Biological Energy Redistribution?

[KUMAR5]

I get the feeling that the word 'evolution' is being used in two different (but related) ways in this thread, and that might be causing some confusion.

1. 'Evolution' as change over time. We commonly see this usage in physics, as in 'the evolution of spiral galaxies' or 'evolution rules in dynamical systems', where the 'evolution rule' of the dynamical system is a function that describes what future states follow from the current state.

2. 'Evolution' in the biological Darwinian sense of change over time in the genetic makeup of biological lineages and the origin of new species by natural selection. It's interesting to note that this is the explanation of a particular kind of (biological) change over time by applying a non-formal evolution rule to it. So #2 would seem to be a particular instance of #1.

But it's important to note that not all changes over time (imagine billiard balls striking each other) are instances of Darwinian natural selection. Not even all changes over time in biological organisms or biological populations are instances of Darwinian natural selection. If lots of efficient predators (human hunters say) or a new disease enter a wilderness area, that might drive other animals to extinction. That is certainly a change in time in population numbers, but it isn't Darwinian evolution. It would be an example of 'evolution' #1.

We will only see Darwinian natural selection (evolution #2) if the species in question has some genetic variants that are better able to tolerate those adverse environmental conditions and those hardier variants are able to pass on those qualities to their offspring who survive and become more numerous in succeeding generations.

 

[KUMAR5]

Yes, one is evolution of beings and other is evolution with variation for survival and fitness as per survival of fittest under changed environment. Former is just natural evolution of any soeci origionally later is secondary evolution. But my feeling is that, Darwin would had just looked one side of secondary evolution i. e. creative and maintaining type, somewhat by directional selection due to secondary natural factors. But how secondary evolution of destructive nature due to disruptive selection by conscious factors is covered, appear not considered by Darwin. Should we classify this later as origional evolution?

 

[KUMAR5]

The directed evolution Kumar speaks of is simply called artificial selection (as opposed to natural selection) - or selective breeding.

But it's the same thing, it still results in the most fit specimens getting to breed more, it's just that the criteria for what is considered "fit" is determined consciously. Dogs that are friendly to humans get bred more than dogs that are not friendly. The environment of these dogs is "among humans", so they re well-adapted to that niche.

If however, humans lose interest in keeping dogs as pets, those dogs will end up in the wild, where they will once again be selected for survivability.

Kumar, there is no such thing as negative or destructive evolution. It always works the same way: individuals who are better adapted to their environment will get to breed, producing more offspring like themselves; individuals who are not adapted well will breed less, and be winnowed from the population.

We are just considering directional selection but we may also need to consider Disruptive selection and Concisios evolution.

 

[KUMAR5]

"These charts depict the different types of genetic selection. On each graph, the x-axis variable is the type of phenotypic trait and the y-axis variable is the amount of organisms. Group A is the original population and Group B is the population after selection. Graph 1 shows directional selection, in which a single extreme phenotype is favored. Graph 2 depicts stabilizing selection, where the intermediate phenotype is favored over the extreme traits. Graph 3 shows disruptive selection, in which the extreme phenotypes are favored over the intermediate."
https://en.m.wikipedia.org/wiki/Disruptive_selection
Consicious selection
https://en.m.wikipedia.org/wiki/Conscious_evolution
We need to better understand and consider above terms of evolution.

 

[Write4U]

Not really - it was outlawed because the of the devastating effects it had on fish eating birds. DDT would build up in the systems of the birds and it had the effect of making the egg shells so thin that they would break when the birds sat on them to brood.
It would have eventually become toxic to humans as it built up in our systems.

As a side note - in some lakes in NY it is recommended to only eat something like 1 lake trout a month from the lake because of DDT. It takes so long to break down that it is still in the environment.

I am not disputing any of this. In fact you are proving my point that DDT was outlawed because it was harmful to all who came in contact with it, except for the locusts, which were the target to begin with.

In one generation (from the survivors) they became immune and ruined the crops even when sprayed with twice the recommended dosage. After that, famers had to use DDT and a secondary even stronger poison, with good effect. Of course the crop itself had to be burned because it was too toxic for any use whatever.
This is from a recorded interview with a farmer, who had to deal with locusts.

