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Re: aerobic capacity (Was: Breast stroke technique)

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  • DDeden
    Hi Rob, From your words: Yes, they needed to know where to find drinking-water while they were active on the savanna and they needed to learn how to avoid
    Message 1 of 17 , Oct 1, 2007
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      Hi Rob,

      From your words:

      Yes, they needed to know where to find drinking-water
      while they were active on the savanna and they needed to
      learn how to avoid territorial ambush-predators - salt was
      needed of course, but it could be obtained while they were
      not engaged in exploiting the savanna.
      Why they would carry dugouts across the savanna is
      not at all apparent to me.

      I think you've said it all right there.

      When you've figured out why an ape would have very little body hair
      but 1+meter head hair and generous SC fat, then perhaps we can proceed
      in discussing our ancestor's typical habitat and respiration. Because
      although some populations do run long distances, most don't, and
      although some populations do climb vertical cliffs, most don't, but
      virtually all Homo sapiens during infancy crawl on their knees when at
      a sandy beach, virtually all Homo sapiens have head hair that grows to
      1+ meter when uncut, virtually all Homo sapiens have very little body
      hair compared to other apes and virtually all Homo sapiens have SC fat
      especially babies and women of childbearing age.

      knee-crawl, long head hair, thin body hair, SC fat: none of these are
      selected for in highland or savanna species, but are at the coast.

      That post H erectus, post H idaltu ran in highlands or savannas for
      various reasons and spread some aerobic-friendly genes into our
      ancestor population is quite possible due to seasonal migrations and
      use of dugout boats.

      DD



      --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@...> wrote:
      >
      > Hello DD........
      > >
      > > Humans sweat while engaged in jogging, along the
      > > seashores salt and water are both easily obtained instantly,
      > > but that's not the case while jogging along inland savannas,
      > > nor in the case of arboreal aerobic climbing or brachiating.
      > > Water may be freely available during the wet season but
      > > that is the muddy season, hard to maintain a rhythmic
      > > cadence. During the dry season, although there is water,
      > > it is concentrated in areas of high predation. Salt may only
      > > be found in ancient inland seas, often with accumulations
      > > of alkali soils as well. If humans had an aerobic capacity
      > > to run for long distances without much sweat, this would
      > > be less of a problem, but that isn't the case typically.
      > >
      > Even though I agree that the savanna is an unlikely
      > environment for the initial adaptation to aerobic endurance,
      > I don't think that the availability of either drinking-water
      > or salt has anything to do with it. Savanna animals require
      > salt on a regular basis and if you want to know where
      > salt is to be found, then you simply follow them until
      > you find where they get it from. This is basic bushcraft.
      >
      > Even more basic bushcraft is to know where potable
      > water can be obtained. I've never been to the African
      > savanna, but I have lived with Australian Aborigines and
      > seen how they exploit a very similar environment....all
      > I can do here is reiterate that they have no trouble in
      > first finding and then remembering where drinking-water
      > can be obtained with very little effort or risk.
      > >
      > > .....The result is that humans evolved in a place where
      > > aerobic running, swimming, climbing, walking, wading
      > > all contributed on a daily basis......
      > >
      > What definition of 'aerobic capacity' are you working
      > with here? Do you disagree with the explanation of the
      > term offered by Lynne Thompson and which I quoted
      > in a previous post?
      > >
      > > Keep in mind that they had sufficient SC fat to keep
      > > warm in water during floating for lengthy periods of
      > > inactivity.....
      > >
      > You seem to be assuming that I also take it for granted
      > that we did in fact have sufficient SC fat to keep warm
      > while floating for lengthy periods (I note the word 'lengthy'
      > is used again here and I misunderstood you when you
      > used it before - perhaps a different word would give
      > me a more precise idea of what you mean?). But I've
      > come across no research to indicate that our SC fat has
      > any significant mitigating effect on the fact that we lose
      > heat twenty-odd times faster in water than we do in a
      > similar temperature on land. If you know of such research,
      > then the ref.would be appreciated. OTOH, I know from
      > personal experience that an athletic 15-25% body-fat
      > does not interfere with either distance-running or vertical
      > climbing......
      > >
      > > .......this would have interfered with long distance
      > > running & climbing where the body is lifted repeatedly
      > > against gravity.
      > >
      >
      > >
      > > Knee crawling and endurance running both developed
      > > along beaches AFAICT, aerobic knee crawling allowed
      > > longer legs and combined bent knees (both knee crawling
      > > and running but not walking). Knee crawling approximates
      > > dog paddling, and was used in infancy for locomotion.
      > >
      > What d'you have in mind for the motivation that would
      > have led a littoral H. to do endurance running along
      > beaches? Wouldn't it had to have been a resource that
      > was initially available only to those whose genetic make-up
      > allowed them to sprint a little further than normal, say
      > a marginally lower lactic acid production? We then need
      > to assume that this marginal advantage in resource
      > gathering translated into a reproductive advantage. Then
      > finally we need to assume that whatever this resource
      > may have been, it then adapted to the gathering and
      > over time required an increasing distance to be run by
      > the littoral H. until the adaptation for distance-running
      > had become a feature of the entire species. I see no
      > such resource either on beaches or savannas.
      >
      > I'm afraid that I've never heard of 'aerobic knee-
      > crawling'.....what is that?
      >
      > >
      > > > .........I think it very likely that early H. were able to
      > > > utilise savanna resources because they already had
      > > > an aerobic capacity when they arrived there and I
      > > > don't see a role for it at all in utilising marine resources.
      > >
      > > No doubt they did but they needed water and salt and
      > > a way to avoid savanna predators. IMO only with the
      > > use of dugouts and push-pole thrusting spears were
      > > they able to stay in the savannas for long periods......
      > >
      > Yes, they needed to know where to find drinking-water
      > while they were active on the savanna and they needed to
      > learn how to avoid territorial ambush-predators - salt was
      > needed of course, but it could be obtained while they were
      > not engaged in exploiting the savanna.
      > Why they would carry dugouts across the savanna is
      > not at all apparent to me.
      > >
      > > .........This was of course more recently.
      > >
      > You say 'of course' as if there's something self-evident
      > about this and at the risk of some embarrassment, I have
      > to say that I just don't see it. Who and why were people
      > more recently (or at any time at all for that matter) using
      > dugouts on the savanna?
      > >
      > > > Well, only in that you've replaced an unlikely savanna
      > > > explanation with an aquatic one that is, IMHO, equally
      > > > unlikely.
      > >
      > > The aquatic explanation fits the water and sweat conditions
      > > very well, the savanna explanation does not.
      > >
      > I most certainly do not agree that there is a plausible
      > aquatic explanation for our thermoregulation system - to
      > the contrary in fact, IMO tropical coasts and tropical
      > rainforests are the least likely environments to produce
      > such a system in a primate due to the high humidity that
      > is characteristic of both environments..
      > >
      > > I read an article on highland East Africans which
      > > reported that the population there had lived there longer
      > > than the Tibetans or Peruvians, but still suffered from
      > > poor adaptations to thin air. I think I copied it here
      > > sometime this last month.
      > >
      > If you compare those East African highlanders to
      > the West African lowlanders, you'll see that the eastern
      > highlanders have adapted to an aerobic capacity which
      > makes them the best distance-runners in the world,
      > while the West African lowlands have produced the
      > best sprinters (anaerobic running) in the world.
      > >
      > > .........Anyway I see no indication that our ancestors
      > > were living on highland plateaus........
      > >
      > The argument is that our aerobic capacity is an indicator
      > that our ancestors adapted to a highland environment. This
      > isn't proof that our ancestors did this, it's a suggested
      > explanation for the fact that any physically fit human can
      > run aerobically and other primates can't.
      > >
      > > .....though they may have gone there for stone tool
      > > quarrying, or as a seasonal activity as the tribal people
      > > here in Nor Calif did during the long rainy season.
      > >
      > I can't think of any compelling reason why some of them
      > couldn't have stayed there and our aerobic capacity is one
      > reason to think that they may well have done just that.
      >
      > Regards,
      >
      > Rob.
      >
      >
      > ----- Original Message -----
      > From: DDeden
      > To: AAT@yahoogroups.com
      > Sent: Saturday, September 29, 2007 12:58 AM
      > Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
      >
      >
      > Rob, after reviewing the paper you cited, a couple thoughts added:
      >
    • DDeden
      Hi Rob, Do you think that long head hair, abundant SC fat, reduced body hair and infant knee crawling were naturally selected in Homo on the Ethiopian
      Message 2 of 17 , Oct 1, 2007
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        Hi Rob,

        Do you think that long head hair, abundant SC fat, reduced body hair
        and infant knee crawling were naturally selected in Homo on the
        Ethiopian Highlands?

