Were there multiple lineages from primate to human?

Likewise, a biological lineage may have allele exchange with other populations (or even other species).

If a population “continues with their language” are you saying that language will never change over time?

For example, Japanese is one of the more isolated languages, due to the period where Japan was largely culturally isolated from China and other neighbours. Japanese, however, changes considerably over this time period, as all languages do. Feel free to look it up.

@DennisVenema

Good description! The only notation I would add is that in this presumably seamless population over thousands or half a million years … if God wanted to identify the FIRST individual to qualify as a MORALLY RESPONSIBLE agent, it would certainly be consistent with our view of God to do so.

God, the author of morality, is in the driver seat on the topic of humans and morality.

As to the question of this FIRST MORAL HUMAN being the ancestor of all humanity … this kind of question has been pondered ever since the Bible tells the story that Cain moved away to marry and found a city. WHOM DID HE MARRY?

This is where I think Genesis loses its relevance. Is it trying to tell us a story about the man who is EVERYONE’s descendant?

Or is the Bible really telling us a story about the FIRST MORAL (or first Morally Responsible) Human? The FIRST is always important and memorable. People who then start trying to apply logic to Eve and Cain and all the rest … well, that’s pretty dubious in my view!

You are right. The Dutch version of the saying is “appels met peren vergelijken” and I translated it directly to English, wrongly.

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No worries, Casper - I can’t imagine having a technical conversation like this in another language!

Though apples and pears are much closer relatives than are apples and oranges. :slight_smile:

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Dennis, maybe we can reference an earlier post you wrote: Evolution Basics: Becoming Human, Part 1: Mitochondrial Eve and Y Chromosome Adam.

One can see similar things appearing in the Amish community with the currently prevalence of the surnames, “Miller”, “Stoltzfus”, “Yoder” and “Zook”. Family surnames were originally more equally distributed but not every family line produced men in the next generation. As a result, the number of surnames in the communities condensed to a few with high frequency. Eventually, only one surname will remain. This inevitable shift to fewer surnames occurs even while the population of Amish community hasn’t dropped a lot — Actually, I think their populations are increasing.

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Yes - the genetics can only illuminate the biology of the situation - which is why I am careful to use “biologically” when discussing human evolution over time. If God decided to single out an individual or couple for a special role, etc (as John Walton argues) that is not something science can detect.

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So what you’re saying is… between the English and Dutch versions of this expression, some things (“apples and”) stayed the same while other things changed radically (“oranges” vs. “pears”)?

Next thing you’ll be telling me this shift was just one of many small changes made by a whole population of speakers! :wink:

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Original poster here.

Any analogy can be problematic. If it’s disputed, try abstraction.

I leave theology to others.

@DennisVenema: I take your angle as correcting some of what I’ve said above, although I think we were closer than you thought. We agree, for example, that change was not sudden. Since everyone in the first 10,000 or more beings was human and change is incremental, then there’s no clear demarcation between them and the preceding number, perhaps 10,000, and with 10,000 as the minimum then some earlier beings may also have been human. I already acknowledged as much. I steered clear of what happened 200,000 years ago and the MRCA and asked instead about the beginning of all of humanity, 4.3 million years ago (i.e., the oldest or least recent common ancestry), and in that context I wrote of an in-between state for a time when nonhumans slowly evolved into humans; that roughly corresponds to what you wrote of hominins. It’s not likely that anyone in any lineage who first met the definition of “human” could have been identified as such at the time or distinguished from their nonhuman contemporaries and nonhuman parents (as opposed to great-. . .-grandparents, who are more easily distinguishable), because of the gradualness of evolution. There’s no nonarbitrary method of identifying the first humans (in any quantity) from their immediate ancestors, given as nonhumans. But that means that whoever we with hindsight were to deem the earliest humans would have been able to reproduce with the nonhumans who were less than a generation older (maybe a bit more), because the genetic similarity was so nearly complete that reproduction between what we might with hindsight only arbitrarily call separate species would have been possible. Pressures on a population could affect the offspring of a human mating with a nonhuman so as to create another nonhuman-to-human lineage within the same community; that is a correction from what I posited above and that is based on or extended from what I understand of what you wrote. I hope I haven’t misunderstood your summary.

