So M2-1 would start producing in a non-human breeding population and after a number of generations displace most or all non-humans with heterozygous humans, and then, eventually, with entirely homozygous humans. If the above description is correct, we must begin with a single human, gradually increase the number of humans to a very small number, gradually increase that number to a larger number, and then eventually increase their number to displace the non-human population entirely.

The population must eventually become completely homozygous so that no possible non-humans are produced. Possibly only the homozygous are truly human since the heterozygous individuals may have non-human characteristics expressed if the non-human allele is dominant. If this were the case, this could provide a mechanism for removing the heterozygous primates and the non-mutated primates since they could not compete as well.

My question is, How can someone say there has always been at least several thousand humans if we must start with one individual human and gradually increase that number?

Whoever wishes to answer this, once you do so, I will have one or more questions for you, but relatively simple ones I think.

Thanks to whoever might help me with this.

I would agree with Randy that it is important to consider that in a given population there is always variation, and not just single gene changes that lead to this variation. Two siblings differ at a number of genes, not just one. Between any two species there are many diferences, and speciation can result from a number of different mechanisms. Two parents having a new species offspring is generally not one, at least for large complex organisms. A great example of speciation occurring among salamanders in California illustrates the point. You see that the parent species is at one end of the state, whereas the newly forming species are on either side of the desert.  Over time, there will be three species where there was originally one.  Now, you can see how it is not correct to ask who the original two parents of the new species were.    Here is the link to that video. http://www.youtube.com/watch?v=YCoEiLOV8jc   Of course, many will say "that's microevolution, not macroevolution." Interestingly, most biologists don't find the term microevolution all that useful. This distinction really misses the point: These are the mechanisms that logically will inevitably lead to changes in species, and if the fossil record and genomic evidence is to be believed, it is reasonable to infer that these smaller changes do accumulate to bring about remarkable changes. 

One can imagine that in some cases it might happen that a very few founder parents could give rise to a new species, in cases of founders to an oceanic island, for example. That would be a different mechanism, and again the changes giving rise to new species (think Galapagos finches) will not come suddenly from two individual parents having that new offspring, but rather due to the differential survival of the great grandchildren and great great great great great...etc grandchildren of those founder parents, with the selective pressures "molding" the direction of the changes over long periods of time. 

If you want to learn more about natural selection, you can do worse than actually reading (or listening to Librivox audio version) of On the Origin of Species by You know Who. It's actually a very understandable and quite remarkable book (that is an understatement). http://librivox.org/the-origin-of-species-by-charles-darwin/

Blessings, 

Craig Story

Randy. I know you are the current Executive Director of the ASA and I appreciate your taking the time to respond to some of these forum discussions when you could probably have a much greater impact speaking or writing in more widely viewed publications. I think you recognize that there is an important ministry simply in speaking to sometimes even just a single individual. There are people like myself who simply need to discuss our questions with a specialist. Could I suggest that, whenever you have opportunity, encourage other specialists to watch the ASA forums, at least check out the topics that are being covered, so that they too might be able to use their expertise to give needed information to nonspecialists like myself? I think they too could find this to be a very important ministry.

P.S. My response to you and Craig will be out soon re the "original human population size."

One thing you are getting into, DJ, is the very challenging topic of "What is a Species?"  or "Species Concept" and just a caution (from a biologist) that this is itself a very challenging topic within the field of biology. Suffice to say there are many ways to define what a species is. Of course Wikipedia can give you a good treatment of the topic. There are over 10 different ways listed there to define a species: http://en.wikipedia.org/wiki/Species   Good luck!  

The story of Genesis obviously has elements both of allegory/poetry while at the same time speaking truth about God, and humanity and their relationships.   The fact that the human species (however it is defined) has an evolutionary origin should not negate the need of man for repentance, and obedience to God's law, which is "written on our hearts."  It also should not negate the truths about Christ's role in salvation. We are now free to better interpret the meaning of Genesis/original sin/the Fall, etc based on our better knowledge of nature, that should help us better interpret the scripture. Just like when observations led folks to realize the earth was not the center of the universe, that led to better theologies of heaven/hell and the like. (in other words, hell is not down there in the earth, very far from the "heavens." 

