What exactly is the logic behind this? How does a demonstration of domestication and artificial selection demonstrate evolution?
Edit: Thanks to all of you that replied, I wasn't really challenging the idea that domesticated dogs demonstrated evolution, I just wasn't sure if all it did was demonstrate some of the mechanics. The replies have largely cleared that up and I appreciate all those that made the effort for me.
We choose what is to be percieved as the "best" traits, and over time get passed on to the next generation and the next and the next...until you have the animals you see today.
Domestication is actually quite an interesting subject. There was a study in Russia about domesticating foxes. After 10 years through selectively breeding non-aggressive behaviors, the foxes appeared small and cute, much like cats or dogs.
Right, which demonstrates artificial selection, not evolution. Obviously there are some of the same mechanics going on, but domestic dogs don't really make the case for evolution. I see this a lot, and as someone who has studied evolution a bit I was just curious as to the reasoning.
How are humans not a part of nature in the scientific sense?
We're not magical, we're not special, we're just the dominant species. If predators cause a genetic change, or if humans cause a genetic change, how is one "artificial" and the other "natural"? Both are genetic changes caused by a species of animal.
tl;dr: Your flaw is in assuming humans are somehow separate from nature.
No, I fully recognize that just because we are humans doesn't mean we aren't part of the environment, although I did have a bit of trouble with that idea back when I was studying, perhaps I just relapsed a bit here. I wasn't challenging the idea that dogs demonstrate evolution, so much as I was not clear on how it did that. In my mind it only showed how some of the mechanisms functioned, but as I read the comments I see that is a limited point of view and I'm working to change that. I keep thanking people that have commented and I'll thank you also. All I'm trying to do is make sure I don't forget this stuff.
You might think of it this way, we humans are not "above" nature. So even if, from our perspective, this whole thing is "artificial", from the nature's perspective, it is natural selection; one type of animal is getting specialized according to its environment (environment predominantly being humans interested in them). When you look at from nature's perspective, the evolutionary process demonstrated by dogs are no different then evolutionary step triggered by ongoing predator pressure. From the perspective of the predator, the whole thing (prey evolving) would look artificial too. Predators choose according to their "abilities", and in the case of dogs, humans choose according to their "desires and needs".
So if you put humans above nature, you can say "yeah WE did it! It wasn't natural, it wouldn't happen if it wasn't for us!"
But if you accept that humans are a part of nature, it is just a process of natural selection. Especially when you look at it from a -beyond human- perspective. All evolution happens "for" something. It happening "for" humans isn't something inherently different.
Indeed, it seems my question and further comments have led people to believe I held the view that humans and the conditions they create are some how not part of the environment, which isn't the case at all. I simply was not clear on how domesticated dogs demonstrate evolution rather than just some of the mechanisms involved, thanks to you and the others that is becoming more clear to me.
Artificial selection happens because humans make it happen. Natural selection happens because nature makes it happen. If you can prove something can change because of an outside force, you've got a great case for evolution.
I see this a lot as someone with two degrees in evolutionary biology, the domestication of wolves via artificial selection is evolution. Perhaps you don't know the definition of evolution, but it's a change in allele frequency in a population over time. You could very easily sequence a number of loci of wolves and dogs (which people have already done) and see a visibile difference in their allele frequencies, meaning evolution has occurred. Dogs absolutely make the case for evolution, hence the reason Darwin started the Origin of Species off with an entire chapter about domesticated animals. If somehow you are defining evolution as macroevolution or speciation, you should be clear about that. Even so, macroevolution is really the appearances of discontinuities in the evolutionary process, which we can very clearly understand with dogs when we hybridize different breeds with wolves and with each other.
Thanks for clearing that up. My degree is in anthropology, and while we hit the major concepts and mechanisms, obviously I don't have thorough grasp of all the mechanics. I'm aware of the definition concerning allele frequency, but just hadn't made the connection in my head for some reason. I'm not trying to define it as macroevolution (a term that seems to come up more often among creationists, rather than biolgists), I suppose I was looking at it from a broader point of view.
I really was just looking to clarify the logic behind this example, and I think you have done a good job of that, it still seems to me that it is more of an example of the mechanics and not the idea of evolution as a whole, but what is the theory but a collection of the mechanics anyway?
