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Author Topic: Why is natural selection so much slower than human-led selection?  (Read 14805 times)

Jim Geeting

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Jim Geeting  asked the Naked Scientists:
   
1. How is that natural selection takes millions of years to change a species or create a sub-species, yet domestication of plants and animals only takes thousands or tens of thousands of years?  Is mankind that good?

2.  Some species such as sharks and crocodiles are said to be millions of years old, which implies a) they are older than many other species and b) have changed little by way of comparison.  Does natural selection address why the rate of change varies from one species to the next?

Jim in Dallas

What do you think?


 

Offline wolfekeeper

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Actually, when you think about it, there's *millions* of species, and mankind has only managed to domesticate a few hundred maybe. And the number of genes that we've modified in each case are likely to very small, a few dozen. So mankind is not that good at it really. I don't think there's ever been any new species made by human selection.
 

Offline Don_1

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Its true that we have 'manufactured' a great number of different breeds of dog (and other domestic/farm animals) and plants in a relatively short space of time, unlike nature, which has evolved different subspecies over a great many years.

Our efforts have resulted in a great many problems for these hybrids. Dogs with problems relating to their eyes, ear, breathing, running, walking and so on, plants with little or no fragrance, susceptible to insect attack and disease. Pigs which result in more meat and less fat, but also less flavour.

Our attempts to improve on nature have been fast and, pretty much, to the detriment of the plants and animals we have played around with. Our success rate would probably be somewhere in the order of zero.

Natures' l-o-n-g,   s-l-o-w efforts have been quite successful.

Current score:
Man - 0
Nature - 1,000,000,000,000 (or thereabout)

I don't think you can say we have produced any real new species or even subspecies. As I wrote above, we have merely hybridised some of natures work. These hybrids need constant interbreeding or they would soon revert to their natural state.

With plants and animals such as the sharks and to a greater extent the crocodilians and, my favourites, the chelonians, evolution reached a point where it did not need to improve any further. Therefore, these animals have remained largely unchanged for millions of years. The modern testudines (tortoises) may be 200 million years old.
« Last Edit: 10/09/2009 08:18:14 by Don_1 »
 

Offline wolfekeeper

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Keep in mind that humans do not make new species.  In fact, we don’t know if species actually come about through evolution.  That’s why we call it the “theory” of evolution.  But we do know that natural selection exists.
That's not right. ALL laws in physics are also theories. The special theory of relativity is now known to be true; but they're not changing the name.

FWIW Newton's Laws are now known to be wrong ;-)

The theory of evolution predicts that new species can occur via various ways. It's not known what the most common ways are. Oh yeah, and the definition of species is very arguable anyway. If two 'species' can't reproduce they must be individual species, right? But what happens if there is a third species they can both reproduce with? This happens all the time, particularly in botany.

Even in humans this happens. Some pairs of people can't successfully have children together; essentially all their children die, their genes are incompatible. If those subgroups were to isolated from the rest of humanity and bred they would constitute different species from each other.

Really, species is mostly a human concept.
 

Offline Geezer

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That’s why we call it the “theory” of evolution. 

The suggestion that evolution is merely a "theory" is anti-science being promulgated by creationists and anti-Darwinists who are are determined to make bible teaching a mandatory subject in public schools in the US. Their lastest tactic is trying to claim that "Intelligent Design" is not religion. It's a science, and therefore, it should be taught in school.

If you want to judge for yourself, visit the Discovery Institute's website. What's interesting about this is how much money they are apparently receiving to support their agenda.
 

Offline wolfekeeper

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Yes, that's right. It's anti-science.

It's completely analogous to claiming that mountains could never be built by plate tectonics because nobody has ever seen it happen. 'Plate tectonics is just a scientific theory not fact!!!!'
 

Offline wanhafizi

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I think the next generation evolution is probably based on technology that humans have today.

This is my idea of universe evolution;

The big bang was the precursor of all.

Next, the sub atomic particles of big bang formed gas clouds and evolved into galaxies, star systems and solar systems.

Next, some solar systems through it's chemical reactions created simple life forms.

Next, these life forms eventually became the granddaddy of intelligent life forms.

Intelligence life forms will evolve into what?

The way I see things are going, probably the next evolution will happen in technology, namely computers. Better and superior AI developed will probably get merged into our organic/biological system. Soon, when we consumed all the biological resources and the earth cannot cope with the endless need of each individuals, probably we have to rethink the way we live.

