Question

[Ouroboros]

But, evolution’s mutation mechanism does not explain how growth of a genome is imaginable. How can point mutations increase a strand of DNA or create new chromosomes? It is very interesting that, in all of the selective breeding in dogs, there has been no change to the dog genome. All breeds of dog can still mate with one another. People have not seen any addition in dog’s DNA, but have simply selected different genes from the existing dog gene pool to create the different breeds.

 

What about Downs Syndrome, a person born with an extra, third copy of chromosome 21.

 

And in some rare exceptions, men with Down syndrome can father a child. And in any pregnancy, a woman with Down syndrome has a 50/50 chance of conceiving a child with Down syndrome, even though many pregnancies are miscarried.

 

But still genetic alteration can happen and can be transfered to children.

 

There are more than 6,000 known single-gene disorders, which occur in about 1 out of every 200 births.

[John]

Yes, but that is harmful. I thought favorable traits were passed on.

[Ouroboros]

Yes, but that is harmful.

 

In most of these occasions yes, but that is how evolution works, new mutations, a huge amount doesn't fit in or is not an improvement. Just wait until one day someone is born with a particular additional gene that is different than ever before, and is transferred to their kids, and it's some kind of ability that makes them strong or better fitted for our society and life. That's the one that will survive as a natural selection. Maybe it's someone with fingers better suited for our keyboards and computer mice?

 

[edit]

 

Not necessarily favorable traits are passed on. Many traits are passed on, and the families with better traits have a larger chance of survival, and the families with less favorable traits have a lesser chance of survival, hence natural selection. You have a plentiful amount of traits that have no function in your body at this moment. The appendix is one, the tail bone is one, excuse me for mentioning this but if you’re male you have nipples, but still not milk producing breast, even though you have the glands for it. IIRC, Males even have some reproductive organs associated only with females.

 

You have to see it as selection of the plethora of traits.

[John]

VVVVEEEERRRYYYYY SSSSSLLLLOOOOOWWWWLLLLLLLYYYYYY

 

But, how slow? Why is it that there is an abrupt increase of animals during certain periods?

 

In 65 million years, according to the theory of evolution, every mammal that we see today such as dogs, elephants, whales, giraffes, bears, horses, moles and bats evolved from small, four-legged creatures like Didelphodon.

 

Imagine trying to start with an opossum and get to an elephant in 65 million years.

 

Another speed problem is from Homo Erectus to Homo Sapiens.

[Ouroboros]

Good question.

 

How fast and how often do you need mutations to get to where we are today?

 

I must admit that I don't know how fast or how long time that is needed. So sorry I don't have a good answer for that.

[MrSpooky]

First, guys, hush up about the taunting and jeering. It has nothing to do with the question we're given.

 

Second...

 

But, evolution’s mutation mechanism does not explain how growth of a genome is imaginable. How can point mutations increase a strand of DNA or create new chromosomes? It is very interesting that, in all of the selective breeding in dogs, there has been no change to the dog genome. All breeds of dog can still mate with one another. People have not seen any addition in dog’s DNA, but have simply selected different genes from the existing dog gene pool to create the different breeds.

 

This is quite untrue. There are many many mechanisms that can increase a genome size. I'll just name a couple...

 

Polyploidy: Where the number of chromosomes increase because the reproductive cells don't divide right and so carry extra chromosomes (like people who have an extra X or Y chromosome)

 

Insertion Mutations: In which an extra nucleotide is added on to a piece of DNA

 

Transposon Copying: In which transposons, which can jump around in a genome, is copied twice during replication.

 

So we DO have mutations that can both INCREASE the number of chromosomes, as well as mutations that can increase the SIZE of the chromosomes.

[John]

Good question.

 

How fast and how often do you need mutations to get to where we are today?

 

I must admit that I don't know how fast or how long time that is needed. So sorry I don't have a good answer for that.

 

Well, an elephant’s brain is hundreds of times bigger than an opossum’s, bearing hundreds of times more neurons, all perfectly wired. An elephant’s trunk contains a lot of muscles (over 100,000).

[John]

Polyploidy: Where the number of chromosomes increase because the reproductive cells don't divide right and so carry extra chromosomes (like people who have an extra X or Y chromosome)

 

Well, this would explain why plants have so many chromosomes, but why isn't occurring now? Why does it take such incredible amounts of time? The grass in my yard doesn't look any different.

[DaveL]

Well, an elephant’s brain is hundreds of times bigger than an opossum’s, bearing hundreds of times more neurons, all perfectly wired. An elephant’s trunk contains a lot of muscles (over 100,000).

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John,

 

I'm not sure what your point is here, we are not here to do your research. There is plenty of information out here. Just go and talk to 'Mr Google' and give him some really good search terms. When 'Mr Google' has referred your to some really informative sites, then come and discuss it with us.

 

Try these:

 

http://faculty.washington.edu/chudler/brainsize.html

http://serendip.brynmawr.edu/bb/kinser/Size3.html

[John]

John,

 

I'm not sure what your point is here, we are not here to do your research. There is plenty of information out here. Just go and talk to 'Mr Google' and give him some really good search terms. When 'Mr Google' has referred your to some really informative sites, then come and discuss it with us.

