Am I getting Evolution right?
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30-05-2012, 03:36 PM
Am I getting Evolution right?
Evolution is simply one of those things that I haven't fully understood until very recently, and even not sure if what I consider the evolutionary process to be is the correct one. I've heard hundreds of different ways of explaining evolution, and some of them very much clash with each other. Considering this is an Atheist forum, and we often base our arguments against creationism on evolution, I was hoping I could get a better understanding of how Evolution works here.

Here's what I generally consider to be evolution:

The DNA replication process isn't perfect, and thus over billions of years, errors occur and form mutations in the DNA. Some mutations are good, others are bad. If the mutation is bad, that specific creature will generally be wiped out before they have a chance to mate. Those with good mutations generally survive longer and have a chance to pass on their DNA to the next generation. That generation then passes on its new gene to the next, and the next generation to the next, until finally the entire species exhibits this trait. This process repeats itself with other mutations until finally that species slowly begins to shift into a brand new species of that animal, or in some cases, a whole new animal.


Is this description of Evolution correct? I've been taking this specific one to be the most reliable for a rather long time now, yet with all the other descriptions and mutilations of the process out there, I just want to be sure that I have the right idea.
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30-05-2012, 04:38 PM
RE: Am I getting Evolution right?
(30-05-2012 03:36 PM)pppgggr Wrote:  Evolution is simply one of those things that I haven't fully understood until very recently, and even not sure if what I consider the evolutionary process to be is the correct one. I've heard hundreds of different ways of explaining evolution, and some of them very much clash with each other. Considering this is an Atheist forum, and we often base our arguments against creationism on evolution, I was hoping I could get a better understanding of how Evolution works here.

Here's what I generally consider to be evolution:

The DNA replication process isn't perfect, and thus over billions of years, errors occur and form mutations in the DNA. Some mutations are good, others are bad. If the mutation is bad, that specific creature will generally be wiped out before they have a chance to mate. Those with good mutations generally survive longer and have a chance to pass on their DNA to the next generation. That generation then passes on its new gene to the next, and the next generation to the next, until finally the entire species exhibits this trait. This process repeats itself with other mutations until finally that species slowly begins to shift into a brand new species of that animal, or in some cases, a whole new animal.


Is this description of Evolution correct? I've been taking this specific one to be the most reliable for a rather long time now, yet with all the other descriptions and mutilations of the process out there, I just want to be sure that I have the right idea.
You are not wrong, but this description is incomplete. I suggest you read one of the books on evolution by Richard Dawkins. He is an evolutionary biologist and an excellent writer.
Try Amazon; some titles:
The Blind Watchmaker
Climbing Mount Improbable
The Ancestors' Tale

Skepticism is not a position; it is an approach to claims.
Science is not a subject, but a method.
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30-05-2012, 04:45 PM
RE: Am I getting Evolution right?
(30-05-2012 04:38 PM)Chas Wrote:  
(30-05-2012 03:36 PM)pppgggr Wrote:  Evolution is simply one of those things that I haven't fully understood until very recently, and even not sure if what I consider the evolutionary process to be is the correct one. I've heard hundreds of different ways of explaining evolution, and some of them very much clash with each other. Considering this is an Atheist forum, and we often base our arguments against creationism on evolution, I was hoping I could get a better understanding of how Evolution works here.

Here's what I generally consider to be evolution:

The DNA replication process isn't perfect, and thus over billions of years, errors occur and form mutations in the DNA. Some mutations are good, others are bad. If the mutation is bad, that specific creature will generally be wiped out before they have a chance to mate. Those with good mutations generally survive longer and have a chance to pass on their DNA to the next generation. That generation then passes on its new gene to the next, and the next generation to the next, until finally the entire species exhibits this trait. This process repeats itself with other mutations until finally that species slowly begins to shift into a brand new species of that animal, or in some cases, a whole new animal.


Is this description of Evolution correct? I've been taking this specific one to be the most reliable for a rather long time now, yet with all the other descriptions and mutilations of the process out there, I just want to be sure that I have the right idea.
You are not wrong, but this description is incomplete. I suggest you read one of the books on evolution by Richard Dawkins. He is an evolutionary biologist and an excellent writer.
Try Amazon; some titles:
The Blind Watchmaker
Climbing Mount Improbable
The Ancestors' Tale
I was expecting you to ask him why he was asking us instead of doing his own research. Tongue


Along with Chas' suggestion, I have Dawkins' "The Greatest Show on Earth: The Evidence for Evolution" on my short list of books to read.