However, the same seems likely to be true of, say, the evolutionary invention of eyes (not to mention whales, chameleons, et al.). Perhaps skin became sensitive to visible electromagnetic frequencies and transmitted what it sensed to the brain which applied it to further its owner’s survival; perhaps some areas of the skin became more light-sensitive than other areas of the same owner’s skin; perhaps a more-sensitive area developed means to protect itself leading eventually to eyelids; and so on. That, too, would have been gradual and the pressure leading to it would have been on a population, probably not 10,000 but probably more or less and probably not exactly one or exactly 40. Yet, as I understand this, scientists have identified 40 places on the evolutionary tree where eyes begin. I think what that means is that at each of the 40 a population of one species evolved eyes but reproduction (here assuming reproduction was sexual) between a light-sensitive individual and a light-insensitive individual could result in a light-insensitive individual who in turn might reproduce with a light-sensitive individual producing a light-sensitive descendant, resulting in two light-sensitive lineages for that species at one spot on the evolutionary tree, because the tree is shorthand for what we know and does not map every individual.

Assuming the same principles apply to all complex evolutionary steps, they’d also apply to humans, so if one early human male were to be identified as “Adam”, that would be arbitrary within a particular generation and community (bounded by available transportation, not necessarily on foot), as there could be other “Adam”-like humans, i.e., male humans born of nonhuman parents, but not enough evidence has been preserved to allow identifying a non-Adam human lineage. Absent that evidence, the shorthand is still useful, even as scholarly shorthand. Thus, as shorthand, there’s only one locus of nonhuman-to-human evolution: one locus defined as within an age range allowing members to reproduce with each other and with sufficient proximity to be considered for our purpose to contain one community.

It still appears that the first male humans did not have to come into existence at the same time or place as the first female humans, although humans of the two sexes would have had to meet in order to continue humanity by the time humans had evolved enough to prevent any more reproducing with nonhumans, and perhaps had to earlier.

Another argument favoring community reproduction rather than being by only two individuals starting humanity comes to mind, but it’s speculative: There’s a taboo now against relationships that result in inbreeding. I think some animals exhibit this, too. My speculation is that perhaps that taboo also existed 4-5 million years ago. If so, if conditions supported pro-human evolution then multiple evolution would have been likelier and many nonhumans might have given birth to humans, albeit only where and when those pro-human-evolution conditions prevailed and not elsewhere or at other times.

I gather that all of the other taxonomic categories of humans, such as Neandertal, evolved later and not directly from nonhumans, so they’re irrelevant to my question opening this topic.

That evidence does not support multiple evolution is something I got from, “while evolution can lead multiple times to similar solutions, this has not happened (yet?) for our own unique capacities”, according to this topic’s moderator, Casper_Hesp, and perhaps other passages, supra. But I acknowledge your point here.

It’s possible, I speculate, that our species has evolved in its few million years of existence. If we could clone and try to reproduce with a million-year-old human, we might be genetically different enough not to be able to reproduce. But we don’t notice that, although million-year-old DNA might exist and even be analyzable, if we haven’t seen evidence of branching of species from the modern human lineage. Branching is a strong reason to label separately.

@Argon: Family names are not as tightly bound to families as are genotypes. Family lineages sometimes change names and one family may have multiple sons. If you’re right about the future of the Amish, they may decide that differentiable names are important for family identity and social relationships and some families will either change family names or adopt another convention.

@AMWolfe: Linguistics is a different kind of field. Languages evolve, but some words are more stable than others. Place names, the name of an entire people who speaks a given language, and the words with the most frequency and distribution of use tend to be evolve more slowly or hardly at all. Written and spoken forms may evolve at different rates. Phrases and words may evolve at different rates.

@GJDS: Different disciplines may have different givens and different standards for sufficiency of evidence. Within a discipline, different groups of specialists can have different standards. At one time, two mathematicians disagreed on a point about infinity and one found himself unable to get his work published in the nation where they both lived, but eventually some of the work was published in another nation. While standards tend to converge, they don’t always, and good work may get done and recognized even without convergence.

