Evolution Thread to continue conversation with BIOFLEX

by NewChapter 71 Replies latest watchtower beliefs

  • PSacramento
    PSacramento

    Speaking of dogs:

    http://biologos.org/blog/the-purpose-of-dogs

    A recurring topic in the discussion about whether an evolutionary account of biological origins is compatible with Christian faith is the question of teleology; that is, does the history of life on earth demonstrate (or even hint at) directionality, or purpose? This general issue takes many forms and opens up many avenues for exploration and argument, including what we mean by “randomness” and “chance” when discussing genetic change and natural selection, as well as observations about the way nature seems to repeatedly produce similar structures or body plans by different routes (convergence). Indeed, while some philosophers of science assert that it is inappropriate to speak of “purpose,” “design” or even “function” with reference to the natural world at all, except in very careful and limited circumstances, it remains the common practice of both materialist and believing writers to speak of everything from cellular microstructures to complex animal behaviors as having purpose, most often in terms of solving a problem and allowing the creature to thrive in its environment.

    Despite all the other possible avenues to explore in thinking about natural teleology, I’d like to follow up on the discussion begun last week around John Leax’s poem “the clever trout,” in which I expanded on the poet’s suggestion that creation gives worship by being itself as it was created to be. Is that sort of “simply being” really just responding to survival threats and opportunities? Is the trout just finding food, the popple just resisting wind, and the jay just avoiding predators, though they be sustained by the Spirit? A couple of recent opportunities to examine the relationship between people and dogs (and my own dog, in fact) have served as reminders that purpose is much more than problem-solving while elucidating another aspect of mankind’s particular call to know and engage with the rest of God’s creation—that of cultivation, and even partnership.

    The remarkable cooperative relationship between humans and canines was the subject of the most recent edition of the venerable science television show NOVA, which examined an expanding scientific interest in the study both of the natural history of the domesticated dog and of the physiological capabilities that have made it so successful in the company of people. The show discussed new research detailing dogs’ ability to scan human faces for emotional cues, for instance, and studies showing that humans can understand different barks and vocalizations which developed as a way to communicate with people rather than with other dogs.

    As one would guess from the title, “Dogs Decoded” places a slight emphasis on the information gleaned from genetic analysis of dogs with regards both to their evolutionary history and potential current usefulness in the understanding of human diseases, but of most interest here are a few claims about the importance of dog domestication for the development of human culture. One speaker—University of Durham archaeologist Greger Larsen—goes so far as to claim that civilization would have been impossible were it not for canine help in the early herding stage, while Larsen’s colleague Peter Rowley-Conwy agreed and suggested that the relationship began as a mutually beneficial hunting partnership, both species being more efficient in bringing down large game in cooperative hunts with the other, thereby gaining a reproductive advantage. As a counter-theme, though, the program spent even more time discussing the way the process of domestication—a kind of “un-natural selection”—has “infantilized” modern dogs, selecting for physical traits that we regard as “cute,” even while equipping them with genetically-based skills of communicating with humans.

    While dramatic (sometimes contradictory) claims are the standard fare of popular science television, what was remarkable about the program was the gulf between the suggested origins of domestication (in cooperative hunting) and the apparent “results” of the process—animals described almost exclusively as pets, companions, and even surrogate children. Surprisingly little mention was made of the long history and continued role of “working dogs” who retain specific traits and abilities from their “natural” state and exercise them regularly in cooperation with humans, or what emotional content such relationships might entail. While the term co-evolution was used for dogs and humans emerging into modern history together, the discussion of intentionality and purpose (in both humans and dogs) in the process of domestication was all but unexplored—a little disappointing considering to program’s focus on the abilities of dogs and people to understand each other’s emotions and intentions.

    Into that “working dog” gap comes my own recent experiences with Griffin, our 16-month old Springer Spaniel, pictured above when just over a year old, on alert for geese in the grass along the James River. While Griffin is every bit as domesticated as the dogs discussed in the NOVA program and likes almost nothing better than to sleep on the sofa with any or all members of his family, what he does like better is hearkening back to his primordial canine job of hunting. In his case, hunting means locating, flushing (or “springing”) and then retrieving downed birds or other prey in partnership with his handler and other shooters. Like other hunting breeds, Spaniels are trained how to stay the proper distance from their human companions to keep birds in gun range, but also in order to receive instructions via voice or whistle, gesture, and eye contact.

