Too-Clean Is Making Kids Sick

A childhood disease on the rise is asthma.  Why is this happening?  Clues have been accumulating.  They point, amazingly, to antiseptics, disinfectants, and antibiotics as culprits.

         For nearly two billion years, all life on earth was bacterial.  So when animals evolved, they did so in a bacterial world.  The result is that animals evolved to depend in many ways on bacteria.  All over our outsides and insides are microbial communities.  They consist of thousands of different types of bacteria, along with viruses and molds, and they keep us healthy. 

         Some obvious ways our microbes contribute to our health: They keep away disease-causing microbes by crowding them out, eating them, or poisoning them.  They contribute nutrients to our diets by digesting what we put into our guts but cannot digest ourselves.

         And now we learn that in some mysterious way, our native bacteria may keep us from getting asthma.  Or if we have the wrong microbial communities in our respiratory or digestive systems, we get asthma.

         So far, no one knows exactly how this works.  But statistics show that it’s true: Children raised on farms and in other rural areas are much less likely to get asthma than children raised in antiseptic, Lysol- and bleach-scrubbed urban environments.  Children born vaginally, exposed to bacteria in the birth canal are much less likely to get asthma than children born by caesarian-section.

         Hm-m-m.  What is going on here?  More on this wonder in my next post.



Pistons & Waterwheels: Is It God, or Is It Evolution?

It’s hard to believe that evolution invented electrical transmission, tunnels, gates, and all manner of devices we humans take credit for.  Respiration, the method by which living cells harvest their energy from sugars, relies on some such inventions, specifically waterwheels and, as it now turns out, piston pumps,

         Inside our cells are micro-microscopic organs (“organelles”) that do the cells’ work.  One of these organelles, the mitochondrion, takes energy from sugar, and uses the energy to recharge the cell batteries that power cell work. 

         The batteries are molecules called ATP (adenosine triphosphate) when they are charged, and ADP (adensine diphosphate) when they need a charge.

         The charger is an enzyme that works like a waterwheel.  Instead of water, protons flow over a molecular dam, powering the waterwheel that packs a new charge into a phosphate molecule, and then attaches that molecule to ADP, to make ATP.

         In the last half of the 20^th century, Paul Boyer and John Walker discovered how this waterwheel enzyme works.  They won the Nobel Prize in 1997 for this discovery.

         Now a Russian researcher, R.G. Efremov has discovered that another enzyme works like a piston pump, to push the protons behind the dam in the first place.

         It seems uncanny that these unbelievably tiny machines could have resulted from evolution.  And not from recent evolution, not in the plants and animals we know today, but in bacteria some 3 billion years ago.

         I've been thinking about the New Atheists and God:  The New Atheists believe in evolution, but not in God.  Yet frankly, if evolution can invent these fantastic atomic and molecular machines and coordinate their workings to maintain life, then evolution begins to sound a lot like God.  Hm-m-m.



Spelunking for a Degree, Part 4: Blind Cave Beetles

Many creatures that live in caves are blind.  Yet their ancestors were sighted.  This is a great example of evolution.

         I did my master’s research on the cave beetle, Ptomaphagus hirtus.  This beetle’s ancestors scavenged for food underneath the leaf litter on forest floors.  Since it’s dark under the leaf litter, eyes were of little use even to these immediate ancestors.  But much earlier ancestors had eyes and used them.

         Though the circumstances differed for the ancestors of other cave animals, like fish or crayfish, the natural selection process was similar.  In the cave, except at the cave mouth, there is absolutely no light.  So eyes are of no use at all.  It takes energy to build eyes, and for living organisms, energy is like money.  The less energy an organism has to expend, the better off that organism is in terms of evolution. 

         Here’s why:  Let’s take my Ptomaphagus beetle.  Like all living things, the Ptomaphagus beetle has to expend energy to mate and lay eggs.  The less energy the beetle expends building and maintaining useless eyes, the more energy it has for building and laying high quality eggs, which lead to successful new beetles.

         “Survival of the fittest” means the most fit beetles will pass on the copies of their genes to more or larger new generations of offspring.  So in a cave, the most fit beetles will be those that lose genes necessary for building and maintaining eyes, for this loss will save energy that otherwise would be wasted.  The very fit blind beetles will pass on all their genes to their offspring, including the mutated eye genes that no longer code for eyes.  Eventually, all the surviving Ptomaphagus beetles will be blind.

          Of course all these blind creatures still must escape predators and must find food, so some of the energy they save in not having vision, must be spent on other senses.  I’ll have more to say about this in my next post.  Stay tuned.



Searching for Clues about Cell Origins

     I planned to write three or four articles about the origin of our kind of cells. The cells we are made of are called “eukaryotic” cells, meaning cells with a nucleus inside. But this topic turns out to have a life of its own. The more I think about it or research it, the more there is to say.
      Our species, Homo sapiens, has been on this planet for perhaps 100,000 years, at most 200,000. We know this because we have been able to retrieve and date human fossils: mummies, bones, or tools.
      We can also find and date fossils of other organisms, but this gets harder to do the longer ago the organism lived. All sorts of interference occurs. An organism may die in a location where its body immediately decays without a trace. It may die and be buried in a way that preserves some parts, hard ones like shell or bone or wood. But later geological activity, like mountain building, earthquakes, volcanoes, or erosion, may expose the fossil parts to decay or may destroy them.
      Finding and dating fossils gets much harder with organisms that didn’t have any hard parts. Yet, remarkably, some of these still leave traces, including bacteria, soft. one-celled, microscopic creatures. Some cyanobacteria (photosynthetic green bacteria from as early as 3.5 billion years ago) left stromatolites for us to find. These are stacks of calcium carbonate deposits that resulted from photosynthesis reactions. Photosynthesis removed carbon dioxide from the sea water in which the photosynthetic bacteria lived, and tiny particles of calcium carbonate powder resulted. This calcium carbonate deposited on top of the bacteria. As the bacterial cells reproduced by splitting in two, new cells remained on top of old cells. Cells by the thousands and millions and billions stacked up, and calcium carbonate deposited on each layer. And that’s what stromatolites look like. They look like rock built up out of layers and layers of material.
      Other such soft, one-celled, microscopic creatures left fossil traces. But a huge number did not. And even the traces we find may not tell us much about the inner workings of these single cells. So the puzzle is: what was going on inside the earliest cells to ever live on earth? We want to know, because we want to follow their evolution. There are clues. But these clues are a completely different kind of “fossil.” I’ll begin to talk about them in my next article.