Evidence for Evolution

[Curubethion]

When's the last time you saw a fish produce milk for their young? I call that a function similarity for whales and humans. And if the form of the DNA follows functions like this, that's a logical explanation.

[Count Comfect]

Those are functions DNA <i>causes</i>. But you have to concede that proportional to the degree of functional similarity between whales and fish, they have very low degree of DNA similarity, while proportional to their functional similarity to us, they have a high degree of DNA similarity.

[Curubethion]

Warm-blooded, produce milk, have hair...these are all characteristics of mammals, and both humans and whales share them. Fish have none of these, and they even swim differently. (Side to side instead of up and down)
[It's getting late, and since Rian's here, I think I'll log off now...can you cover for me, Rian?]

[Count Comfect]

I think you're messing up causes and effects, but I'm tired (I didn't eat until 7 pm today, it being Yom Kippur) and I can't thread it out right now. Basically, DNA CAUSES the form AND the function, in the end, so you can't really say that "form following function explains it". That, and DNA similarity IS a function of relatedness - look at my children, they will have MORE SIMILAR DNA to me and my wife than to any other humans... and be next most similar to those humans next closest to them in blood... it comes from how DNA is transfered from generation to generation, and it is provable. Hence, it IS a proof of how related species are.

[Curubethion]

It can be from relatedness, sure, but that isn't necesarily the only cause. And here's my form vs. function argument: if two animals do almost identical things, then the DNA coding for those things will be very similar. Just like there are graphics engines that apply a universal graphics code to several video games...
[I really should go to bed now...]

[brownjenkins]

Originally Posted by Curubethion

It can be from relatedness, sure, but that isn't necesarily the only cause. And here's my form vs. function argument: if two animals do almost identical things, then the DNA coding for those things will be very similar. Just like there are graphics engines that apply a universal graphics code to several video games...
[I really should go to bed now...]

but sometimes two different animals do the same thing in quite different ways... insects, birds and bats all fly, but the physical attibutes that allow them to are quite different... yet those with similar physical attibutes for flying (i.e. feathers), tend to also be similar in other completely unrelated physical aspects

you don't, for instance, have some insects with feathers and jointed wings

[Insidious Rex]

Originally Posted by Curubethion

Form follows function, so wouldn't that explain the DNA similarities? E.G., the similarity between chimp and human DNA is explained by our anatomical similarities. It doesn't mean we evolved from a common ancestor.

But what about the massive amount of 'junk' DNA that also shows degrees of relatedness quite nicely? These dont express a phenotype at all but they still work out mathematically quite nicely. So how do you explain that?

[Nurvingiel]

Environmental factors also affect phenotype; how much depends on the species. It is certainly the case with trees. A good* phenotype often indicates a good genotype, but this is not always the case. How many dead branches remain on the trunk of a Douglas-fir (Pseudotsuga menziesii) depends on the density of the stand and on genetics. The microsite (the environment directly around and under the tree) can affect growth, tree health, tree form, etc.


* By "good", I mean "expressing qualities desired by people"

[rohirrim TR]

scientific variables again,

[Nurvingiel]

Originally Posted by rohirrim TR

scientific variables again,

Of course there are variables. The genotype of, say a Lodgepole pine (Pinus contorta), is not necessarily the same as its neighbour's. In fact, it's probably different. Trees have very complex genetics, and Lodgepole pine is one species that demonstrates a high degree of speceficity - that is, they are highly locally adapted. This is why, though they do grow, Lodgepole pine seedlings from one area are not happy (and often die) if moved too far from where their seed originated.
Western redcedar (Thuja plicata), is much less locally adapted, though it does have genetic differences. For example, the amount of thujoplicins* that occur in the tree's sapwood is influenced, as far as we can tell, completely by genetics.

Obviously environmental factors like soil, climate, weather, slope, topography, elevation, percipitation, etc. etc. are also highly variable.

Characteristics of a species are affected by genetics and environment on a continuum that ranges from 100% genetics to 100% environment.

* Thujoplicins are a chemical compound that prevents disease and rotting in the sapwood, and also puts deer off eating the foliage if it occurs in high enough amounts.

[rohirrim TR]

i like your stuff about trees like this, i never thought about trees having genetics and stuff, but it makes sense; on the other hand i didn't know trees had emotion either but seriously it is quite interesting, especially to me and curub cause we live in kansas and there are, sadly, very few trees

[Curubethion]

Originally Posted by Insidious Rex

But what about the massive amount of 'junk' DNA that also shows degrees of relatedness quite nicely? These dont express a phenotype at all but they still work out mathematically quite nicely. So how do you explain that?

