Hi All,
It's worth being attuned to one complexity which pops up here;
Lets just say there exist two populations of a species; A and B.
And let's say all members of the first carry genetic marker X whilst all members of the second carry genetic marker Y.
And let's say that BOTH genetic markers are necessary to obtain (genetically speaking) a new species C.
We could posit an instance in which individuals from these two populations interbreed with the result that we get offspring which bear both genetic markers and are thus members of species C.
I think it can be seen that if the initial groups are large enough then we would actually get, within the population more than one member of species C arising independently.
A trivial example of the sort of thing had in mind can be seen in cross-breed dogs. Even allowing that there is, chronologically, a first dog which is the offspring of a cross between a Labrador and Cocker Spaniel, it should be obvious that not all dogs which are lab-spaniel crosses are descendants of this one individual.
It is, in other words, possible to get more than one individual, of essentially the same genetic "stuff" being born quite independently given that the circumstances are right.
Blessings,
Murray.
Cameron Wybrow wrote:
> Dennis:
>
> Your remark below needs to be explained, because as it stands it
> obscures what you are saying, both in reference to biology and in
> reference to the notion of Adam and Eve.
>
> Obviously there must be a "first" in every biological line. If we take
> the classic neo-Darwinian example of the hypothetical okapi-like animal
> which became the giraffe, presumably all modern giraffes can in theory
> be traced back to a *first* okapi-like animal which grew a neck
> significantly longer than the other members of its population, and
> survived food shortages (because it could reach higher leaves), thus
> leaving more offspring, etc. Neither biologically nor logically could
> there have been a "first population" of long-necked okapi-like animals
> until there was a "first individual" of this type. Supposing that the
> evolution of the giraffe began when an animal five feet tall produced a
> longer-necked offspring that was five foot six, the
> five-foot-six offspring is what is normally meant by the phrase
> "ancestor of the giraffe". The term "ancestor" is perfectly justified
> by common sense: if that five-foot-six animal had been eaten by a
> predator before reproducing, there would have been no giraffes -- or at
> the very least their evolution would have been delayed by however long
> it took to come up with another five-foot-six offspring, which would be
> by no means a certain thing. And the five-foot-six ancestor was an
> individual, not a "population" -- though of course he or she
> eventually produced a population (of longer-necked okapi-like animals).
> So your objection to a first ancestor does not make sense. You need to
> flesh out, in layman's language, what you mean by a "population" in this
> context. Why does a "first population" exclude a "first individual"?
>
> Consider these two possibilities, which as far as I can tell exhaust the
> logical alternatives:
>
> 1. All human beings are genetically descended from a single pair of
> ultimate parents (6,000 years ago, 30,000 years ago, 100,000 years ago,
> a million years ago, whenever).
> 2. The current crop of human beings on this planet is genetically
> descended from more than one pair of ultimate parents, parents who were
> themselves unrelated.
>
> Then there is a further distinction to be made between human and
> non-human, which when applied to the first distinction yields four
> possibilities:
>
> 1. a. The single pair of ultimate parents was fully human.
> 1. b. The single pair of ultimate parents were highly
> sophisticated primates, but not yet human.
>
> 2. a. The different pairs of unrelated ultimate parents were fully human.
> 2. b. The different pairs of unrelated ultimate parents were highly
> sophisticated primates, but not yet human.
>
> Now:
>
> If 1a is the case, there is no reason why you should object to the
> notion of a first human pair. I therefore presume that you reject 1a.
>
> If 2a is the case, then the human species emerged *more than once* from
> the evolutionary process. This is most unlikely on neo-Darwinian
> premises. Therefore, I presume that you (whom I take to be a
> neo-Darwinian) reject 2a.
>
> If 2b is the case, then either the descendants of the two (or more)
> unrelated primate lines mixed, or they did not. If they did not mix
> over thousands of generations, it was because they could not mix, and
> then the different types of modern human beings (e.g., Australian
> aborigine, Caucasian, Mongoloid, etc.) would not be able to mix,
> either. But all modern human beings can interbreed. Also, after
> thousands of generations, more like tens of thousands, of separation
> from two originally distinct primate species, we would expect at least
> species-level differences among human beings, not mere differences in
> pigment or hair curliness and so on. But no one thinks that different
> types of human beings today are of different species. So clearly the
> (hypothetical) distinct primate lines must have mixed to produce a
> common human race. But would the lines have been able to mix? That
> depends on how different the two unrelated primates were in the first
> place. If they were as different as, say, a baboon and a spider monkey,
> or a gorilla and an orangutan, or a human being and a gorilla, they
> would not be interbreedable, and then scenario 2b is impossible. On the
> other hand, if the two distinctive primate lines were close enough to be
> interbreedable, then they undoubtedly themselves sprang from a common
> ancestor, in which case 2b is just a slight variation on 1b.
