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Re: Probability of speciation/Ark

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  • qkvcs1
    ... hi ralph, genesis 6 : 20 mentions which types of animals to bring --fowls , cattle and ... every creeping thing OF THE EARTH... nothing about sea
    Message 1 of 19 , Dec 1, 2002
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      --- In creationevolutiondebate@y..., Ralph Krumdieck <ralphkru@o...> wrote:
      >
      > >--- In creationevolutiondebate@y..., Ralph Krumdieck <ralphkru@o...> wrote:
      > > > Hey, welcome to the group new member.
      > > >
      > > > >had a Flood FAQs
      > > > > > where this question was addressed. Their answer was: God
      > > > > > didn't bother about the insects.
      > > > > >
      > > > > > Their answer to overcrowding on the Ark was that many of the
      > > > > > animals came in as small babies and/or as eggs. That takes
      > > > > > care of the whales. They came in as fish eggs! :)
      > > > >
      > > > >genesis 7:15 "... all flesh wherein is the breath of life"
      > > > >went into the ark .--how do insects breathe? do they have " breath"? or
      > > > >absorb oxygen through their skin?
      > > >
      > > > Darn good question. Try here:
      > > >
      > > > http://www.sciencenet.org.uk/database/Biology/0109/b01008d.html
      > > >
      > > > >also the bible doesn't mention that any sea creatures [ whales] were
      > > to be
      > > > >taken into the ark .
      > > >
      > > > Well, we just had a thread on this but you might have missed it. Certainly
      > > > the verses in question are open to interpretation. There are plenty of
      > > > sea creatures that have lungs, just as you and I do, so it seems hard to
      > > > argue that they were excluded. What do you think?
      > > > ralph
      > >
      > >HI,Ralph
      > >great link on the insects " breathing".
      > >i think i understand but am not sure if this is an example of what the
      > >bible means by " breath of life"
      >
      > Yeah. Like all the rest of the Bible, that's open to personal interpretation.
      >
      > >just because whales have lungs doesn't mean that they were supposed to be
      > >on the ark
      > >if you look in the pertenant verses in genesis you will see that it was
      > >certain kinds of animals in the earth that had to be taken of each " kind" .
      > >
      > >it is also common sense that the FLOOD JUDGEMENT was to have basically
      > >little detrimental effect upon sea creatures but would be lethal upon all
      > >creatures upon the earth in whose nostrils were the " breath of life".
      > >
      > >--Anthony
      >
      > Well, as I said before, I find it hard to understand why dogs or pigs or
      > horses had
      > to die but the whales, dolphins, etc. were exempt. Whales have lungs. If
      > dogs,
      > sheep, goats, etc. have the "breath of life", I don't understand why whales
      > don't.
      > ralph

      hi ralph,

      genesis 6 : 20 mentions which types of animals to bring --fowls , cattle and"... every creeping thing OF THE EARTH..."

      nothing about sea creatures.
    • Will Pratt
      Damn! I scrubbed one almost completed reply by accident! This may not be as careful. Sorry to take so long answering, my time was bespoke during the holiday
      Message 2 of 19 , Dec 3, 2002
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        Damn! I scrubbed one almost completed reply by accident! This may
        not be as careful. Sorry to take so long answering, my time was
        bespoke during the holiday break.

        --- In creationevolutiondebate@y..., Schmuel <schmuel@n...> wrote:
        > Hi CED,
        >
        > > Schmuel <schmuel@n...> wrote: [snip]
        > > > > > 6-10 cats doesn't sound offhand like a deal-breaker, a lot
        > >depends on what that means on other families, however dogs/wolf
        and cats
        > > > > > seem to be two of the more diverse mammals families..
        although
        > > > > > that may be mostly appearance because we think in terms of
        so
        > > > > > many domesticated strains ...
        >
        > Will Pratt
        > >Actually, both cats and dogs are low in diversity compared to
        > >carnivora in general. The cat family, Felidae, contains three
        > >genera. The dogs, Canidae, are more diverse, with 15 genera. But
        > >the big groups in Carnivora are the weasels, Mustelidae, with 25
        > >genera, and the civets, Viverridae, with 36.
        >
        > Schmuel
        >
        > However, that doesn't really tell us *what* the distinctions between
        > the weasel genera are ... a little research tells us that
        >
        > http://www.allaboutwhales.com/painting/Mustelids.shtml
        > Mustelids: The Weasel Family
        > Mustelids include 65 species (and 25 genera) of weasels, badgers,
        ferrets,
        > fishers, grisons, martens, otters, polecats, skunks, stoats, minks,
        tayras,
        > wolverines, and more.
        >
        > So since the "weasel family" includes all sorts of animals that we
        normally
        > don't think of as weasels, as the same family, it is not surprising
        that it
        > has more genera than the cat family, which is commonly linked in
        our minds
        > (from a housecat to a bobcat to a lion)