@AMWolfe Evidently you need to spend a few more years studying linguistics…

@Nick There is this thing people do called ‘irony’…:grinning:

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I don’t think there is any such thing as “the first male humans” and “the first female humans” as you are envisioning it. There is no line that was crossed by some individuals into biological humanity whereas others in the group were left behind in non-humanity and then the ones who had crossed the line had to find mates who had also crossed the line. That conception is flawed.

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@Christy: I’m not surprised you thought that’s what I was saying, since this thread has gotten so long. But I wasn’t. We’re somewhat arbitrary in placing a dividing line between human and immediate nonhuman ancestral species. Individuals next to the dividing line were only so slightly different that they could reproduce with each other. Thus, a human of that time could mate with a nonhuman of that generation. Eventually, however, as humans continued to evolve they could no longer reproduce with contemporary nonhumans of the species from which the humans had evolved. The humans would have changed too much. Thus, for humanity to continue, mating by humans eventually had to be with other humans, whereas earlier it did not have to be. Where I wrote “perhaps had to earlier”, I was referring to a little earlier, not so much earlier that we’d be back to the dividing line or before, but rather that the two human sexes had to meet in time to be able to produce enough offspring to form a surviving and growing community of humans who in turn reproduced until we have today’s large population. The alternative, if the two human sexes had not met in time to have enough offspring for community stability and growth, could have been inbreeding with early death of so many individuals that the community and humanity could become extinct. Evidently, the sexes met in time. It’s still the case, though, if evolution was slow enough, that the first human females and the first human males may not have met, and the first meeting could have been by later generations, and before then humans could have mated with individuals we, with hindsight, would define as being of the ancestral species. We define a dividing line without naming all of the individuals on either side; but the individuals back then, even if they knew the same science we do, could not have identified who was on which side of the line, even if they were mating.

On irony, I think the poster was being humorous in a misplaced way but probably not ironic. But that’s an interpretation and the poster might have another view. It’s minor, anyway.

I don’t think this “dividing” line existed.

Individuals in the same population would continue to evolve with their contemporaries. I’m confused by what you are talking about when you keep talking about this line between humans and non-humans. We are talking about a progression that happened to a population over a very long period of time, over many, many generations, right? It doesn’t make sense to talk about individuals. Presumably for an ancestor species to evolve in a different direction, it would be in an population that had been isolated from the future homo sapiens population for many many many generations. There would not be an opportunity for inter-breeding.

It sounds like in your conception group A evolves human females but the males are non-human. Group B evolves human males but the females are non-human. Luckily some of the human females from Group A hook up with some of the human males from group B and wa-la, humanity is saved. Is that what you really think or am I misunderstanding?

Individuals don’t change into a different species than their parents. Populations diverge over many many generations. At some point, the entire population is reckoned a separate species from the other descendants of an ancestor population. There are no individuals crossing some biological threshhold into “new species” one at a time. You cannot have a population where the males are a different species than the females. That doesn’t make any sense.

@Christy: Considering linear evolution (I’ll deal with branching below), in part you’re saying the same thing I’ve been saying, although not entirely.

The exact dividing line, as noted, is arbitrary but exists within broad parameters. There are humans today and have been for about 4.3 million years. There were nonhuman ancestors immediately before that and long before that. The nonhuman ancestors evolved into humans, and did so gradually, perhaps with as little as one molecule changing at any time. Even if every individual who lived 4-4.5 million years ago had been preserved under ideal conditions and we had everyone’s DNA and age and place and identified some as human and some as nonhuman, we still would be left with some individuals who could be either. Those who could be either were in what I called an in-between state and what I think a biologist above referred to as hominins; any of them might have been a human or a prehuman ancestor but we don’t know which and if we could time-travel back and meet them and conduct full medical examinations we still wouldn’t know. We could classify the genes and chromosomes so that every single body had to be one or the other, but that would, at the in-between stage, be arbitrary, in that it would be so precise as to have only weak scientific underpinning, at least as of now (that could change in the future as we develop good reasons for tighter taxonomic boundaries but I think we haven’t yet). So there was a community that we’re unsure about; they could have been either human or nonhuman.

