Earth's Carrying Capacity

In article
4.229, Thomas Palm
writes
(Henry Spencer) wrote in
:

In article ,
Pete Lynn wrote:

Contraception is used to control the timing of having children, but
it's also used to *prevent* having children (or to prevent having
*more* children), and that's an outright reduction, not a shifting of
the wanted/unwanted balance.
Contraception will not lower birth rate in the long term...

It *does* lower birth rate in the long term. (Effective contraception
has been available in the industrialized countries for a couple of
centuries now; the condom was an 18th-century invention, if I recall
correctly.)

This is not long term from an evolutionary perspective. Some people have
a
genetic tendency to want more children and they will not want to use
contraceptives. What is to stop their genes to spread throughout the gene
pool? It will take many generations, but in a society where just about
everyone survives to reproductive age the primary trait selected for is the
ability and intention of having many babies.

Read "The Mote in God's Eye" by Niven and Pournelle for a
depressing view on what might happen if this reproductive
evolution has time to take control.

I think you are very wrong. Humans are not Moties.

There are species on Earth which have thousands of offspring, or
more, which usually get eaten. Most mammals gestate way
shorter times than we do, and have more multiple pregnancies.
Even hens lay one egg a day when they're on form.

We reproduce slowly. And moderately prosperous citizens
reproduce even more slowly, because our offspring do not qualify
as mature and not requriring parental care until they're through
college, whereas elsewhere if they can walk then they can look
after themselves - well, I exaggerate more than a little, but... what I
mean is, we spend more time looking after each individual child,
educating them instead of putting them to work, therefore we
produce children more slowly.

Also, proportionately more of our children live to adulthood, live to
reproduce. Relatively few of /our/ offspring are quickly eaten, or
even get sick and die. Therefore, we don't need to reproduce so
fast.

At least part of our behaviour is not Darwinian but Lamarckian -
that is, we learn from our parents' life experience - so once a new
cultural balance control for the reproductive urge is set right, it will
perpetuate itself.

Why doesn't this apply to the Moties? Because Niven and
Pournelle decided to play a trick on them and make them villains
in a book, basically.

The human race is now evolving via its brains rather than its gonads.
Biology is no longer in control, and is unlikely to make a comeback.

Don't underestimate biology! For a long time doctors did, and
watch where that got us in term of multi-resistent diseases that
are harder to kill than ever before. We may not like to admit how
much biology control our behabior, but it does.

Fleming knew, and said, to the public, that using penicillin would
lead to penicillin-resistant bacteria. The public apparently didn't
pay attention. I don't think the mistake is doctors', except in for
instance allowing their paying patients to take antibiotic for a virus
which it won't affect. Oh, and feeding antibiotics to healthy meat
animals to get more meat faster /and/ more, eviller bacteria.

Robert Carnegie at home, at large
--
I am fully aware I may regret this in the morning.

Psalm 110 wrote in message . ..
On Tue, 17 Aug 2004 08:08:25 -0500, "Paul F. Dietz"
wrote:

Well, for example to make salination irrelevant, you can go to desalinated
water to irrigate.
It's expensive, but technically possible.

You can also periodically flush the farmland with excess water, which
carries away salts.

It's called irrigation. It's the source of the salts. Read Hillel,
"Out of the Soil".

Strangely enough, that's not a refutation of the idea. Salt buildup
also happens (on a smaller scale, and sometimes much faster) in potted
plants. Watering/irrigating in such a way that the water flows out is
the basic method for making the problem go away, tested more or less
constantly by millions of indoor gardeners everywhere, myself
included, and probably sometimes by junior high schoolers for science
fairs too. I think day to day experience in millions of little
pragmatic experiments trumps your grand ideologically motivated
paraphrased generalization of (misunderstood, I hope, since Press
books should know better than to claim that salts can't be flushed
away) authorities.

