The Evolution of Dogs: Domestication in a Short Time Period?

[jaydnul]

I understand and completely accept the evidence for the former but i was just reading the greatest show on Earth and richard was saying how our domestic dogs are directly evolved from wolves, not foxes or anything else. If that's the case, wouldn't the lame argument "if we evolved from chimps, why are there still chimps around" apply to wolves? Or did humans directly influence the evolution of dogs leaving the majority of the wolves alone? If so, how is it possible to have evolution take place in such a small time period?(domestication) thanks

 

[Evo]

I understand and completely accept the evidence for the former but i was just reading the greatest show on Earth and richard was saying how our domestic dogs are directly evolved from wolves, not foxes or anything else. If that's the case, wouldn't the lame argument "if we evolved from chimps, why are there still chimps around" apply to wolves? Or did humans directly influence the evolution of dogs leaving the majority of the wolves alone? If so, how is it possible to have evolution take place in such a small time period?(domestication) thanks

Selective breeding.

 

[D H]

If that's the case, wouldn't the lame argument "if we evolved from chimps, why are there still chimps around" apply to wolves?

This isn't just a lame argument. It's an incredibly ignorant and wrongheaded argument. It's ignorant of how evolution works in general and it is ignorant of human evolution. We didn't evolve from chimps. We evolved from a common forbear of chimps, bonobos, and humans.

There is no magic switch that tells every individual in some population to evolve toward the same end goal. Evolution is blind and local. Our ancestors took to the savannah. The ancestors of chimps and bonobos took to the tropical rainforest. Different environments mean different evolutionary pressures.

Or did humans directly influence the evolution of dogs leaving the majority of the wolves alone? If so, how is it possible to have evolution take place in such a small time period?(domestication) thanks

Most likely, we selected for tameness.

Selective breeding can operate very quickly compared to natural evolution. Natural evolution is blind, local, and oftentimes slow. All that matters is whether a member of a population successfully has offspring. Those genetic traits that are somehow conducive to having offspring get magnified, those that somehow hinder having offspring get suppressed.

Selective breeding is not blind, and it's much more vicious than nature. Suppose a human found a pack of wolf cubs and picked the one or two pups that didn't flinch or bite when the human picked them up. The rest are left behind. That potential for tameness is partly genetic. The next generation, the selection can be even tighter. It can take a surprisingly short time, just a few generations, to change a wild species into a domesticated one. Here's an interesting read on an experiment that started in 1959 with regard to taming foxes: http://blogs.scientificamerican.com...tten-russian-experiment-in-fox-domestication/.

 

[russ_watters]

The answer in this specific case may be selective breeding, but it is a part of a more general issue of schedule: the longevity of species and frequency of branches can both vary widely, since there is an element of randomness to it.

 

[Darwin123]

I understand and completely accept the evidence for the former but i was just reading the greatest show on Earth and richard was saying how our domestic dogs are directly evolved from wolves, not foxes or anything else. If that's the case, wouldn't the lame argument "if we evolved from chimps, why are there still chimps around" apply to wolves? Or did humans directly influence the evolution of dogs leaving the majority of the wolves alone? If so, how is it possible to have evolution take place in such a small time period?(domestication) thanks

Domesticated dogs are not directly descended from currently living wolves. That would be impossible. Your analogy is not precise.

Your analogy is "Dogs are descended from chimps" the way "humans are descended from chimps".

However, the usual about humans is "humans are descended from apes". The species called "chimpanzee" evolved within the last 5 MY. The word "ape" refers to any tailless primate.

Animals closely resembling extant chimpanzees only evolved within the last 5 MY. The common ancestor of humans and chimpanzees (Ardi something or other) lived 16 MYA. The common ancestor did not look precisely like either a human or a chimpanzee. In fact, Ardi had feet that resembled human feet more than chimpanzee feet. The chimpanzee foot is a "recent" specialization.

"Wolf" is not a species name. It is a general word for "large wild dog". The word "wolf" is being used in the most general sense of a big wild canine. The ancestor of the dog was a wild animal that may have superficially resembled an extant wolf. However, it would have been different from living wolves in some ways.