Since the reality which we are living each moment is merely electrical impulses going in and out of our brain, probably things like "The Matrix" will become a reality.

Just a thought, just a thought...
 

Offline Geezer

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I think we (humans) are incredibly arrogant for even claiming to be intelligent. Intelligent life forms would not be brainwashed into believing complete mumbo-jumbo then use that as a justifiaction for running around killing each other.
 

Offline Variola

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I think we (humans) are incredibly arrogant for even claiming to be intelligent. Intelligent life forms would not be brainwashed into believing complete mumbo-jumbo then use that as a justifiaction for running around killing each other.

Humans are the only species to put reasoning behind killing.
Religion is just another excuse for humans to be crappy towards each other, it it wasn't that it would be something else.
Why are we like this? I have not seen an explanation yet that hits it square on the head.

Ontopic- humans select to produce what is beneficial for us, not for the plant/animal,whereas evolution does the opposite.
 

Offline JimBob

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Yes, that's right. It's anti-science.

It's completely analogous to claiming that mountains could never be built by plate tectonics because nobody has ever seen it happen. 'Plate tectonics is just a scientific theory not fact!!!!'

I would ask you how do you know you were born and not delivered by the stork?

Indirect evidence - that is how. Someone told you you were and you may have seen other things born. That type of reasoning is also how we are aware that plates tectonics is real.

That does ignore the fact that the movement has been measured. During my lifetime of 65 years North America has moved 0.3575 meters west with respect to Europe (5.5 cm/year.) That is a FACT.


« Last Edit: 14/09/2009 01:38:46 by JimBob »
 

Offline Variola

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Will western science ever divorce itself from the Bible?

Yes, it already has. Science is based on inductive and deductive reasoning, where as the Bible is based on someone's invisible friend.
 

Offline _Stefan_

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DiscoverDave,

One of the great things about science is that it doesn't care what you believe.

Your personal inability to accept that a scientific theory is the highest status that any scientific idea can acheive, does not affect how accurate the theory is. Evolution is not "just a theory". The Big Bang is not "just a theory". What matters to a theory is how logical it is, how powerfully it explains, and the quality of the evidence supporting it.

What you might call "just theories" are actually hypotheses.

To argue otherwise is the logical fallacy of Persional Incredulity.

Please, you are on a science forum. Readers take posts seriously. What are they to think when they are looking for good information but instead find irrational opinions?

Finally, hopefully you already know this, but the origin of life (and the origin of earth and the universe) is not part of the theory of evolution. Evolution explains what happens after life (including simple precellular precursors to organisms) has been formed. There is currently some good research investigating several plausible ways in which life could have originated.
 

Offline Don_1

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To Don_1:
• The phenomenal effect humans have on the world shows that we can significantly affect the environment and that we can, and have, created breeds and hybrids of various animals and plants.  The fact that these animals and plants continue to thrive shows that humans have succeeded in doing so.  We are the environment; we define what is the fittest; we control their survival.  And, if nature is so perfect, how come I'm going bald, and why do some kids get leukemia and die?

Our 'creations', such as thoroughbred dogs, only retain their characteristics due to our continued intervention in their reproduction. The same applies to hybrid plants. Left to nature, they would soon revert to their natural state. Our creations cannot survive without us.

I don't say nature is perfect. It does make mistakes. Or at least it makes mistakes according to our criteria.
 

Offline Variola

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Yes, science is supposed to be very objective, but I still see the influence.  I went too far with my exaggerations but, most of all, I simply can't believe the Big Bang Theory.  For example, how could it be a unique event?  Its popularity leaves little information about, or desire to discuss, other theories.  Non-scientific people accept it without ever considering the details. 


The only time I see the influence of the Bible, or any other religion is when creationists try and link the two together.
I cannot understand or get my head round the big bang theory either, but then I am not a physicist. Evolution however, I can understand, and believe.
Theories like the big bang may not be anywhere near perfect in their explanation, but creationism argues from a point of no proof whatsoever.It is arguing that something exists despite there never being one shred of proof ever. The big bang is at least based on scientific data. interestingly, both firm creationists and those who strongly believe in alien life use the same arguments based on the same logic, the invisible friend who needs no explanation or proof.  And then for people to fight over religion really is arguing whose invisible friend is best!
 

Offline _Stefan_

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The invisible/imaginary friend argument is my favourite, Variola :D Unfortunately the one intelligent person I used it on did not see the relevance to their belief in God.
 