God Bless,

Craig

Dennis,

  You raise many important issues to discuss. Let me focus here on one of your original issues that started this topic. You state that " In any case a single individual will always be responsible for getting a new gene going that will make the new organism substantially different than the others." But I think what Craig and Keith and I were trying to say is that while it is true that a mutation, or small set of mutations, can occur in one individual and eventually propagate to 100% of the population, such mutations in complex organisms seldom, if ever, define a species or subspecies of the type that might differentiate humans from non-humans. Of all the characteristics that biologists and paleontologists use to identify a "human", I don't think there is any single one where they would define a precise value above which is a human and below which is non-human. In other words, the transition from non-human to human is more than a single, or several, generation's worth of changes. It may be more helpful to think of a continuum in each characteristic trait.

 As a result, if one differentiates human from non-human in purely biological terms, then the notion of a "first human" or a "first couple" is hard to sustain in light of our observations and understanding. That leaves a spiritual definition, which is an interesting option and which raises its own set of questions.

Hello again Keith,

I said that humans must have certain physical capacities, that there is a minimum of intellectual abilities necessary for humanness. I agree with you that this is only a necessary and not a sufficient condition to have humanness. Any organism lacking these abilities and the genetic code needed to produce these mental abilities cannot be human unless God somehow miraculously intervenes to allow such abilities. Yet one who has these intellectual capacities is still not necessarily human. One may have the capacity to be aware of God and still not be aware of God should God not choose to allow one this awareness. This awareness need not be anything like what we might think of as a religious experience. It could be nothing more than the awareness that God could be there and that one has a moral obligation to this God should this God exist. This is more of a moral awareness though we might also call it a spiritual awareness.

So yes, it seems that God does have to specially act to give us our humanness, the image of God, and having all the right mental abilities is not enough. I could be wrong, but it does seem to me that this kind of moral awareness cannot result from mere physical capacities of the brain. I would certainly claim this of human consciousness (as well as animal sentience insofar as we can assume that animals do have sentience). J. P. Moreland, for example, develops an argument for God’s existence from human consciousness. No increase in complexity or in new arrangements of complex neural parts can produce consciousness in humans any more than making Star Trek’s android, Commander Data, more complex can actually give him consciousness. To claim otherwise is a category mistake. What I am questioning concerning moral awareness is whether, given human consciousness, this awareness can result naturally from some feature of human intelligence which in turn results from our complex brain structure. As I say, I don’t think it can.

You make the point that it would thus be very difficult to determine from studies in population genetic or archeology when the first humans came to be. But even if the characteristics I’ve suggested to be sufficient for humanness are genetically determined—that once we are physically made a certain way and behave and think accordingly, we must be human—it would still be just as difficult to say when the first human came on the scene. Might one in the line of common ancestors for the chimp and human line have been human? I claimed earlier that humans and non-human primates might have interbred until one line was left and the other became extinct or that both became distinct species. If all it takes to be human is a sense of God’s existence (or an awareness of the possibility of God’s existence), and an awareness of the obligation to relate to this God in a certain way (worship, obedience, etc.), and maybe a more general moral awareness also, then it seems very possible that the first human could be very early. I had mentioned the Upper Paleolithic Revolution as a likely starting point for humans because it seems that here the artifacts and other evidence indicate clearly modern human behavior whereas for any previous primates we can hardly tell the difference between their behavior and artifacts and that of any other higher animal. And I still think this is the more likely point at which humans appeared. But as I say, if we truly consider humanness to consist of moral and spiritual characteristics like those I’ve suggested, the first humans could have existed much earlier.

You have suggested some other characteristics such as creativity, logic, etc. which might put some rough limits as to when humanness could begin. But as you say, with this it is "futile to try to discern the beginning of humanity in a theological sense from the fossil and anthropological record.” I’m not sure if you are saying that to be human in a theological sense requires one to be in relationship with God. It should at least require the potential of relationship with God, that one may choose that relationship and God may allow it. But certainly those who refuse this relationship are (and were) no less human than those who choose it.  