        Will Pratt:

        In other words, "the reason mustelids are more diverse than
        felids is
        that they're more diverse." If the felids included "all
        sorts of
        animals we normally don't think of as [cats]" they would be
        included
        in the family Felidae, and it would be more diverse than it presently
        is. In the fossil record there is a much more diverse fauna of
        felids, but I suspect that you don't accept the fossil record, at
        least as science understands it, so . . .

        >So the greater or lesser diversity is simply a matter of
        classification and
        > perception....

        Will Pratt:

        Taxonomic _families_ are simply a matter of classification. Species
        exist in nature, at least arguably. All higher categories are an
        attempt to describe the relationships we see between species. But
        the classification in this case goes back to Linnaeus, who believed
        that "The number of species is as G-d made them" or words to
        that
        effect. The families Mustelidae and Felidae, and their content were
        established by taxonomists who assumed the creation of species. They
        did their work carefully, and it continues to be accepted by
        taxonomists who assume the evolution of all species from common
        ancestors.


        > Schmuel
        > > [snip] > So share with us your views on the following..
        > > > > Is there generally any difficulty in micro-evolution from one
        > >species to another within a family of beetles ?
        > > >
        > > > My understanding is that two almost identical beetles, one in
        the
        > >Great Lakes, and another is a non-contiguous geography, could
        easily count
        > > > as two species.. would you be of the same understanding ?
        > > >
        > > > Why don't you give us an example of functional differences
        > > > between two species in a family .. some large differences,
        > > > some small......
        > > >
        > > > You could also tell us if comparing across the 500 families,
        > > > there are always radically different functions
        > > > (e.g. the famous bombardier beetle would clearly count as a
        > >different > function :-)
        >
        > Will Pratt,
        > >Schmuel, first off, the basic process of speciation is the
        > >accumulation of enough genetic difference between two populations
        > >that they no longer normally interbreed in nature. When this stage
        > >is originally reached they normally show very little morphological
        > >difference. As each species continues to accumulate new mutations
        > >not shared with the other, the difference increases.
        >
        > Schmuel
        > Right, since the "difference" can even largely they factor of
        geography ...
        > I noticed your careful usage of ..
        > "no longer normally interbreed in nature"
        > Meaning that the the various species could in fact be functionally,
        > even genetically, identical (identical in an overlapping sense,
        > that one could make no genetic distinction between the two..)

        Will Pratt:

        No. Meaning that species in nature may occasionally produce hybrids
        without merging, and that many species for which we have never found
        a natural hybrid can nevertheless be hybridized in the laboratory.
        Lions will rarely cross with tigers, with leopards, and with jaguars,
        for example. (All three hybrids are sterile.) I suppose that I
        should have said "that no longer normally interbreed in nature in
        localities where they occur together." In cases where two
        closely
        related but distinguishable populations don't overlap they may be
        presumed to be subspecies, or distinct but closely related species,
        depending upon the size of gaps between undoubted species in the
        group, so long as all we have to work with is preserved material. (If
        they aren't distinguishable nobody will be testing them,
        they'll just
        be treated as disjunct populations of the same species, unless there
        are unusual conditions, such as one population being in California
        and the other in Chile.) Today we may run DNA comparisons. A few
        decades ago we would have resorted to hybridization experiments. If
        two populations, not known to occur together in nature, could not be
        hybridized in the laboratory, though both could be bred within
        populations, or if they bred, but the offspring were sterile, they
        were tentatively classified as distinct species. If they interbred
        freely, producing hybrids that bred freely and successfully with each
        other, and with both parents, they were assumed to be the same
        species. Intermediate levels of fertility produced vigorous
        discussion. Note that such tests are trumped by what sympatric
        populations do in nature: they are applied to cases where there _are_
        no sympatric populations.