    These specific behaviors and the physical attributes bred to make them more efficient in practice mean that Griffin is as much a cultural artifact as a product of nature, though as “Dogs Decoded” made clear (and generations of sporting dog breeders and trainers agree), culture and training must have a basis in genetics. The critical point here is that nature and nurture have combined to produce something beautiful and remarkable: not just the dog himself, not even the elegant way he fulfills his half of our partnership by finding birds and putting them to wing, but the palpable sense of joy he communicates when he is doing what he was literally “made to do.” To begin circling around again to the idea that “purpose” is more than just solving a problem, Springers may have been bred initially to help in hunting birds hiding in the underbrush, but the end result of generations of guided evolution of the breed is not a product or even a practice, but a relationship.

    Though only dogs seem to have had the right combination of traits to achieve the level of communication and emotional attachment to humans that dog owners everywhere take for granted, the kind of careful observation, understanding, and imagination our human forebears paid these once-wild creatures need not be limited to them alone. Indeed, the continuation of the meditation on human identity and the imago Dei begun with Leax’s poem last week is that laying aside our desires for glory ought to lead to a more grace-filled exercise of our dominion, a sense that we can and should seek the shalom of the creation first by seeking to understand it and appreciate it as it truly is.

    To borrow from the language of the contemporary church, it is often said that the goal of ministry should not be to figure out what we can “do for the Lord,” but to discern what the Lord is already doing through the Spirit and join into that effort. Sometimes that means taking the time to recognize patterns, potential, possibility rather than just needs to be filled, problems to be fixed. God’s work, after all, is not just a problem-solving practice (despite the centrality of Jesus’ own saving and restoring work), but one of beauty and synthesis, of bringing things together in new ways for greater relationship in scale and complexity, for His ultimate glory in the New Jerusalem. If the defining experience in that day will be worship and joy throughout the creation, perhaps we can learn to recognize—even in the eyes of our canine companions—what makes for joy and worship in the creation now, as well.

  • NewChapter
    NewChapter

    PS--that was interesting. I'm not sure it factors in on the evolution discussion, but I love my dog. I don't fully understand the connection of dogs with a god though.

    I think we can pretty much explain canine traits, and even the relationship they have with humans, in scientific terms.

    NC

  • Retrovirus
    Retrovirus

    Thanks for your reply, Bioflex.

    A lot has already been answered, but I'll put my way anyway:

    But all i am asking is, do you think over enough time those not-dogs could change extensively in their body structure as to be considered as totally different animals? like maybe goats?

    As I said, the name we give a type of animal, such as "dog" is arbitrary. Given enough time, changes could indeed be so great that "not-dogs" would appear to be a completely different animal. But, careful, expert examination would still show their ancestral relationship to dogs.

    My problem lies in how one species can split into two or more speices on its own. I know viruses and algae can reproduce on their own but no matter how they split all the end up producing is another of their kind.

    Consider the small differences you can find in any breeding population. Then if one of these differences makes the organism stronger, tougher, or able to digest better, over time the critters that carry this trait beget more offspring. Over more time, almost the whole population has this difference, so that it's no longer a "difference". Then, a refinement on the difference appears, again one that helps survival. Round 2.

    Consider also that the original population may also not have survived unchanged. It is theorised that population change happens fastest when the environment changes, which would make sense.

    Can you see that after hundreds of "rounds", the two populations would be substantially different? Perhaps no longer able to interbreed?

    If i am correct fishes and reptiles cant interbreed so how do you prove a fish splitting to produce a reptile without these two having any kind of sexual interferance?

    Again, you are asking why the two "end result" populations cannot interbreed. Isn't this exactly what the evolutionary scenario above would cause? The theory of evolution suggests that once both fish and reptiles descended from one ancestral population. These were neither modern fish nor modern reptiles. But those in deeper water evolved the differences that helped survival there, and those in the shallows benefited, from being able to, for instance, survive short times out of water, and put weight on their fins. Caedes has explained this very well.

    i find it hard to accept that natural selection or speciation can link features of a girrafe from a fish. Its like saying evolution is the reason why dogs have tails like reptiles.

    The postulated common ancestor of giraffes and fish is a long way back. But although they are very different, they do have some structures in common. Most notably, a backbone. They are both vertebrates. Now if you could find a mammal-like creature without a backbone, you could cast serious doubt on the theory!

