🚀 go-pugleaf

In article <1598@rayssd.RAY.COM> m1b@rayssd.RAY.COM (M. Joseph Barone) writes:
>Now, to refute the premise that the average lifespan
>during the Middle Ages was 30, people are exempting just about every
>condition that brought that average down!  So I suppose that if you
>discount infant mortality, wars, pestilence, famine, and plagues, then
>the average lifespan is indeed much higher!  Somehow, though, I don't
>think this is sound statistical analysis.

We're getting into a matter of definitions here - what is "life span" vs.
"life expectancy"? Let's put it this way - if half the people die by age 5
(which they did, and still do in much of the world), but the "average life
span" is 30-35, most of the rest must last a while. My own understanding of
the meaning of "life span" is something like the biblical three score and ten-
how long can a person with the luck to survive these scourges expect to live.

In article <1057@mipos3.intel.com> ekwok@cadev4.UUCP (Edward C. Kwok) writes:
>Does anyone know of any theory being proposed that blamed a virus for
>[the dinosaurs'] extinction?

The difficulty with the Cretaceous extinctions has always been explaining
the demise of half the species on the Earth at the time, including plants,
phytoplankton, fishes, etc. etc.  Getting rid of just the dinosaurs is
(relatively) easy.  The impact theory has the merit of explaining all
of these extinctions with a single event we know for a fact can happen.
   I think we know for a fact it did happen;  Luis Alvarez has an article
on the current status of the impact theory in the July _Physics Today_.
Must reading, and accessible to lay persons.
				Steve Walton, Cal State Northridge

In article <1057@mipos3.intel.com>, ekwok@cadev4.intel.com (Edward C. Kwok) writes:
> Does anyone
> know of any theory being proposed that blamed a virus for their extinction?
> I can imagine a virus attacking a particular nucleic acid sequence found 
> only in dinosaurs, leading to inability to produce, say dinosaur growth
> hormone or any other essential protein. Or plainly causing dinosaur 
> acquired immune deficiency syndrome. I am afraid the human species may
> be facing the same problem.

It may be possible for new viruses to wipe out species, and it is
certainly the case that HIV is a major health problem reaching
epidemic proportions. But if you are seriously concerned about
the potential extinction of the human race, HIV is not a likely
cause. 

For several centuries Europe lived with an epidemic disease that
was incurable, had a high mortality rate, and was transmitted
through bodily fluids by sex and birth. This disease was
syphilis. While it killed many, it did not cause severe
population decrease, in sharp contrast to the plague. Why? Two
reaons. (1) Its mode of transmission is very restrictive. Like
HIV, syphillis is hard to get. You have to have sexual
intercourse with someone who has it, be born of an infected
woman, or (in this age) share needles. (2) You can live a long
time with it. Syphillis (and HIV) can take years to kill. If you
get it when you are twenty by the most likely means, you will
likely live to see twenty-five or thirty, maybe not even showing
symptoms then. While this seems short today, in times past this
was almost a normal life span. 

AIDS is a terrible disease that is taking many victims, and I
hope that a cure or effective vaccine is developed soon. If it
was more contagious, like the flu, concern about human extinction
would be warranted. Fortunately, it isn't. 

Russell

In article <9114@ut-sally.UUCP> turpin@ut-sally.UUCP (Russell Turpin) writes:
>. . . (2) You can live a long
>time with it. Syphillis (and HIV) can take years to kill. If you
>get it when you are twenty by the most likely means, you will
>likely live to see twenty-five or thirty, maybe not even showing
>symptoms then. While this seems short today, in times past this
>was almost a normal life span. 

In the midst of an otherwise excellent posting, Russell repeats a common
misconception: that in years gone by, 30 was a "normal" life span.  The
confusion arises because in years past the life expectancy at birth was
about 30 to 35.  This was NOT because people tended to live to be that
age, however, but because infant mortality was so high, pulling the mean
down.  Anyone who survived childhood had an excellent chance of reaching
70 or more.  A glance at the life spans of historical personages shows
the "normal" life span of an adult to have been very little different
from what we see today, at least among the upper classes able to live in
decent dwellings and eat adequate food.
-- 
D Gary Grady
(919) 286-4296
USENET:  {seismo,decvax,ihnp4,akgua,etc.}!mcnc!ecsvax!dgary
BITNET:  dgary@ecsvax.bitnet

In article <1057@mipos3.intel.com> ekwok@cadev4.UUCP (Edward C. Kwok) writes:
>
>I am told that dinosaurs became extinct within a very short period of 
>time, leading scientists to believe that some catastrophic event caused
>the extinction (e.g. large meteorite struck the earth etc.) Does anyone
>know of any theory being proposed that blamed a virus for their extinction?
>I can imagine a virus attacking a particular nucleic acid sequence found 
>only in dinosaurs, leading to inability to produce, say dinosaur growth
>hormone or any other essential protein. Or plainly causing dinosaur 
>acquired immune deficiency syndrome. I am afraid the human species may
>be facing the same problem.