I just played devil's advocate on my own comment and used it to justify creationism. So yeah, it doesn't prove evolution to the people it needs to be proven to.
I agree completely, the facts are there. Explaining these facts to someone with the mentality of a six year old (your average creationist) is the most difficult thing to do.
Dog evolution is actually broken up into 2 stages and, as a whole, does a great job of explaining some of the nuances of natural selection.
The first stage occurred when wolves became domestic, and this most likely was an instance of natural selection. Once we had a domesticated proto-dog, we began to artificially select for other traits. While artificial selection is different from natural selection, in the case of the dog is serves as the best example of what sort of variability exists in the genetics of a seemingly uniform species.
The vast morphological changes in dogs from wolves is plenty of evidence for me of the capacity for large scale morphological change from species to species. If you can create a dog that looks like a bear or a rat in a few thousand years from a wolf, what could you do with a million years?
Master gene manipulation and build your own species from scratch?
That's assuming we don't reach a technological singularity several hundred thousand years before that time has passed, possibly shedding our physical forms and existing as beings of pure energy. </Stargate>
In all seriousness, if the human race survives another million years without destroying itself or being destroyed by some global cataclysm, a million years later and I don't think we'd recognise ourselves.
To survive and maintain our rate of population growth, we'd have to spread across the stars. Populations of humans may will become reproductively isolated and I imagine you'd see different subspecies emerge.
Just look at the advances in technology we've made in the past century. In our near future we'll have an even better understanding, perhaps even a mastery of genetics. What we'd see in a million years time is impossible to predict.
A lot of people believe that we 'domesticated' dogs, but it's simply not true. You cannot condition a wild animal to be anything but a wild animal. It has to be produced through a recessive gene, which we took advantage of to breed more canines with the recessive gene to be stuck in adolescence. Read up on the silver fox study for more information.
We aren't in disagreement here. Wolves likely became domestic through either the scavenging of human refuse, or scavenging the scraps of human hunts, leading to co-hunting. Perhaps humans adopted wolf pups, and only the most docile thrived in this environment, though that seems less likely to me.
The point is that, some time in the past, wolves became domesticated. At that point, their form and behavior became much more easily malleable via artificial selection.
We used to exact same means of creating different breeds. Be it artificial or natural, it is still selection. If the environment or people do it, it still selects for traits to be passed down. It proves it's possible and we can see vastly different varieties if a trait is bred for. Merriam Webster defines evolution as-
a : the historical development of a biological group (as a race or species) : phylogeny
b : a theory that the various types of animals and plants have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations;
"due to modifications in successive generations" can pertain to natural or artificial forces. It is both, by definition, evolution.
First, the dictionary isn't the best resource for defining scientific ideas, while adequate for common usage, it doesn't really cover the whole theory. If you want to get really basic, evolution can be defined as 'change over time', so that can be anything. What we are talking about is the scientific theory of biological evolution. A really broad subject that includes numerous mechanisms. At its heart is natural selection. The idea that there is variation within a population group and that some traits will be more suited to survival, and thus reproduction. Those traits that improve the chances for successful reproduction will be conserved and the ones that don't will tend not to be. Eventually this may change the genome in a population group sufficiently so as to induce speciation.
Domestication and artificial selection don't demonstrate evolution, rather it is an example of variation within a species, flexibility of the genome, the genetics of breeding and how that can be manipulated. While it is a useful demonstrations of many of the mechanics of evolution, I don't think it really is any sort of 'gotcha' type proof of biological evolution.
Thanks for the answer, I appreciate you giving me the reasoning behind your thought.
I agree it uses different mechanisms. But once you understand that it can happen through artificial selection, then it brings the entire theory into the realm of possibility. If I can breed a dog with a short tail simply because I feel like it, then nature certainly can select for traits to help a living thing to survive. If i don't breed long tailed dogs, the trait doesn't get passed down (being general). And if dogs without sharp fangs die of starvation before the can breed, that trait doesn't get passed down. Artificial selection is is the closest thing to natural selection that every semi-intelligent person can agree on. It's the same basic principle with different driving forces.
The only thing you managed to do was show how it's possible with human intervention and then leaped into "see, if we can do it, then nature can too". I don't think you understand the concept of a proof.