There are several species of extinct "wolves". For instance, the "dire wolf". The dog could have been descended from a dire wolf. There are many different species of wolves now. A coyote is considered a type of wolf, though it isn't nearly as big as its European and Asian brothers. Wolf is not a species name. Wolf is a general word, the way ape is a general word.

Domestic dogs are descended from wild dogs. The paleontological evidence is that Domesticate dogs are descended from larger dogs with larger brains. There are many varieties of dogs. Some of these varieties may have been descended from different species of "wolves". It is possible that "domestic dogs" are a multiphyletic group on the species level.

I don't know the evolution of dogs all that well. It is possible that there were animals so closely related to wolves that there would be no way to tell them apart, side to side. In that case, one could say "humans are descended from wolves". However, they still aren't descended from extant wolves.

The generality of a particular "common name" is always a matter of context. The word "ape" can mean all primates. The word "ape" can mean any tail less primate, which would include Barbary monkeys. "Ape" can mean quadrapeds only (humans, chimpanzees, orangutang, gorillas). "Ape" can mean all quadrapeds excluding human. The word "ape" does not include "dog".

However, it can mean any wild dog. On the other hand, some use it to mean European wolf. "Wolf" does not mean "ape". The word wolf does not include fox, because of differences in chromosomes.

However, your comparison between statements is still incorrect.

 

[Darwin123]

The answer in this specific case may be selective breeding, but it is a part of a more general issue of schedule: the longevity of species and frequency of branches can both vary widely, since there is an element of randomness to it.

The real question is the use of common words. Domestic dogs are not descended from foxes. However, foxes are not dogs or wolves. "Wolf" can include any wild dog.

Domestic dogs are descended from large, wild dogs. Dogs are much different from these early ancestors. Extant wolves may resemble prehistoric wolves more than domestic dogs. If this is so, one can vaguely say that "dogs are descended from wolves". This is probably what Dawkins meant.


Dawkins made a more important point in the same book. This other statement is important in that it provides context for the other statement. There are so many different varieties of dogs, varying so much in anatomy, that for all intents and purposes they are different species. Not only are they very different from their common ancestor, they are very different from each other. Each one is "a different species". So evolution of different species has been demonstrated. Whatever that common "dog" ancestor was, it couldn't resemble all these different breeds at once. All these dog breeds "evolved" in a very short time, geologically speaking.

Also, foxes are not wolves or dogs. They can't cross with wolves or dogs. Foxes are fully omnivorous. They like fruits and vegetables more than any dog or wolf. There was a common ancestor of foxes and wolves that lived even earlier than the common ancestor of wolves and dogs.

Cladogenesis is far more common in nature than anagenesis. Species usually don't morph directly from one species to another. Generally, one species branches into many species at nearly the same time. One species of extinct "wolf" turned into many species of wolf and dog. So a lot of evolution went on "simultaneously".

 

[AlephZero]

There are so many different varieties of dogs, varying so much in anatomy, that for all intents and purposes they are different species. Not only are they very different from their common ancestor, they are very different from each other. Each one is "a different species". So evolution of different species has been demonstrated. Whatever that common "dog" ancestor was, it couldn't resemble all these different breeds at once. All these dog breeds "evolved" in a very short time, geologically speaking.

I think that is a bit misleading, because it ignores the difference between genotype and phenotype.

It could be more accurate to say that the genotype of the "first" domesticated dog contained the possibility of looking like anything from a St Bernard to a chihuahua. But in its natural environment, there was a selective advantage in looking the way it actually looked, which meant that all the animals (phenotypes) of the species (genotype) looked similar to each other.

But as soon as humans took away the environmental pressures on selection (providing "free" food, shelter, etc) and introduced the new pressures of selective breeding, the whole range of phenotypes within the original "dog" species could be expressed with no consequence to the survival of the animals, and so they were expressed in a relatively short time.

AFIAK all varieties of domestic dogs are capable of interbreeding, though because of the size differences this may require human intervention, and natural pregnancy and birth may be impossible.

