Descent of testicles.

Introduction:Evolution is a directed process in which the neodarwinian forces of random mutation and natural selection play no role. Evolution is a predetermined process established by spirit and directed by internal forces of unknown characters.Materialistic biology has only a restricted capacity to solve the great mystery of evolution. Great scientists of the past coined the term "orthogenesis". The only scientists nowadays who continues in their work is professor John Davison with his "Evolutionary Manifesto". I would like to extend and support his ideas of "evolution governed by law" by some interesting thoughts about evolution of descent of testicles. This is the partial problem of evolution where on my opinion neodarwinism hasn't offered a coherent and plausible explanation. Obviously behind the descent of testicles are evolutionary forces that govern beyond "natural selection", and we are facing some evolutionary forces with their own rules.Mammalian species are often characterised by having testicles outside their bodies. Evolution of descent of testicles outside body has been a puzzle for evolutionary biology for a long time and the most common and accepted explanation for many years has been it was due to "cooling sperma". The history and enumeration of concepts explaining descent of testicles are to be found in the article by doctor Myers at Pharyngula: What I want to stress is that the most common explanation is probably only a hypothesis with no scientific backing, because it is untestable: I think it is not only untestable, but utterly dubious neodarwinian explanation.The problem cannot be solved by "cooling sperma" explanation, because:

1. Some mammalian species have testicles inside their bodies and obviously haven't "cooling spermatozoa" problems.
   ​
2. Birds often have temperatures of 42^o Celsius and do not have "cooling spermatozoa" problems either:
   ​
   dormancy | Definition, Examples, & Facts | Britannica

We should take into the consideration that having testicles outside the body is a very dangerous place.The whole phenomenon can be observed in females too - descent of ovaries during evolution. But of course it is not as aparent and manifest as in males.What we observe is increasing structuring of mammalian bodies and their functions in the two poles. The head pole - responsible for individual orientation towards the world (here are almost all senses: vision, taste, hearing, smell) and the opposite pole responsible for reproduction.So the evolution of the descent of testicles into dangerous places outside of the body is directed by evolutionary forces that stand above random mutation and natural selection and cannot be reduced to them. It cannot be explained by neodarwinian formula "form follows fuction" either.

I have two points.I. If such changes were possible in reproductive system of birds I see no reason why such changes in reproductive system would not have been possible in mammalian lineages too. It is only speculation that it was somehow impossible.II. I think that the concept of sperms withstanding this or that temperature has two explanation. Either yours or the opposite one - sperms adapted to lower temperature in external scrotum. Now you consider sperms seeking lower temperature to be the source of their descent. The opposite view - their lower temperature as adatation on environment is also possible. I would say the second explanation is more in accord with the spirit of neodarwinism than the first one, but it is only my personal opinion. Not at all. We have two poles. The evolutionary "polarization force" do not care for survival advantage of species or for selfish gene's opinion. It do it job regardless of natural selection and do not care if it's outcomes are fittest or not. Maybe in some periods fittest were reptilians, dinos etc, but mammalians went their way. I do not deny "natural selection" but is only force removing extremities.

Granny Magda I don't see your point. The process of polarization involved both sexes.

I consider all these "if" unreal examples as dialectical and off-topic. I cannot find there your deduction about golden moles and elephant shrews. Could you please quote it? How are you so sure? Authors are more carefull- they call their hypothesis "untestable". What I proposed is that neodarwinian explanation is wrong. If you insist that you posses valid explanation of bad solution so I respect it. I've never heard about neodarwinian explanation of polarization head vs reproductive part of body. That is what I can really see. Of course I do not insist that everyone can see it same way. Maybe you do not see it and consider it as pure speculation.

