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Thread: Increasing acceptance of biological evolution in the US

  1. Top | #111
    Administrator lpetrich's Avatar
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    It's interesting that human evolution is considered the big issue of evolution. The evolution of anything else does not seem to provoke anyone as much as human evolution. "How dare you say that we are descended from monkeys and apes!!!" Never "How dare you say that birds are descended from little dinosaurs!!!" or "How dare you say that whales are descended from land animals!!!" or "How dare you say that flower parts are modified leaves!!!" or "How dare you say that insect mouthparts are modified limbs!!!" or "How dare you say that chloroplasts are cyanobacteria that were eaten by some long-ago ancestor!!!" or "How dare you say that vertebrates are upside down relative to most invertebrates!!!" or "How dare you say that tardigrades are heads without bodies!!!" or ...


    An issue that is devastating for creationism is biogeography. Why do most species have limited range? Especially when they can often flourish in similar environments outside their ranges? Why are pre-human-involvement ranges limited to where the species members can travel to in the absence of human technology or anything more advanced? Much the same is true of spread enabled by human technology -- why is there no spread enabled by anything more advanced than that technology?

    It also offers big constraints on evolution by genetic engineering -- the putative engineers don't seem to have transplanted any of their creations.

    Why are rattlesnakes and cactus plants found only in the New World?

    Why did rabbits only appear in Australia only when brought there by human settlers? Likewise for foxes, cats, horses, donkeys, bovines, water buffalo, goats, deer, camels, pigs, chickens, ostrich, cane toads, cactus plants, ... dingoes are essentially feral dogs brought to the continent some millennia ago by human travelers.

  2. Top | #112
    Administrator lpetrich's Avatar
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    Biogeography proved devastating for the Noah's Ark story. There were lots of animals that would be awkward to bring from the Ark's landing spot. Why were all the rattlesnakes brought to North America with none being left behind? Would anyone enjoy sharing a small boat with a breeding pair of them?

    In the mid 18th cy., Comte de Buffon proposed the existence of "centers of creation", spots where the ancestors of species were poofed into existence. Thus, rattlesnakes' ancestors were poofed into existence in North America, sloths' ancestors were poofed into existence in South America, kangaroos' ancestors were poofed into existence in Australia, etc.

    That became a common theory, and in the early 19th cy., that was extended into time, with poof-poof-poof-poof over geological time, like what present-day creationist Hugh Ross believes. Around 1800, Georges Cuvier established that extinction happened, and he came to believe that our planet was afflicted by catastrophes that exterminated just about everything.

    Since the mid 19th cy., however, geologists and paleontologists preferred to avoid hypotheses of great catastrophes, in part because they were not very well-defined hypotheses back then. Uniformitarianism triumphed for a while. But in recent decades, hypotheses of catastrophes have made a comeback, not out of armchair debates between catastrophism and uniformitarianism, but by showing that some geological features are evidence of catastrophes, like the K-Pg iridium-enhancement layer.

  3. Top | #113
    Administrator lpetrich's Avatar
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    Speculations about descent with modification have been around for a long time.

    Anaximander | Internet Encyclopedia of Philosophy
    8. Biology

    The doxography tells us that according to Anaximander life originated from the moisture that covered the earth before it was dried up by the sun. The first animals were a kind of fish, with a thorny skin (the Greek word is the same that was used for the metaphor “the bark of a tree” in Anaximander’s cosmology). Originally, men were generated from fishes and were fed in the manner of a viviparous shark. The reason for this is said to be that the human child needs long protection in order to survive. Some authors have, rather anachronistically, seen in these scattered statements a proto-evolutionist theory.
    But most speculation about descent with modification were about relatively small-scale changes. The first to speculate about large-scale DwM was Jean-Baptiste Lamarck, around 1800. He is best known for proposing the inheritance of acquired characters, but that theory was around long before him. "Maternal impressions" are some folklore that what one experiences can shape one's fetus, for instance (Maternal impression), and a version of that is the genetic engineering described in Genesis 30, making cattle streaked by showing their parents striped sticks when they were being conceived.

    Lamarckian inheritance seems like common sense, but there are oodles of evidence that mutilations are not inherited. In the late 19th cy., biologist August Weismann raised some generations of mice, cutting off their tails when they were born. They still grew tails, as long as if their ancestors had never been deprived of those appendages.

    There is, however, plenty of evidence that gene editing can be inherited. One form of that is from viruses that insert themselves into their hosts' genomes and await a time to reproduce. They can get stuck there, and they then become a component of "junk DNA".

    Even so, it is very poorly understood how one gets from genes to shapes, especially macroscopic shapes. We have learned about how genes' proteins can tag parts of organisms as having some fate, as developing in some way, but it's been hard to get to actual shapes.

  4. Top | #114
    Elder Contributor Keith&Co.'s Avatar
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    Quote Originally Posted by lpetrich View Post
    Never "How dare you say that birds are descended from little dinosaurs!!!" or "How dare you say that whales are descended from land animals!!!"
    Well, not NEVER. I have seen people poo-poo these very ideas. But they offer them as obvious proof that the entire theory is foolish. "Look at a whale and a ____! Do they look related! Evolution is stupid!"
    Of course, i think the reason for the objection is just the 'give an inch, take a mile' fear. If they let evil satanic atheist so-called scientists have fossil or DNA evidence that horses or whales or birds can evolve, then it's harder to draw a line between humanity and all the other life forms. So, yeah, it's still 'we are descended of apes' that is the driving force of the rejection.