        If your answer is yes, please explain.
        If your answer is no, then why do you think aerobic capacity was
        naturally selected in Homo at that location?

        I don't know whether dolphins and sea otters have high or low aerobic
        capacity, but I'm certain that their traits were not naturally
        selected at highlands. The same goes for Homo, previous to Hs AFAICT.

        Here in California, there is Mono Lake, a natural high elevation salt
        lake with freshwater tributaries and an island where gulls reproduce
        safely from the coyotes that live in the area. The city of Los Angeles
        piped most of the freshwater, but recently reduced consumption,
        because the lake level shrank so that the island became a peninsula,
        allowing coyotes to invade.

        That's an interesting parallel regarding near-shore islands which were
        bridged during low sea levels in the past, and effects on residents,
        including possible Homo spp.

        Are there any parallels among the salt and brackish lakes of the
        Ethiopian highlands? If so, it could prove an example of inland high
        elevation life combined with semi-aquatic diving and cliff climbing.
        I don't know how high is the elevation of the Rift, but obviously
        hominids were there.

        DD



        --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@...> wrote:
        >
        > Hello DD........
        > >
        > > I notice that your former tactics have not changed......
        > >
        > DD, I'm not employing any tactics. I'm trying hard to
        > engage you in a conversation about the origins of a human
        > aerobic capacity for endurance activity. If you think
        > that I'm employing 'tactics', then I assume you also
        > think that I have an agenda to achieve through the use
        > of these 'tactics'.....what agenda would that be, d'you
        > think?
        >
        > In fact my only agenda is to have a pleasant conversation
        > with someone who has thought long and hard to come up
        > with their point of view. I don't want to change your mind
        > about anything and I have no theories or hypotheses of my
        > own that I think you or anyone else ought to adopt. I will
        > admit to some disappointment that you think I'm employing
        > 'tactics'.
        > >
        > > ......Pardon my brevity answering your questions.
        > >
        > I take your brevity as a somewhat grumpy way of
        > ending the conversation. Please ignore my last post on
        > the topic and I'll not bother you again.
        >
        > Thankyou for your time so far,
        >
        > Regards,
        >
        > Rob.
        >
        >
        > ----- Original Message -----
        > From: DDeden
        > To: AAT@yahoogroups.com
        > Sent: Monday, October 01, 2007 1:34 PM
        > Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
        >
        >
        > Hi Rob,
        >
        > I notice that your former tactics have not changed. Pardon my brevity
        > answering your questions.
        >
        > --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@> wrote:
        > >
        > > Hello DD........
        > > >
        > > > > Why would our ancestors have engaged in '....lengthy
        > > > > flutterkicking prone or backstroke...' to the degree that it
        > > > > had reproductive and eventually phenotype consequences?
        > > > > I suspect that a lengthy time doing such a thing in tropical
        > > > > waters would simply raise the ante in terms of predation
        > > > > risk and those who tried it would've been at a selective
        > > > > disadvantage.
        > > >
        > > > Why wouldn't they? lengthy as in a pool's length, not a
        > > > marathon. I'm comparing Homo to apes and primates.
        > > > With the thousands of humans swimmers doing precisely
        > > > that, I would suggest that their ancestors did the same....
        > > >
        > > I'm not arguing that a littoral ancestor wouldn't have
        > > engaged this sort of movement at all - I'm asking what
        > > sort of reproductive advantage such activities offered that
        > > they should select in favour of an aerobic capacity? But
        > > even if covering short distances is what you mean, then the
        > > same question arises - how would this provide a reproductive
        > > advantage that results in phenotypical change for aerobic
        > > endurance?
        >
        > How wouldn't it? Any activities in water, other than strictly
        > floating, selects for more efficient respiration, including anaerobic
        > and aerobic endurance, depending on the type.
        >
        > > In response to my point about the risks of predation,
        > > you comment.....
        > > >
        > > > One in ten million people today are killed by a shark.
        > > > Far more are killed by bees.
        > > >
        > > Are you suggesting that the threat of shark attack in
        > > tropical coastal waters is no different today than it was
        > > whenever you think our ancestors were there adapting
        > > to an aerobic endurance capacity?
        >
        > no.
        >
        > I've read recently
        > > that we are currently killing about one million sharks
        > > each year; then include those that have become extinct
        > > for other reasons - include the megadont here - and I
        > > think you need to mount an argument to support the
        > > relevance of your comment.
        >
        > ??
        > You snipped the context, I've no idea what you are talking about.
        >
        > > > Vertical position. Cliff climbing is bimanual tension
        > > > + bipedal compression, where a linear form is often
        > > > important, aerobic. Jogging is bipedal compression,
        > > > where a linear form is less important than the rhythmic
        > > > timing, aerobic. Likely some vertical climbing (combined
        > > > with regular swimming) preceded the ability to endurance
        > > > run.
        > > >
        > > I'm afraid I don't understand the connections you're
        > > making here. I find it entirely plausible that some vertical
        > > climbing and some swimming preceded the ability for
        > > aerobic running, but I fail to see any plausible causative
        > > connections with the aerobic capacity in modern H.ss.
        >
        > I do.
        >
        > > You say that vertical climbing is an aerobic activity, but
        > > I can tell you that my vertical climbing certainly wasn't....
        > > that's a long way down if you're not slow and careful.
        >
        > Mine was, along many bluffs along the Mississippi river, not so
        > dissimilar to pocket beach cliffs.
        >
        > > >
        > > > As far as I know, most primates have the ability to
        > > > walk aerobically. Gibbons have a swift aerobic
        > > > bipedal walk, (same speed as a jogging human)
        > > > not because their ancestors were endurance runners,
        > > > but because their ancestors were bipedal and they
        > > > have a high metabolism. Humans just move the
        > > > pendulum back a bit farther and bend the knees
        > > > further on the upstroke, something done in swimming
        > > > as well in the flutter kick and frog kick.
        > > >
        > > It's dawning on me that we just aren't discussing
        > > the same thing. Athletic distance-walking (as in that
        > > rolling gait that makes people look as though they've
        > > been caught far too short of a toilet) is undoubtedly
        > > an aerobic activity, but ordinary walking is not
        >
        > hmm Rob, you err. Sleeping is an aerobic activity, apneic sleeping is
        > anaerobic activity.
        >
        > and
        > > while that skipping gait of the gibbon looks as though
        > > it could become an aerobic activity, I very much
        > > doubt that gibbons spend enough time at it at any
        > > one go for it to ever become aerobic.
        >
        > Not now.
        >
        > > >
        > > > I'm comparing Homo with anthropoids. IMO,
        > > > natural selection in diving resulted in better aerobic
        > > > and aerobic respiration, improvements in breath-hold
        > > > diving rendered improvements in other breath-related
        > > > activities......
        > > >
        > > Yes I can see that this is what you're doing, but it seems
        > > to me that the results of the comparisons take away any
        > > of the normal meanings of the term 'aerobic endurance
        > > capacity'. Walking has become aerobic, climbing has
        > > become aerobic, floating has become aerobic and
        > > not breathing has become a way to improve oxygen
        > > delivery to muscle-tissue through breathing. I can only
        > > say that I find no logical or functional reasons to agree
        > > with you.
        >
        > OK.
        >
        > > > Selection in Zebras produced a zebra that is able to
        > > > run a bit farther & faster than a lion. Selection in humans
        > > > produced one that can dive, backfloat and swim for
        > > > hours in rhythmic cycles.
        > > >
        > > There's no doubt about why zebras were selected by
        > > being a favoured prey of lions, but I can only repeat that
        > > I can find no aerobic relevance in holding the breath for
        > > diving. I am still unable to find any plausibility in the idea
        > > that our ancestors spent hours swimming and floating in
        > > rhythmic cycles in a warm tropical marine environment -
        > > to be frank, I'm not even sure what this could actually
        > > mean. Floating involves hardly any movement at all and
        > > I'm at a bit of a loss to see how this could be in any way
        > > a causative precursor to an aerobic endurance capacity
        > > (in the usually accepted use of that term - see the quote
        > > from the Lynne Thompson paper I cited previously).
        >
        > It's the combination of things. Backfloating alone would be the same
        > as resting on your back on sand.
        >
        > > > > > Through daily diving, human respiratory - metabolic
        > > > > > control evolved from a macaque-like phase of 30
        > > > > > second dives to (likely) between 1.5 - 2.5 minute dives
        > > > > > in Homo (current Hs record 10 minute breath hold),
        > > > > > during which the body travelled through a large pressure
        > > > > > and temperature gradient and then on the ascent reversed
        > > > > > the order, repeatedly.
        > > > >
        > > > > There's also a fairly sharp light gradient in a potentially
        > > > > lethal environment and while it may well be due to a limitation
        > > > > of my imagination, I just can't see why our early ancestors
        > > > > would have done the sort of diving you describe.
        > > >
        > > > There's yummy vittles down there, just sitting there.
        > > >
        > > Ok, but they are down there in the dark and patrolled
        > > by some of the most effective predators that nature has
        > > produced in any environment.
        >
        > Humans are very visually oriented , I've no doubt they were able to
        > see at depth. Most sea predators have no idea what a human is, some
        > don't care.
        >
        > Then there's highly venomous
        > > sea-snakes, fish with poisonous spines and drifting masses
        > > of jelly-fish that can cause anaphylactic shock in even the
        > > fittest of individuals, all to be avoided in the dark while
        > > holding the breath as food is first identified (by touch?)
        > > and then gathered.....maybe DD, but I'm very sceptical.
        >
        > Those are defense mechanisms against predators. Vision was used.
        > Moken kids see well under water with only a few hundred or thousand
        > years of part-time diving. I'd think they had a simple knife-tool.
        >
        > > >
        > > > > AFAICS, you've set up a false dichotomy as it's
        > > > > no more likely that our aerobic capacity was an
        > > > > adaptation to either open savannas or to climbing,
        > > > > than it was due to the exploitation of marine resources.
        > > > > I think it very likely that early H. were able to utilise
        > > > > savanna resources because they already had an
        > > > > aerobic capacity when they arrived there and I don't
        > > > > see a role for it at all in utilising marine resources.
        > > >
        > > > Perhaps. I consider our ancestors have been near
        > > > coasts for 20+ million years.
        > > >
        > > Is 'near coasts' a term that could be interchanged with
        > > 'littoral'?
        >
        > Littoral is strictly the tidal zone. Emperor penguins walk 75 miles
        > inland from the coast, Homo may have trekked much more for various
        > reasons. Earlier, depending on climate and terrain, it could have
        > included inland waterways, etc. There was both a tidal effect and a
        > saline effect.
        >
        > Do you think our ancestors have been diving
        > > (in the way that you've speculated here and in other
        > > threads) for that long? If not, then for how long? I don't
        > > really have much of an idea about the time-line that you
        > > envisage.
        >
        > Diving & backfloating 2.5 ma max probably, 100 ka min. probably
        > Previous to that, mix of swimming types, prone floating with air sacs,
        > vertical floating.
        >
        > > >
        > > > > Well, only in that you've replaced an unlikely savanna
        > > > > explanation with an aquatic one that is, IMHO, equally
        > > > > unlikely.
        > > >
        > > > Perhaps. It fits with 1m long head hair quite well. Are
        > > > there any highland species with 1m long head hair, SC
        > > > fat and virtually no body hair?
        > > >
        > > Y'got me again! What has the length of head hair got
        > > to do with an adaptation for aerobic endurance?
        >
        > Hydrodynamics.
        >
        > > >
        > > > > There is another possibility. Here's a paper arguing
        > > > > that altitude is the key and I find that proposition is
        > > > > considerably more plausible....
        > > >
        > > > Altitude in air is similar to pressure at depth in some
        > > > ways. A difference is that highlanders cannot draw in
        > > > high O2 air unless they change elevation, while divers
        > > > can quickly.
        > > >
        > > It's also markedly different in some very significant
        > > ways.....the oxygen is thinner at altitude, but at least
        > > you can still breath there and on a clear day you can
        > > see a very long way. The predatory risk would have
        > > been considerably less at altitude than it would have
        > > been in tropical coastal waters.
        >
        > Hs does poorly at high altitude, even after 10,000 years. Leopards and
        > amur tigers do better physiologically IIRC. No record of humans ever
        > having lived at high altitude before 15,000 yrs ago.
        >
        > > Most importantly, modern highland populations show
        > > a progressive physiological adjustment to altitude that is
        > > very similar to the changes made by lowlanders who
        > > have trained for aerobic endurance.
        >
        > Except the accumulating brain damage, and low iodine and often salt,
        > none of which occur at shores. Flint collection in highlands is quite
        > possible, being short-term seasonal, warm weather.
        >
        > This provides a
        > > mechanism for the H. phenotypical adaptation for the
        > > capacity to use oxygen aerobically.
        >
        > How many humans live there today? There are 7,000,000,000 humans
        > alive, the vast majority near sea level, very few at high altitude
        > even with roads and technology.
        > DD
        >
        > > I see there's another response from you in this thread, so
        > > I'll continue this interesting discussion in my reply.
        > >
        > > Regards,
        > >
        > > Rob.
        > >
        > > ----- Original Message -----
        > > From: DDeden
        > > To: AAT@yahoogroups.com
        > > Sent: Friday, September 28, 2007 2:34 PM
        > > Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
        > >
        >
      • Rob Dudman
        Hello DD........ ... To be precise, I quoted a paper by Peter W. Hochachka et al.that used comparative arguments to suggest that the highlands were a good
        Message 3 of 17 , Oct 2, 2007
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          Hello DD........
          >
          > Do you think that long head hair, abundant SC fat,
          > reduced body hair and infant knee crawling were
          > naturally selected in Homo on the Ethiopian Highlands?
          >
          > If your answer is yes, please explain. If your answer
          > is no, then why do you think aerobic capacity was
          > naturally selected in Homo at that location?
          >
          To be precise, I quoted a paper by Peter W. Hochachka
          et al.that used comparative arguments to suggest that the
          highlands were a good candidate location for this aerobic
          endurance capacity selection......I happen to find their
          arguments well-founded and their conclusions plausible,
          but I don't claim their conclusions to be my opinion or
          something I need to defend beyond what Hochachka et al.
          have presented in their paper.