Carcinogenicity[edit]
In 2015, the International Agency for Research on Cancer classifies DDT as Group 2A "probably carcinogenic to humans".[85] Previous assessments by the U.S. National Toxicology Program classified it as "reasonably anticipated to be a carcinogen" and by the EPA classified DDT, DDE and DDD as class B2 "probable" carcinogens; these evaluations were based mainly on animal studies.[1][38]

A 2005 Lancet review stated that occupational DDT exposure was associated with increased pancreatic cancer risk in 2 case control studies, but another study showed no DDE dose-effect association. Results regarding a possible association with liver cancer and biliary tract cancer are conflicting: workers who did not have direct occupational DDT contact showed increased risk. White men had an increased risk, but not white women or black men. Results about an association with multiple myeloma, prostate and testicular cancer, endometrial cancer and colorectal cancer have been inconclusive or generally do not support an association.[38] A 2017 review of liver cancer studies concluded that "organochlorine pesticides, including DDT, may increase hepatocellular carcinoma risk."[86]

A 2009 review, whose co-authors included persons engaged in DDT-related litigation, reached broadly similar conclusions, with an equivocal association with testicular cancer. Case–control studies did not support an association with leukemia or lymphoma

https://en.wikipedia.org/wiki/Dichlorodiphenyltrichloroethane#Chronic_toxicity

 

[exchemist]

You're right, that was Thalidomide.
another one of those wonder drugs.
But I think the list you provided is a clear indication that DDT is harmful to humans directly or indirectly .
I hope you are not advocating continued use of this pesticide.

This is a science forum and I am trying to keep the standard up, so that history is not lazily rewritten by people who do not check their facts (or are incapable of reading them correctly when they do).

 

[origin]

I am not disputing any of this. In fact you are proving my point that DDT was outlawed because it was harmful to all who came in contact with it, except for the locusts, which were the target to begin with.

You are such a hoot and so predictable! You are wrong about why DDT was outlawed but you will waste post after post obfuscating and dodging just to keep yourself from the horror of having to admit that you made a slight error.

I really don't get you type of people....

 

[spidergoat]

All should equally survive at least upto their reproductive age because all took birth as fittest.

Evolution works on variation, which is why we have sex in the first place. It creates the variation and differential survival rates that lead to evolutionary change. Non-sexual species are more similar, but mutation makes perfect copies impossible.

 

[Write4U]

You are such a hoot and so predictable! You are wrong about why DDT was outlawed but you will waste post after post obfuscating and dodging just to keep yourself from the horror of having to admit that you made a slight error.

I really don't get you type of people....

Human Health Harms
The science on DDT's human health impacts has continued to mount over the years, with recent studies showing harm at very low levels of exposure. Studies show a range of human health effects linked to DDT and its breakdown product, DDE:

• breast & other cancers
• male infertility
• miscarriages & low birth weight
• developmental delay
• nervous system & liver damage

• You want more?

http://www.panna.org/resources/ddt-story

This is a science forum and I am trying to keep the standard up, so that history is not lazily rewritten by people who do not check their facts (or are incapable of reading them correctly when they do).

Thank you.

 

[KUMAR5]

Evolution works on variation, which is why we have sex in the first place. It creates the variation and differential survival rates that lead to evolutionary change. Non-sexual species are more similar, but mutation makes perfect copies impossible.

Yes but those variations should be of my types by many type of selections not necessarily of fittest. Many type of selection are indicative. Natural selection.. Directional selection, disruptive selection, balancing or stabalizing selection etc. Now consicious or artificIal selection is also exist.

 

[Write4U]

• You want more?

http://www.panna.org/resources/ddt-story

Just in case you refused to read the link, I'll make it easy and post a few more facts.

• Food supplies: USDA found DDT breakdown products in 60% of heavy cream samples, 42% of kale greens, 28% of carrots and lower percentages of many other foods.
• Body burden: DDT breakdown products were found in the blood of 99% of the people tested by CDC.
• Health impacts: Girls exposed to DDT before puberty are 5 times more likely to develop breast cancer in middle age, according to the President’s Cancer Panel.