 

Try these:

 

Why is there this forum if no one has any desire to post to someone. My point had nothing to do with intelligence, but how could all those neurons be perfectly wired.

[Mr. Neil]

Why is there this forum if no one has any desire to post to someone. My point had nothing to do with intelligence, but how could all those neurons be perfectly wired.

You know what, John. This is primarily a non-Christian site. It's not a science site. Many of us are knowledgable, but we're not scientists.

 

Well, some of us are, but I haven't seen Zach here in a while.

 

But anyway, that which you want us to explain is not something that can be explained in a few short paragraphs or even a few long paragraphs. It's like you expect us to sit down and, in ten minutes, write a perfect proof for evolution. That's not going to happen.

 

The best we can do is show you the literature and hope you understand evolution a little better. We're also here to help you understand your misconceptions of evolution, which you had a few right in your opening post. It's quite evident that a lot of your questions are a the result of simply being misinformed.

 

I don't mean to sound condescending, but read a book. Go to your library or an online bookstore, and look for some books written by actual biologists. I suggest you look up molecular biology, because it's really loaded with fascinating stuff.

 

 

Now about the "perfectly wired" question. You keep falling back on this idea that things are "wired", as if it happens all at once. It's not a "wiring", but more of a refining. Sort of like an ax-grinder. An ax-grinder is a mechanism which chips away imperfections, and eventually it takes the dull, imperfect ax and turns it into a well-crafted weapon. That is how natural selection works. It's not all-at-once.

 

Even if there are certain holes in our understanding of the mechanism of evolution, there is still absolutely no doubt that evolution happens. This can be confirmed by identifying common pseudogenes (link) and endogenous retroviruses (link) in which common ancestory can be of absolutely no doubt.

[MrSpooky]

Well, this would explain why plants have so many chromosomes, but why isn't occurring now? Why does it take such incredible amounts of time? The grass in my yard doesn't look any different.

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Oh, of course it's occuring now. It's just that these are singular events that occur only during gamete formation and fertilization, and that they're quite rare. You see it in agriculture all the time... plants are the best example of this. In the animal kingdom, a prime example of polyploidy is the donkey-horse distinction. They share an ancestral species and are thus related, but due to polyploidy, one of them has an extra chromosome.

 

What's also interesting to note is that polyploidy can also be a speciation event... donkeys and horses can still reproduce with each other, but due to the weird chromosome count in the offspring, the mule is sterile.

 

Another interesting sidenote, lions and tigers can interbreed too, because they are related species. Check it out, they call it a "Liger."

 

[John]

Oh, of course it's occuring now. It's just that these are singular events that occur only during gamete formation and fertilization, and that they're quite rare. In the animal kingdom, a prime example of polyploidy is the donkey-horse distinction. They share an ancestral species and are thus related, but due to polyploidy, one of them has an extra chromosome.

 

What's also interesting to note is that polyploidy can also be a speciation event... donkeys and horses can still reproduce with each other, but due to the weird chromosome count in the offspring, the mule is sterile.

 

Another interesting sidenote, lions and tigers can interbreed too, because they are related species. Check it out, they call it a "Liger."

 

How does this prove anything since they're sterile?

 

You see it in agriculture all the time... plants are the best example of this.

 

Doesn't this have to do with human intervention?

 

Polyploidy: Where the number of chromosomes increase because the reproductive cells don't divide right and so carry extra chromosomes (like people who have an extra X or Y chromosome)

 

I thought they can't reproduce since the chromosomes won't line up correctly?

[MrSpooky]

Why is there this forum if no one has any desire to post to someone. My point had nothing to do with intelligence, but how could all those neurons be perfectly wired.

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Heh. This is right up my alley. I'm a double-major working in Cognitive Neuroscience as well as Genetics... it's quite surprising how handy that comes in in an evolution debate.

 

The interconnection of neurons really isn't all that surprising. You see it as a step-by-step process of neurons being GROWN into their connections and positions rather than being PLACED there. There's something very very special about something growing as opposed to being pieced together, because something that is GROWN can use a relatively simple blueprint as opposed to something CONSTRUCTED. It is due to this fact that DNA can be considered to be a biochemical fractal seed.

 

Take the Sierpinski triangle, for example...

 

 

Looks incredibly complex, and it certainly would be a pain if this pattern had to be made in a non-fractal manner. But you can actually construct this with a very very simple algorithm.

 

1. Start with any triangle in a plane. The canonical Sierpinski triangle uses an equilateral triangle with a base parallel to the horizontal axis, (first image).

2. Shrink the triangle by 1/2, make three copies, and position the three copies so that each triangle touches the two other triangles at a corner, (image 2).

3. Repeat step 2 with each of the smaller triangles, (image 3 and so on).

 

Our bodies are made the same way. DNA doesn't code for the construction of every single capillary in the human body... that'd be a ridiculous amount of intricate information! Rather, DNA codes for the UNDERLYING FRACTAL PATTERN that describes the blood flow.