(In case it's not clear, this is not to say that irrigation isn't the
cause of the problem, too; to appeal to the potted plant world again,
watering inappropriately is the basic method for creating the problem
in the first place. In particular, irrigating in such a way that the
water evaporates should tend to contribute to the problem unless the
water has already been purified by some process more effective than
the impromptu field distillation process that is created. Solvents are
marvellous things, and just because you can do distillation with them
doesn't mean you can't do chromatography too, or vice versa.)

(It might even be that watering enough to flush the soil somehow
doesn't scale up well enough to be practical for some kinds of
agricultural irrigation situations, or tends to have perverse
consequences of some sort, in which case it would probably be
interesting to hear about it. But even if so, the response above,
implying that it's bogus in principle, seems badly off the mark.)

Psalm 110 wrote:

You can also periodically flush the farmland with excess water, which
carries away salts.


It's called irrigation. It's the source of the salts. Read Hillel,
"Out of the Soil".

It's the source of the salts, and IF YOU FLUSH ENOUGH, it also carries
them away.

Paul

"Henry Spencer" wrote in message
...
In article ,
Pete Lynn wrote:

Contraception will not lower birth rate in the long term...

It *does* lower birth rate in the long term. (Effective contraception
has been available in the industrialized countries for a couple of
centuries now; the condom was an 18th-century invention, if I recall
correctly.)

As you are probably aware the Kangaroo evolved the capacity to delay the
length of gestation in response to food supply. Sort of a natural
contraceptive, this must have increased overall effective birth rate for
it to be naturally selected for.

...Some among us can independently sustain high birth rates
at first world levels. For example the Mormons. Given time, such
populations might be expected to take over.

Other things being equal, you might expect that. But other things
*aren't* equal. Even religions are subject to natural selection; ones
which tend to impoverish their believers, without compensating
benefits, don't last well.

Yes I have long considered religions in evolutionary terms, an extension
of group altruism. I should note that evolution does not care how
impoverished you are, just what you leave behind, one does not
necessarily imply the other.

Bear in mind that many organized religions are still grappling with
the 20th-century transition of Western society from a population
dominated by farmers to one dominated by urban employees. On a
*farm*, kids are an economic asset.

And it will take a long time for our culture to adapt to modern times,
(I tend to consider religion as culture reduced to belief, and so harder
to change). Urban employment in no way prevents kids as economic
assets, except in so far as modern expectations with regard to child
labor tend to be weaker in rural areas.

While I expect birth rates to remain low for the next few
generations, in the long term I expect cultural adaptations that
again increase birth rate.

On what basis do you expect such a counterproductive change?

Why is it counter productive? A stagnant population, (monopolistic
species), is hardly a recipe for long term survival, nor is it likely.
There are evolutionary pathways, like competition between males that can
lead to ever greater size, (ivory towerness?), that might eventually
push the species out of its niche and to extinction. Is this what you
advocate?

Human evolution might be currently flummoxed, but it will find its
bearings, and the human race will again get serious...

The human race is now evolving via its brains rather than its gonads.
Biology is no longer in control, and is unlikely to make a comeback.
Evolution is not "flummoxed", it is proceeding more rapidly than
ever, but in a different arena.

I tend to think of human evolution in the modern era as a control system
that has just received a very large step input, (modern technological
advancement), the output is oscillating widely but failing further on
going disruption will eventually settle down again. But to what?
Punctuated equilibrium and all that.

I think humans must always be tested by their environment, the poor must
always be with us, to keep us honest. Otherwise, we set our entire
species up for a fall. Our intelligence must still pass the test of the
real world.

Pete.

Matt Ruff writes:

John Savard wrote:

That reminds me.

Flax is what linen is made from.

I remember an article, by an agriculture student, in a local student newspaper
which was a rebuttal to the propaganda of how allowing hemp to be grown would
solve the world's problems, because it was a wonder plant.

He noted that flax can do anything hemp can do - except make you high - and do it
better.