          Having made that proviso, I'll have a go at your questions....

          Do I think that long head hair/reduced body hair was an
          adaptation to a highland environment?
          No, I think that's very unlikely. If indeed early H. ever
          lived there, then I think they probably arrived as an ex-
          littoral H.e with more or less the hair distribution of modern
          humans. I would've thought that longer and thicker body-
          hair would be more predictable for highland adaptation.

          Do I think our characteristic amount and distribution
          of fat was an adaptation to a highland environment?
          I think this idea is worth some more thought. While
          I'm not so sure that this amount and distribution of fat
          would make a significant difference to heat-loss in
          water, the rate of heat-loss on land is many times
          less and above 2000m the fat just might have made
          adaptational 'sense' for a hair-reduced H. that hadn't
          yet invented clothing.

          Do I think that infant knee crawling was an adaptation
          to a highland environment?
          No. If an early H.e went to the highlands, then they
          went with a post-cranial morphology within the range
          of modern humans and so I'll reasonably assume that
          their infants behaved in much the same way as our own.
          As a guess I'd say infant knee-crawling began at mega-
          Lake Chad between 5 & 8 Mya.

          And a question that you didn't ask....
          Why would this early H.erectus have left the highlands
          and gone down to where their fossils are found?
          One possibility is that it eventually got too cold up
          there and by then they had the aerobic endurance
          capacity to exploit the lowland savanna resources that
          were not being exploited by other hominids extant at
          the time. They were then so successful at this that they
          spread across the world and lasted with only quite
          minor changes for the next million-plus years...clearly
          the most successful H. of us all in terms of survival.
          >
          > I don't know whether dolphins and sea otters have
          > high or low aerobic capacity but I'm certain that
          > their traits were not naturally selected at highlands.
          >
          Here we're in full agreement. :-)
          >
          > The same goes for Homo, previous to Hs AFAICT.
          >
          Hochachka et al. make their comparisons between
          modern humans living at different altitudes and I find
          these far more pertinent than comparisons between
          modern humans and dolphins or sea-otters.
          >
          > Here in California, there is Mono Lake, a natural high
          > elevation salt lake with freshwater tributaries and an
          > island where gulls reproduce safely from the coyotes
          > that live in the area. The city of Los Angeles piped most
          > of the freshwater, but recently reduced consumption,
          > because the lake level shrank so that the island became
          > a peninsula, allowing coyotes to invade.
          >
          LA residents are to be congratulated on their restraint -
          it seems to have saved Mono Lake.
          >
          > That's an interesting parallel regarding near-shore
          > islands which were bridged during low sea levels in
          > the past, and effects on residents, including possible
          > Homo spp.
          >
          Yes. Such changes would have significant ecological
          consequences and I think it plausible that similar changes -
          caused by climatic fluctuations on a global scale - were the
          reason why H.erectus left the littoral and went to where
          we find their fossils. Did they go via the highlands of
          Ethiopia? Maybe.
          >
          > Are there any parallels among the salt and brackish
          > lakes of the Ethiopian highlands? If so, it could prove
          > an example of inland high elevation life combined with
          > semi-aquatic diving and cliff climbing. I don't know how
          > high is the elevation of the Rift, but obviously hominids
          > were there.
          >
          I don't know enough about Ethiopia to comment on
          such parallels - I saw a Nat. Geo doco once about a
          large freshwater lake in the Ethiopian highlands which
          had a huge mosquito population - not a welcoming
          situation for a relatively hairless H. without clothes. (I
          read that even the salty Mono Lake is plagued by
          midges.)

