the end of that process came the invention of fire-lighting techniques.

[Sensei]

1 hour ago, zapatos said:

Cell differentiation.

The fact that a particular cell says 'now is the time to do something different', and by following some set of directions, this cell rather than the one next to it, knows it is time for a change.

Isn't that too easy to grasp?

There are even self-modifying computer programs..

https://en.wikipedia.org/wiki/Self-modifying_code

ps. Now you sound like a humanist.. "the cell wants this or that" (i.e. giving the cell a human mind, perception and the ability to consciously do something)....

1 hour ago, zapatos said:

a particular cell says

In what language?

 

Edited December 17, 2022 by Sensei

[zapatos]

7 minutes ago, Sensei said:

ps. Now you sound like a humanist.. "the cell wants this or that" (i.e. giving the cell a human mind, perception and the ability to consciously do something)....

Yes, I literally meant the cells have status meetings and use tiny blueprints.