        > Meaning that the difference may be "no difference at all"
        Will Pratt:

        As explained above, no.

        > Will Pratt,
        > >A further problem is the fact that animals that "look" quite
        > >different to each other may be very hard for us to tell apart. A
        > >case in point is the Gray Tree Frogs of eastern North America.
        _Hyla
        > >versicolor_ and _Hyla chrysoscelis_ share a camoflauge pattern and
        > >structure so similar that we can distinguish them only by the calls
        > >of the male, and their chromosome pattern. We can't distinguish
        > >preserved specimens at all. Yet the females of each respond only to
        > >the male calls of their own species,
        >
        > Schmuel
        > "normally .... in nature", can you say that they would never respond
        > to the male calls of the other species ?

        Will Pratt:

        No more than occurs between any other random pair of frog species.
        Calling male frogs and toads will clasp with any female that bumps
        into them. (Or sometimes with males, or fish, or floating sticks.)
        Under these conditions there will always be a small percentage of
        mispaired males and females. In a typical case, mispairings of _Hyla
        cinerea_ and _H. gratiosa_ in Alabama amounted to 11%. In the same
        study, mispairings of _H. chrysoscelis_ and _H. versicolor_ amounted
        to 6.6%. (Gerhardt, H C, et al. 1994. Hybridization in the diploid-
        triploid treefrogs _Hyla chrysoscelis_ and _Hyla versicolor_. Copeia
        1994: 51-59.)

        > Will
        > >and they not only do not hybridize, but eggs of one experimentally
        > >fertilized by the sperm of
        > >the other don't develop.
        >
        > Schmuel
        > Do you think that experiment proved an absolute boundry for the two
        species ?
        > ... in all situations, geography, for all male and female ?
        > If so, would you point me to the study.. ?

        Will Pratt:

        Let me say from the outset that I misremembered details from 40+
        years ago when I was an undergraduate lab assistant to one of the
        people who was working on this problem. But yes, an absolute barrier
        exists to exchange of genetic material between the species. Today,
        we know that _H. chrysoscelis_ is diploid (2n=28) and _H. versicolor_
        is tetraploid (4n=56). Any hybrid offspring is triploid and will
        have serious developmental problems. (Wasserman, A O. 1970.
        Polyploidy in the common tree toad _Hyla versicolor_ LeConte. Science
        167: 385-386.) In the experimental crosses (Johnson, C F. 1959.
        Genetic incompatibility in the call races of _Hyla versicolor_
        LeConte in Texas. Copeia 1959: 327-335) we didn't give the frogs
        a
        choice. Stripped eggs were exposed to a suspension of fresh sperm.
        (This is a well-tested technique that produces large numbers of
        healthy young when used within species.) The control crosses,
        within what we then called "call types", produced an average
        of 70%
        fertilization. Exogastrulation (in which a mature blastula
        evaginates instead of invaginating, with fatal results, did not
        occur. In the between call type crosses fertilization averaged 34%,
        with 32% exogastrulation. Of the surviving larvae, between 50% and
        90% died before metamorphosis. (Between 10% and 25% of the control
        crosses died before metamorphosis.) A few larvae did metamorphose in
        most hybrid batches, but most died within days. The combined results
        of a large number of rearing pans did provide a few adult hybrids.
        When these were backcrossed with the parents, none of the few free-
        swimming larvae lived to metamorphosis. (Johnson, C F. 1963.
        Additional evidence of sterility between the call types in the _Hyla
        versicolor_ complex. Copeia 1963: 139-143.)

        > Will
        > >The thing is, these frogs are nocturnal and
        > >they don't distinguish each other by appearance. They recognise
        > >"same" or "different" based on sound and smell. The frogs "look"
        > >quite different, to each other.
        > >
        > >Insects are very small, as compared to mammals, and so they can
        pack
        > >more densely into the same space, splitting the available habitat
        > >into smaller niches. That is, a given area may support two cat
        > >species, one feeding mostly on mouse sized animals, and one mostly
        on
        > >larger, rabbit-sized and up, prey. In the same region we may have
        a
        > >genus of carnivorous beetles of which one lives under rocks and
        feeds
        > >on smaller beetles, while another lives under the same rocks but
        > >feeds on earthworms, and a third rock dweller exploits carrion,
        while
        > >under fallen logs we find a fourth species, that feeds on beetles,
        a
        > >fifth that eats crickets, a sixth that competes with the third for
        > >carrion, and under loose bark on standing dead trees a seventh that
        > >feeds on Plant Bugs, and so on. And on. And on. Species whose
        > >individuals require a few square meters to sustain an individual
        can
        > >pack a lot more closely than species that require home ranges
        > >measured in hectares.
        >
        > Schmuel
        > Is it your claim that these six species of carivorous beetles could
        > simply never interbreed in any way, place or form ?