 

The development of the brain works in the same manner. From a tiny group of stem cells, the embryo forms a brain (simplified). You don't have to read this part, I just think it's interesting...

 

 

1.  The notochord induces the folding of the superior surface of the flat sheet of tissue that will form the neural tube.

2.  The neural tube induces other cells to differentiate to form somites and crest cells.

3.  The neural tube grows and bulges here and there forming the three primary vesicles of the nervous system.  The cell bodies in the brain migrate to the surface of the vesicle.

4.  The primary vesicles differentiate into the secondary vesicles.

5.  As the telencephalon swells and grows, the vesicle and the surface of the vesicle bends and folds.  The synapses retain their axonal connections that they held earlier on... nothing really tells them "grow here, grow there" specifically.  The axons just elongate as the brain grows.

6.  The growing brain fills up with extraneous synaptic connections and a huge amount of glial cells... only 10% of our brain is a complex of interconnecting neurons.

7.  The human brain is developed, but it has a huge overabundance of synaptic connections.

 

Part 7 is probably the most relevant portion to your question. The neurons DO NOT have specific instructions of "hey, connect here and do this thing." Instead, we are born with trilliong and trillions of connections, many times more than we'll ever need. When the connections form, it's just a chaotic mess of "grow dendrites and make connections to as many other nearby neurons as you can."

 

Afterwards, the extra connections die off, leaving only the connections that were stimulated by interactions with the environment.

[MrSpooky]

Doesn't this have to do with human intervention?

 

No. Not at all. Polyploid plants can be found in the field. While genetic engineers can probably stimulate polyploidy, it occurs quite naturally and with surprising frequency.

 

I thought they can't reproduce since the chromosomes won't line up correctly?

 

To my knowledge, it's not that their chromosomes won't line up correctly, it's that their chromosome count makes for weird gametes when the gametes interact with those of its parent species.

 

I'm afraid I honestly don't know much about polyploidy in animals, because it occurs so much more prevalently in plants. However, we all use the same stuff, DNA, so the mechanisms should be pretty similar. In plants, the new polyploid specimen is sterile mainly to its host species. If one polyploid plant can interact with another polyploid plant of similar chromosome count, you can get a nice budding start of a new species.

[John]

Oh, I see now. So, DNA has particular properties that make evolution work more expeditiously. I just couldn’t comprehend how only a few genes in the human genome tell those many neurons how to accurately wire themselves in the human brain.

[MrSpooky]

Ah, here we go. This has some pretty interesting stuff on animal polyploidy...

 

http://www.talkorigins.org/origins/postmonth/jan99.html

 

http://www.talkorigins.org/indexcc/CB/CB141.html

[MrSpooky]

Oh, I see now. So, DNA has particular properties that make evolution work more expeditiously. I just couldn’t comprehend how only a few genes in the human genome tell those many neurons how to accurately wire themselves in the human brain.

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Fractals occur all the time in nature... it is the very definition of "growth."

 

Crystals will self-replicate via fractal mechanisms, clays will self-replicate via fractal mechanisms. It's an awesome process. I really do think that people need to emphasize more on fractals in grade school education because it's the perfect merger between mathematics and the empirical world.

[MrSpooky]

How could a fish-like species evolve into an amphibian-like species?

 

Have you ever heard of mudskippers (sorry Neil I just saw your post after I mailed this)? These little guys hang out in mangrove swamps and mudflats. Living close to the shore wouldn't be too advantageous unless you can exploit the natural environment. These little guys have speak volumes for evolutionary theory.

 

 

http://members.ozemail.com.au/~thebobo/intro.htm

 

Best read up on mutations.

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Are those mudskippers mackin' it?

[Ouroboros]

Fractals occur all the time in nature... it is the very definition of "growth."

 

Crystals will self-replicate via fractal mechanisms, clays will self-replicate via fractal mechanisms.  It's an awesome process.  I really do think that people need to emphasize more on fractals in grade school education because it's the perfect merger between mathematics and the empirical world.

 

Amen MrSpooky! Fractals, I love fractals!

 

Just to add a little example, the cauliflower’s shape can be reproduced with fractal geometry.

[Antihero]

And fractal L-systems can produce quite realistic trees.

[MrSpooky]

Amen MrSpooky! Fractals, I love fractals!

 

Just to add a little example, the cauliflower’s shape can be reproduced with fractal geometry.

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If you love them so much WHY DON'T YOU MARRY 'EM????

[Ouroboros]

If you love them so much WHY DON'T YOU MARRY 'EM????

 

No because I don't like the small fractals making such a chaos at home.

 

[MrSpooky]

No because I don't like the small fractals making such a chaos at home.

 

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*BA-DUM KSHHHHHHHHHHHHHHHHH*

[DaveL]

Are those mudskippers mackin' it?

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LOL yep they look a bit frisky to me too.

Perhaps they should get a room somewhere.

 

No it's actually 2 males having some territorial biffo.

 

Might make a good avatar.