"All that is necessary for the triumph of Calvinism is that good Atheists do nothing." ~Eric Oh My
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30-05-2012, 04:55 PM
RE: Am I getting Evolution right?
(30-05-2012 04:45 PM)Erxomai Wrote:  
(30-05-2012 04:38 PM)Chas Wrote:  You are not wrong, but this description is incomplete. I suggest you read one of the books on evolution by Richard Dawkins. He is an evolutionary biologist and an excellent writer.
Try Amazon; some titles:
The Blind Watchmaker
Climbing Mount Improbable
The Ancestors' Tale
I was expecting you to ask him why he was asking us instead of doing his own research. Tongue


Along with Chas' suggestion, I have Dawkins' "The Greatest Show on Earth: The Evidence for Evolution" on my short list of books to read.
I have done my own research. As I said, many people describe evolution differently and I was unsure as to whether or not I had the correct description.
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30-05-2012, 05:12 PM
RE: Am I getting Evolution right?
Bearded or Robot will be along soon to grade your work. Big Grin

"All that is necessary for the triumph of Calvinism is that good Atheists do nothing." ~Eric Oh My
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30-05-2012, 05:58 PM
RE: Am I getting Evolution right?
(30-05-2012 04:55 PM)pppgggr Wrote:  
(30-05-2012 04:45 PM)Erxomai Wrote:  I was expecting you to ask him why he was asking us instead of doing his own research. Tongue


Along with Chas' suggestion, I have Dawkins' "The Greatest Show on Earth: The Evidence for Evolution" on my short list of books to read.
I have done my own research. As I said, many people describe evolution differently and I was unsure as to whether or not I had the correct description.
Then you haven't yet done enough research. Erxomai's suggestion is excellent; also Why Evolution is True, Jerry A. Coyne

The reason I suggest Dawkins is that his explanations are among the clearest. But none of these books are really meant to be casually read or read just once. Evolution is an idea that is so subtly pervasive, that it takes some effort. It's not a complicated idea, it's simply that the implications are not entirely or immediately obvious.

Your current understanding is a simplification; not a bad start, but only a start and you are missing the main point.

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Science is not a subject, but a method.
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30-05-2012, 07:15 PM
RE: Am I getting Evolution right?
The Greatest Show on Earth, I'm going to say, has got to be the worst book I've ever trudged through. The information is all good, but I did not like the style that Dawkins wrote with. Basically he made a subject I'm interested in extremely boring. I would recommend any book other than that one.

One thing I want to make clear is that there is no such thing as "microevolution" and "macroevolution." Those are terms that some creationists like to use to rationalize why there is such evidence for evolution. They use microevolution to describe changes in DNA (random mutations) which may change a species slightly, but they will not admit that small changes over a long period of time result in big changes (in other words, they are stupid and trying to ACT smart).
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30-05-2012, 07:25 PM (This post was last modified: 30-05-2012 07:45 PM by Hafnof.)
RE: Am I getting Evolution right?
Here is my lay summary:

* We start with life that exists. Before life is abiogenesis[1], which evolution is not concerned with.

* Life has the property that it reproduces to make pretty good copies of themselves, or at least pretty good copies of their genes. In the case of sexual reproduction there is a deliberate gene shuffling involved which helps out later on.

* Life also has the property that it exists in an environment consisting of non-living things and also other living things that can influence the survival and reproductive success of individuals

* Although the copies are pretty good, they are not perfect. Changes occur at a genetic level. Changes can include duplication of genes and modification to those genes. Sometimes genes are effectively rewritten to such a degree that they bear no apparent relationship to the existing gene, such as occurs in a frameshift mutation[2].

* Individuals that are well suited to their environment survive and reproduce at a higher rate than their less suited cousins. This leads to traits that are well suited to the environment becoming firmly established in a species' genome. The most suited genes stay while genes that make individuals unsuitable for their environment are whittled away.


So this is the simple framework, but the detail gets more complicated. Some of the more complicated detail includes:

* Punctuated equilibrium. Genes that are well suited to a relatively unchanging environment can last for millions or billions of years without changing. Only when the environment changes does selective pressure start to change the genome. This means that species are often unchanged for long periods, and then adapt over a relatively short periods of time when the non-living or living environment changes.

* Genetic drift. For genes that are not strongly advantageous or disadvantageous in a given environment the genes effectively survive or do not survive at random. Small populations can randomly acquire different traits to populations elsewhere, and populations can change from their parent populations over time for no particular reason and in no particular direction if the traits resulting from the genes are neutral.

* Unfavourable genes can have favourable effects. Even very deadly genes can sometimes be preserved in genomes due to positive effects they can have. A classic case is the gene for sickle cell anaemia, where two copies of this gene will probably kill without modern medicine. However genes almost always come in pairs across two chromosomes, so the faulty gene won't kill you if the good gene is still present. Moreover the combination of faulty and good gene in the same individual appears to protect against malaria. There are many examples like this, including (it is argued) the genetic basis for solely homosexual inclinations. Exclusive homosexuality would seem naively to be bad for the individual's ability to reproduce, however we are honing in on possible benefits such as increased social cohesion that can lead to greater success for close relatives of the individual as well as possible gene combinations that would be advantageous to close relatives of the individual.