          Regards,

          Rob.


          ----- Original Message -----
          From: DDeden
          To: AAT@yahoogroups.com
          Sent: Tuesday, October 02, 2007 4:50 AM
          Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
        • DDeden
          Hi Rob, I do not understand how they could have survived when they arrived at the highlands from seashores. They would have been completely ill-equipped for
          Message 4 of 17 , Oct 2, 2007
          • 0 Attachment
            Hi Rob,

            I do not understand how they could have survived when they arrived at
            the highlands from seashores. They would have been completely
            ill-equipped for that habitat. All the animals there would have been
            superbly adapted to that environment except Homo. How could they have
            survived long enough to develop long-term aerobic capacity? Unlike
            coastal cliffs; few birds lay eggs there, there are no shellfish or
            fish, coconuts, bananas, figs. What would attract them there? Flint?
            Are you suggesting they ran after prey in an oxygen deprived area or
            did they have spears of some sort? How did their babies survive, where
            were they when the mothers gathered food?

            I can imagine that the coastal people might have gone upland during
            the wet season when diving was poor, to collect highland foods of some
            sort and quarry for flint or obsidian, perhaps a few months
            (theoretical). But I cannot see them living there long term, unless as
            I said there was a salt/brackish sea or so.

            I recall that the Ethiopian highlands have uplifted geologically
            recent and are still uplifting, so perhaps they were low 4ma?

            I doubt Homo lived at high altitude until after idaltu, most likely
            the aerobic capacity was developed elsewhere and that allowed sapiens
            to live in the highlands perhaps as early as 75ka but more likely 20ka
            or less. However, I'm not familiar with the highlands, I'm thinking of
            a high plateau which is hot and dry on summer days, quite cold at
            night and winter, and serious flooding seasonally.

            DD



            --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@...> wrote:
            >
            > Hello DD........
            > >
            > > Do you think that long head hair, abundant SC fat,
            > > reduced body hair and infant knee crawling were
            > > naturally selected in Homo on the Ethiopian Highlands?
            > >
            > > If your answer is yes, please explain. If your answer
            > > is no, then why do you think aerobic capacity was
            > > naturally selected in Homo at that location?
            > >
            > To be precise, I quoted a paper by Peter W. Hochachka
            > et al.that used comparative arguments to suggest that the
            > highlands were a good candidate location for this aerobic
            > endurance capacity selection......I happen to find their
            > arguments well-founded and their conclusions plausible,
            > but I don't claim their conclusions to be my opinion or
            > something I need to defend beyond what Hochachka et al.
            > have presented in their paper.
            >
            > Having made that proviso, I'll have a go at your questions....
            >
            > Do I think that long head hair/reduced body hair was an
            > adaptation to a highland environment?
            > No, I think that's very unlikely. If indeed early H. ever
            > lived there, then I think they probably arrived as an ex-
            > littoral H.e with more or less the hair distribution of modern
            > humans. I would've thought that longer and thicker body-
            > hair would be more predictable for highland adaptation.
            >
            > Do I think our characteristic amount and distribution
            > of fat was an adaptation to a highland environment?
            > I think this idea is worth some more thought. While
            > I'm not so sure that this amount and distribution of fat
            > would make a significant difference to heat-loss in
            > water, the rate of heat-loss on land is many times
            > less and above 2000m the fat just might have made
            > adaptational 'sense' for a hair-reduced H. that hadn't
            > yet invented clothing.
            >
            > Do I think that infant knee crawling was an adaptation
            > to a highland environment?
            > No. If an early H.e went to the highlands, then they
            > went with a post-cranial morphology within the range
            > of modern humans and so I'll reasonably assume that
            > their infants behaved in much the same way as our own.
            > As a guess I'd say infant knee-crawling began at mega-
            > Lake Chad between 5 & 8 Mya.
            >
            > And a question that you didn't ask....
            > Why would this early H.erectus have left the highlands
            > and gone down to where their fossils are found?
            > One possibility is that it eventually got too cold up
            > there and by then they had the aerobic endurance
            > capacity to exploit the lowland savanna resources that
            > were not being exploited by other hominids extant at
            > the time. They were then so successful at this that they
            > spread across the world and lasted with only quite
            > minor changes for the next million-plus years...clearly
            > the most successful H. of us all in terms of survival.
            > >
            > > I don't know whether dolphins and sea otters have
            > > high or low aerobic capacity but I'm certain that
            > > their traits were not naturally selected at highlands.
            > >
            > Here we're in full agreement. :-)
            > >
            > > The same goes for Homo, previous to Hs AFAICT.
            > >
            > Hochachka et al. make their comparisons between
            > modern humans living at different altitudes and I find
            > these far more pertinent than comparisons between
            > modern humans and dolphins or sea-otters.
            > >
            > > Here in California, there is Mono Lake, a natural high
            > > elevation salt lake with freshwater tributaries and an
            > > island where gulls reproduce safely from the coyotes
            > > that live in the area. The city of Los Angeles piped most
            > > of the freshwater, but recently reduced consumption,
            > > because the lake level shrank so that the island became
            > > a peninsula, allowing coyotes to invade.
            > >
            > LA residents are to be congratulated on their restraint -
            > it seems to have saved Mono Lake.
            > >
            > > That's an interesting parallel regarding near-shore
            > > islands which were bridged during low sea levels in
            > > the past, and effects on residents, including possible
            > > Homo spp.
            > >
            > Yes. Such changes would have significant ecological
            > consequences and I think it plausible that similar changes -
            > caused by climatic fluctuations on a global scale - were the
            > reason why H.erectus left the littoral and went to where
            > we find their fossils. Did they go via the highlands of
            > Ethiopia? Maybe.
            > >
            > > Are there any parallels among the salt and brackish
            > > lakes of the Ethiopian highlands? If so, it could prove
            > > an example of inland high elevation life combined with
            > > semi-aquatic diving and cliff climbing. I don't know how
            > > high is the elevation of the Rift, but obviously hominids
            > > were there.
            > >
            > I don't know enough about Ethiopia to comment on
            > such parallels - I saw a Nat. Geo doco once about a
            > large freshwater lake in the Ethiopian highlands which
            > had a huge mosquito population - not a welcoming
            > situation for a relatively hairless H. without clothes. (I
            > read that even the salty Mono Lake is plagued by
            > midges.)
            >
            > Regards,
            >
            > Rob.
            >
            >
            > ----- Original Message -----
            > From: DDeden
            > To: AAT@yahoogroups.com
            > Sent: Tuesday, October 02, 2007 4:50 AM
            > Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
            >
          • Rob Dudman
            Hello DD........ ... You ve raised a question that has to be addressed if the highland living explanation for our endurance capacity is to get past the good
            Message 5 of 17 , Oct 4, 2007
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              Hello DD........
              >
              > I do not understand how they could have survived
              > when they arrived at the highlands from seashores.
              > They would have been completely ill-equipped for
              > that habitat. All the animals there would have been
              > superbly adapted to that environment except Homo.
              > How could they have survived long enough to develop
              > long-term aerobic capacity? Unlike coastal cliffs; few
              > birds lay eggs there, there are no shellfish or fish,
              > coconuts, bananas, figs.......
              >
              You've raised a question that has to be addressed
              if the 'highland living' explanation for our endurance
              capacity is to get past the 'good idea' stage. It now
              requires paleo-ecological data on any highland locations
              that could be feasible....the Ethiopian highlands are one
              such location, but there are other possibilities further
              south in East Africa that, presently at least. have very
              different ecologies to Ethiopia.

