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Posted: 22 February 2007 02:05 AM   [ Ignore ]
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For those of you who live in Canada: [i:aead803d46]National Post[/i:aead803d46] (Post Comment section, A20) has launched new series called [i:aead803d46]Faith: Lost and Found[/i:aead803d46]. I am interested to see how this will progress since the "score" is so far Lost:0, Found: 2.

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Posted: 22 February 2007 12:39 PM   [ Ignore ]   [ # 1 ]
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Subtle bias there.  A personal example (other than not living in Canada):  From my earliest memories I didn’t have faith.  I believed what I could observe by my own senses and everything else, even what my parents said, ended up in a suspense bin in my mind, to be followed if I was told to, but not to believe until I had a chance to check it out for myself. 

So, Faith lost/Faith found leaves people like me out.  And that’s biased.

Occam

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Posted: 22 February 2007 01:31 PM   [ Ignore ]   [ # 2 ]
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[quote author=“Occam”]From my earliest memories I didn’t have faith.  I believed what I could observe by my own senses and everything else, even what my parents said, ended up in a suspense bin in my mind, to be followed if I was told to, but not to believe until I had a chance to check it out for myself.

Some time ago while reading Courious George to my kids I noticed that George, even though he didn’t have a tale, was referred to as a monkey. I told my kids that this is probably incorrect because monkeys have a tale; it is the apes that don’t have one. Therefore George is an ape, not a monkey. (I might be wrong. :?) I told them about the five great apes: chimp, bonobo, gorilla, orangutan, and, to their surprise :wink:, also us, the humans. Fine. They were surprised, but they “believed” me.

Yesterday my younger son (4) came home from school and told me that his teacher said that we are NOT apes. I showed him pictures of apes and humans, trying to explain to him why we look alike. Then I asked him what he thought of it: Are we apes or not? To which he answered: I don’t know. I was satisfied. I was happy that he was willing not to believe me. Now he’ll have to decide on his own.

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Posted: 23 February 2007 04:25 AM   [ Ignore ]   [ # 3 ]
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Update:

Lost:1, Found: 2

smile

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Posted: 23 February 2007 09:53 AM   [ Ignore ]   [ # 4 ]
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George,

As a former primatologist, and a parent of a six year old, I enjoyed your post. I’m glad your son couldn’t decide, because frankly I don’t think there is a simple answer to the question. Classification schemes in biology always have a certain arbitrariness to them. Where exactly to draw a line depends on what you think is important. Morphological characteristics were the first truly scientific criteria, but these can lead to nonsense like putting bats closer to birds than mammals because of their wings. Phylogenetic criteria are more dominant now, though that leaves us lumping rock hyraxes and elephants together and putting prairie dogs somewhere else, despite the fact that it’s a lot harder to tell hyraxes and rodents apart at a distance than hyraxes and elephants!

Anyway, when I was still studying chimpanzees, humans were in Hominidae and chimps/gorillas/orangutans were in Pongidae, so we weren’t technically apes. But there is little sense to that genetically or phylogenetically, so I understand things have been re-arranged and now we are apes in the superfamily Hominoidea, with a variety of subdivisions to try and show the relative phylogenetic relationships between us and the others. Having or not having tails is a pretty minor, and unreliable, characteristic for locating primates in the classification scheme.

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

I guess whether you call us apes depends on your purpose. Trying for accuracy according to the current scientific classification scheme says we are (though be prepared to check up often since the scheme is frequently revised). Emphasizing the primacy of evolution and our integral membership in the community of organisms on Earth (as opposed to religious notions of special creation and souls) would also justify including us as apes. This, I suspect from your anecdote, was what you were aiming for. On the other hand, no matter how trivial the genetic differences between chimps and humans on a % base pair basis, there’s no denying significant, and meaningful real differences in biology, evolutionary history, behavior, etc. A great book with regard to these questions is The Great Ape Project, a collection of essays supporting the principle that the similarities between humans and the other apes are sufficient to justify some change in the legal status of the others (e.g. inclusion under the UN Convention for Human Rights). A great set of discussions of the importance, or lack of importance, of variables used to categorize species.

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Posted: 23 February 2007 12:26 PM   [ Ignore ]   [ # 5 ]
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Interesting, Brennen.  What are the pros and cons of using genetic similarity to determine closeness of species?

Occam

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Posted: 23 February 2007 01:08 PM   [ Ignore ]   [ # 6 ]
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What are the pros and cons of using genetic similarity to determine closeness of species?

Well, I’m certainly no expert (I trained in behavior and physiology, and have since switched to clinical veterinary medicine), so I hope what I remember from school is reasonable. Genetic similarities represent true relationships by common descent, so they get closest to the evolutionary relationships that link species. In important ways humans and other apes are similar because they share common ancestors from which they inherited common genes. And they are more similar than say humans and mice because apes share a much more recent common ancestor than humans and mice, and so more genes. Specific comparison of DNA can quantify very precisely (with some assumptions about rate of mutation, etc) how closely-realated two specis are, so it is very accurate and reliable. Classification by this kind of relationship then allows us to say some things about the characteristics of a species based on its evolutionary relationships to other species.

