Isaac Asimov once wrote
“Perhaps the first great advance in medical science was the recognition by physicians that good health called for a simple balanced diet.”
The key to that sentence is the word balanced.
He goes on to point out that we humans are more specialized than most organisms. We do not have enzymes that can form all the amino acids that we require even if we bring in all the building blocks for those amino acids.
Quick chemistry refresher, amino acids are the components of proteins. Proteins are required for, well, nearly everything. Without proteins you will not function, they make up both structural and functional aspects of our body. Proteins makeup enzymes, antibodies, are required for blood to carry oxygen, and to clot when necessary, they are our muscles, and wrap our muscles, they...well they do lots and lots. So having all the amino acids necessary to make all the correct proteins is critical.
But we can’t do that. We need some amino acids in our diet. These are often called essential amino acids. Humans make proteins from 20 (now 21 amino acids). There are some nuances, we can make limited amounts of some: Asimov would tell us there are 8 essential amino acids. Then we would add 2 for growing children since those 2 can be made but not in much quantity. That reasoning has changed somewhat, there are now considered to be 9 essential amino acids, with 6 additional amino acids being needed in the diet under some conditions (like fast growing children).
By the way, if you are an adult stop freaking out about protein intake, if you think you need to scale up your protein intake, you are probably wrong. You get more than enough protein with less than 12 ounces of meat. Which is much more meat than you should be eating in a day anyway. You also get protein in eggs, milk (and cheese), yogurt, fish, beans, nuts, spinach, peas; lots and lots of stuff. Eat a varied diet, limit you meat intake, and stop freaking out.
By the way, as Asimov tells us, as scientist were figuring out the nutrition thing, they determined that some things were essential and had amine groups—that’s the group that amino acids contain, thus the name. They started calling them life amines, or vit amines = vitamins. Then of course they figured out that many, or even most, didn’t have amine groups, but the name vitamin still stuck.
Of course one of the things they figured out, but boy did it take a while, is that vitamin C would prevent scurvy. Because humans cannot store vitamin C for long periods, we need a relatively constant intake of it. Other things they figured out, vitamin D would prevent Ricketts, vitamin B would prevent Beri Beri: But of course it’s more complicated, it turns out vitamin B isn’t a single vitamin, now we call this a complex, the B complex.
Asimov was a prolific writer, 300+ books, and his science guide to biology is 800+ pages, so we should move on to another section of that book.
He discusses the varieties of life on the planet. There is a problem here, well with this whole book a bit, it might not age well, it was written in 1960, that’s before I was born, and I’m old. Some sections age worse than others, the section on species doesn’t age well:
The number of described species Asimov lists is 1 million, 250 thousand. That’s not too far off from the described species today (nearly 2 million) but the estimate of all species is more like 8 million. A million is one of those numbers I have a hard time picturing. I can picture 10, a small room is crowed with 10 people. I can picture one hundred, a medium sized parking lot starts to fill up with 100 cars. I can almost picture in my mind 1000. 1000 people will start to fill a university courtyard. But once we go beyond 1000 I start to blank out, can’t picture it. 10,000? 100,000??? 1,000,000 ? Totally clueless. Yet there are far more species on the planet than that. Mind boggling and amazing, all in one.
Asimov discusses the first animals to move onto land. Particularly focusing on vertebrates. These days we have much more to ponder. Tiktalik, a fish-like amphibian, or is it an amphibian-like fish? Wasn’t described until 2006. Besides the work on Tiktalik, many vertebrate fossils have been uncovered since Asimov wrote this tome. But some of the material is still true to form. Lungfishes, have features that eventual terrestrial vertebrates would need, an organ that could get oxygen from air. And the coelacanth also has features that these landlubbers would need, that is fins (legs) that had robust bones and not just tiny rays like your local trout. Breathing and moving on land are necessary requirements if you want to invade the forests.
There is another connection here that both lungfishes and coelacanths have, that is an alteration is their nitrogen metabolism. Fish can excrete ammonia at their gills and swim happily on, leaving this toxic chemical in the water behind them. On land, this isn’t an option. You can’t exude ammonia without injury to yourself, and neither can a lungfish during a dry spell when the pond dries up. Thus these fishes, and land vertebrates, covert ammonia to urea, allowing storage of this less toxic nitrogen compound. Tiktalik probably did this, though it’s a fossil, so we will never know if it did.
I care so little about the science of human behavior, except to note that more people should leave me alone when I’m drinking coffee at Method (local coffee/bar/bike shop), so I will skip over Asimov’s stint on this topic. I’ll skip, over his stint on human evolution too: Which is a heady area of research that changes so much every decade that, well, what’s the point in rehashing work done decades ago. And his bit on the human mind, because, that related topic has also undergone massive change. Let me sum it up; Freud is dead, and none of his stuff is worth a plug nickel.
Well then, that sums up the volume, or mostly, or maybe not even mostly: Go read it yourself 😜
Sources and readings:
This was all stolen from:
Asimov, I. 1960. The intelligent man’s guide to science: volume two the biological sciences. Basic Books, Inc. New York.