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Religion and Spirituality, Science and Philosophy Use this forum to discuss what you believe in. This is a place where everyone may share their views freely.

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Some questions regarding evolution, and perhaps more to come - June 6th 2012, 11:42 PM

I just started reading Richard Dawkins's book, "The Greatest Show on Earth -- The Evidence for Evolution." The questions I have will be 1) for people who understand evolution more in depth than myself and 2) for people who have read this book.

The first question I have is strictly about evolution:

Richard Dawkins, on page 28, is cited saying, "The matter remained open until molecular genetic evidence came along to clinch it. There is now no doubt Domestic dogs have no jackal ancestry at all. All breeds of dogs are modified wolves: not jackals, coyotes and foxes."

Now, you may see where I am going with this...

In domestication, all animals are connected genetically through a random "shuffling" of genes. Thereby assuming all dogs should genetically be related to a jackal, coyote, and fox. Perhaps not immediately, but this connection should still be in their DNA.

My question is, what does Dawkins mean? How can they have no ancestry all?

MY second question is to deal with the book. Although, this may be also for people who have read "The Blind Watchmaker." On page 40 in the book he shows a biomorphs illustration. He attempts to explain this, but perhaps I am too ignorant to understand this, or he did not explain it clearly, either way, I don't understand this exercise. Can someone explain this graph to me and the one on page 42? I just don't quite understand the point of his illustrations

I believe he is simply showing that if you place a couple of different things and they reproduce, their variances, over time, will be drastically different. However, the illustrations seem to complicate his point.

Thanks.


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Re: Some questions regarding evolution, and perhaps more to come - June 7th 2012, 12:20 AM

Mike, I'm going to look at those sections in the book again and get right back to ya.

Okay, concerning the relationship between jackals, dogs, and wolves. Wolves, coyotes, and jackals all share a common ancestor- the jackals are descendants of an offshoot of that, but the wolves and coyotes evolved later on, and more closely. Anatomically, it doesn't take a genius to look at the coyote, wolf, and common dog and see this. Now, genetically, no other DNA shares significant commonalities with dogs other than wolf DNA. There are however a number of crossbreeds and the like- the sullimov dogs, but these are the products of human intervention. They aren't naturally occurring. Here is some reading on those.

Now, I lost my copy of the book, so I had to erm, acquire a pdf of it. If I'm looking at the right page, you are talking about the part where he shows the various biomorphs that can be created by the computer program he developed? Wherein exactly does your question lie? He articulates the purpose of the program pretty well- it is akin to what a dog breeder does: look at traits that are favorable and have dogs with those traits breed. The chart is simply an example of the different biomorphs that can be created with that program.


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Re: Some questions regarding evolution, and perhaps more to come - June 7th 2012, 02:40 AM

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Originally Posted by Toz View Post
Mike, I'm going to look at those sections in the book again and get right back to ya.

Okay, concerning the relationship between jackals, dogs, and wolves. Wolves, coyotes, and jackals all share a common ancestor- the jackals are descendants of an offshoot of that, but the wolves and coyotes evolved later on, and more closely. Anatomically, it doesn't take a genius to look at the coyote, wolf, and common dog and see this. Now, genetically, no other DNA shares significant commonalities with dogs other than wolf DNA. There are however a number of crossbreeds and the like- the sullimov dogs, but these are the products of human intervention. They aren't naturally occurring. Here is some reading on those.

Now, I lost my copy of the book, so I had to erm, acquire a pdf of it. If I'm looking at the right page, you are talking about the part where he shows the various biomorphs that can be created by the computer program he developed? Wherein exactly does your question lie? He articulates the purpose of the program pretty well- it is akin to what a dog breeder does: look at traits that are favorable and have dogs with those traits breed. The chart is simply an example of the different biomorphs that can be created with that program.
Thanks for the response.

My question towards the dogs, then, is this, apart from being anatomically similar, are there any genetic similarities between the jackal and the dog, even if they are insignificant? That is, Dawkins seems to say they are NOT related. But, he seems to be saying the rest of the chapter that through domestication everything has a common genetic code in their DNA. That is, there is a link to me and a giraffe, a giraffe and a crocodile, a crocodile and a bird, and logically, a jackal and a dog. However, he seems to be saying that it is possible for there to be no genetic similarities between two species. If we are all related, then how can there be no similarity? I guess I'm confused how there can be no ancestry between the two, yet all things are some how related?

Secondly, the chart is just altogether confusing. What I mean is, I don't know what I should be looking for. I re-read his explanation, but I don't believe I understand either of the charts at the end of the chapter. It seems to me I understand the purpose of them, but I don't quite see any pattern or anything logically intelligible about them. I guess it isn't too important, as I understand what he is saying, I just don't see what I should be comprehending through the illustrations. Is there a start or end? Or is it just sporadic?