>
> Thus, by elimination, it looks as if you are plumping for 1b.
>
> So, is your notion that the "first pair" from which all human beings
> have descended was *not yet human*, so that human beings did not come
> onto the scene until hundreds or thousands of generations later than the
> "first pair", by which time there would have been a population of them?
>
> Or, to put it another way, are you granting that all human beings did
> indeed come genetically from a first pair, but not from a first *human*
> pair? Just as the present-day population of giraffes came genetically
> from a "first pair" (an okapi-like animal with a long neck crossed with
> an okapi-like animal with a normal neck), though that "first pair" was
> not itself a pair of giraffes? So that the Biblical story is
> inaccurate, not in postulating a first pair of genetic ancestors for all
> human beings, but in postulating that the first pair was *human*?
>
> Cameron W.
>
>
> ----- Original Message -----
> *From:* Dennis Venema <mailto:Dennis.Venema@twu.ca>
> *To:* Gregory Arago <mailto:gregoryarago@yahoo.ca> ; George Murphy
> <mailto:GMURPHY10@neo.rr.com> ; Dick Fischer
> <mailto:dickfischer@verizon.net>
> *Cc:* muzhogg@netspace.net.au <mailto:muzhogg@netspace.net.au> ;
> asa@lists.calvin.edu <mailto:asa@lists.calvin.edu>
> *Sent:* Monday, October 05, 2009 5:52 PM
> *Subject:* Re: [asa] Re: Reading Genesis theologically NOT historically
>
> Gregory,
>
> The point (biologically) is that there is a first *population*, not
> a first individual. Your logic, if I understand it correctly,
> doesn’t hold. Speciation for humans was a population event, not via
> a single individual or pair, as far as we can tell.
>
> Dennis
>
>
> On 05/10/09 2:26 PM, "Gregory Arago" <gregoryarago@yahoo.ca
> <mailto:gregoryarago@yahoo.ca>> wrote:
>
> George Murphy wrote: "Adam IS mankind."
>
> If that is the case, George, and if you accept the logic *there
> must have been a first,* then do you accept that the 'first
> human' was ADAM, i.e. the first of 'mankind' or 'humanity'? If
> not, then why not? Are you a *degree, not kind* guy?
>
> ------------------------------------------------------------------------
> *From:* George Murphy <GMURPHY10@neo.rr.com
> <mailto:GMURPHY10@neo.rr.com>>
> *To:* Dick Fischer <dickfischer@verizon.net>
> *Cc:* dickfischer@verizon.net; muzhogg@netspace.net.au;
> asa@lists.calvin.edu
> *Sent:* Tuesday, October 6, 2009 12:47:31 AM
> *Subject:* Re: [asa] Re: Reading Genesis theologically NOT
> historically
>
>
> When humankind (not just a single individual) is said to be
> created in the image & likeness of God in Gen.1:2, it's quite
> legitimate (IMO) to interpret the following words, "and let them
> [N.B.] have dominion over the fish of the sea, and over the
> birds of the air, and over all the wild animals of the earth,
> and over every creeping thin that creeps upon the earth" (NRSV).
> I.e., humans are to be God's representatives in ruling the
> other creatures of the world. The word "emissary" is really too
> weak for this. But more importantly, there is no suggestion
> that oen human being is commissioned to be an emissary to other
> human beings. So the point remains, there is no canonical texts
> that says - ot implies - "that Adam was God’s emissary to
> mankind." Adam IS mankind.
>
>
>
> Shalom
> George
> http://home.roadrunner.com/~scitheologyglm
>
>
> ------------------------------------------------------------------------
> Looking for the perfect gift?* Give the gift of Flickr!*
> <http://www.flickr.com/gift/>
To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Mon Oct 5 21:39:52 2009
This archive was generated by hypermail 2.1.8 : Mon Oct 05 2009 - 21:39:52 EDT