But the community’s members were so similar in terms of what defines a species that they could reproduce with each other. Thus, it is possible that individuals who were among the first humans might have reproduced with individuals who were among the last prehuman ancestors. (If someone wanted to be gross and toss accuracy out the window, they might say, “you mean that beautiful lady in the red dress had sex with a hairy gorilla?” Remove the exaggeration and what’s true is that I’m saying that probably a human had sexual intercourse with a prehuman and thereby had a baby and probably that happened many times with no heightened medical risk or social disapproval.) They wouldn’t have known the difference even if today’s scientists had time-travelled back, arrived with precise classifications, proceeded to say, “you, standing by the tree, you’re human” and “you, wading in the brook, are a prehuman ancestor”, and taught the individuals all of our modern science. Even so, the two individuals could have looked at each other with no idea how to confirm or deny the modern visitors’ findings or declarations. If those two individuals were adults of different sexes and chose to attempt reproduction, they’d have had no unusual difficulty (beyond that faced by any two who are clearly of the same species). The baby might be either human or prehuman, then could grow up and reproduce the same way within the same paradigm of species-definition uncertainty, repeating the cycle until evolution had advanced enough that there’d have been no doubt that the resulting children were all human and any attempt by any of them to reproduce through a primate’s service would eventually fail, because the genetic differences would have become large enough to make certain that they were of different species.

In other words, human females from Group A did not have to wait for human males from Group B to save humanity. Group A could have reproduced within itself and Group B could have reproduced within itself, each Group being composed of members at an in-between stage and thus any member could have been newly human or an almost-human ancestor, with all of the members of one Group being similar enough genetically that they could reproduce together. If environmental conditions continued to pressure evolution in favor of humans, babies in both groups would have tended toward being human until humans predominated and then would have evolved enough that they could no longer reproduce with nonhuman primates.

There may be a way in which the first humans, whom I understand numbered at least 10,000, did not have sexual intercourse with any individuals who were prehuman ancestors. That would be if the first 10,000 included both males and females who were adults at the same time and in the same geographic community/ies and in sufficient numbers of each sex to generate enough offspring to lead to today’s 7,000,000,000+. Possible, but that’s less likely. If evolution from sexually-reproducing ancestral species required creating both sexes temporally that close together when they had not been doing so before, then that would be one more reason why most mutations fail: the two sexes not being even nearly simultaneous would end the evolutionary attempt. But if a new-species adult of either sex could reproduce with an immediate nonparental nearly-lateral ancestor because they’re similar enough to support the possibility, then that would make evolution easier, and I think that possibility is the more plausible of the two.

You wrote, “[i]ndividuals don’t change into a different species than their parents. Populations diverge over many many generations. At some point, the entire population is reckoned a separate species from the other descendants of an ancestor population.” I take the second and third sentences as correcting or counterbalancing the absolutism of the first. In that case, we agree. I’ve already said that change is gradual. But change happens. If some number of generations occur between what is clearly one species until there is clearly another species, and all of the generations in between changed in the same direction, we don’t say that the in-between individuals are not of any species. Either they’re in-between and thus of one or the other species (although we don’t say which) or we arbitrarily assign a species to each.

You wrote, “[y]ou cannot have a population where the males are a different species than the females. That doesn’t make any sense.” Yes, it does, and yes, we can have that population, provided the members who are of one sex and one species are able to reproduce with their immediate ancestral neighbors of the other sex, unless there are even more failed mutations because both sexes did not evolve into existence at about the same time and place. But because of the uncertainty of species-boundary definition, it’s likely that the genetically extremely similar could reproduce together across the arbitrary boundary.

Branching became a subject in this topic but I think I may have confused things there. The primate species from which humans evolved still, I think, exists, albeit itself having evolved, too. Humans branched off from a species of primate. But if two species branch from one so that three species result, the observation of that makes a more compelling case for recognizing and naming all of the species involved and for attempting to describe the species precisely enough to make identification of more members easier. But that’s a trivial point (meaning me who’s being trivial), because it doesn’t change that there’s a vaguely-defined area in between at each junction where one species evolves into another, where some individuals could be either the “before” species or the “after” species but we don’t know which.