              Then to the north there's the Caucasus and those
              enigmatic fossils. I'm not suggesting that georgicus
              was the ex-littoral H.e, but they do seem to have
              survived ok at altitude.
              >
              > What would attract them there? Flint?
              >
              Let's assume for the purposes of discussion, that
              prior to ca.2 Mya H.e had been exploiting and
              adapting to the Indian Ocean littoral. Then we see
              a steady deterioration of those littoral conditions
              and eventually a move inland....a move that would
              have been made by many different groups along the
              coast and at different times depending on local
              conditions.

              Only some (a few?) of these groups would have
              followed routes that led them to highlands. Others
              would have tried to exploit the lowlands and in
              order to do this in East Africa (where the earliest
              H.e fossils are found) they would have found
              themselves in competition with the residents (habilis/
              apiths?) who were already there and themselves
              dealing with the inland ecological consequences
              of a fluctuating climate.....their resources were
              diminishing.

              We know that someone was knapping stone tools
              in East Africa ca.2.6 Mya and there's no reason at
              all to think that this was H.erectus.Whether it was
              garhi or habilis is not so much the issue here, but
              rather the implication that when groups of H.e
              arrived after having abandoned the source for their
              shell cutting-tools, they were able to observe the
              locals achieving much the same results knapping
              rocks.

              So with some in the highlands discovering flint
              and some in the lowlands discovering that in terms
              of tool material not all rocks are equal.....get these
              two groups together on a regular basis and there's
              all the conditions for the beginnings of a barter
              system of resource exchange.

              We know that H.e were using highland flint and
              they had to get it somehow....could it be that some
              were specialist flint suppliers and they not only
              periodically brought down this valuable raw
              material (which may well have conferred high
              status and made them attractive in terms of
              reproduction), but also their genes that were by
              then adapting to the thinner oxygen level at the
              flint source? Of course it's only a story....but then,
              aren't they all?
              >
              > Are you suggesting they ran after prey in an
              > oxygen deprived area...........
              >
              No. I think there's a possibility that eventually
              they were able to run prey to exhaustion on the
              savanna and it was this niche, previously unexploited
              by other hominids, that gave them the survival edge
              while the other contemporaneous hominids became
              extinct.
              >
              > ...........or did they have spears of some sort?
              >
              While I know of no evidence whatsoever that
              H.e were using spears with hafted flint points and
              the earliest known javelin-spears don't show up
              until ca.400 Kya, I'd say it's a very good bet that
              H.e did use javelins. These can be easily made
              simply by rubbing one end of a long stick against
              some rock and this would be well within the
              capacities of an H.e who was capable of knapping
              flint. They certainly had the post-cranial morphology
              to accurately throw javelins.
              >
              > How did their babies survive, where were they
              > when the mothers gathered food?
              >
              It rather depends on the climatic conditions and the
              highland ecology that prevailed at the time and at this
              point I don't know enough about either to speculate.
              Some hominids managed at Dmanisi ca.1.8 Mya so
              we know it could be done.
              >
              > I can imagine that the coastal people might have
              > gone upland during the wet season when diving was
              > poor, to collect highland foods of some sort and
              > quarry for flint or obsidian, perhaps a few months
              > (theoretical). But I cannot see them living there
              > long term, unless as I said there was a salt/brackish
              > sea or so.
              >
              You could be right here and we certainly need more
              data on the conditions that prevailed at the time....
              whenever that might have been. All Hochachka et al.
              have shown so far is that highland conditions at present
              are consistent with the adaptations we use for aerobic
              endurance activity.
              >
              > I recall that the Ethiopian highlands have uplifted
              > geologically recent and are still uplifting, so perhaps
              > they were low 4ma?
              >
              I hadn't really considered much before ca.2 Mya
              because H.e turns up just after this time without an
              obvious (or even likely) precursor and by then
              there's reason to think that the Indian Ocean littoral
              had become an uncomfortable and fluctuating
              environment. That our ancestors were absent from
              Africa about 4 Mya has to be the null-hypothesis
              given the RV evidence and I suppose a highland
              location outside Africa is a possibility, but I see no
              reason to think that they were in Ethiopia to avoid
              an Africa-wide RV (possibly two).
              >
              > I doubt Homo lived at high altitude until after
              > idaltu, most likely the aerobic capacity was
              > developed elsewhere and that allowed sapiens
              > to live in the highlands perhaps as early as 75ka
              > but more likely 20ka or less. However, I'm not
              > familiar with the highlands, I'm thinking of a high
              > plateau which is hot and dry on summer days,
              > quite cold at night and winter, and serious flooding
              > seasonally.
              >
              Do you pick this time-span because you think clothing
              was the critical factor?

              Regards,

              Rob.



              ----- Original Message -----
              From: DDeden
              To: AAT@yahoogroups.com
              Sent: Wednesday, October 03, 2007 3:29 PM
              Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
            • DDeden
              Hi Rob, If there was no seawater in the highlands, Homo pre-sapiens didn t stay there AFAIK, though they may have died there. Note the straight hair common to
              Message 6 of 17 , Oct 5, 2007
              • 0 Attachment
                Hi Rob,

                If there was no seawater in the highlands, Homo pre-sapiens didn't
                stay there AFAIK, though they may have died there. Note the straight
                hair common to Hss except inland tropical people, indicating recent
                move inland (20-100ka?).

                I follow the hair evidence. Everything else is less certain.

                Near-shore reefed isles with high dead volcanoes could have produced
                people that were shore living but spent time at high elevation
                collecting obsidian, flint, some foods not at sea level.