The problem is that closely-related species can be very different if the population of their common ancestor or intermediate ancestors moved into very different environments. Hyraxes and prairie dogs are a lot more similar than hyraxes and elephants despite their phylogeny because prairie dogs and hyraxes live in very similar environments, or more accurately occupy similar niches and so share similar selective criteria shaping their characteristics, whereas elephants have developed in response to a very different niche since their last common ancestor with the hyrax. Convergent evolution, as it is called, leads phylogenetically distant species to be very much alike in important physical and behavioral ways, so then the relative importance of physical and behavioral characteristics versus phylogenetic relationship is hard to decide.And what is the most important kind of similarity between species (genetic, physical, behavioral, etc) depends of what we’re interested.

As a simple example, I was a lot more worried about catching infectious diseases when I worked with primates than now, when I hand;e mostly dogs/cats/rodents. The fact that I am more distantly related to carnivores and rodents than to primates reduces the chances that we will share disease organisms. A more complex example might be the issue of how we decide to treat other animals. People may be sympathetic to giving chimps special treatment or legal status because they are much like us behaviorally and physically. And that seems rational. They may or may not be inclined to grant such status because of a phylogenetic relationship, since this may not itself be relevant to the moral question (except that, on average, closely-related species tend to be more alike in the ways that are relevant than distantly-related species). But what about, say, cetaceans? They may have the same behavioral characteristics that we believe are important with regard to how we treat them as a function of convergent evolution, even though we are not closely-related. But even if they do, we may find it hard to tell or less emotionally compelling because they are so different from us physically. Should we decide on the basis of phylogeny or behavior?

The lines we draw in classification are, as I mentioned, always somewhat arbitrary, and their utility is connected with what we are trying to accomplish. Was that useful at all?

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Posted: 23 February 2007 01:55 PM   [ Ignore ]   [ # 7 ]
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This is all very interesting, Brennen. I always enjoy reading your posts.

I’d like to ask you something else: can all the hundreds of different breads of dogs mate with each other? (For example Chihuahua and Saint Bernard?) Are any of the breads genetically farther apart from the rest?

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Posted: 24 February 2007 04:21 AM   [ Ignore ]   [ # 8 ]
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Well, in terms of germ cells, all dog breeds can produce fertile offspring. For obvious mechanical reasons, Chihuahua/St. Bernard crosses don’t happen, though :wink: . The technical definition of a species involves the ability to mate and produce fertile offspring under natural conditions. Thus, wolves and dogs are officially in different species, though they can produce fertile hybrids, because they don’t normally mix in the wild. Of course, there are a lot of significant physical and behavioral differences between dogs and wolves that reflect their different lineages and selective environments, and these also argue for their being different species (and against some of the common mispercetions about dogs as really wolves inside, which plays into a lot of popular nonsense about “dominance” hbierarchies and feeding practices for pet dogs). I know some genetic characterization of dog breeds has been done, with an eye to tracing their derivation, but I don’t know a great deal about the results. Certainly, different breeds have different predispositions for certain diseases, which have a basis in underlying genetic differences, though we don’t have the research (or the research fudning) to tell us much about these specifically.

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Posted: 24 February 2007 06:53 AM   [ Ignore ]   [ # 9 ]
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Thanks, Brennen. When I read The Origin of Species I found it interesting that Darwin dedicated a large portion of his book to the definition of species vs. “variation” (race), of course, Darwin didn’t know anything about genetics. We now understand it, but strangely, it doesn’t seem to have helped us to clearly solve the species/race problem. Interesting stuff.

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Posted: 24 February 2007 10:31 AM   [ Ignore ]   [ # 10 ]
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Thanks, Brennen.  So, as I understand it, genetics is the best way of identifying the place on the various branches of each species, but that’s only one way of classifying the various animals.  We could also classify them by similarity of anatomy, behavior, or whatever is important to the particular humans doing so. 

for example, someone could classify chickens and pigs as very close because “everything tastes like chicken.”  :D

Thanks again.

Occam

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Posted: 28 February 2007 04:00 PM   [ Ignore ]   [ # 11 ]
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[quote author=“George Benedik”]Update:

Lost:1, Found: 2

smile

Surprisingly enough, they didn’t even try to edit it to make it sound more bitter or extremist. The editor was surprisingly reasonable.

(yes, I did write the article, and yes, I did google for blog/discussion about it in a fit of egoism. I can hardly be blamed for it, I think; the National Post, for all its faults, is still a national newspaper and to be published is to be ecstatic raspberry )

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Posted: 28 February 2007 04:40 PM   [ Ignore ]   [ # 12 ]
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[quote author=“coefficient”][quote author=“George Benedik”]Update:

Lost:1, Found: 2

smile

Surprisingly enough, they didn’t even try to edit it to make it sound more bitter or extremist. The editor was surprisingly reasonable.

(yes, I did write the article, and yes, I did google for blog/discussion about it in a fit of egoism. I can hardly be blamed for it, I think; the National Post, for all its faults, is still a national newspaper and to be published is to be ecstatic raspberry )

Conratulations, coefficient! You are famous. :wink:

I understand you are from the “lost souls” group (?). Stick around!

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