You say, "I don’t see why there need be any biological difference at all between those individuals that God revealed himself to and made His image bearers. Becoming human was not a speciation event -- it was a divine act of grace.” Well, so long as they all have those minimal mental abilities and yet they still have that relationship with God (or, as I suggest, even the potential for that relationship), they certainly should all be considered human even though they be of different biological species. If there ever were more than one biological species of humans, then all must have become extinct except one.

It is rather hard to say how many species fail to be fossilized because it depends on many factors: the species (soft body vs a shell or bones), how easily the organism is recycled into the environment and preservation of the rock formation (to name a few considerations).

One way or another, in order to have a fossil to look at, it needs to have been taken out of the recycling process for long enough. 

First, you need conditions where other animals don’t have any chance to carry off any edible parts; microorganisms don’t have a chance to break down whatever is there, and UV doesn’t eventually destroy the remains.  The easiest way for that to happen is that the remains are buried under an avalanche of fine sand and preserved in an anaerobic environment.   The ocean is more likely to provide ideal conditions compared to land.  So first of all, you need rare conditions that produce fossils.

Second, there may be many fossils "out there”, but most of them are unreachable because they are buried in unexposed rock formations.  You can only find fossils where you can reach them.  Moreover, these rock formations must be exposed enough that you can get at them without a lot of effort, but not so exposed that they come in contact with the elements for any significant length of time.    Eventually, even these rocks are eroded away, or melted away in subduction zones, or the fossil is distorted beyond recognition in metamorphic rocks, etc.   So second of all, you need to be lucky enough to find these things.

Consider how many people have artifacts from their family dating from 100 years ago.  How about 1000 years ago?   How many artifacts do we have that are 5000 years old in general?  How many documents and books were written in the ancient world that still exist today?  The materials we have the most data on are ones preserved on stone tablets.  Many of those were lost in wars, though sometimes, like in the case of Assyria, they were so hated, that, ironically, the library was preserved because it was flattened.   Without that, we would have very few records from that era.  If every decade after a person has passed away, 20% of his/her artifacts are lost each decade, after 100 years, only 10% of those items remain; a chest of drawers, some necklaces, etc.  After 1000 years, we’re talking parts per billion.  That means you need to leave a lot of stuff behind to have one artifact survive.  

Hence, it is rather hard to say what exactly is preserved or not when we really cannot say a lot about what was there and what was not.  Nevertheless, considering the odds of anything being preserved even a millennium (with willful human effort to boot), it seems like a reasonable claim to say that 90% of the species are never fossilized (a matter left entirely up to chance).

by Grace we proceed,

Wayne 

Sorry for the delay in this posting.  I have just come upon this forum topic.

 I hold that the biological species concept is most pertinent in this context in that it is functional in the dynamics of nature.  I also hold that the Genesis accounts (chapters one vs two) refer to separate events.  If one accepts the ekpyrotic universe model of Steirnhardt and Turok, (Google the topic if unfamiliar) then, I suggest, the Garden of Eden was and still exists in what I call the "heaven brane".  Note that in Genesis one, humans are "created" (I hold by God's natural process involving survival of the favored--see Psalm 104), but there is here no restriction to an original pair.  It is in the Genesis 2 account that Adam is designated and named.  God places him in the Garden of Eden.  I hold that this involves the transferal of "one" (Eve?) into the heaven brane.  Here the fall occurs.  Eve and Adam eat of the tree of the knowledge of good and evil.  Did this result in genetic mutations?  In any event, they have now achieved sufficient sentience to willfully dishonor God by disobedience so that God now must banish them back into the "earth brane" where their offspring interbreed with the earthly population of H. spapiens which subsequent population becomes fully human in sentience.  So we see that biologically our species always had a sizable population, but Adam and Eve were, as a single pair the original sentient (with understanding sufficient to allow willful obedience/disobedience to God's will) beings.

 Perhaps this is not the context to further expand on this perspective.  My book "Why the Universe Bothers to Exist, Theistic Determinism, Evidences and Implications" should be at press before the year is out.  Here this issue and several others such as "why is a new heaven (as well as earth") needed?  What is wrong with heaven as it now exists? are dealt with.

David V. McCorkle