        Will Pratt:

        I intended this as a hypothetical example to explain species packing,
        as it is normally seen, but in the Noonan study I cited previously,
        of 149 sites collected, more than one species of _Harpalus_ was
        collected at 76. Two species were found together at 43 sites, three
        at 19, four at 12, and five and six species at one site each. No
        hybrids have ever been found between any of the species involved.
        Hybrids are known, and easily recognized, between populations of
        _Harpalus_ sometimes called distinct species. Noonan treated each of
        these as morphs of a single species: _H. nigritarsus_, morphs
        nigritarsus, and seclusus; and _H. desertus_, morphs desertus and
        furtivus.


        > Will Pratt
        > >As an example of a beetle genus with a lot of species, lets look at
        > >_Harpalus_, a mostly carnivorous Ground Beetle (Carabidae) that is
        a
        > >member of the same family as the bombardier Beetles you mentioned.
        >
        > Schmuel
        > kewl..go bombadiers :-)
        > Nice name for a football team in the Bowl..
        >
        > Will Pratt
        > >The genus was recently revised (G.R. Noonan, 1991, _Classification,
        > >cladistics, and natural history of native North American Harpalus
        > >Latreille (Insecta: coleoptera: Carabidae: Harpalini) excluding
        > >subgenera Glannodes and Pseudophonus_, Lanham, MD: Entomological
        Soc
        > >America, Thomas Say Foundation Volume XIII.) _Glannodes_ (7
        species)
        > >and _Pseudophonus_ (12 species in NA) were excluded because they
        had
        > >been revised by G.E. Ball in 1962 and 1972. In the course of this
        > >study Noonan spent about 180 days in the field during 1984 and
        1985,
        > >collecting 2,546 fresh specimens, and studied an additional 35,530
        > >specimens in collections. He had to cut away a lot of dead wood.
        > >Carabidae is one of the families on which Thomas L. Casey (1857-
        1925)
        > >was inflicted. Casey had a "thing" about species: if he could tell
        > >two beetles apart they were different genera, and if he couldn't,
        > >they were different species, and we're only just now completing the
        > >job of shoveling away the debris. Casey erected 85 species in
        > >_Harpalus_ three of which are now considered valid.
        >
        > Schmuel
        > Demonstrating again how squirrelly the speciation concepts are...

        Will Pratt:

        No. There are always squirrels, such as Casey. Though he always
        grouped his "species" together with the same species that we
        consider
        them to be synonyms of, today. But there is a familiar phenomenon
        that is the core of all the various species concepts. This is the
        Nondimensional or Naturalist's species concept. When a local
        naturalist studies the insects, or birds, or reptiles and amphibians
        of his county, or similar small region, he finds that the species are
        clearly defined and each is sharply separated from all similar groups
        of animals. In a study in the Arfak Mts of New Guinea, Ernst Mayr
        (_Animal species and evolution_, Cambridge: Harvard U Press, 1966; p
        17) found 137 species of birds. The local natives had recognized and
        named 136 of these. The basic species concept that has developed
        from this one expands it to cover the situation when we consider
        populations distributed on a continental scale. The most familiar
        definition to modern taxonomists is probably Ernst Mayr's
        Biological
        Species Definition: "groups of actually or potentially
        interbreeding
        natural populations which are reproductively isolated from other such
        groups." Theodosius Dobzhansky defined it as "the largest
        and most
        inclusive . . . reproductive community of sexual and cross-
        fertilizing individuals which share in a common gene pool."
        Notice
        that this does not account for non-sexual reproduction, such as all-
        female lizard species that lay parthenogenetic eggs. The plethora of
        species definitions are attempts to expand the concept to cover such
        exeptions, or to view it from the vantage of some particular
        discipline. All these definitions include the species recognized by
        the "Biological Species concept" as a core, but expand the
        definition
        to include one or more adjacent areas. A large proportion of
        species, 90+% at a guess, are included in _all_ the definitions.

