Oct 30 2020

Evolution of Dogs

Published by under Evolution
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The evolution of dogs from wolves is a long and complex one. A recent study adds some further information to this tale – as long as 11,000 years ago there were already at least five different distinct breeds of dog. These different breeds partly tracked along with human populations, but not completely. But let’s back up a bit and see where this new information fits into the story.

Experts actually don’t agree on exactly when and where dogs first appeared, or even if it was one event or multiple independent origins. What is clear is that dogs are essentially domesticated wolves. Their likely origin was in Europe sometime between 19 and 32 thousand years ago. This makes dogs the first domesticated animal. I have often considered (being a life-long dog owner myself) how useful dogs would have been to ancient people. They are excellent guardians, sending up an alarm when anything strays too close to camp. My dog will let me know when racoons are poaching the bird feeder at 3am. They are territorial and will keep critters small and large out of the area. And in an emergency they will even fight for their masters. More developed and trained dogs can also do all sorts of jobs, from herding to hunting.

The extreme usefulness, not to mention companionship, of dogs to humans lead to the early hypothesis that humans domesticated wolves, probably by first raising wolf pups. Tamed wolves are more aggressive than dogs, but they can bond with humans and function in the human world. We know from the silver fox experiments that some mammal species can be significantly domesticated in just a few generations. So it would not take long for these tamed wolves to become more docile, loyal, and obedient. But experts now suspect this is not what actually happened.

The history of human and wolf interaction is mainly one of competition and eradications. Humans have always treated large predators as a threat. Wolves specifically have mostly been eradicated where humans flourish, often deliberately. This still does not preclude the exception of tamed wolves, but it did give rise to an alternate hypothesis – perhaps wolves domesticated humans rather than the other way around, meaning that it was the wolves who changed the nature of our relationship first. In this scenario wolf populations living near humans may have learned to poach at the edges of settlements, perhaps eating the bones or other refuse that humans discarded. The more cute and friendly wolves would have had more success at this strategy, while the more aggressive wolves would have been killed or driven off. This could have led to a subpopulation of friendly wolves mostly living off of human refuse. Selective pressures could have then quickly domesticated these proto-dog wolves, who were only later taken as companions by humans. Human selection would then have taken them the rest of the way to modern dogs.

Humans and dogs, therefore, likely evolved a symbiotic relationship together, rather than humans domesticating fully wild wolves. Dogs have certainly thrived with their relationship with humans, far better than the wild ancestors they left behind. And dogs have been an undeniable boon to humans. Wolves were already social and intelligent creatures, but tens of thousands of years of domestication has made dogs incredible human companions. They can understand human gestures and even a sizable human vocabulary. They also evolved the ability to have enhanced facially expressions themselves, to better tug at human heart strings.

Dogs are also a great example of evolution at work, because their evolution occurred during the course of human history, and much of it has been recorded. The details of their early history are still unclear, but with the advent of DNA evidence a clearer picture is slowly emerging. So far it seems that all dogs evolved from one population of now-extinct wolves. From wolves, over 20-30 thousand years, we have all the modern breeds of dogs. There are 339 officially recognized breeds, falling into 10 major categories. To me this has always been great evidence for the potential power of evolution. If evolution can produce poodles and chihuahuas over thousands of year, then imagine what it can do over millions of years, or hundreds of millions.

What dog breeds demonstrate is that the basic components of evolution, variability and selection, do actually work, even over the time frame of hundreds to thousands of years. That original wolf population contained the genetic variability to produce dachshunds and terriers. Further, selective pressure also works, and can produce profound morphological changes. This is undeniable – but of course, that does not stop creationists from denying it.

One strategy of creationists is misdirection, essentially saying that it doesn’t prove something else. Casey Luskin, for example, writes: “’Breeders selected” and “the selective considerations of breeders’ sure sound a lot like intelligently-guided artificial selection, not natural selection. But these scientists don’t let little distinctions like that get in the way of finding support for Darwinism.”

Because dog breeds result from artificial selection rather than natural selection, the evidence doesn’t count. This argument is nonsense, technically a non-sequitur. Dog breeds are evidence of the power of natural variation and selection, regardless of the nature of the selection. You also see how they play with the term “design”. This is where they make a circular argument – they assume that design requires a designer, then they argue for design in nature. But they ignore the fact that evolution can be a designing force. In dog breeds they have to admit that artificial selection can be a designing force, and they never articulate why natural selection would not also be a designing force in the exact same way (because there is no reason).

Another objection to the dog breed evolution argument is that in the end all dog breeds are still dogs. But this is ignorant of how evolution proceeds. We could, for example, argue that all mammals are still mammals, even though they differ from whales to mice. Whales and mice are both still mammals, and they will never evolve into birds or reptiles. Stephen J. Gould pointed out decades ago that as evolution proceeds groups become more constrained by their evolutionary history. Each sub-group evolves further variations on the basic theme, but they cannot undo their prior evolution. Animals evolve into vertebrates, and all vertebrates are variations on the vertebrate theme. The same is true for those vertebrates that evolve into mammals, and those mammals that evolve into carnivora, and those carnivores that evolve into wolves.

Another way to look at it is this – if you were starting with wolves, you would never get all the disparity in vertebrates that we currently have. You would never get giraffes. But you might get a giraffe-like wolf, but it would still be a variation on the basic wolf theme. Yet another important point is time – we have all the breeds of dogs over thousands of years. But given millions of years there would be more time for rare mutations to occur that might substantially change the basic theme. You are still not going to get birds, but you might get flying dogs, or elephant-sized dogs, or aquatic dogs.

Dog breeds are indeed powerful evidence for parts of evolutionary theory, the power of natural variation and selection over thousands of years. There are, of course, many other lines of evidence for evolution. No one line of evidence proves every single aspect of evolution, nor does it need to and nor do scientists claim that it does. But creationists will deny the evidence piece by piece for what it isn’t, without acknowledging what it is. This is because they are not in the business of understanding reality or of science, they are in the business of doubt and confusion.

In any case, the symbiotic relationship between dogs and humans is a precious one. Dogs really are the ultimate human companions (OK, I have cats to, they have their place, but dogs are special). Dogs have been with us for tens of thousands of years, and they chose us as much as we chose them.


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