  5. Top | #115
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    Quote Originally Posted by Keith&Co. View Post
    Quote Originally Posted by lpetrich View Post
    Never "How dare you say that birds are descended from little dinosaurs!!!" or "How dare you say that whales are descended from land animals!!!"
    Well, not NEVER. I have seen people poo-poo these very ideas. But they offer them as obvious proof that the entire theory is foolish. "Look at a whale and a ____! Do they look related! Evolution is stupid!"
    Fair enough.

  6. Top | #116
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    Quote Originally Posted by lpetrich View Post
    Quote Originally Posted by Keith&Co. View Post
    Quote Originally Posted by lpetrich View Post
    Never "How dare you say that birds are descended from little dinosaurs!!!" or "How dare you say that whales are descended from land animals!!!"
    Well, not NEVER. I have seen people poo-poo these very ideas. But they offer them as obvious proof that the entire theory is foolish. "Look at a whale and a ____! Do they look related! Evolution is stupid!"
    Fair enough.
    No, it's not fair. It's even worse. They don't like ape(ish) baby, so they also throw out the whalewater and the horsewater and the chickenwater. Thinking that just by glancing at, say, a whale and a proposed ancestor, they can SEE the reason all the actual evidence they dismiss is dismissable.
    These are like the guys that dismissed the A-Bomb because they were dynamite expersts, and they KNEW bashing rocks together would never knock over a building. Because they kicked rocks all the time and never even got a bruise.

  7. Top | #117
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    But Lamarckian inheritance was a side issue in Lamarck's theory of evolution, and his main proposed mechanism was evolution by internal forces: orthogenesis. That was a popular theory in the 19th and early 20th cys., and it is now recognized that statistical effects and successive niche occupation can produce quasi-orthogenetic effects. Like increases in size from small to large, common in vertebrates generally. Cope's rule

    Horse evolution is a well-known sequence, and it seems like a straight line form Eohippus species of some 50 million years ago, about 3 hands shoulder height to present-day equines at 9 to 18 hands. Horses: 14 to 18, donkeys: 9 to 16, zebras: 11 to 15. I'm using a "metric hand" of 10 centimeters instead of an English-unit hand of 4 inches (10.16 cm).

    But it is more complicated than that, with plenty of branching and even some size reversals. For instance, present-day species are the result of some branching over the last few million years. Even so, it's not very difficult to follow the lineage that led to the present-day species. Evolution of the horse


    Charles Darwin pretty much founded evolutionary biology with his monumental book Origin of Species. He wanted to produce a comprehensive case for evolution by natural selection, but he was cut short when Alfred Russel Wallace came up with a nearly identical theory. So he rushed into print with what he had, and what he had was a *lot*.

    He started out with pigeon breeding, of all things, showing how artificial selection can produce varieties of pigeons not found in the wild. He went on from there to describe artificial selection more generally. IIRC he noted that cattle breeders breed the tastiest beef cattle by selecting herds of cattle whose members have the tastiest meat. We now recognize this as kin selection.

    He discussed many issues, like biogeography and species vs. varieties, noting long-running controversies about which groups of organisms are separate species or else subsets of some shared species. He didn't have much of a clue about heredity, however.

  8. Top | #118
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    The Origin of Species by Charles Darwin - an online copy. I'd like to find some good annotated copy, assessing CD's work in the light of present-day knowledge.

    The Origin of Species: Chapter 13 has my favorite part, the section on "Rudimentary, atrophied, or aborted organs" -- vestigial features

    After noting several of them, he notes "In works on natural history rudimentary organs are generally said to have been created `for the sake of symmetry,' or in order `to complete the scheme of nature;' but this seems to me no explanation, merely a restatement of the fact."

    So pre-Darwinian biologists recognized that many vestigial features exist across a wide range of species. Vestigial features can have functions, so it is their structure that makes them vestigial.

    Human vestigiality notes
    n 1893, Robert Wiedersheim published The Structure of Man, a book on human anatomy and its relevance to man's evolutionary history. This book contained a list of 86 human organs that he considered vestigial, or as Wiedersheim himself explained: "Organs having become wholly or in part functionless, some appearing in the Embryo alone, others present during Life constantly or inconstantly. For the greater part Organs which may be rightly termed Vestigial."
    Some creationists inflate this number to 100 or 150 or so.

    But RW was mistaken about several of them, like endocrine glands. They secrete their products into the bloodstream, thus making their functions not as obvious as other glands' functions.

    Even so, several features are still recognized as vestigial. Our canine teeth are shrunken fangs, though functioning as extra incisors. Wisdom teeth, however, typically lack function. Another vestigial feature is the tops of our eye sockets, the supraorbital ridges or brow ridges. It typically sticks out a little bit, and I can feel mine with my fingers.

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