 

[russ_watters]

I don't think I'd argue out of this based on a technicality of labeling. I think the more general question of whether a species can exist at the same time as its ancestor is at least a little better.

 

[Darwin123]

I don't think I'd argue out of this based on a technicality of labeling. I think the more general question of whether a species can exist at the same time as its ancestor is at least a little better.

It reminds me of what Aristotle said to Plato !-)

In the same way there are dozens of varieties of wolves, there were probably dozens of species of Ardipithecus. There could be a little gene flow across genus boundaries. Sometimes, the precise line of demarcation between genus and species is not always thin.

Ardipithecus was not a human, chimpanzee, an orangutan, or a gorilla, or a baboon. It is an extinct species of animal that shared some features with all of them. However, you could probably call Ardipithecus an ape. It was a tailless primate. So if humans were descended from Ardipithecus, then one could say that humans are descended from apes.

Humans were not descended from all apes that lived at the time of Ardipithecus. In fact, it is unlikely that there were only two individuals living at that time which are ancestors of human beings. There could have been a population of hundreds all of which can be considered ancestors of human beings. The individual associated with this fossil may have been among that number. In any case, it would probably be difficult to distinguish this individual from the hundreds that are our ancestor.

The common ancestor of humans and chimpanzees may have been in the Ardipithecus genus, depending on how precisely the genus gets to be defined. So far, there is only one species known from this genus. I would take the claim that Ardi wasn’t a “the” common ancestor rather loosely.

There isn’t enough information, and probably never will be enough information, to determine if the organism that left that fossil also left any extant descendents at all. There will never be any proof that humans are descended from THAT fossilized skeleton owner. We may find some small difference that makes it unlikely that anyone in here immediate family was an ancestor of human beings. However, the common ancestor of humans and chimpanzees probably was similar to Ardi in most physical features.

Link
http://www.dailymail.co.uk/sciencet...a-closest-thing-missing-link-humans-apes.html
“Ardi - short for Ardipithecus ramidus or 'root of the ground ape' - stood 4ft tall and weighed 110lb.
She lived a million years before the famous Lucy, the previous earliest skeleton of a hominid who was dug up in 1974.
Experts believe Ardi is very, very close to the 'missing link' common ancestor of humans and chimps, thought to have lived five to seven million years ago. “

 

[dschlink]

OP - Dogs were selectively breed from a small portion of the wolf population. If you allow dogs to breed in an uncontrolled fashion, you do not get wolves back; so something was breed out in the process.

The remaining wolves continued to be wolves.

People and chimps are two (actually three including the bobonos) branches that evolved separately from a common ancestor. Existing species are only the tips of the branches. The ancestor is long gone, as are all of the intermediate stages.

 

[jwbales]

Wolves are not the only wild canines. There are various wild dog species all over the world including African and Australian dingos, Indian pariahs and in North America the Carolina dog. None of these canines would be mistaken for wolves nor is there any evidence that they were selectively bred by man. Carolina dogs look no different from a domestic dog and you would not give one a second look if you saw it on the street.

 

[Evo]

Carolina dogs look no different from a domestic dog and you would not give one a second look if you saw it on the street.

They appear to be a breed that was once domesticated that became feral.

Another example of a comparatively recent North American landrace that developed from European dogs is the Carolina Dog (also called Yellow Dog, and which has also been established now as a formal breed).

http://en.wikipedia.org/wiki/Landrace#Dogs

Landraces are not all derived from ancient stock unmodified by human breeding interests. In a number of cases, most commonly dogs, domestic animals have reverted to "wild" status by escaping in sufficient numbers in an area to breed feral populations that, through evolutionary pressure, form new landraces in only a few centuries.

http://en.wikipedia.org/wiki/Landrace

 

[jwbales]

Chimps are old, dogs are new (in evolutionary time scales)

Chimps and man have had five million years to evolve from their common ancestor. Dogs have had only tens of thousands of years and can still interbreed with wolves and other canines. And there are other species of wild canines besides wolves. The Carolina dog looks no different from a domestic dog. Perhaps domestic dogs derived from wild dogs and not wolves?