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Re: Some questions regarding evolution, and perhaps more to come - June 7th 2012, 02:59 AM

I reviewed the illustration, and I think I understand it now. It is basically representing non-random selection. The shapes are genes. The top right is the first "selection" of the "breeder" and it gives offspring to the next gene, which the breeder selects, which gives rise to the next, and so on, etc. until the breeder gets the desired result. Is that what it is?

If this is the case, then the second illustration, with the shells, is the embryology which is the genes effecting the shape of the shell. Correct?

I had misunderstood something which is why I found it confusing.

This means, in a sense, he is showing the non-random selection variances in a short amount of time, to make a case that if this can happen in a short amount of time, then over more time through random selection, there can be the vast variances we see today. Light bulb? I hope.


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Re: Some questions regarding evolution, and perhaps more to come - June 7th 2012, 07:48 AM

You are correct.

I guess an apt way to think of it would be like this.

Imagine, years ago, two brothers come to the states. One moves to the opposite coast and has two sons. The other stays on his coast and has one son. The two branches of the family perpetuate, and continue to flourish for generations. The one with two sons, his two sons have developed two different branches. Those branches one day come into contact again- a very distant, although noticeable relationship is palpable. This would be the relationship between, say, dogs and wolves. The branch of the family that descends from the brother with only one son would be the jackal. They all share a common ancestor- the father of the immigrant, but they are remarkably different.


It isn't useful to think of evolutionary branches as successive species- think of it as a family tree. Some traits pass, and some don't. The more you learn about your family tree, the more you see prototypes of your current standing. Here is a very simple, but succinct and informed infograph on it.
Link


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Re: Some questions regarding evolution, and perhaps more to come - June 8th 2012, 05:02 AM

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Originally Posted by Of Mike and Men View Post
My question towards the dogs, then, is this, apart from being anatomically similar, are there any genetic similarities between the jackal and the dog, even if they are insignificant? That is, Dawkins seems to say they are NOT related. But, he seems to be saying the rest of the chapter that through domestication everything has a common genetic code in their DNA. That is, there is a link to me and a giraffe, a giraffe and a crocodile, a crocodile and a bird, and logically, a jackal and a dog. However, he seems to be saying that it is possible for there to be no genetic similarities between two species. If we are all related, then how can there be no similarity? I guess I'm confused how there can be no ancestry between the two, yet all things are some how related?
Although Dawkins does explain this in beautiful detail, better than I ever could, he sometimes gets a bit too wordy in his attempt to use a simplistic vocabulary. Genetic similarity can be seen across species in the form of tissues and organs. For example, all vertebrate and invertebrate members of the phylum Chordata must have at some point in their lives a) notochord, b) dorsal hollow nerve cord/tube, c) pharyngeal slits, d) post-anal tail and e) endostyle. Genetic similarity can also be narrowed down to only vertebrates through molecular genetics, such as the apical ectodermal ridge (found in the developing embryo) involved in limb development. Through these two examples, there is genetic similarity across a wide range of species. The similarity implies they are by some means related evolutionarily.

On the other hand, there can be genetic similarity between specific organisms. Dawkins mentioned an excellent example of artificial natural selection, or simply breeding a desired dog. For example, labro-doodles are a hybrid of only a lab and poodle. If somehow a German shepherd mated with the poodle, the outcome will no longer be labro-doodle. The breeder would keep that litter and the German shepherd away from the lab and poodle.

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Originally Posted by Of Mike and Men
This means, in a sense, he is showing the non-random selection variances in a short amount of time, to make a case that if this can happen in a short amount of time, then over more time through random selection, there can be the vast variances we see today. Light bulb? I hope.
Light bulb indeed. A practical approach that may improve your understanding: "superbugs", which are bacteria or viruses that have become resistant to the commonly given treatment. When the treatment is administered, a large amount of the bacteria die off or sometimes all the bacteria die off. Eventually, when some survive, they may be able to adapt to the new environmental conditions. This can result in superbugs, such as vancomycin-resistant Enterococci (VRE), methicillin-resistant Staphlococcus aureus (MRSA), anti-biotic resistant gonorrhea (strain H041) and several others.


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Re: Some questions regarding evolution, and perhaps more to come - June 9th 2012, 01:48 PM

Tl;dr. Jk.

I have this book on my shelf at the moment, but won't have time to get stuck into it for at least another two weeks. I'm actually surprised someone else even knows this book exists; seems all that comes out of the perception of Dawkins is that he wrote 'the God Delusion' and he's renowned for it. I must stop assessing the locals' intelligence and ignorance as being the universal standard.

Anyway, just making my presence known in this thread because I'm interested in the topic (clearly am too ignorant to understand most of it at this stage, but bear with me). Props for the thread.


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