    Keep asking and reading, and good luck! Retro

  • PSacramento
    PSacramento

    Understanding Evolution: Speciation and Incomplete Lineage Sorting

    http://biologos.org/blog/understanding-evolution-speciation-and-incomplete-lineage-sorting

    Populations and genetic diversity

    One consequence of speciation being a population event is that populations have genetic diversity – not all members of the population are genetically identical. For any particular gene, then, a population may have several slightly different forms present within it. These different forms are called alleles. An example in humans that is fairly well-known is the different alleles that control blood types: one allele gives rise to the A type, another to the B type, and a third allele the O type. Individuals may be either blood type A (either two A alleles or A + O); blood type B (either two B alleles or B + O); type AB (one A allele + one B allele) or type O (two O alleles). Any one individual can have only two alleles of this gene (one from mom, the other from dad), but as a population we collectively maintain all three. Other human genes have many more alleles than three (for example, some genes of the immune system have hundreds of alleles) despite the fact that any given individual can have at most two. The larger a population is, the more alleles of a given gene it can maintain. Smaller populations are more at risk of losing alleles due to chance (something called genetic drift).

    Genetic diversity and speciation

    The fact that populations maintain genetic diversity is important to remember when considering speciation. Speciation events are commonly represented with branching tree diagrams (“phylogenies”, or “species trees”) such as this one:

    Here we see that Species 1 and Species 2 are more closely related to each other than they are to Species 3. What this says is that Species 1 and Species 2 shared a common ancestral population more recently with each other than either did with Species 3. So far, so good – but what this doesn’t mean, however, is that comparing gene sequences between these species will always group 1 & 2 together as more similar to each other than to 3. While this will be true most of the time, it is expected that some of the time this pattern will not hold. The reason is due to something called incomplete lineage sorting, and it has to do with the fact that populations going their separate ways carry genetic diversity with them. Let’s try to explain what is going on here.

    Imagine that the ancestral population of all three species (the 1,2,3 common ancestor) has four alleles of a certain gene (represented by different colors in the diagram). These alleles originally arose due to a single mutational difference during DNA copying. Once there is a difference in place, two alleles can go on to acquire other differences over time, again, through copying errors. As a result, alleles can be compared to each other, just like species. Alleles that are recently separated will have more similarities in common, and alleles that have been separate for longer will have acquired more differences. In this example, the blue and green alleles are more similar to each other than either is to red or orange, and vice versa. The blue and green alleles arose from a common ancestral allele, and the red and orange alleles arose from a common ancestral allele. Further back in time, these two ancestral alleles themselves arose from one common starting allele. All four alleles will have a great deal in common (nucleotide sequences inherited from the single ancestral allele), as well as differences (for example, the red and orange alleles will share all changes that occurred between the time they split off from the blue/green lineage and when they themselves separated into two distinct alleles).

    Now consider the time when the (1,2,3 common ancestor) population divides to become the (1,2 common ancestor) species and the Species 3 ancestor (the first branch in the diagram). As this population divides into two species, it is not guaranteed that all four alleles will be present in the founding population of each new species, simply by chance. Each founding population is a sample of the original population, but any given sample may omit certain alleles:

    In the example above, we see that the red allele has been lost from the (1,2 common ancestor) species, and that the Species 3 ancestor has lost the blue and orange alleles. What this means is that the founding population of the (1,2 common ancestor) species didn’t have any individuals that carried the red allele, and that the Species 3 ancestor founding population didn’t have any individuals that had the blue or orange alleles. Both events happened simply by chance, because the founding populations are not representative samples of the original population.

    Later, as the (1,2 common ancestor) species separates again into Species 1 and Species 2, the same issues arise. The two founding populations may not transmit all of the genetic diversity of the (1,2 common ancestor) population:

    In this case, the founding population leading to Species 1 did not include a member with the green allele, and the founding population leading to Species 2 did not include any members with either blue or orange alleles. Also, the green allele has been lost in the lineage leading to Species 3 (it became rare and was eventually not passed on due to chance).