                DD


                > --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@> wrote:
                > >
                > > Hello DD........
                > > >
                > > > I do not understand how they could have survived
                > > > when they arrived at the highlands from seashores.
                > > > They would have been completely ill-equipped for
                > > > that habitat. All the animals there would have been
                > > > superbly adapted to that environment except Homo.
                > > > How could they have survived long enough to develop
                > > > long-term aerobic capacity? Unlike coastal cliffs; few
                > > > birds lay eggs there, there are no shellfish or fish,
                > > > coconuts, bananas, figs.......
                > > >
                > > You've raised a question that has to be addressed
                > > if the 'highland living' explanation for our endurance
                > > capacity is to get past the 'good idea' stage. It now
                > > requires paleo-ecological data on any highland locations
                > > that could be feasible....the Ethiopian highlands are one
                > > such location, but there are other possibilities further
                > > south in East Africa that, presently at least. have very
                > > different ecologies to Ethiopia.
                > >
                > > Then to the north there's the Caucasus and those
                > > enigmatic fossils. I'm not suggesting that georgicus
                > > was the ex-littoral H.e, but they do seem to have
                > > survived ok at altitude.
                > > >
                > > > What would attract them there? Flint?
                > > >
                > > Let's assume for the purposes of discussion, that
                > > prior to ca.2 Mya H.e had been exploiting and
                > > adapting to the Indian Ocean littoral. Then we see
                > > a steady deterioration of those littoral conditions
                > > and eventually a move inland....a move that would
                > > have been made by many different groups along the
                > > coast and at different times depending on local
                > > conditions.
                > >
                > > Only some (a few?) of these groups would have
                > > followed routes that led them to highlands. Others
                > > would have tried to exploit the lowlands and in
                > > order to do this in East Africa (where the earliest
                > > H.e fossils are found) they would have found
                > > themselves in competition with the residents (habilis/
                > > apiths?) who were already there and themselves
                > > dealing with the inland ecological consequences
                > > of a fluctuating climate.....their resources were
                > > diminishing.
                > >
                > > We know that someone was knapping stone tools
                > > in East Africa ca.2.6 Mya and there's no reason at
                > > all to think that this was H.erectus.Whether it was
                > > garhi or habilis is not so much the issue here, but
                > > rather the implication that when groups of H.e
                > > arrived after having abandoned the source for their
                > > shell cutting-tools, they were able to observe the
                > > locals achieving much the same results knapping
                > > rocks.
                > >
                > > So with some in the highlands discovering flint
                > > and some in the lowlands discovering that in terms
                > > of tool material not all rocks are equal.....get these
                > > two groups together on a regular basis and there's
                > > all the conditions for the beginnings of a barter
                > > system of resource exchange.
                > >
                > > We know that H.e were using highland flint and
                > > they had to get it somehow....could it be that some
                > > were specialist flint suppliers and they not only
                > > periodically brought down this valuable raw
                > > material (which may well have conferred high
                > > status and made them attractive in terms of
                > > reproduction), but also their genes that were by
                > > then adapting to the thinner oxygen level at the
                > > flint source? Of course it's only a story....but then,
                > > aren't they all?
                > > >
                > > > Are you suggesting they ran after prey in an
                > > > oxygen deprived area...........
                > > >
                > > No. I think there's a possibility that eventually
                > > they were able to run prey to exhaustion on the
                > > savanna and it was this niche, previously unexploited
                > > by other hominids, that gave them the survival edge
                > > while the other contemporaneous hominids became
                > > extinct.
                > > >
                > > > ...........or did they have spears of some sort?
                > > >
                > > While I know of no evidence whatsoever that
                > > H.e were using spears with hafted flint points and
                > > the earliest known javelin-spears don't show up
                > > until ca.400 Kya, I'd say it's a very good bet that
                > > H.e did use javelins. These can be easily made
                > > simply by rubbing one end of a long stick against
                > > some rock and this would be well within the
                > > capacities of an H.e who was capable of knapping
                > > flint. They certainly had the post-cranial morphology
                > > to accurately throw javelins.
                > > >
                > > > How did their babies survive, where were they
                > > > when the mothers gathered food?
                > > >
                > > It rather depends on the climatic conditions and the
                > > highland ecology that prevailed at the time and at this
                > > point I don't know enough about either to speculate.
                > > Some hominids managed at Dmanisi ca.1.8 Mya so
                > > we know it could be done.
                > > >
                > > > I can imagine that the coastal people might have
                > > > gone upland during the wet season when diving was
                > > > poor, to collect highland foods of some sort and
                > > > quarry for flint or obsidian, perhaps a few months
                > > > (theoretical). But I cannot see them living there
                > > > long term, unless as I said there was a salt/brackish
                > > > sea or so.
                > > >
                > > You could be right here and we certainly need more
                > > data on the conditions that prevailed at the time....
                > > whenever that might have been. All Hochachka et al.
                > > have shown so far is that highland conditions at present
                > > are consistent with the adaptations we use for aerobic
                > > endurance activity.
                > > >
                > > > I recall that the Ethiopian highlands have uplifted
                > > > geologically recent and are still uplifting, so perhaps
                > > > they were low 4ma?
                > > >
                > > I hadn't really considered much before ca.2 Mya
                > > because H.e turns up just after this time without an
                > > obvious (or even likely) precursor and by then
                > > there's reason to think that the Indian Ocean littoral
                > > had become an uncomfortable and fluctuating
                > > environment. That our ancestors were absent from
                > > Africa about 4 Mya has to be the null-hypothesis
                > > given the RV evidence and I suppose a highland
                > > location outside Africa is a possibility, but I see no
                > > reason to think that they were in Ethiopia to avoid
                > > an Africa-wide RV (possibly two).
                > > >
                > > > I doubt Homo lived at high altitude until after
                > > > idaltu, most likely the aerobic capacity was
                > > > developed elsewhere and that allowed sapiens
                > > > to live in the highlands perhaps as early as 75ka
                > > > but more likely 20ka or less. However, I'm not
                > > > familiar with the highlands, I'm thinking of a high
                > > > plateau which is hot and dry on summer days,
                > > > quite cold at night and winter, and serious flooding
                > > > seasonally.
                > > >
                > > Do you pick this time-span because you think clothing
                > > was the critical factor?
                > >
                > > Regards,
                > >
                > > Rob.
                > >
                > >
                > >
                > > ----- Original Message -----
                > > From: DDeden
                > > To: AAT@yahoogroups.com
                > > Sent: Wednesday, October 03, 2007 3:29 PM
                > > Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
                > >
                >
              • Rob Dudman
                Hello DD........ ... I ll insert from your more recent post here ..... ... As you previously pointed out, some stories are better than others. ... Ok. Back to
                Message 7 of 17 , Oct 6, 2007
                • 0 Attachment
                  Hello DD........
                  >
                  > > ....the Ethiopian highlands are one such location, but
                  > > but there are other possibilities further south in East
                  > > Africa that, presently at least. have very different
                  > > ecologies to Ethiopia.
                  >
                  > Perhaps, but if they have no seawater?
                  >
                  I'll insert from your more recent post here .....
                  >
                  > If there was no seawater in the highlands, Homo pre-
                  > sapiens didn't stay there AFAIK, though they may have
                  > died there. Note the straight hair common to Hss except
                  > inland tropical people, indicating recent move inland
                  > (20-100ka?).
                  >
                  > I follow the hair evidence. Everything else is less certain.
                  >
                  As you previously pointed out, some stories are better
                  than others.
                  >
                  > Near-shore reefed isles with high dead volcanoes
                  > could have produced people that were shore living
                  > but spent time at high elevation collecting obsidian,
                  > flint, some foods not at sea level.
                  >
                  Ok.

                  Back to the present post.......
                  >
                  > > ...........Then we see a steady deterioration of those
                  > > littoral conditions and eventually a move inland....
                  >
                  > What was this? Temperature change?
                  >
                  Cooler and drier are the two terms I've seen most
                  commonly used to describe the climatic changes at
                  the time (ca. 2Mya). But changes in sea-surface-
                  temperature and sea-level fluctuations would have
                  played a major role in littoral resource depletion as
                  northern hemisphere glaciation progressed. In the
                  southern hemisphere ca.3 Mya there were plants
                  growing in Antarctica and by ca. 2 Mya the ice cover
                  was much as we know it today. The Indian Ocean
                  coastline was constantly shifting over this period due
                  to sea-level changes.
                  >
                  > > Only some (a few?) of these groups would have
                  > > followed routes that led them to highlands.
                  >
                  > No swimming?
                  >
                  No, they undoubtedly walked.
                  >
                  > > ....They certainly had the post-cranial morphology
                  > > to accurately throw javelins.
                  >
                  > Perhaps.
                  >
                  Ok.
                  >
                  > Further distance from seashore = technology (boats,
                  > nets, fiber).......
                  >
                  Well, in the context of H.e, I just settle for 'further
                  distance from the seashore = further to walk'.
                  >
                  > Later, more physiological adaptations (frizzy hair
                  > in Hss), changes in hypertension, salt retention,
                  > malaria/sickle cell anemia, hypothyroidism.
                  >
                  Ok.

                  DD, I think that at this point we'll just have to
                  agree that while we share an interest in human
                  evolution, we approach the topic from very different
                  perspectives - you've been a diver for a long time
                  and I've been an enthusiastic runner for a long time,
                  you see H.ss as been extensively selected by diving
                  and I can't relate to that at all, while I think running
                  may have been the key to survival for H.e and you
                  dismiss the idea as just not feasible. As a result we
                  seem to just talk 'past' each other for much of the
                  time, but we've been able to do it within the frame-
                  work of mutual respect and I thank you for that.

                  Regards,

                  Rob.

                  ----- Original Message -----
                  From: DDeden
                  To: AAT@yahoogroups.com
                  Sent: Saturday, October 06, 2007 1:53 AM
                  Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)


                  --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@...> wrote:
                  >
                  > Hello DD........
                  > >
                  > > I do not understand how they could have survived
                  > > when they arrived at the highlands from seashores.
                  > > They would have been completely ill-equipped for
                  > > that habitat. All the animals there would have been
                  > > superbly adapted to that environment except Homo.
                  > > How could they have survived long enough to develop
                  > > long-term aerobic capacity? Unlike coastal cliffs; few
                  > > birds lay eggs there, there are no shellfish or fish,
                  > > coconuts, bananas, figs.......
                  > >
                  > You've raised a question that has to be addressed
                  > if the 'highland living' explanation for our endurance
                  > capacity is to get past the 'good idea' stage. It now
                  > requires paleo-ecological data on any highland locations
                  > that could be feasible....the Ethiopian highlands are one
                  > such location, but there are other possibilities further
                  > south in East Africa that, presently at least. have very
                  > different ecologies to Ethiopia.

                  Perhaps, but if they have no seawater?

                  >
                  > Then to the north there's the Caucasus and those
                  > enigmatic fossils. I'm not suggesting that georgicus
                  > was the ex-littoral H.e, but they do seem to have
                  > survived ok at altitude.

                  That area has also been uplifted AFAIK.

                  > >
                  > > What would attract them there? Flint?
                  > >
                  > Let's assume for the purposes of discussion, that
                  > prior to ca.2 Mya H.e had been exploiting and
                  > adapting to the Indian Ocean littoral. Then we see
                  > a steady deterioration of those littoral conditions
                  > and eventually a move inland....

                  What was this? Temperature change?

                  a move that would
                  > have been made by many different groups along the
                  > coast and at different times depending on local
                  > conditions.
                  >
                  > Only some (a few?) of these groups would have
                  > followed routes that led them to highlands.

                  No swimming?

