The Essentials – A Survival Story

Last April I walked across the parking lot into work after a long spring nights soaking and was greeted by thousands and thousands of worms.  I couldn’t help but walk in a little slower that morning as I pondered the worms paristalticly parading across the pavement.  

This is what I remember observing and thinking that day.

As I walked from my car to the front door at work one rainy April morning I noticed 100s if not thousands of worms sprawled across the expanse of the parking lot.  There were small worms and big worms, and all were completely stretched out, presumably in an attempt to not drown in the supersaturated earth.  My first thought was that if a guy wanted to collect worms this would be a great time to do it.  This in fact is a favorite childhood past time for many people. I remember a lot of good times collecting worms on a rainy day or soaking an area of the lawn to collect worms before going fishing. As useful as this phenomenon is for would be fisher kids, to a worm this is a survival mechanism.

 I don’t know enough about the biology of worms at this moment to comment very specifically but I am aware that worms have a nervous system and a capacity for some sensory responses but they are not on level with mammals or fish or other higher organisms in terms of intelligence, decision making or anything like that.  What worms do have is a survival instinct.  They have an instinct that triggers a response if they are in danger of suffocating because the ground is filling with water just as people have a survival instinct of getting out of water if we are being held under water and couldn’t breathe. Our instinct, like the worm’s, is to get out.  Worms don’t have the capacity to want. Worms have an instinct (or nature or biochemistry or whatever you want to call it) to get out in order to survive.

As a result of this instinct, as I was walking into work that rainy April morning, there were thousands of worms within 100 feet of me that were surviving the rain. They were surviving this horrible situation, making an attempt to avoid drowning in the murky soil below. Their home had become inhospitable and as a result they fled.

Fast Forward through 8 ½ hours of work,  five delicious cups of coffee, three pieces of peanut butter toast, a bowl of delicious lasagna supplemented with hard boiled eggs and tobacco sauce, I emerged from work having survived it (having satiated my instincts for survival by eating all of that food of course).  I emerged to find, not all of the worms, but many of the worms, as worm carcasses, splayed out across the blacktop. Dead.  These worms were not survivors. They followed an instinct to get out of a situation that would have surely caused their death but their response also caused their death.

Not all fleeing worms however, remained to die on the blacktop. Some of the worms went back to the soil, some of the worms found higher ground or found a moist place that would not consume them and fill their little membranes with the aqueous poison that would subsequently claim their fallen comrades. In short, they survived. This is the battle worms fight every time there is a rain, every time their home becomes inhospitable to life. They have to survive it.

Those worms that return and continue burrowing through the ground once it dries out a bit and especially those worms that procreate (that is go have little worm babies) with other worms, those worms survived.  Not just as individuals and not just in terms of their family name or to live another day.  Their specific genetic makeup survived the flood and those genes became more likely to be passed on to the next generation of worms.

 Perhaps if there is something about the survivors genetic make up that caused them to have an affinity for higher ground or sensed a finer range of moisture levels that would be hospitable or if they just got lucky, their genes will go on and the genes of their mates on the blacktop will not.  

So some of the worms survived, some of them did not, some of the gene variations will be passed on, some will not. In this story, and in an evolutionary sense, genes are the ultimate survivors.

While this is quite a harrowing tale it is certainly not the picture of survival of the fittest that is painted by some authors regarding cruelty or violence between organisms.  There is certainly no direct conflict or fight between two individuals.  This is not the story of the lion tracking and stalking a gazelle to catch it and rip open its throat to subdue and eat it (though that is certainly also an example of something surviving and something not surviving and ultimately linked to the survival of genetic material).

The worms give us a survival story with evolutionary consequences but not the type of survival we always think of. This is characteristic of evolution in a lot of ways. To understand and accept evolution we have shift our paradigms toward those of greater and more minute scales than we often have the mental capacity to comprehend (I know it’s the case for me). 

How long is a billion years?  What is a gene? How is a gene expressed and what impact does that have on me? These are mind bending questions and questions that we ultimately have little to no frame of reference to answer unless we examine them intentionally and with tools that are useful for exploring them.

The Essentials - What is Survival and who are the Fittest?

I can't believe that Survivor has lasted 24 seasons.  But then again I can't believe Ben gave Courtney a rose last night. I mean how could he be so blind? Wait... strike the last two sentences from the record. In the show Survivor, contestants have to be strong or smart or sneaky or some combination of those traits. But that's just a dumb TV show.  What does it mean to be a survivor from an evolutionary perspective? What is a survivor and who are the fittest?