        > Will Pratt
        > > In _Harpalus somnulentus_ [snip paragraphs of mine that Schmuel
        didn't comment on]
         >
        > >I think part of what you are worried about here is the Creationist
        > >concept of "kinds". Most generally they will try to put all
        species
        > >that can hybridize with each other under laboratory conditions, in
        a
        > >single "kind". Very few groups have been the subject of the kind
        of
        > >detailed study needed to test this. But we do have one well tested
        > >group, the fruit flies of the genus _Drosophila_. And these
        studies
        > >have been conveniently reviewed, by I.R. Bock, 1984, 3.
        Interspecific
        > >hybridization in the genus _Drosophila_, 41-70, in M.K. Hecht, et
        > >al., _Evolutionary Biology_, volume 18, (New York: Plenum Press).
        > >
        > >Worldwide there are about 1500 described species of _Drosophila_,
        > >divided into three subgenera and about 16 species groups.
        Literally
        > >hundreds of studies conducted since 1922 have produced a clear
        > >pattern. First, hybridization between _Drosophila_ species in
        nature
        > >is extremely rare. Of the hundreds of thousands, if not millions,
        of
        > >specimens collected in the wild, 8 wild hybrids have been found.
        In
        > >the laboratory, however, virtually all fruit flies can be crossed
        > >with some other species.
        > >But here too there is a clear pattern.
        > >Hybrid crosses occur only within the groups of closely related
        > >species. The viability of the hybrids varies, from those that die
        as
        > >larvae or pupae, to those that produce fertile adults of both
        sexes.
        > >But no attempted cross between members of different species groups
        > >has ever succeeded.
        >
        > Schmuel
        > So the issue here is whether a few thousand years could develop
        species groups
        > from a smallish beginning point... since there obviously is
        movement along
        > the Drosophila trail ....

        Will Pratt:

        It's been done. (Rodriguez-Trelles, F. et al. 2001.
        Erratic
        overdispersion of three molecular clocks: GPDH, SOD and XDH. Proc Nat
        Acad Sci 98: 11405-11410.
        http://www.pnas.org/cgi/content/full/98/20/11405#References )

        Assuming divergence at currently observed rates, "since there
        obviously is movement along the Drosophila trail", divergence
        between
        _Drosophila melanogaster_ and _D. similans_ (same species group
        remember) occurred at 5 mya. Species groups within _Drosophila_
        average divergence at 55 mya, and _Drosophila_ from related genera at
        65 mya. (Fossils of living subgenera of _Drosophila_ are known from
        Oligocene amber (~36 mya).)

        Actually, insects are a poor choice to look for rapid
        differentiation. Like Mollusca, they are well known for being slow
        evolving (based on conventional paleontological dating) and Rodrigues-
        Trelles et al. confirm this based on observed rates of change. In
        the same study, _Bos_ and _Synceras_ (African buffalo) diverge at
        ~2.5 mya, about 26 times as fast. Mammals are the _fastest_ evolving
        group.

        In short, observed rates of change won't fit the post-ark time
        scale. You would have to assume rates fantastically higher than any
        observed to fit it into a 5,000 year timescale. At observed rates of
        change, microevolution from a small number of "kinds" simply
        won't
        fit. You either have to have rates on the order of 500 times the
        greatest observed or a set of "kinds" approaching the entire
        existing
        fauna in size.

        > So who has the definitive paper on how much speciation
        > occurs in 50,000 generations ?
        >
        > Will Pratt,
        > >And within some of the larger species groups,
        > >subgroups have been found that cannot be hybridized.
        >
        > Schmuel
        > "cannot" involves extrapolating certain lab results to a much wider
        > ranging real-world environment...

        Will Pratt:

        As I have pointed out above, many species that do not
        hybridize in
        nature, defined as "despite a _lot_ of looking we've never
        seen a
        wild hybrid", can be hybridized in the laboratory. The extent to
        which laboratory hybridization can be done has been used as a rough
        index of genetic relatedness of species, which is why much of the
        laboratory hybridization work has been done. In some cases where a
        mixed pair will not reproduce due to behavioral isolating mechanisms
        we can artificially bring sperm and egg together. (It's
        complicated
        to do with tiny flies but it's been done a few times to test
        pairings
        in _Drosophila_. In short, laboratory hybridization experiments are
        a far more rigorous test than the finding of natural hybrids.