You think they would ban DDT to save a bird species when there are millions of dollars of crops at stake?
Apparently you missed the part that double doses of DDT plus DDE did kill most of the locusts, but also made the crop so toxic that it had to be burned.

p.s. I usually do my research before posting . If the links I provide are unreliable, then I'd like to see some counter facts and links, instead of kneejerk ad hominem responses.

 

[spidergoat]

Yes but those variations should be of my types by many type of selections not necessarily of fittest. Many type of selection are indicative. Natural selection.. Directional selection, disruptive selection, balancing or stabalizing selection etc. Now consicious or artificIal selection is also exist.

Artificial selection always existed in the form of sexual selection, the result of deliberate choices in sex partner. There is no such thing as stabilizing selection. There is also no such thing as a natural balance.

 

[KUMAR5]

Artificial selection always existed in the form of sexual selection, the result of deliberate choices in sex partner. There is no such thing as stabilizing selection. There is also no such thing as a natural balance.

Pls look at see also part on following link. Many type of selections are indicated. Stabalizing slection is also there.
https://en.m.wikipedia.org/wiki/Disruptive_selection
Probably, natural selection may only be possible when naturality in all exposures are maintained i. e living in natural environment and chosing partner for mating naturally by sole and natural will of other partner. But today, we are exposed to many unnatural exposures then how natural selection can be possible? Probably, we are getting evolved to Disruptive selection apparent by our preferances of two extremes i. e. on Creative and destructive sides.

 

[spidergoat]

OK, there is such a term as stabilizing selection, but it doesn't describe a force that stabilizes, it describes the passive tendency of a population to avoid extremes in a specific trait. It's mechanism is negative selection. Natural selection didn't disappear in modern humans.

 

[KUMAR5]

OK, there is such a term as stabilizing selection, but it doesn't describe a force that stabilizes, it describes the passive tendency of a population to avoid extremes in a specific trait. It's mechanism is negative selection. Natural selection didn't disappear in modern humans.

Yes but even within the scope of natural selection many type of selections are possible. We need to relate, how natural and unnatural environmental exposures choose which type of selection? Moreover status of natural environment and its inhabitants may also trigger variations in selection. Let us say, if over population of any speci is there, some natural forces may bring such selection which may lower or balance it. Low sperm count, gender aversions, depression in sexual and reproductive willingness etc. can suggest movement toward decrease in population. Moreover we can add fuel to it by preferring modern unnatural, unhealthful and deadly tools. Our modern selection seems to be of Disruptive selection type(preferring extreme of both sides i.e of creation and destruction) to which probably we are already evolved

 

[spidergoat]

Our modern selection seems to be of Disruptive selection type(preferring extreme of both sides i.e of creation and destruction) to which probably we are already evolved

If that were true, we would see a wide variety of genetic traits in modern humans and that's not true. We are one of the least diverse primate species genetically.

 

[KUMAR5]

If that were true, we would see a wide variety of genetic traits in modern humans and that's not true. We are one of the least diverse primate species genetically.

If that were true, we would see a wide variety of genetic traits in modern humans and that's not true. We are one of the least diverse primate species genetically.

If that were true, we would see a wide variety of genetic traits in modern humans and that's not true. We are one of the least diverse primate species genetically.

How can we claim we are least diverse primate species? Don't we see much changes in our behavior & preferences as compared to our primates esp of extreme creative and destructive nature?

 

[spidergoat]

How can we claim we are least diverse primate species? Don't we see much changes in our behavior & preferences as compared to our primates esp of extreme creative and destructive nature?

How? We look at the genome, that's how. External behavior tells us little about DNA.

 

[DaveC426913]

How can we claim we are least diverse primate species? Don't we see much changes in our behavior & preferences as compared to our primates esp of extreme creative and destructive nature?

You are talking about social complexity, not genetic heredity.
And no, social dynamics are not genetic.

 

[KUMAR5]

How? We look at the genome, that's how. External behavior tells us little about DNA.

Phenotypic changes?