Re: Selective pressures
Posted: Sat Feb 09, 2013 3:45 am
This is all a good discussion of the physics of evolution.
This reminds me of a conversation with my brother who is an economist. We were talking about how change in tax law can lead to decentralisation, when that is a policy objective. He pointed out that in economic terms, the main result would not be that firms would move from the city to towns, but that existing firms in towns would do better and be more competitive against city firms, so over time the structure of the industry would change.
Similarly, if we now adopt policies aimed at supporting climate adaptation, it is not that denialists will change their views, but that the economy and society will be better prepared for expected changes. The pressure does not cause the adaptations, but it does enable them to flourish.
But this example does not show it is universal that adaptation to pressure is deleterious. Sometimes what challenges us makes us stronger. Saint Paul recognised this when he said at Romans 5 that Christians rejoice in adversity because suffering produces perseverance; perseverance, character; and character, hope. And hope does not disappoint us.
The argument that climate change is a selective pressure is entirely compatible with the science of evolution. I am not 'pinching' anything. The imperatives from evolution apply directly to the need to adapt to climate change. Adaptation is a central theme in response to global warming. In broader evolutionary terms, mitigation (ie action to slow global warming) is a central part of human strategies to adapt to a warmer world.DWill wrote:Robert, I suspect you of pinching from evolution some higher-order imperative for your argument about climate change. How do you plead
Only because it doesn’t discuss it. I linked that article in response to your question about whether selective pressure exists. It is obvious that fish moving toward the poles constitutes an adaptation to global warming under selective pressure.DWill wrote: The wiki article doesn't support the warming planet being a pressure that will cause adaptations.
This reminds me of a conversation with my brother who is an economist. We were talking about how change in tax law can lead to decentralisation, when that is a policy objective. He pointed out that in economic terms, the main result would not be that firms would move from the city to towns, but that existing firms in towns would do better and be more competitive against city firms, so over time the structure of the industry would change.
Similarly, if we now adopt policies aimed at supporting climate adaptation, it is not that denialists will change their views, but that the economy and society will be better prepared for expected changes. The pressure does not cause the adaptations, but it does enable them to flourish.
Selective pressure does not necessarily produce a decline in fitness, although it does so in the case of anaemia. Malaria imposes a selective pressure on human life, and one indicator is anaemia which is a genetic illness that is mildly adaptive to malaria.DWill wrote: When a population begins to lose numbers because of environmental conditions, what can happen, according to the article, is that the species might adapt in ways that will enable it to keep reproducing, even if the adaptation is deleterious to the organism. The example is given of the sickle-cell trait that provides some protection against malaria. Malaria will be more fatal than having the sickle-cell trait eventually is. The pressure must refer to that possibility of the overall fitness declining, even as reproduction is helped along by the adaptation.
But this example does not show it is universal that adaptation to pressure is deleterious. Sometimes what challenges us makes us stronger. Saint Paul recognised this when he said at Romans 5 that Christians rejoice in adversity because suffering produces perseverance; perseverance, character; and character, hope. And hope does not disappoint us.
And I did not say it does. Mutations are random, but their success is a function of selective pressures. That is basic evolutionary science.DWill wrote: The word 'pressure' still doesn't apply to the environmental condition producing some impulse in adults to have offspring with favorable mutations.
Climate provides an interesting test for memetics. Science can see how the planet will change, and how plants and animals are already adapting. But the unprecedented nature of this change is rather like the Yucatan meteor; if we do not prevent it beforehand we face risk of extinction. Human intelligence is our great adaptive trait. Intelligence caused global warming, and only intelligence can stop it. But intelligence has produced a phase shift in evolution from genetics to memetics: never before have organisms changed at the pace we now see in human culture. But our current change process has not somehow enabled us to transcend nature. That is the great conceit of human culture, a conceit that could be our nemesis. This alienation from nature is the conceit of supernatural religion. Religion has helped us get where we are, but we now have to kick away the ladder of the supernatural in order to evolve further.DWill wrote: With climate change, if the increasing temperatures begin to lower ability to reproduce, then maybe some offspring will have an adaptation for heat resistance, without necessarily having an overall better fitness. When you talk of climate change as a potential, as a threat in the future, then for certain there is no physical adaptation to it that could occur.
Global warming is predicted because it is already happening. Of course the effect does not precede the cause.DWill wrote: Suitability to a predicted world cannot cause genes to prosper.
The Catholic Church is like the Titanic, whose builders imagined it to be indestructible, but then it hit an iceberg and sank. Past success is a highly uncertain indicator of future prospects in a changed environment. The dinosaurs prospered for several hundred million years.DWill wrote: I could adopt some of your evolutionary talk and say that fitness is the only criterion that matters for ideas. If we say that the ideas of the Catholic Church were false, we nevertheless have no choice but to recognize that they contributed toward the astounding successes of "Christendom." How long do they have to persist to be sustainable?
Yes it will be because of natural law, if you trace the causality clearly. People will only develop a moral repugnance towards climate denial as an unacceptable evil when denial is seen as preventing necessary action, and when that action is broadly understood to be necessary because of our understanding of the laws of nature.DWill wrote: [the insistence that humans are not responsible for rising temperature will become as unacceptable as the denial of Hitler's genocidal intent against the Jews] - No argument in principle against that happening, but it won't be because of natural law.
The physics is quite simple. CO2 is a greenhouse gas, letting light in and trapping heat. Geologically, hotter times go with higher CO2 levels. Imagining that the laws of physics will miraculously change is central to the denial myth. Pumping increasing amounts of carbon into the air is a recipe for kaboom.DWill wrote: the alternative is that denial won't become illegal or vilified, but will win the day. Where then is the inevitability of its demise, according to natural law, that you claim?