        To give a particular example, Dobzhanksy (1973. Is there gene
        exchange between _Drosophila pseudoobscura_ and _Drosophila
        persimilis_ in their natural habitats? American Naturalist 107: 312-
        314) "estimated that during his lifetime he examined at least
        27,099
        chromosomal complements, and among these only 4 instances were found
        of progeny of wild-caught females that were F1 hybrid larvae.
        Unfortunately, as he pointed out, wild-caught males and females are
        often kept together overnight in their collecting vials, so the
        adults may have mated, not in nature, but after capture. Dobzhansky
        did have one case of natural hybridization; a female whose offspring
        were unmistakably backcross hybrids. Thus this female was a natural
        F1 hybrid." (
        http://www.jamesreserve.edu/ejournal/Articles/spring00/Moore/moore.htm
        l )

        As of 1984 (Bock, op cit.) the following wild _Drosophila_ hybrids
        had been observed: melanogaster x simulans; aldrichi x mulleri,
        montana x flavomontana; pseudoobscura x persimilis; metzii x
        pellewae; septosimentum x ochrobasis; heteroneura x sylvestris; and
        malerkotliana x bipectinata. Each was found in the course of an
        intensive study and the hybrids, parentage verified by repeating the
        cross in the lab, were a few instances amid thousands of specimens
        collected and bred. Each natural cross was within a species group.
        This is 8 hybrid crosses known to occur in the wild out of 266
        achieved in the laboratory, up to the date of the review, that
        produced at least eggs that hatched into larvae. In more than half
        the cases (139) the cross was obtained only one way, despite
        attempting reciprocal pairings. In only 13% (35) of the pairings
        were fertile adults of both sexes produced.

        > Perhaps you could point me to the papers that say the subgroups
        > "cannot" be hybridized....

        Will Pratt:

        I did. I suppose that you aren't being deliberately
        obtuse, but
        simply aren't familiar with the scholarly shorthand of Biology.
        A
        review volume summarizes an area of research, with references to the
        pertinent literature. The paper I cited provides a summary of the
        _Drosophila_ hybridization research with citations within the text to
        the original reports.

        > Will Pratt,
        > >Thus there are
        > >a minimum of 32 "kinds" in _Drosophila_ by the test of possible
        > >hybridization in the laboratory,
        >
        > Schmuel
        > As above, there is a very important phrase "in the laboratory"
        >
        > Will Pratt
        > >regardless of the viability of the
        > >offspring. Figuring the remaining genera of _Drosophila_ as
        "kinds",
        > >that's about 92 "kinds" in this single largish family of fly.
        > >Morphologically, incidentally, they are at least as diverse as any
        > >mammal family: they are just smaller, so that we have to use
        > >magnification to see the details.
        >
        > Schmuel
        > An interesting claim, why don't you give an example of one or two
        > of the largest morphological differences in the fruit-fly family....

        Will Pratt:

        There is a, perhaps inevitable, human tendency to equate
        importance
        of a character with the absolute size of the difference, not it
        importance proportionate to the size of the organism. Drosophilids
        vary in the color of the integument from pale yellow to black, with
        or without contrasting markings of stripes, blotches, or spots. The
        texture of the integument varies from shiny to pruinose (appearing to
        be covered by a fine dust or coarse powder, that cannot be rubbed
        off). The body and eyes usually covered by a pile of fine hears that
        varies from moderately close to widely spaced, to occasionally
        absent. The wings vary from clear, to definite and varied dark
        patterns, to solid dark, and the wing venation varies in numerous
        details. There are numerous long bristles on the body and legs that
        vary in size, placement, and number, separately in each body area
        (for example, the ocular bristles may be weak while the orbitals are
        strongly developed, or vice versa). Legs vary from about as long as
        the abdomen to longer than the entire body (that is, from short to
        very long and "stilty").

        Now, instead of quibble after quibble, suppose you demonstrate
        possession of some background knowledge and give an example of
        variation in a mammalian family. (Not order, not genus, but family,
        to be parallel with my example.)