It's your neodarwinian view and I have nothing to add. No it is not as silly as it sounds. Do you consider sperms to be dead matter or what? I suppose it not as impossible idea that they can differentiate between different temperature. But it is only thought.Silly is darwinian explanation of it. I don't know where originally testicles should have been placed in "common ancestor". Now moving by random mutation througout the body survived only those individuals whose testicles moved along some non-speciefied temperature gradient inside body or what? That's fine. I didn't expect such answer here. Head - centre of individuality. The opposite pole - centre of reproduction of species. Clearly visible in higher mammals.

Look. We should be first clear what the cladogram or what it is means. I have before me Evolutionary chart of mammalia, the old morphological as well as the new molecular. In boths charts I see Lagomorpha and Rodentia having common ancestor and only their common ancestor having common ancestor with primates. The same here:http://whozoo.org/mammals/mammalianphylo.htmIn the chart in Myers article primates and lagomorpha has the common point sooner than with rodentia. What this chart should represent? Is it evolution of mammals or what?

That chart do not agree with my charts not only in this point, but let it be preliminary.

That discussed scrotal testicles has nothing to do with any kind of neodarwinian best or worst solution has been demonstrated by elephants. They testicles are inside their bodies near the kidneys. Having their penis 1 meter long evolution has somehow found the best solution and behold - cooling spermatozoa or testicles is no problem anymore. One should wonder what kind of force it is that has prevented other species like horses, deers, lions or apes and their ancestors to find the same solution for more than 50 million years.

Dialectical approach. Let us consider or reconsider the evolution of descent of testicles from as many points that no one knows anymore what we are discussing. The problem of descent of testicles is unresolved - on my opinion at least - but authors would like to solve ther ascent first.The same authors claim:

quote:

---

...because descensus in many respects is a costly process that will be lost in mammal lineages as soon as an alternative solution to the problem of the temperature sensitivity of spermatogenesis is available.

---

The problem has been solved by elephants. The alternative solution to costly process in mammals exist. What's the problem?

This is only hypothesis. It is not eternal truth which have been discovered by two scientists in 1999. Their phylogeny tree do not conform others phylogeny trees of mammalian evolution. We don't have information about position of testicles of extinct mammalian orders and families. Authors themselves admit it, if you have read it more carefully:

quote:

---

We suggest that the scrotum may have evolved before the origin of mammals, in concert with the evolution of endothermy in the mammalian...

---

So they just suggest. They do not reveals any evidence it really happened. It is still open to discussion. It wouldn't be quite correct if we took it for granted at this time.

quote:

---

There isn't a problem. The paper states that the scrota solution would be 'lost in mammal lineages as soon as an alternative solution' is found. The phylogeny shows that the lineage which includes elephants has indeed lost it. Why do you think there is a problem?

---

The problem is also with the mentioned research. Scientists proposed three division of testicles. I would started with two - testicles inside body or testicles outside body. We can see that seals (Carnivora) or tapirs have testicles inside their bodies too. I cannot accept explanation that scrota solution would be "lost in mammal lineages as soon as an alternative solution". It has been solve so many times in different mammalian families - if they are correct - that one should really wonder why this didn't happened in all mammalian families.

Paul, I am afraid your latest post hasn't bring nothing new for ongoing discussion. As you know I am opponent of neoadarwinism and so your enumeration of neodarwinian approaches has left me unimpressed - it has no explanatory value for me as far as I can see that elephants, seals, bats, tapir etc... have testicles inside their bodies but other species and families don't.For me it means that all "cooling spermatozoa" explanation is ad hoc neodarwinian explanation with no scientific value. I admit that spermatozoa are sensible for higher temperature, but it can be acquired adaptation to "outdoor" condition and not the reason of descent of testicles. And obviously no such sensitivity exist amongst elephants anymore.