The idea of an epidemic being the cause of the extinction of
the dinosaurs seems a bit suspect, since ALL of the very
diverse species of dinosaurs, but not the smaller reptiles, 
were wiped out at approximately the same time.  

It's very easy to think of "the dinosaurs" as one big
homogenous species of critter, but of course they were
undoubtedly as genetically assorted as the mammals are
today (with, I assume, interesting variations according
to climate, vegetation, etc.)  

-- 
   Mike Urban
	...!trwrb!trwspp!spp2!urban 

"You're in a maze of twisty UUCP connections, all alike"

> > ... While [25-30] seems short today, in times past this
> > was almost a normal life span. 

> In the midst of an otherwise excellent posting, Russell repeats a common
> misconception: that in years gone by, 30 was a "normal" life span. ...
> ... A glance at the life spans of historical personages shows
> the "normal" life span of an adult to have been very little different
> from what we see today, at least among the upper classes able to live in
> decent dwellings and eat adequate food.

But it isn't the upper classes who are under discussion, it's the "normal"
people.  Gary, do you have information on the lifespans of those you *haven't*
heard of?  I don't, but I think that age 70 was pretty rare.

Mark Brader

In article <1987Sep27.223915.8232@sq.uucp> msb@sq.UUCP (Mark Brader) writes:
>
>But it isn't the upper classes who are under discussion, it's the "normal"
>people.  Gary, do you have information on the lifespans of those you *haven't*
>heard of?  I don't, but I think that age 70 was pretty rare.

It isn't just the upper classes on whom there exists data. Parish priests kept
detailed records of births and deaths throughout Europe. In fact, if a person
survived childhood, wars, and the grimly regular famines, he stood an excellent
chance of reaching, if not 70, at least 60. The masculine pronoun is
intentional - childbirth was a major killer also. Of all these, the rich were
exempt only from famine.
  People today don't know what a real epidemic is. As recently as 1918-19, a
flu epidemic killed an estimated 20 million worldwide. It did so by weakening
its victims so that they were susceptible to massive bacterial infection. Sound
familiar?

	The first divergence from the original discussion concerned
syphilis being a wimpy epidemic during the Middle Ages because it took
so long to kill its victims.  The article stated that since the average
lifespan during the Middle Ages was around 30, people normally died from
something else.  Now, to refute the premise that the average lifespan
during the Middle Ages was 30, people are exempting just about every
condition that brought that average down!  So I suppose that if you
discount infant mortality, wars, pestilence, famine, and plagues, then
the average lifespan is indeed much higher!  Somehow, though, I don't
think this is sound statistical analysis.

Joe Barone ---------------------------> m1b@rayssd.RAY.COM
{cbosgd, gatech, ihnp4, linus, mirror, uiucdcs}!rayssd!m1b
Heroes have an infinite capacity for stupidity.  Thus are legends born!

(M. Joseph Barone) writes:
> .......
> Now, to refute the premise that the average lifespan
> during the Middle Ages was 30, people are exempting just about every
> condition that brought that average down!  
> .......
> Somehow, though, I don't think this is sound statistical analysis.

Right Joe.  In fact it isn't even good english.  There is a difference
between the average lifeSPAN and life expectancy.  The fact is that the
lifespan of humans hasn't really changed all that much over many hundreds,
maybe even thousands, of years.  What HAS changed dramatically is the life
expectancy (number of years you can expect to live).  This has gone up,
fairly continuously, for the same hundreds/thousands of years. (I think that
there have been some very small, local, dips within my lifetime - but the
trend is overwhelmingly upward).

The point is that although people have always been ABLE to live to 80 they
haven't done so, very often, until relatively recent times. 

Read some on the Middle Ages - it was a brutal, disease ridden time.  The
chances were overwhelmingly good that you would only live to see your
thirties.
-- 
These opinions are solely mine and in no way reflect those of my employer.  
John M. Pantone @ GE/Calma R&D, Data Management Group, San Diego
...{ucbvax|decvax}!sdcsvax!calmasd!jnp          jnp@calmasd.GE.COM