Who's to judge what's "junk" DNA and what's not? Our knowledge of biology is pitiful, like it or not.

[Nurvingiel]

Originally Posted by rohirrim TR

i like your stuff about trees like this, i never thought about trees having genetics and stuff, but it makes sense; on the other hand i didn't know trees had emotion either but seriously it is quite interesting, especially to me and curub cause we live in kansas and there are, sadly, very few trees

Thanks! Forestry geek mode... on.

Tree genetics are really imporant in forestry. Breeding programs can actually improve tree volume or make them more resistent to pests among other things. The pedigree of trees in these programs is tracked, just like a rancher tracking the pedigree of his cattle. The rancher and the forester do this for the same reason - if a tree is pollinated by a tree it's closely related to, this can cause genetic problems and a disruption in the breeding program.

Kansas has a lot of grasses! I love grass. And they have genetics too.
And I didn't just say the ranching analogy just because you're from Kansas - it's just a good example.

[Count Comfect]

Originally Posted by Curubethion

Who's to judge what's "junk" DNA and what's not? Our knowledge of biology is pitiful, like it or not.

Junk DNA is a) the DNA that we don't think has any purpose, after observation, but also b) the DNA that gets removed from the DNA strand before the DNA is expressed. So at least some of it VERY clearly is not expressed and can be called junk.

[Curubethion]

If it's not expressed, it's not important to survival and therefore it is unrelated to natural selection. So maybe it was made similar with an intent and purpose..(hint, hint...)

[Count Comfect]

But what intent or purpose would it have if it is not expressed? Sorry, argument falls down for you too.

And junk DNA is most likely (in my view) DNA that used to have a purpose and doesn't anymore - that is, it has evolved away from having a purpose. Why would a supposedly intelligent designer put in purposeless parts? By contrast, it makes sense for DNA to possibly stop being expressed (by the evolution of the enzyme that snips away junk DNA) over a long evolutionary period.

[Curubethion]

Ok, but wouldn't some organisms evolve ways to not even have the DNA in the first place? Furthermore, evolution is based on DNA mutation, not non-expression.
If any DNA isn't needed anymore, it's because the function it used to code for has changed, coming from a mutation in the DNA. However, then this DNA which supposedly mutated would be the very DNA that's not needed anymore! The argument self-contradicts.

Originally Posted by Count Comfect

Why would a supposedly intelligent designer put in purposeless parts?

Ok, here you said these parts were "purposeless", but...

Originally Posted by Count Comfect

Junk DNA is the DNA that we don't think has any purpose, after observation

So you say here that we haven't proven that "junk" DNA is a bunch of "purposeless parts".

[Count Comfect]

So you say here that we haven't proven that "junk" DNA is a bunch of "purposeless parts".

Right... in the limited sense that it COULD have some purpose that we don't know (see, science doesn't like saying "it has no purpose" right out front) but there is a TON of empirical evidence pointing to it having no purpose.

Furthermore, evolution is based on DNA mutation, not non-expression.
If any DNA isn't needed anymore, it's because the function it used to code for has changed, coming from a mutation in the DNA. However, then this DNA which supposedly mutated would be the very DNA that's not needed anymore! The argument self-contradicts.

The DNA that mutates is the DNA that codes for the polymerase that cuts the junk DNA out, not the junk DNA itself. The polymerase cuts more DNA than it was supposed to - but the gene now expressed happens to be actually more beneficial, and so the new polymerase coding is selected for.

I really should point out here that I am not an expert on junk DNA, since I'm not a practicing biologist.

But I still fail to see why junk DNA would be MORE likely to be a sign of "intelligent" design than of evolution - as I've just proposed an evolutionary mechanic for it, and it doesn't seem intelligent.

[Nurvingiel]

Originally Posted by Count Comfect

Right... in the limited sense that it COULD have some purpose that we don't know (see, science doesn't like saying "it has no purpose" right out front) but there is a TON of empirical evidence pointing to it having no purpose.

<snip>

Trees have the largest known genomes. A lot of that could be DNA that doesn't serve any purpose to the tree (and is therefore junk), but then again, we know jack all about trees.

But maybe this DNA is useful later in possible beneficial mutations (in which case it would have a good chance of passing this on), or harmful mutations, in which case it might not even germinate. (Thus ending the possibility of someone inheriting the harmful mutation.)

I agree that junk DNA would point more to evolutionary process.

[Spock]

Originally Posted by Nurvingiel

Trees have the largest known genomes. A lot of that could be DNA that doesn't serve any purpose to the tree (and is therefore junk), but then again, we know jack all about trees.
\.

Yeah, how do you think we got ENTS?