        > Will Pratt
        > >Careful scientific studies of hybridization are otherwise hard to
        > >come by. Some work has been done with frogs and toads, though,
        aimed
        > >at sorting out degrees of relationships within genera, based on the
        > >viability of hybrids as a measure of genetic closeness. (It's an
        > >archaic technique in a time when we can compare DNA strands.) In
        > >general successful crosses were within a single genus, with species
        > >groups within some genera that would not cross. A few bi-generic
        > >crosses were achieved, between closely related genera, but the
        > >hybrids were deformed and of low viability. There have also been
        > >some hybridization studies done in rodents. The results are
        similar
        > >to what we see in frogs and toads, though i don't know of any bi-
        > >generics. And we do have some data for groups that fanciers beed,
        > >and hybridize, in captivity. In reptiles, again, successful
        > >hybridizations are generally between species within a single genus,
        > >though viable, fertile "bi-generic" crosses have been produced
        within
        > >the very closely related rat snakes (_Elaphe_), king snakes
        > >(_Lampropeltis_), and gopher snakes (_Pituophis_). There's
        > >questionhere whether they should not be combined into a single
        > >genus. (If they were insects of similar morphological diversity
        the
        > >argument would be whether they should be put into different species
        > >groups.) In birds, and in fish, a similar pattern is found, though
        > >sterility of the hybrids is more common. We can make a
        conservative
        > >estimate of hybridization defined "kinds" by counting genera. The
        > >few "bi-generic_ crosses are enormously overcompensated by the
        > >numerous non-hybridizing species groups within genera.
        > >
        > >A quick calculation based on known numbers of species and genera of
        > >insects described from NA and Europe suggests about 7.4 species per
        > >genus on the average, which, based on about 1,000,000 described
        > >species world-wide, would give a rough figure of 135,000 genera of
        > >insects worldwide.
        >
        > Schmuel
        > One problem with these figures is they seem to be based on the lots
        > of extrapolations, even in the relatively controlled subject, the
        drosophila,
        > there was huge extrapolation to the wild done from very limited lab
        results,
        > see my questions above....

        WL Pratt:

        Any attempt to test anything involves extrapolation. The
        YEC
        attempt to salvage the ark involves massive extrapolation and special
        pleading from a few paragraphs of Hebrew. (Five paragraphs that are
        actually involved with the ark and its cargo.) The whole content of
        theology is extrapolation, often strained, from the text.

        >I remember my questions on drosophilia
        > were not minor, they really had to do with whether in 50,000
        generations,
        > the starting vector would be 1 or 10 or 32 or 92 to get to 1500
        species,
        > (I gather we are assuming that drosophila is a "completely
        distinct" genus?)
        >
        > >For vertebrates actual counts can be made (R.T. Orr, 1971,
        > >_Vertebrate Biology_, 3rd ed, (Philadelphia: Saunders).)
        > >
        > >Ignoring a lot of "minor" groups (like about 2000 "kinds" of
        > >spiders), and not including aquatics like fish and cetaceans (in
        > >other words, giving the maximum benefit of the doubt to
        creationists)
        >
        > Schmuel
        > Well the claim that Genesis put fish on the arc seemed very
        strained,
        > so please don't overestimate the amount of this benefit....
        >
        > (Yitzak's valiant attempt below notwithstanding....)

        Will Pratt:

        Yitzak is Will Pratt, same person. See my Yahoo name.
        (There was
        no conceivable version of Will Pratt that wasn't already taken,
        so I
        used my Hebrew name.) Noting that you use the Hebrew form of your
        name, I signed with my Hebrew name as a friendly gesture.