These terms have created some backlash, especially for Christians, as they stir up images of ravenous lions tearing the flesh off of an innocent, majestic, bounding antelope. I've heard several people say that they couldn't believe in evolution because God wouldn't work through such a violent and senseless mechanism. While I won't speak to the theological implications of the conclusion this unfortunate image produces, in the next few posts I will try to shed some light on the two evolutionary concepts of survival and fitness.

The Essentials: The Dawn of Dogs - Artificial & Natural Selection

Announcement:  I'm adding another topic to the list of typical evolution topics. New topic: What is survival and who are the fittest?

There are a lot of different types of dogs. Big dogs, little dogs, smart dogs, dumb dogs. Pretty much any characteristic you want in a dog you can get, as long as it already existed in a wolf.  All domestic dogs share a common ancestor with wolves. The story of early dog domestication from wild wolf relatives is pretty interesting and has close similarities to the natural selection process that drives evolution.  Before getting into the dawn of the domesticated dog age, a review of modern breeding basics will prove helpful. 

The methods for creating, and refining dog breeds are pretty straight forward. If you to want to breed a certain shape, size, or characteristic into a dog you simply faithfully select for that trait from generation to generation and allow that trait to accumulate more and more in the individuals of subsequent generations.  As an example, let's say you want to develop a really fast dog.  To get thing going quickly you could start by finding a pair of relatively fast dogs then mate them.  However, while pre-selecting for speed in the founding generation will surely help in your doggie development duties, it isn't necessary. To end up with faster and faster dogs you just have to choose the fastest dogs in each generation and continue to pair them with other fast dogs.  Following this simple method will result in faster dogs.  (Real breeders, those who are careful, keep detailed records of lineage in order to prevent family lines from crossing their own paths.  Aside from the cringe factor, inbreeding has some serious and negative genetic consequences that are worth the effort to avoid.)

Variety truly is the spice of life

Artificially selecting for particular traits has produced an incredibly wide variety of dogs but the key to the possibility of selective breeding is that there is inherent variety in every population of dogs.  Every litter will have slow, average, and fast dogs.  This universal variability is true for any population and isn't limited to speed.   Every trait imaginable is variable and is therefore selectable. This is one of the basic, yet revolutionary ideas Darwin described as he laid out his case for evolution.  Variability occurs naturally in populations and variability provides the raw materials for breeders, and nature, to select from.

Variability is what allowed dogs to be domesticated in the first place.  As I mentioned above all domestic dogs are descended from wolves. So what crazy breeder mated wolves and selected the ones most willing to wear sweaters and chase after tennis balls?  The easy answer is there was no breeder.*  The more tricky answer is that the wolves actually selected themselves for domestication.   

This may seem like a crazy idea but it is true and it all connects back to variability in populations.  Just as there are fast and slow dogs there are also skittish and trusting individuals in wolf populations.  Skittishness is a survival mechanism for wolves because it keeps them away from danger.   Trusting behavior has the potential to be very harmful.  Imagine throwing caution to the wind when approaching a dangerous animal. In many natural environments the possibility for being killed goes way up if you are too trusting.   However the natural environment is always changing and what was once an undesirable trait can actually become useful if the situation is right.  

In the case of wolf domestication the major environmental change that happened was the introduction of humans.  In the presence of humans a more trusting wolf will have a new food source open up in the form of human refuse.  To a skittish wolf the garbage pile just outside a human encampment would put them too close for comfort but to the trusting wolf the garbage is just in reach.  This extra source of nourishment increases the trusting wolf’s chance of survival and it will therefore be more likely to produce offspring.  Just like the dog artificially selected for speed by the breeder, the trusting wolf will be naturally selected by its increased ability to survive in the presence of this new food source.  As generations pass, the trusting trait will accumulate in the population and due to variability more and more trusting individuals will result. 

Of course the timid wolves haven't gone extinct because the trusting wolves have moved toward domestication.  As described above there are certainly advantages to being timid and the natural environment of the wolves will continue to provide selection pressures to increase their fitness for survival in that environment too.  

Final note: Wolves can't decide to be timid or trusting any more than I could decide to be 6'11 or have blue eyes. In artificial selection a thoughtful breeder chooses traits to survive from generation to generation.  These traits are available for selection because every population has variety.  Natural selection doesn't have a thoughtful breeder but rather uses survival as its selecting agent.  Traits survive on their own (naturally, if you will) if they help an individual survive and ultimately produce offspring.

* The easy answer is there is no spoon, oops Matrix flashback.  This sentence was originally in the essay but a very dedicated focus group was pretty sour on its inclusion so I promptly removed it.