Am I getting Evolution right?
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31-05-2012, 12:12 AM
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.
Nice attempt at your part Smile With regards to your definition, you covered one mechanism of evolution (natural selection), and the fact that mutations contribute to variation for natural selection to act on. Just one thing, whether a mutation is good or bad depends on the environment the organism is living in. For instance, a mutation leading to a thicker fur coat is very beneficial in colder regions, for it protects against the cold, but detrimental in equatorial regions.

Evolution is quite a broad topic, so I suggest a more general definition for evolution, which basically sums up what evolution is about:
Evolution refers to changes in allelic frequency in a population over a period of time.


The others above me have covered quite nicely on the details of evolution. The suggested books are good too. I too recommend "The Greatest Show on Earth", as it's very extensive in providing information and case studies.

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31-05-2012, 12:16 AM
RE: Am I getting Evolution right?
(31-05-2012 12:12 AM)robotworld 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.
Nice attempt at your part Smile With regards to your definition, you covered one mechanism of evolution (natural selection), and the fact that mutations contribute to variation for natural selection to act on. Just one thing, whether a mutation is good or bad depends on the environment the organism is living in. For instance, a mutation leading to a thicker fur coat is very beneficial in colder regions, for it protects against the cold, but detrimental in equatorial regions.

Evolution is quite a broad topic, so I suggest a more general definition for evolution, which basically sums up what evolution is about:
Evolution refers to changes in allelic frequency in a population over a period of time.

The others above me have covered quite nicely on the details of evolution. The suggested books are good too. I too recommend "The Greatest Show on Earth", as it's very extensive in providing information and case studies.
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31-05-2012, 01:48 AM
RE: Am I getting Evolution right?
(30-05-2012 07:25 PM)Hafnof Wrote:  * 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".
In evolutionary biology, there are no 'kinds'. That is a Biblical and creationist concept.

By your logic, we are lobe-finned fish. Cats are lobe-finned fish. I think you are trying to say something useful, but the way you have put it is confusing and a bit misleading.

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31-05-2012, 10:01 AM
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.
What you have described here is only a partial explanation of one of the mechanisms of evolution. The big picture here is that evolution is a collection of mechanisms and pathways which explain the diversity of life and how new species emerge. It is all unified by Darwin's theory of Natural Selection i.e. those animals with the traits that make them most adaptable and survivable will live and reproduce, those that do not are eliminated from the gene pool.

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31-05-2012, 11:28 AM
RE: Am I getting Evolution right?
Everyone has done a good job of giving you some pointers. It is really difficult to surmise evolution in a few short paragraphs. I would add one additional piece to what has been said (building mainly off of Robotworld's post).

Evolution requires genotypic variation in some way, shape, or form. Mutation is only one of the ways that variation is produced, other ways would be things like sex or mistakes made during meiosis. Natural selection does not act upon the genotype though, it acts upon the phenotype. That is to say that the genotype leads sometimes (but not always because some genes go unexpressed, there are diseases for instance that don't manifest themselves until later in adulthood) to an expressed phenotype. Natural selection acts upon these phenotypes by selecting for beneficial phenotypes and selecting against harmful or non-beneficial ones (A good example here is sexual selection where females often select males for a particular trait, but it may serve no other purpose other than the females like it).

Read up on some of the recommended reading, I have a lot to catch up on myself, including finishing "The Greatest Show on Earth" by Dawkins and finding some good Stephen Jay Gould to read (I feel so ashamed as a paleontologist to have not yet read anything of his in its entirety).

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31-05-2012, 11:42 AM
RE: Am I getting Evolution right?
I'm also going to back the greatest show on earth as the first book to read. It really explains a lot about the subject. I will just chip in with a bit of an observation. Everyone seems to be talking about how the copying pattern for DNA isn't perfect. If DNA cloned itself then the life form which first existed would've died out and DNA would not exist. The mutations and other alterations are what has allowed life to exist for so long. The habitat changes and with it life must also change. Remember that over 90% of the species to exist on the earth no longer exist (forgot the exact percent). Just a small issue with this discussion of DNA replication not being perfect when it is done in the way which allows it to continue existing for as long as it has.

I'm not a non believer, I believe in the possibility of anything. I just don't let the actuality of something be determined by a 3rd party.
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31-05-2012, 12:37 PM
RE: Am I getting Evolution right?
(31-05-2012 11:42 AM)Lilith Pride Wrote:  I'm also going to back the greatest show on earth as the first book to read. It really explains a lot about the subject. I will just chip in with a bit of an observation. Everyone seems to be talking about how the copying pattern for DNA isn't perfect. If DNA cloned itself then the life form which first existed would've died out and DNA would not exist. The mutations and other alterations are what has allowed life to exist for so long. The habitat changes and with it life must also change. Remember that over 90% of the species to exist on the earth no longer exist (forgot the exact percent). Just a small issue with this discussion of DNA replication not being perfect when it is done in the way which allows it to continue existing for as long as it has.
More like >99%

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31-05-2012, 09:58 PM
RE: Am I getting Evolution right?
Which is why I said in parenthesis forgot the exact percentage =p Do you at least agree with me Beardy?

I'm not a non believer, I believe in the possibility of anything. I just don't let the actuality of something be determined by a 3rd party.
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01-06-2012, 08:43 AM
RE: Am I getting Evolution right?
(31-05-2012 01:48 AM)Chas Wrote:  
(30-05-2012 07:25 PM)Hafnof Wrote:  * 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".
In evolutionary biology, there are no 'kinds'. That is a Biblical and creationist concept.

By your logic, we are lobe-finned fish. Cats are lobe-finned fish. I think you are trying to say something useful, but the way you have put it is confusing and a bit misleading.

I'll try to clarify. This is a line of understanding that is important due to the "crocoduck" fallacy and related fallacies. It's easy for someone who doesn't understand the process well to imagine chimeras which are part one animal and part another being characteristic of evolution, when in fact such forms would generally be evidence against the theory. Generally the correct way to categorise life is as monophyletic groups based on common ancestry. Each member of the group will be identifiable by key traits that are specific to their particular grouping. I use the word "kind" here as a deliberate trigger to nail this point home, particularly to creationists who misunderstand evolution.

You're suggesting that because we have left the water we are no longer lobe-finned fish. Well, fish is really not a good term to use in classifications for various reasons. However, as descendants of Sarcopterygii[2] - YES - we are still Sarcopterygii. Cats are still Sarcopterygii also, and will always remain so Smile Discard these weird notions of paraphyletic clades, and swim with me among its descendants!





[1] http://en.wikipedia.org/wiki/Clade
[2] http://en.wikipedia.org/wiki/Sarcopterygii

Give me your argument in the form of a published paper, and then we can start to talk.
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01-06-2012, 09:23 AM
RE: Am I getting Evolution right?
(31-05-2012 09:58 PM)Lilith Pride Wrote:  Which is why I said in parenthesis forgot the exact percentage =p Do you at least agree with me Beardy?

I'm not sure actually. DNA is volitle in the sense that mutations occur at regular rates and accumulate at regular rates, but I'm not sure if it is fair to say that the common ancestor would have gone extinct if not for them. The common ancestor was probably some archae bacteria and I just don't know enough about how environmental changes affect that environment. My guess is not very much since it was an ocean-dwelling organism. Mutations must have conveyed a benefit but may not have been necessary for its survival. Mutations were necessary for mixing up genetic information in order to produce change and therefore successive species but I'm just not fluent enough in microbiological evolution to say one way or the other.

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