    In the present day, examining the alleles of the three modern species will reveal different levels of similarity. The blue allele is now only found in Species 1, and it is most similar to the green allele in Species 2, and less similar to the red allele in Species 3. This pattern matches the overall “species tree” pattern for these three species:

    The orange allele in Species 1, however, tells a different story: it is most similar to the red allele in Species 3, and less similar to the green and blue alleles. If we knew only about the orange allele in Species 1, we might conclude that Species 1 and Species 3 are the closest relatives. This is because the “gene tree” for these alleles places orange closest with red, even though the true “species tree” reveals an overall pattern of speciation that is different:

    The orange allele thus has a gene phylogeny that is said to be “discordant” with the overall species phylogeny.

    How do biologists assemble species trees if gene trees can be discordant?

    It might seem from the above discussion that assembling a species phylogeny from gene phylogenies is a hopeless task: after all, if any individual gene tree might be misleading, how can we be certain we have the correct species tree?

    The solution is to realize that while any individual gene tree might be discordant, gene trees that match the species tree will be the most common category. In our example above, Species 1 and Species 2 share a common ancestral population for some time after the (1,2 common ancestor) and the Species 3 common ancestor populations diverge. This means that any event that happens to this population (loss of an allele, for example) will be reflected in all descendant species (in our example, Species 1 and Species 2). This common history favors gene trees that match the species tree. For a discordant tree, the ancestral (1,2) population needs to maintain two alleles, and these alleles cannot sort equally into Species 1 and 2. This can happen, but it is less likely.

    What this means in practice is that biologists expect a certain pattern of gene trees when comparing related organisms. Using our three species as an example, most gene trees should match the species tree. The less likely outcome is a gene tree where an allele from Species 1 is more similar to the allele in Species 3. We can be confident we have the correct species tree because the majority of the gene trees favor one species tree over the alternatives.

    A problem for common descent?

    The fact that gene phylogenies/trees and species phylogenies/trees don’t always match is not something that surprises scientists, since it is a well-known phenomenon and the mechanisms underlying it are understood: species arise from genetically diverse populations and that diversity does not always sort completely down to every descendant species. Discordant phylogenies, however, are commonly used among Christians as a means to cast doubt on to common ancestry and/or evolutionary biology as a whole. One example from the Intelligent Design movement will serve as an illustration. In a blog post discussing discordant trees found when comparing the human genome to that of other primates, Casey Luskin argues

    Since humans are typically said to be most closely related to chimps, this data conflicts with the standard supposed tree … the basic problem is that one gene (or portion of the genome) gives you one version of the tree, while another gene (or portion of the genome) gives you a very different version of the tree. This leads to discrepancies between molecule-based trees, wherein DNA data fails to provide a consistent picture of common ancestry.

    In the end, molecular trees are based upon the sheer assumption that the degree of genetic similarity reflects the degree of evolutionary relatedness … Clearly this assumption fails when different genes paint contradictory pictures of evolutionary relationships.

    As we have seen, these differences are the natural, expected consequence of genetic diversity from an ancestral population sorting itself incompletely into different descendant species. The data set Casey is concerned about is primate evolution, where the species tree for humans, chimpanzees, gorillas and orangutans is as follows:

    In the article linked above, Casey is discussing a recent comparison of the newly-completed orangutan genome with the human genome. The availability of the orangutan genome allowed researchers to scan the human genome for locations where humans are more similar to orangutans than to chimps. These regions are rare in the human genome, and very short in length. Indeed, the researchers found a pattern: chromosome segments in humans most often match chimpanzees, and do so for thousands of nucleotide base pairs at a time, on average. Those regions that match orangutans are tiny (on average less than 100 base pairs) and rare. This is exactly what one expects from the species tree: humans and chimps are much more likely to have gene trees in common, since they more recently shared a common ancestral population (around 4-5 million years ago). Humans and orangutans, on the other hand, haven’t shared a common ancestral population in about 10 million years or more, meaning that it is much less likely for any given human allele to more closely match an orangutan allele. It is certainly possible, however, and in scanning over the entire genome rare sites that have this pattern can be found. Indeed, the authors of the paper above used previously-determined speciation times and population size estimates to predict what fraction of the human genome would be expected to match more closely with orangutans. Based on these parameters obtained in other studies, they predicted 0.9% of the human genome would have a human : orangutan gene tree. Their observed value was 0.8% - a result that provides additional support for the population size estimates and speciation times from other studies.

    Why is this data interesting?