                  Others
                  > would have tried to exploit the lowlands and in
                  > order to do this in East Africa (where the earliest
                  > H.e fossils are found) they would have found
                  > themselves in competition with the residents (habilis/
                  > apiths?) who were already there and themselves
                  > dealing with the inland ecological consequences
                  > of a fluctuating climate.....their resources were
                  > diminishing.
                  >
                  > We know that someone was knapping stone tools
                  > in East Africa ca.2.6 Mya and there's no reason at
                  > all to think that this was H.erectus.Whether it was
                  > garhi or habilis is not so much the issue here, but
                  > rather the implication that when groups of H.e
                  > arrived after having abandoned the source for their
                  > shell cutting-tools, they were able to observe the
                  > locals achieving much the same results knapping
                  > rocks.
                  >
                  > So with some in the highlands discovering flint
                  > and some in the lowlands discovering that in terms
                  > of tool material not all rocks are equal.....get these
                  > two groups together on a regular basis and there's
                  > all the conditions for the beginnings of a barter
                  > system of resource exchange.
                  >
                  > We know that H.e were using highland flint and
                  > they had to get it somehow....could it be that some
                  > were specialist flint suppliers and they not only
                  > periodically brought down this valuable raw
                  > material (which may well have conferred high
                  > status and made them attractive in terms of
                  > reproduction), but also their genes that were by
                  > then adapting to the thinner oxygen level at the
                  > flint source? Of course it's only a story....but then,
                  > aren't they all?

                  Some are more likely than others.

                  > >
                  > > Are you suggesting they ran after prey in an
                  > > oxygen deprived area...........
                  > >
                  > No. I think there's a possibility that eventually
                  > they were able to run prey to exhaustion on the
                  > savanna and it was this niche, previously unexploited
                  > by other hominids, that gave them the survival edge
                  > while the other contemporaneous hominids became
                  > extinct.
                  > >
                  > > ...........or did they have spears of some sort?
                  > >
                  > While I know of no evidence whatsoever that
                  > H.e were using spears with hafted flint points and
                  > the earliest known javelin-spears don't show up
                  > until ca.400 Kya, I'd say it's a very good bet that
                  > H.e did use javelins. These can be easily made
                  > simply by rubbing one end of a long stick against
                  > some rock and this would be well within the
                  > capacities of an H.e who was capable of knapping
                  > flint. They certainly had the post-cranial morphology
                  > to accurately throw javelins.

                  Perhaps.

                  > >
                  > > How did their babies survive, where were they
                  > > when the mothers gathered food?
                  > >
                  > It rather depends on the climatic conditions and the
                  > highland ecology that prevailed at the time and at this
                  > point I don't know enough about either to speculate.
                  > Some hominids managed at Dmanisi ca.1.8 Mya so
                  > we know it could be done.

                  > > I can imagine that the coastal people might have
                  > > gone upland during the wet season when diving was
                  > > poor, to collect highland foods of some sort and
                  > > quarry for flint or obsidian, perhaps a few months
                  > > (theoretical). But I cannot see them living there
                  > > long term, unless as I said there was a salt/brackish
                  > > sea or so.
                  > >
                  > You could be right here and we certainly need more
                  > data on the conditions that prevailed at the time....
                  > whenever that might have been. All Hochachka et al.
                  > have shown so far is that highland conditions at present
                  > are consistent with the adaptations we use for aerobic
                  > endurance activity.
                  > >
                  > > I recall that the Ethiopian highlands have uplifted
                  > > geologically recent and are still uplifting, so perhaps
                  > > they were low 4ma?
                  > >
                  > I hadn't really considered much before ca.2 Mya
                  > because H.e turns up just after this time without an
                  > obvious (or even likely) precursor and by then
                  > there's reason to think that the Indian Ocean littoral
                  > had become an uncomfortable and fluctuating
                  > environment.

                  Fluctuating? The seashores are normally the most stable.

                  That our ancestors were absent from
                  > Africa about 4 Mya has to be the null-hypothesis
                  > given the RV evidence and I suppose a highland
                  > location outside Africa is a possibility, but I see no
                  > reason to think that they were in Ethiopia to avoid
                  > an Africa-wide RV (possibly two).
                  > >
                  > > I doubt Homo lived at high altitude until after
                  > > idaltu, most likely the aerobic capacity was
                  > > developed elsewhere and that allowed sapiens
                  > > to live in the highlands perhaps as early as 75ka
                  > > but more likely 20ka or less. However, I'm not
                  > > familiar with the highlands, I'm thinking of a high
                  > > plateau which is hot and dry on summer days,
                  > > quite cold at night and winter, and serious flooding
                  > > seasonally.
                  > >
                  > Do you pick this time-span because you think clothing
                  > was the critical factor?

                  Further distance from seashore = technology (boats, nets, fiber)
                  Later, more physiological adaptations (frizzy hair in Hss), changes in
                  hypertension, salt retention, malaria/sickle cell anemia, hypothyroidism.
                  DD
                • DDeden
                  Hi Rob, ... I was actually thinking of the Afar triangle, per Elaine s books, with high dry plateaus surrounded by coral reefs and seashores, if the climate
                  Message 8 of 17 , Oct 6, 2007
                  • 0 Attachment
                    Hi Rob,



                    --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@...> wrote:
                    >
                    > Hello DD........
                    > >
                    > > > ....the Ethiopian highlands are one such location, but
                    > > > but there are other possibilities further south in East
                    > > > Africa that, presently at least. have very different
                    > > > ecologies to Ethiopia.
                    > >
                    > > Perhaps, but if they have no seawater?
                    > >
                    > I'll insert from your more recent post here .....
                    > >
                    > > If there was no seawater in the highlands, Homo pre-
                    > > sapiens didn't stay there AFAIK, though they may have
                    > > died there. Note the straight hair common to Hss except
                    > > inland tropical people, indicating recent move inland
                    > > (20-100ka?).
                    > >
                    > > I follow the hair evidence. Everything else is less certain.
                    > >
                    > As you previously pointed out, some stories are better
                    > than others.
                    > >
                    > > Near-shore reefed isles with high dead volcanoes
                    > > could have produced people that were shore living
                    > > but spent time at high elevation collecting obsidian,
                    > > flint, some foods not at sea level.
                    > >
                    > Ok.

                    I was actually thinking of the Afar triangle, per Elaine's books, with
                    high dry plateaus surrounded by coral reefs and seashores, if the
                    climate had been less scorching and more monsoonal. I assume the area
                    was tectonically/volcanically active at times. With it's geologic
                    connection to the north rift (Israel, Turkey) and south rift
                    (Ethiopia..), at various times it would have been either a land bridge
                    or isolated island for multi-directional migrations. The fact that
                    Khoisan people had lived near there much earlier, and that some people
                    there have caucasoid facial features (watusi), mongoloid facial
                    features (dinka), and negroid facial features (bantu), plus the
                    various fossils found there including Hs idaltu, one with Asian
                    erectus facial features, and relative nearness to Neandertals, Flores,
                    Java, Dmanisi, Peking all point to that general area, and the eritrean
                    reef tools as well.

                    I think long distance running aerobic capacity evolved in ancient Homo
                    along shorelines where water was always available nearby. Further from
                    water = walking, except in special cases where water holes were well
                    known.

                    Yes, different interpretations, not unexpected with so little relevant
                    data, hopefully that will improve with net access and more
                    archaeological investigative diving research along coasts. Thanks Rob.