Yeah, but "Free the flax!" just isn't as catchy a slogan.


Hmm.

Flax for victory!

Nah.

FIVE TONS OF FLAX might be okay, though.

Really, though, "hemp" doesn't get you high -- that's like trying
to run a power plant by rubbing sweaters on cats.




--
Chimes peal joy. Bah. Joseph Michael Bay
Icy colon barge Cancer Biology
Frosty divine Saturn Stanford University
www.stanford.edu/~jmbay/ yes right i am the king of limousines

On 17 Aug 2004 20:42:49 GMT, Ian Stirling
wrote:

It is possible (though expensive) to remove the salts from water used
for irrigation.
This would usually need to be combined with measures to reduce evaporation.

Idiot. Speaking before learning.

On 17 Aug 2004 16:10:55 -0700, (William
Newman) wrote:

Strangely enough, that's not a refutation of the idea. Salt buildup
also happens (on a smaller scale, and sometimes much faster) in potted
plants. Watering/irrigating in such a way that the water flows out is
the basic method for making the problem go away, tested more or less
constantly by millions of indoor gardeners everywhere, myself
included,

Idiot. Knows nothing of irrigation, compaction, hardpan causes for
saliniation of soils. Teaches before he has even learned. Blind
leading blind.

On Tue, 17 Aug 2004 18:21:24 -0500, "Paul F. Dietz"
wrote:

It's the source of the salts, and IF YOU FLUSH ENOUGH, it also carries
them away.

Can't do it if there is high water table, saline water table,
compaction, or hardpan. Read the cite and learn something before
trying to teach. You are an idiot.

Robert Carnegie wrote in
:

In article
4.229, Thomas Palm

This is not long term from an evolutionary perspective. Some people
have a
genetic tendency to want more children and they will not want to use
contraceptives. What is to stop their genes to spread throughout the
gene pool? It will take many generations, but in a society where just
about everyone survives to reproductive age the primary trait selected
for is the ability and intention of having many babies.

Read "The Mote in God's Eye" by Niven and Pournelle for a
depressing view on what might happen if this reproductive
evolution has time to take control.

I think you are very wrong. Humans are not Moties.

You may think I am wrong, but you fail to explain in what way.

We reproduce slowly because in our native environment it paid better to
have a few children and take care of them for a long time so that most
survived. This simply isn't true anymore from an evolutionary
perspective, still the genes that reproduction hasn't had time to change.

Also, proportionately more of our children live to adulthood, live to
reproduce. Relatively few of /our/ offspring are quickly eaten, or
even get sick and die. Therefore, we don't need to reproduce so
fast.

Evolution isn't about need but about opportunity. Assume there is a gene
in some people that causes them to be much happier about having many
children, and thus will cause families with it to be larger. What is to
stop that gene from spreading in the population?

At least part of our behaviour is not Darwinian but Lamarckian -
that is, we learn from our parents' life experience - so once a new
cultural balance control for the reproductive urge is set right, it
will perpetuate itself.

It may perpetuate itself until biology catches up. As you say culture is
only part of the story, and you can't look at only a part and expect to
get the full truth.

Why doesn't this apply to the Moties? Because Niven and
Pournelle decided to play a trick on them and make them villains
in a book, basically.

The moties are victims of a tragedy more than villains. N&P made sure to
hammer down the problem by adding the quirk that they died if they didn't
reproduce regularly, but that wasn't really necessary.

:: I think you are very wrong. Humans are not Moties.

: Thomas Palm
: You may think I am wrong, but you fail to explain in what way.

I thought he was refering to the notion that humans are k-strategists,
while Moties seem to be obligate r-stragegists. And the fact that this
setup is fairly strained (that is, that Moties can't gain control of their
own reproduction because any group that does is outcompeted; if the issue
is resource starvation, that shouldn't universally be the case).

Or so it seems to me.


Wayne Throop http://sheol.org/throopw