Offline Variola

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The invisible/imaginary friend argument is my favourite, Variola :D Unfortunately the one intelligent person I used it on did not see the relevance to their belief in God.

;D Yes I like it too because it brings is back down to the basics of proof,something many creationsists overlook.
Nope Cog. D. will ensure most believers have an unshakeable belief. 
 

Offline Nizzle

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God is the collective name for all things we do not understand yet.

In ancient Egypt and Greece, the sun was carried through the skies by a god for example.
At this time, people are still attributing things we don't understand to a god, like big-bang or beginning of the universe, but some other people started to see a trend developing, which is called science.

We've seen several versions of god throughout history.
In ancient times, the gods where all kinds of nature phenomena,
In the middle ages, god was a tool even of the monks and bishops to get rich of the hard earned money of the poor people, paying indulgences to get into heaven. Now, god is sought out for comfort and consolidation for the fact that when you die, there's nothing coming anymore and you'll be either worm food or flame food.

god is shrinking, while science is growing.
There's only one thing left to say as far as I'm concerned: god did not create mankind, mankind created god, for the sole purpose of using him like a tool
 

Offline Variola

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God is the collective name for all things we do not understand yet.

In that case why don't men call women God(dess)? ;D
 

Offline Don_1

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Because 'inexplicable' is a more fitting term. Opps, now what have I said?
 

Offline Geezer

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It might seem that I am a bit negative about "intelligent design". Actually, I have more respect for out-and-out creationists who make claims like "the earth was created last Thursday night while I was washing my hair". The reason I really abhor "intelligent design" is because it accepts some science, while rejecting good science that does not align with its preconceptions.

Now, that's anti-science.
 

Offline Variola

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Variola (an interesting name, by the way), Occam’s razor conveniently gets rid of “imaginary friends”.

Thank you  :)

Occam's razor isn't just a convenient tool to be used to discourage other theories. it gives a grounding to work from, if the basic idea doesn't fit satisfactorily then and only then can you move on to more exotic ideas. The problem there is humans, we like the exotic!
Evolution may have holes in it, but I believe that is because we don't understand it enough yet to be able to explain it all.
But it sure beats an idea that some self-contained deity, of whom we have no existence created the lot on his day off!

Science is always challenging itself, sometimes it can take decades for the proof to be found but the challenge always remains. Hence medical advice and treatments, for example have changed so much. Blood letting was once thought of as a useful medical treatment, until science eventually proved otherwise.

Take a eukaryotic cell, just a normal cell. The complexity of that cell, and how it regulates and how it functions is mind-blowing!! It is absolutely mind-blowing, and we still do not understand it all. Sometimes I look at it and think there is no way all that has happened by chance, it must be intelligent design. But then I look again and think it must be by chance, or diseases like cancer wouldn't happen.
( for the biologists, I am meaning the cancer cell's ability to ignore what it is supposed to be doing)

I do empathise with you on the physics, mostly I find it hard to swallow because much of it is all theory, I know that is why some people love it, but I prefer the solid-squishyness of biology.  :)
 

Offline Variola

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The reason I really abhor "intelligent design" is because it accepts some science, while rejecting good science that does not align with its preconceptions.

Now, that's anti-science.



It's cognitive dissonance too  :)
 

Offline Geezer

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The reason I really abhor "intelligent design" is because it accepts some science, while rejecting good science that does not align with its preconceptions.

Now, that's anti-science.



It's cognitive dissonance too  :)

Right!

(crap - now I'll need to look up dissonance.)
 

Offline Variola

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LOL!! sorry  [:X]

Start with Festinger first http://en.wikipedia.org/wiki/Leon_Festinger

There is a link on there to Cog D

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Festinger is perhaps best known for the Theory of Cognitive Dissonance, which suggests that inconsistency among beliefs or behaviors will cause an uncomfortable psychological tension. This will lead people to change their beliefs to fit their actual behavior, rather than the other way around, as popular wisdom may suggest. [1]




 

Offline Geezer

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LOL!! sorry  [:X]

Start with Festinger first http://en.wikipedia.org/wiki/Leon_Festinger

There is a link on there to Cog D

Festinger is perhaps best known for the Theory of Cognitive Dissonance, which suggests that inconsistency among beliefs or behaviors will cause an uncomfortable psychological tension. This will lead people to change their beliefs to fit their actual behavior, rather than the other way around, as popular wisdom may suggest. [1]

Oh! I thought it was maybe something to do with self-abuse. See, you learn something every day!
 

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