When scientists draw a tree of evolution, I think humans come into existence from an ancestral species at only one locus on that tree. The tree is a summary, a scientifically valid summary but still a summary, and does not map every individual, but summarizes what’s known about species. Whether the number of prehuman-to-human evolutionary loci (on that conceptual tree) is limited to only one is what I was asking about at the beginning of this topic and that seems to be the consensus answer, unless I hear otherwise.

To answer the question in the title of this thread:

Are there multiple lineages from WOLF to the various breeds of the modern domestic dog?

If you can define your terms adequately for canines… then I suppose we can apply the same logic to primates. Off hand, I would suggest that Neanderthal and Sapien are as closely related as Wolf and modern Dog… which, in other words, is JUST PARTIALLY.

It’s more like 200,000 years. I don’t really follow the rest of your post.

[quote=“Nick, post:59, topic:4935”]
If someone wanted to be gross and toss accuracy out the window, they might say, “you mean that beautiful lady in the red dress had sex with a hairy gorilla?” [/quote]

Have you ever considered writing for Game of Thrones?

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@beaglelady: The 200,000-year figure I think refers to when the most recent common ancestors (MRCA), male and female, of us today were living. That’s not when the first humans were living. Some lineages died out or were absorbed, so they can’t supply an MRCA for us. The figure of 4.3 million years ago is what I’ve read in various sources for when the first humans existed. Ignoring pre-human species, humans themselves have evolved through several species. Approximately similar year figures are available from other sources. The Smithsonian cites 6 million years by starting at Sahelanthropus tchadensis in the Ardipithecus group, which it describes as “[t]he first humans” (http://humanorigins.si.edu/evidence/human-family-tree and http://humanorigins.si.edu/evidence/human-fossils/species/sahelanthropus-tchadensis). At 4.4 million years ago there was Ardipithecus ramidus (http://humanorigins.si.edu/evidence/human-fossils/species/ardipithecus-ramidus) and at 4.2 million years ago began the lives of Australopithecus anamensis (http://humanorigins.si.edu/evidence/human-fossils/species/australopithecus-anamensis); the Smithsonian lists both under human fossils (on the web pages, see the boxes on the left). Homo habilis, an early Homo species, began living around 2.4 million years ago (http://humanorigins.si.edu/evidence/human-fossils/species/homo-habilis). The “human-chimpanzee divergence” was said in 2001 in the Journal of Heredity by a Pennsyvania State University professor to have happened 4.3-6.5 million years ago (http://jhered.oxfordjournals.org/content/92/6/469.full). The BBC reported in 2005 on “the remains of at least nine primitive hominids that are between 4.5 million and 4.3 million years old” (http://news.bbc.co.uk/2/hi/science/nature/4187991.stm). In what may be too popular a treatment for accuracy, Discovery.com says, “the first accepted ancestors of humans branched off from other primates [”‘4.3 million years’" ago], said [Prof. Thure] Cerling" (http://news.discovery.com/earth/plants/savannas-dominated-cradle-of-human-species-110805.htm). All URLs were as accessed May 13, 2016.

In response to “I don’t really follow the rest of your post”, I don’t want to rewrite the whole thing and its context, but if there’s a point you don’t understand, feel free to post your question.

My only exposure to Game of Thrones is to some advertising. I don’t even know if it’s a game, a show, a movie, or something else. If you want to write for it/them, I’m not competing. Enjoy.

No, actually we descended from a population of modern humans (Homo sapiens) who have been around about 200,000 years. No modern humans were around 4.3 million years ago. Just ancestors of humans.

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True that Homo sapiens began around then, 200,000 years ago, but it’s not agreed that some of the predecessor species were not humans, too. They were not modern humans, but they were humans, and the time of divergence from what were not humans was millions of years ago, per the sources cited. If you know of contrary authoritative sources, please cite.

That descent was from a larger population rather than from only two individuals I don’t dispute. I originally thought two, but the case for a larger-population origin was made above.

I don’t know what you consider human. Please explain, with the earliest human species. Take a look at The Emergence of Humans from Berkeley’s Understanding Evolution web site.

Or take a look at the book called “Evolutionary Analysis” 4th edition, by Scott Freeman and Jon C. Herron. Chapter 20 discusses human evolution.

Physical anthropologists don’t agree about too much, anyway

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