Re: Ping Rumple

"High Miles" <2blues1723@xxxxxxxxxxx> wrote in message news:EKAtm.14069$6f4.1155@xxxxxxxxxxxxxxx
Islander wrote:
Rumpelstiltskin wrote:
On Sat, 19 Sep 2009 18:46:48 -0700, Islander <nospam@xxxxxxxxxxx>
wrote:

Rumpelstiltskin wrote:
On Sat, 19 Sep 2009 12:47:11 -0700, Rita <Rita@xxxxxxxxxxx> wrote:

In a post in reply to Emily about eugenics -- improving the
gene pool -- I cited Darwin and natural selection:

Another argument against is that
eugenic policies could also lead to loss of genetic diversity, in
which case a culturally accepted improvement of the gene pool could
very likely, as evidenced in numerous instances in isolated island
populations (e.g. the Dodo, Raphus cucullatus, of Mauritius) result in
extinction due to increased vulnerability to disease, reduced ability
to adapt to environmental change and other factors both known and
unknown. A long-term species-wide eugenics plan might lead to a
scenario similar to this because the elimination of traits deemed
undesirable would reduce genetic diversity by definition.

The cheetah is in danger because there's so little diversity in its DNA. There's a lot of concern about
the lack of genetic diversity in, for example, commercial wheat, since a plague organism could rapidly devastate all the grain since all would be equally affected, and there would be no varieties that might have greater resistance and thereby provide a basis for a grain more resistant to that plague.

A "Eugenics plan" sounds very dangerous to me,
though life is dangerous anyway, for individuals and for whole species. We humans don't know what we're doing. As is well known, trying to protect children against everything produces adults who are not hardened to weather subsequent viral and
bacterial attacks in adulthood. As to mankind's
wisdom and expertise, Voltaire noted that "The course of rivers to the sea is not so swift as the course of man into error", and Burns of course wrote:

Now mousie, thou are no thy lane
In finding forethought might be vain.
The best-laid plans o' mice and men
Gang aft agley,
And leave us nought but grief and pain
For promised joy.

Humans had a bottleneck, it's now thought - about 150,000 years ago. Homo sapiens is about 200,000 years old. The modern theory (opposed to Darwin's gradualism) is that Homo sapiens arose as a result of rapid speciation ("punctuated equilibrium") and hasn't changed much since. According to the site below, humanity might have been down to just 2000 people at that time. If we'd gone extinct, we
wouldn't have evolved again. Perhaps something
from another hominid line would have mutated into
a large-brained species like ourselves, or perhaps
something else would, or perhaps it wouldn't happen at all for the foreseeable future.
I don't think that you can claim with any degree of certainty that any species that becomes extinct might not appear again if the evolutionary environment favors it. In the DNA study of biological evolution, it has been shown that the tree of life is, in fact, not a tree but a network of reconvergent branches. Specific DNA traits appear, disappear, and reappear again over time.


It's not certain, only 99.999999999999999% certain,
about as certain as I am that there is no god. That's just the odds of the DNA. Any animal that goes extinct is done for, except for human intervention. We might get the dodo and the quagga back, just because we have the DNA and might be able to clone it, in the manner of "Jurassic Park". Even if we only had the complete DNA map, we might be able to recreate an extinct animal, but there is the complication, of unknown severity, that the development of an animal is not just the product of its DNA, but also of the environment of the placenta. And very recently, "epigenetics" has been suggested. I hope "epigenetics" does have a future, and isn't just a chimera, because it would be interesting to have Lamarckian components of evolution resurrected.



I certainly do not mean to imply that we should dismiss extinction because the species "might" reappear. As you point out, the chances of that are pretty remote for anything more complex than a few cells. On the other hand, given enough time...

Epigenetics sounds interesting. First I heard of it. Hmmm. Cells behaving in ways that are not in their "program." An external effect?

Mutation is not in their original program, but it's essential for evolution.

The 'external effects' on cells which cause cancer are pretty easily traced.
If you add years of ingesting fluoridated and chlorinated water, plus
recycled water that contains heavy metals and chemicals...........
We have only scratched the dust off all the things that trigger cell
changes.



A couple of men who spoke to my club some time ago were explaining the reasons for the PCB cleanup in the Hudson River.

The eagle eats the frog or the fish (which contains the PCB's from the polluted river) Then the eagle shits over the corn field. Then the people eat the corn or other vegetables from the field. The PCB's are still there, and end up in us, causing cancer.

Then of course there are the flavors and fragrances and cleaning products. The water pollution and the pesticides. Lead was in paint and in gasoline for years. Loads of it is still in the environment. The list goes on. All the prescription meds that end up in the waterways and in our kids.

We are all part of such a toxic mess after all this, it is a wonder we aren't all sick.

--

Evelyn

"Even as a mother protects with her life her only child, So with a boundless heart let one cherish all living beings." --Sutta Nipata 1.8

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