Discussion in 'Biology & Genetics' started by KUMAR5, Dec 21, 2017.
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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?
We are just considering directional selection but we may also need to consider Disruptive selection and Concisios evolution.
"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."
We need to better understand and consider above terms of evolution.
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.
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).
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....
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.
You want more?
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.
Just in case you refused to read the link, I'll make it easy and post a few more facts.
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.
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.
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
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?
How? We look at the genome, that's how. External behavior tells us little about DNA.
You are talking about social complexity, not genetic heredity.
And no, social dynamics are not genetic.
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