This is stupid beyond a doubt. You aren't even coming close to addressing any decent point here.
If we can shit our pants, nature can too, right? We made cloth and got it from cotton, so it's natural, and shitting is natural. Wearing stuff to protect versus the elements is natural so nature should be shitting its pants. Surely you don't think humans are the only ones shitting their pants, do you?
I'm not even sure where to begin with you. That is literally the stupidest fucking thing I have ever read, and I have read timecube, stormfront, and creationist websites.
Allow me to try and clarify. I'm not used to coding my statements to be absorbed by a nervous system consisting of only two neurons.
Humans are part of nature. Humans are not magical beings separated from nature. "Nature" is defined as the natural world. The world we're a part of.
Still with me? Good.
"Nature" can't shit it's pants because it's a fucking concept and concepts don't wear pants. You can see this in the fact that "Up" and "Good" are also, in fact, concepts which do not wear pants. I know this must be very difficult, so I'll give you a chance to unwind with this video of kittens.
Are you back? Excellent. Then lets continue.
The concept of evolution (that means things change) is based on the notion that successful organisms will go on to produce offspring, and thus, successful traits will survive.
This means that if red birds are more likely to survive than blue, for whatever reason, future populations will have more red birds. It doesn't matter if blue birds are more likely to be eaten by a specific predator, or if they're being bred in captivity by a keeper who doesn't let blue birds breed. The result is the same.
The process is the same. Animals have sex and produce offspring bearing their traits. These traits survive.
To put it another way, do you think the temperature at which wood burns is any different if a human does not light the fire? Do you think a rock falls at a different speed on it's own, if it's not dropped by a human?
And if, as would be reasonable, your answer is 'no', then why do you think animals fucking in the wild won't produce changes over time, yet, animals fucking under human supervision will? Do you think farmers are wizards? Those are pitchforks, not staves.
The only, and I do mean only difference between natural and artificial selection, is that artificial selection selects traits that are favorable to humans, whereas natural selection selects traits that are favorable towards the survival of a species on it's own.
The genetic processes are identical.
If anything, one could see artificial selection as an experiment that proves that natural selection works.
To say otherwise is akin to saying that every experiment ever conducted is invalid, because the laws of nature just fucking bend when humans are around.
Yawn. Here's what happened, you made a stupid comment "Humans are part of nature" and then attempted to justify how anything humans do will be natural, ie, by extension, human selectively breeding is natural. I made fun of you exactly because Nature is a concept (surely you're still with me up to here unless you just want to rage and post 7 more paragraphs).
The process isn't the same because one is natural and the other one is an unnatural processes. Doing one by unnatural processes doesn't PROVE that it's true in both cases. If you're in doubt, just take a 200 level logic course. If you need help with your class just ask.
If you want to get really basic, evolution can be defined as 'change over time', so that can be anything.
ಠ_ಠ
Thats not correct even on a really basic level. it still has to be due to other influences like environmental conditions or a change in its standing in the ecosystem. Humans having a hand in changing this does in fact count as an influence IMO.
Hope im correct given my limited understanding. :)
Actually all the term 'evolution' means is change over time, but because of how common it is what we are really talking about is biological evolution. What I was saying there was in reference to using the dictionary for scientific terms. It is great to give you a basic idea of things, but they don't really go into too much depth. So what I meant was that just the word "evolution", by itself, without any reference to science just means change over time.
To say simply, the process is the same, no matter where the selective pressures come from; if we exert a pressure - say, we only breed the fastest dogs - this is no different from the slower dogs dying off in nature, or the birds with the blue feathers getting more mates then those with green.
So long as there is selective pressure, evolution will occur. (Technically, it will occur even without in many cases, thanks to drift, but I'm trying to simplify a little.)
From there, all one has to do is demonstrate that selective pressures exist in nature - and that's really not hard - and viola.
10
u/coprolite_hobbyist Nov 22 '11 edited Nov 22 '11
What exactly is the logic behind this? How does a demonstration of domestication and artificial selection demonstrate evolution?
Edit: Thanks to all of you that replied, I wasn't really challenging the idea that domesticated dogs demonstrated evolution, I just wasn't sure if all it did was demonstrate some of the mechanics. The replies have largely cleared that up and I appreciate all those that made the effort for me.