    Aside from its misinterpretation by the ID movement, this sort of data actually provides us with information about the population size of the species that went on to give rise to orangutans, gorillas, chimpanzees and humans, as well as times for the various speciation events. I have discussed similar data for the (gorilla/chimpanzee/human) and (chimpanzee/human) common ancestor populations elsewhere; this new data merely confirms previous estimates of the population sizes of the various ancestral groups, and extends back to the (orangutan/gorilla/chimpanzee/human) common ancestor population with greater precision. As before, these results continue to strongly support the hypothesis that the human lineage has never been as low as two individuals at any point in our evolutionary history. Indeed, these new results confirm that the human : chimp common ancestor population was large (about 50,000 members). As Darrel Falk and I have discussed here on BioLogos in the past, all methods used to date (numerous approaches, all using independent assumptions) would have to be wildly wrong (by several orders of magnitude) if indeed our species arose from just two individuals.

  • Mad Sweeney
    Mad Sweeney

    Before genetic sequencing there *might* have been some valid debate. Now there is none. Evolution is real. Read about it. Learn it. Deal with its repercussions in a rational way. People who don't "believe in" evolution, do not understand evolution.

    "The Magic of Reality" is Richard Dawkins' latest book. It is illustrated by Dave McKean (in addition to many photos, charts, and graphs). It is written so that people approximately age 12 and up can understand the wonders of the natural world. In other words, it is written at around the upper level of Watchtower literature. Engaging and clearly stated. I highly recommend it. (It's a $30 book but you can get it online for just over half that.)

  • PSacramento
    PSacramento

    Richard has alientated far too many religious people with his militant attitude.

    I doubt many would care to read anything from the man.

    Luckly there are MANY great writers out there that express thier view on the sceince of evolotuion without expressing their view on Darwinisim.

  • unshackled
    unshackled

    it is written at around the upper level of Watchtower literature.

    Sweeney...that's pretty much it. Checked out Dawkins' new book the other day...filled with illustrations and a simplified writing approach. Kinda surprised me...wasn't expecting a classroom/textbook type when first hearing of it.

    PSac...I know how much you love Richard! You have such a man crush on that guy. ;-) Only flipped thru it the book for a few minutes but didn't see much of his usual barbs at religion and/or creationists. If so, then it would be a great book to get into young hands. Keep to the facts, leave out the opinion and then it could have a more broad, beneficial impact.

  • PSacramento
    PSacramento
    PSac...I know how much you love Richard! You have such a man crush on that guy. ;-) Only flipped thru it the book for a few minutes but didn't see much of his usual barbs at religion and/or creationists. If so, then it would be a great book to get into young hands. Keep to the facts, leave out the opinion and then it could have a more broad, beneficial impact.

    LMAO !

    I have his "greatest show on earth" and love it and I have his "God delusion" and lost a bit of respect for him ( theology is NOT his strength and he should stick to evolutionay biology and let science do the talking).

    That book may indeed be great but he burned his bridge with believers because of his attitude against religion.

  • unshackled
    unshackled

    Scratch that PSac....obviously in my brief flip-thru I missed his jabs at religion. Just read this review....to quote:

    Second, this book will not be very popular with devoutly religious people. Dawkins once more takes square aim at the major religions, pointing out how unlikely some of their "stories" are.

    Sigh. I agree it would have been better to focus on the scientific method and let it speak for itself. No need to go on an offensive against religious as it alienates the very group he's trying to reach. Then there was this that stood out from that review too....

    It's aimed at people who aren't familiar with science and its explanations (e.g., Dawkins cites ~20% of Europeans don't know how long it takes us to orbit the sun, and why- this is the book for them).

    20% of Europeans don't know a year is one rotation around the sun? Wow. Okay...I'm off topic...back to our regular scheduled programming.

  • PSacramento
    PSacramento

    I have suggest a few books to believer that help reconcile their faith with evolution, books that don't threaten or insult them for believing but show that just because they believe in God, doesn't mean they have to be close minded about evolution.

    A few even choose to accept evolution because of reading them.

    They admited that they felt intimidated by science, they felt they would onderstand if what they were reading was true or just fancy jargon used to confuse them and cast doubts.

    When they saw that many scientists are also believers they trusted what they were reading.

    That is truly the key, TRUST and believer just don't trust Dawkins because he has an aggenda and that aggenda is what discredits his evolutionary views for believers.

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