I am afraid it refutes anything. Maybe for you claims like "having scrotum outside their bodies gives horses survival advantage" and "on the contrary having scrotum inside bodies gives elephants survival advantage" that this use of non-specified "survival advantage" explain something is only illusory for me. What sufficient evidence do you have on your mind?
Authors described their explanation as "untestable". Or using other words there is no evidence supporting it. Repeating doesn't made it more plausible. My argument is this - spermatozoa adapted to lower temperature outside body during descent of testicles. What evidence do you have that you dismiss my logic but you consider yours for the right one? I don't see also difficulty to see the same condition in early birds. Yet there were no descent of testicles. This argument seems to me to support my view.

I am not catching up. Maybe someone who is following our discussions would make wrong conclusions that problem has been solved by reading your post. I don't see there also any "evidence". The varycolored chart is not evidence it only presents observed facts. And this is really the point. The chart is misleading for our discussion. I claimed that "cooling spermatozoa" is no valid explanation for descent of testicles. You focused your attention to red linneages which represent only testicond organisation. But the problem are also grey ones. Obviously they are inside bodies so they are not cooled anymore and I suppose they have body temperature. Now imagine also those grey lineages as red and tell me if you see there any parsimonious explanation.

quote:

---

You are being now-centric. The phylogeny seems to show an increase in the frequency of ascrotism over time. Whose to say that this pattern won't continue until all mammalian families are ascrotal?

---

Ascrotal are also grey. I don't see there any increase or decrease of ascrotism over time. Random distribution I would say.

You have written probably finally. I don't know in which points that chart represents other evolutionary charts of mammalian phylogeny. I haven't enough time for redrawing several charts and comparing them. Certainly I will do it if I am convince that the problem is worth of it. For me it is preliminary only a possible chart for phylogeny which is marked with families or orders with or without descent testicles.The possibility that testiles descended several times independently is not overruled by the chart. They ascended also several times independently according the chart. Yes it looks like that. But what you are doing is that you drives the discussion off topic. I didn't addressed the problem if descended testicles arose once or several times during evolution. I addressed the neodarwinian explanation of it and it is that descend testicles are device for cooling spermatozoa. The chart shows us that in cca 1/2 of cases testicles are in mammalian bodies. So obviously "cooling spermatozoa" is not such a difficult problem that shouldn't be overcome.We should take into consideration that adaptive radiation of mammalian orders was relatively fast process. Lineages must have been splitting from each other very fast. No mammalian orders arose last 40 million years, so every outlined orders has had enough time to get rid of scrotal testicles (if neodarwinian explanation is right). The evolutionary chart looks more like this:Page Not Found | We cannot find your page (404 Error) | Memorial University of Newfoundlandand there is no reason to look at distorted chart because the time scale is also important value at y-axis.
Edited by MartinV, : No reason given.

[Apologies for accidental edit (hitting "edit isntead of reply and not noticing) I have attempted to restore the original text so far as is possible. I invite Martin V to further correct these changes]There is an interesting post following doctor Myers article author of which claims that Werdelin and Nilsonne are wrong (see the post from Conrad Knauer) using outdated phylogeny tree. It means the authors are wrong with their supposisition of descended testicles of ancestral mammals. It would also means that descended testicles evolved exclusively in Boreoeutheria.comment 3726 by Conrad Knauer
Pharyngula - Hotell anbefalinger BarcelonaTHe authors of the original study used the wrong phyologenyThe author writes with capital letters this:EVERY SINGLE PLACENTAL MAMMAL WITH TESTICONDY IS IN AFROTHERIA.I have checked it and it seems to be true. And according the link he has given:They (afrotheria) appear to be the most primitive of the placental mammals.there was a split between Afrotheria and Boreoeutheria with the former mostly maintaining testicondy, while Boreoeutheria evolved exclusively descended testicles.see http://users.rcn.com/...yPages/V/Vertebrates.html#PlacentalsThis shows that elephants did not have ancestors with descended testicles and disproves the "cooling" hypothesisEdited by AdminPaul, : No reason given.Edited by AdminPaul, : [Correcting accidental edit so far as possible. Again, apologies]Edited by AdminPaul, : No reason given.