                    DD




                    >
                    > Back to the present post.......
                    > >
                    > > > ...........Then we see a steady deterioration of those
                    > > > littoral conditions and eventually a move inland....
                    > >
                    > > What was this? Temperature change?
                    > >
                    > Cooler and drier are the two terms I've seen most
                    > commonly used to describe the climatic changes at
                    > the time (ca. 2Mya). But changes in sea-surface-
                    > temperature and sea-level fluctuations would have
                    > played a major role in littoral resource depletion as
                    > northern hemisphere glaciation progressed. In the
                    > southern hemisphere ca.3 Mya there were plants
                    > growing in Antarctica and by ca. 2 Mya the ice cover
                    > was much as we know it today. The Indian Ocean
                    > coastline was constantly shifting over this period due
                    > to sea-level changes.
                    > >
                    > > > Only some (a few?) of these groups would have
                    > > > followed routes that led them to highlands.
                    > >
                    > > No swimming?
                    > >
                    > No, they undoubtedly walked.
                    > >
                    > > > ....They certainly had the post-cranial morphology
                    > > > to accurately throw javelins.
                    > >
                    > > Perhaps.
                    > >
                    > Ok.
                    > >
                    > > Further distance from seashore = technology (boats,
                    > > nets, fiber).......
                    > >
                    > Well, in the context of H.e, I just settle for 'further
                    > distance from the seashore = further to walk'.
                    > >
                    > > Later, more physiological adaptations (frizzy hair
                    > > in Hss), changes in hypertension, salt retention,
                    > > malaria/sickle cell anemia, hypothyroidism.
                    > >
                    > Ok.
                    >
                    > DD, I think that at this point we'll just have to
                    > agree that while we share an interest in human
                    > evolution, we approach the topic from very different
                    > perspectives - you've been a diver for a long time
                    > and I've been an enthusiastic runner for a long time,
                    > you see H.ss as been extensively selected by diving
                    > and I can't relate to that at all, while I think running
                    > may have been the key to survival for H.e and you
                    > dismiss the idea as just not feasible. As a result we
                    > seem to just talk 'past' each other for much of the
                    > time, but we've been able to do it within the frame-
                    > work of mutual respect and I thank you for that.
                    >
                    > Regards,
                    >
                    > Rob.
                    >
                    > ----- Original Message -----
                    > From: DDeden
                    > To: AAT@yahoogroups.com
                    > Sent: Saturday, October 06, 2007 1:53 AM
                    > Subject: [AAT] Re: aerobic capacity (Was: Breast stroke technique)
                    >
                    >
                    > --- In AAT@yahoogroups.com, "Rob Dudman" <ansell@> wrote:
                    > >
                    > > Hello DD........
                    > > >
                    > > > I do not understand how they could have survived
                    > > > when they arrived at the highlands from seashores.
                    > > > They would have been completely ill-equipped for
                    > > > that habitat. All the animals there would have been
                    > > > superbly adapted to that environment except Homo.
                    > > > How could they have survived long enough to develop
                    > > > long-term aerobic capacity? Unlike coastal cliffs; few
                    > > > birds lay eggs there, there are no shellfish or fish,
                    > > > coconuts, bananas, figs.......
                    > > >
                    > > You've raised a question that has to be addressed
                    > > if the 'highland living' explanation for our endurance
                    > > capacity is to get past the 'good idea' stage. It now
                    > > requires paleo-ecological data on any highland locations
                    > > that could be feasible....the Ethiopian highlands are one
                    > > such location, but there are other possibilities further
                    > > south in East Africa that, presently at least. have very
                    > > different ecologies to Ethiopia.
                    >
                    > Perhaps, but if they have no seawater?
                    >
                    > >
                    > > Then to the north there's the Caucasus and those
                    > > enigmatic fossils. I'm not suggesting that georgicus
                    > > was the ex-littoral H.e, but they do seem to have
                    > > survived ok at altitude.
                    >
                    > That area has also been uplifted AFAIK.
                    >
                    > > >
                    > > > What would attract them there? Flint?
                    > > >
                    > > Let's assume for the purposes of discussion, that
                    > > prior to ca.2 Mya H.e had been exploiting and
                    > > adapting to the Indian Ocean littoral. Then we see
                    > > a steady deterioration of those littoral conditions
                    > > and eventually a move inland....
                    >
                    > What was this? Temperature change?
                    >
                    > a move that would
                    > > have been made by many different groups along the
                    > > coast and at different times depending on local
                    > > conditions.
                    > >
                    > > Only some (a few?) of these groups would have
                    > > followed routes that led them to highlands.
                    >
                    > No swimming?
                    >
                    > Others
                    > > would have tried to exploit the lowlands and in
                    > > order to do this in East Africa (where the earliest
                    > > H.e fossils are found) they would have found
                    > > themselves in competition with the residents (habilis/
                    > > apiths?) who were already there and themselves
                    > > dealing with the inland ecological consequences
                    > > of a fluctuating climate.....their resources were
                    > > diminishing.
                    > >
                    > > We know that someone was knapping stone tools
                    > > in East Africa ca.2.6 Mya and there's no reason at
                    > > all to think that this was H.erectus.Whether it was
                    > > garhi or habilis is not so much the issue here, but
                    > > rather the implication that when groups of H.e
                    > > arrived after having abandoned the source for their
                    > > shell cutting-tools, they were able to observe the
                    > > locals achieving much the same results knapping
                    > > rocks.
                    > >
                    > > So with some in the highlands discovering flint
                    > > and some in the lowlands discovering that in terms
                    > > of tool material not all rocks are equal.....get these
                    > > two groups together on a regular basis and there's
                    > > all the conditions for the beginnings of a barter
                    > > system of resource exchange.
                    > >
                    > > We know that H.e were using highland flint and
                    > > they had to get it somehow....could it be that some
                    > > were specialist flint suppliers and they not only
                    > > periodically brought down this valuable raw
                    > > material (which may well have conferred high
                    > > status and made them attractive in terms of
                    > > reproduction), but also their genes that were by
                    > > then adapting to the thinner oxygen level at the
                    > > flint source? Of course it's only a story....but then,
                    > > aren't they all?
                    >
                    > Some are more likely than others.
                    >
                    > > >
                    > > > Are you suggesting they ran after prey in an
                    > > > oxygen deprived area...........
                    > > >
                    > > No. I think there's a possibility that eventually
                    > > they were able to run prey to exhaustion on the
                    > > savanna and it was this niche, previously unexploited
                    > > by other hominids, that gave them the survival edge
                    > > while the other contemporaneous hominids became
                    > > extinct.
                    > > >
                    > > > ...........or did they have spears of some sort?
                    > > >
                    > > While I know of no evidence whatsoever that
                    > > H.e were using spears with hafted flint points and
                    > > the earliest known javelin-spears don't show up
                    > > until ca.400 Kya, I'd say it's a very good bet that
                    > > H.e did use javelins. These can be easily made
                    > > simply by rubbing one end of a long stick against
                    > > some rock and this would be well within the
                    > > capacities of an H.e who was capable of knapping
                    > > flint. They certainly had the post-cranial morphology
                    > > to accurately throw javelins.
                    >
                    > Perhaps.
                    >
                    > > >
                    > > > How did their babies survive, where were they
                    > > > when the mothers gathered food?
                    > > >
                    > > It rather depends on the climatic conditions and the
                    > > highland ecology that prevailed at the time and at this
                    > > point I don't know enough about either to speculate.
                    > > Some hominids managed at Dmanisi ca.1.8 Mya so
                    > > we know it could be done.
                    >
                    > > > I can imagine that the coastal people might have
                    > > > gone upland during the wet season when diving was
                    > > > poor, to collect highland foods of some sort and
                    > > > quarry for flint or obsidian, perhaps a few months
                    > > > (theoretical). But I cannot see them living there
                    > > > long term, unless as I said there was a salt/brackish
                    > > > sea or so.
                    > > >
                    > > You could be right here and we certainly need more
                    > > data on the conditions that prevailed at the time....
                    > > whenever that might have been. All Hochachka et al.
                    > > have shown so far is that highland conditions at present
                    > > are consistent with the adaptations we use for aerobic
                    > > endurance activity.
                    > > >
                    > > > I recall that the Ethiopian highlands have uplifted
                    > > > geologically recent and are still uplifting, so perhaps
                    > > > they were low 4ma?
                    > > >
                    > > I hadn't really considered much before ca.2 Mya
                    > > because H.e turns up just after this time without an
                    > > obvious (or even likely) precursor and by then
                    > > there's reason to think that the Indian Ocean littoral
                    > > had become an uncomfortable and fluctuating
                    > > environment.
                    >
                    > Fluctuating? The seashores are normally the most stable.
                    >
                    > That our ancestors were absent from
                    > > Africa about 4 Mya has to be the null-hypothesis
                    > > given the RV evidence and I suppose a highland
                    > > location outside Africa is a possibility, but I see no
                    > > reason to think that they were in Ethiopia to avoid
                    > > an Africa-wide RV (possibly two).
                    > > >
                    > > > I doubt Homo lived at high altitude until after
                    > > > idaltu, most likely the aerobic capacity was
                    > > > developed elsewhere and that allowed sapiens
                    > > > to live in the highlands perhaps as early as 75ka
                    > > > but more likely 20ka or less. However, I'm not
                    > > > familiar with the highlands, I'm thinking of a high
                    > > > plateau which is hot and dry on summer days,
                    > > > quite cold at night and winter, and serious flooding
                    > > > seasonally.
                    > > >
                    > > Do you pick this time-span because you think clothing
                    > > was the critical factor?
                    >
                    > Further distance from seashore = technology (boats, nets, fiber)
                    > Later, more physiological adaptations (frizzy hair in Hss), changes in
                    > hypertension, salt retention, malaria/sickle cell anemia,
                    hypothyroidism.
                    > DD
                    >
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