* There is no ladder of life. Evolution is not trying to get to "us" or to some specific form of advanced life. It is only interested in the survival value of genes. We just turned out to be a good solution to the problems our species was facing.

* Body plans. Typically large animals will have major problems if the basic genes controlling foetal development change significantly. Animals with extra arms or legs will tend to fail. Once a basic body plan is locked in we tend to be stuck with that plan. Our front limbs are specialised as hands. The front limbs of our cousins the birds are specialised as wings. Once a part of the body has become specialised it is hard to undo that specialisation, and over time we can start to run out of body parts to specialise. After a major extinction event it is often the animals most similar to the earliest members of their evolutionary tree that will still have a generalised enough body plan to be able to specialise into the new ecological niches that have opened up.

* Speciation. A species is essentially a group of animals that either can't or won't breed with other species. New species can emerge simply because two groups become isolated from each other. Ring species are a classic form of speciation where a particular species migrates down two distinct paths only for its descendants to meet up with each other at the end of their respective journeys. Often due to genetic drift or having passed through different environments along the way the two populations are quite different when they meet, and sometimes so different that they either can't or won't breed with each other anymore. The crazy thing is that all of the way along both migration paths every individual can still breed with its neighbours, so in theory a new gene in one of the separate populations can be transmitted along that path to make its way into the other population despite the incompatibility between the two populations themselves. Eventually however these groups are likely to become increasingly different from each other and to cease transmitting genes.

* Graduation between species. No child is ever a different species to its parent(s). There are a few possible caveats here, but the basic idea is that any change that occurs between generations is going to be so small between a parent and a child generation that it will be impossible to say precisely where the old species ended and the new species began. Over a hundred or a thousand generations you'll be able to clearly see the difference between a fish and amphibian, but between a parent and child the variations will be too small to identify in such a simple way. In evolution "kind begets kind".


* Species grouping and shared traits. All child species are still part of the parent group. You ancestors were human, theirs primate, theirs mammal, theirs vertebrate, theirs animal. Your descendants will always be animals, always vertebrate, always mammal, always primate, always human. If domestic cats became parents to a new species that took to the oceans like dophins, they would still be cats. If dogs became parents to a new species that could take to the sky on furry wings, those descendants would still always be dogs. Descendants of a parent species will always carry the majority of the traits of their parent species, and will always be identifiable at some level as being part of their parent group. Again, "kind begets kind".

* Information is added by filtering. In information theory you can't increase information by introducing random data. All you are doing is increasing noise. As such, all mutation can be seen as adding noise rather than adding information. So how does information in a genome increase? The first thing to understand is that there is not all that much information in a genome. Wikipedia puts the figure at about 800 megabytes, plus another 4 for each individual... but I think that figure includes the "junk" DNA as well as the coding sections. In the end we are relatively simple with less thank 30000 genes per human. Counter-intuitively the information content (the signal) is added not through the mutation process (the noise) but through the natural selection process. Natural selection is a filtering process that removes genes not suited to survival. The remaining genes therefore contain a strong "fit for survival" signal, which constitutes their information content.

You might want to go right to the source and read "The origin of species" by Darwin. Although this work is outdated and incomplete in many ways, the thrust is both accurate and generally readable even today. Here is a short reading: http://youtu.be/ojzV7gK7KlgSome good sources on youtube include:
* DonExodus2, eg http://youtu.be/OfybuMJVWj0 - this is an awesome video
* potholer54, eg http://www.youtube.com/playlist?list=PLDB23537556D7AADB
* thunderf00t, eg http://youtu.be/x5YhE3a5dqw
* TheraminTrees, eg http://youtu.be/atJE1Mih4VQ

If you want a geological perspective my absolute favourite person on youtube is WildwoodClaire1. Check out her creation geology series and make sure to watch coffee with Claire. It has definitely taken over from the atheist experience as my favourite weekly show on youtube.

[1] http://en.wikipedia.org/wiki/Abiogenesis
[2] http://en.wikipedia.org/wiki/Frameshift_mutation

Give me your argument in the form of a published paper, and then we can start to talk.
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30-05-2012, 08:05 PM
RE: Am I getting Evolution right?
Quote:* Life has the property that it reproduces to make pretty good copies of themselves, or at least pretty good copies of their genes. In the case of sexual reproduction there is a deliberate gene shuffling involved which helps out later on.
There is nothing deliberate in evolution. There is no intention, no foresight, no planning, no deliberation.

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Science is not a subject, but a method.
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30-05-2012, 08:29 PM
RE: Am I getting Evolution right?
What I mean is that there is an explicit gene shuffling step that occurs as part of sexual reproduction.



Give me your argument in the form of a published paper, and then we can start to talk.
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