        > Will Pratt
        > >there would be 74 kinds of cloven hoofed animals (and of these 64
        > >would be "clean", so that Noah would need 7 pairs), 6 kinds of
        horses
        > >and tapirs, 2 kinds of elephant, 95 kinds of carnivores (this is
        > >allowing 3 cats), 356 kinds of rodents, 6 kinds of hares, rabbits,
        > >and pikas, 14 kinds of sloths, anteaters, and armadillos, 48 kinds
        of
        > >primate, 170 bats, 72 shrews and moles, and 81 marsupials, or a
        total
        > >of 927 kinds of mammals.
        > >
        > >Then there'd be 1151 kinds of bird (about 750 of them clean, hence
        > >requiring 7 pairs). About 783 reptiles including 8 kinds of
        > >alligator and crocodile. 312 amphibians. Oh yes, and 135,000
        > >insects. Total, about 138,173 kinds of animal, including about 800
        > >clean animals, requiring 7 pairs each, some of them rather large
        > >types. That's 142,973 pairs of animals. With 8 keepers, that's
        > >35,743 animals per section. Schmuel, even with a generous (to
        > >creationists) calculation of the kinds, that's just not doable.
        > >(Logically this is called proof by reductio absurdum.)
        >
        > Schmuel
        > So you figger that Noah had a feeding schedule for each of the
        > 135,000 insects ? 6:16AM one blade of grass for the beetle,
        > 6:16:01 bluegrass for the Kentucky beetle...
        >
        > It seems that your really are not claiming necessarily a
        space/supply problem,
        > as Yitzak did below, simply a logistics concern ...
        >
        > And by making the insects the same as the mammals in the count,
        > you can easily reach your time schedule absurdum....
        >

        Will Pratt:

        Insects require care, just as mammals do. Not so long per
        specimen, perhaps, but if you neglect them, they die. They have
        specific humidity requirements (ranging from some that dehydrate at
        90% relative humidity to some that die of too much humidity at 50%),
        their containers have to be cleaned of waste, and they have to be
        fed. Their food ranges widely, and is often very specific, plants of
        a particular family, for instance, and most have to have fresh, non-
        dried fodder. Then there are all the predatory forms, and they
        won't
        eat dead food, it has to be alive and moving. An invertebrate keeper
        can handle more cages in a section than a large mammal keeper, but
        there are limits. An invert section is at max about 100 containers
        ("cages"). (And very few critters of different species can
        be safely
        kept together.) But about half a keeper's time is devoted to jobs
        other than the simple care of his section, so say 100 containers
        checked and tended to in 4 hours. That's 5400 keeper hours, per
        day. That's 675 hours per keeper per day for the ark's staff
        of 8.

        As to the herps, that's 1095 x 2 = 2190 herps to be kept. That
        would
        be a larger number than any reptile house I know of, though not
        impossibly so. But a herp section typically runs about 30 cages to
        clean, water, and feed as needed, and it takes about four hours a day
        to keep your section. (This half the day to tend the section and
        half to work on interpretation, scenery maintenance, etc. is typical
        on the part of the zoo management. You have to pay attention to the
        show/education aspect.) Some herps can be combined, others will
        cheerfully eat each other. Call it an average of 3 pairs per
        container. That's 365 containers, or a labor requirement to
        clean,
        feed, and water of 48 hours. That's a keeper staff of 12 for a
        reptile house this size, but we can cut it in half for cage tending
        only, or 6, and we're not limited to 8 hour days. It's only
        six
        hours a day for each of our staff of eight.

        I've never been a bird or mammal keeper, so I can't speak to
        their
        time requirements, but as I recall they're greater on a per
        critter
        basis. The large mammal keepers in particular seemed to spend all
        their time toting feed and hauling waste. The carnivore keepers
        could hose down the concrete cage floor to clean it, but the ark
        won't have high pressure water mains.

        On a realistic time-per-critter estimate for feed-clean-water only,
        assuming active adult animals, the labor-hours required are
        completely unrealistic. Even assuming the same time-per-cage
        requirement as herps for birds and mammals, which is utterly
        unrealistic, the labor hour requirement for the vertebrates aboard
        would come to 1270 hours, or 158 hours a day per staff member.
        That's assuming the same number of kinds per container as for
        herps,
        and the same time to feed, water, and clean each container, which is
        wildly over optimistic.

        (And you _don't_ want to go with juveniles. They're harder
        to feed
        and labor time per individual goes _way_ up when you're taking
        care of
        babies.)

        [snip material not referenced by Schmuel]


        Here's a question, Schmuel. Flood advocates usually cite what
        geologists call Quaternary deposits as deposits laid down by the
        flood. Do you follow this, or what _do_ you consider these deposits
        to be? If we start from the assumption that these deposits are
        flood-laid, then they contain a sampling of the fauna from which the
        ark's cargo must have been drawn and we can make a realistic
        estimate
        of the minimum species list for well represented groups. Are you
        prepared to follow this up?

        Will Pratt
        Prattw@...
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