These creationalists seem to believe that scientists can
find no genetic evidence for evolution. I am fully aware that
there are people here who are well majored in this domain
of understanding (biology / genetics). The purpose of this
topic is for such people to read what is written in the above
link, and then provide feedback/arguements as to why
it may be wrong (if so). I am more or less just interested in
feedback to the arguements made on that page.


http://www.drdino.com/cse.asp?pg=news&specific=26

Although I am a strong believer in evolution, I have listened tot the arguments of many in the past who do not believe in it. DNA is a crazy thing and I think that it somewhat depends on the complexity of the organism you are looking at. Take for example the single celled bacteria, it is simple and single celled. and has very few if any organelles. I am sure that most of you have heard about these bacteria in the hospitals that are becoming resistant to our antibiotics. WHy does this occur? Evolution is the ability for an organism to adapt to its environment and this little bacteria is adapting and evolving to better suit itself for the environment to save itself, through stronger genes and the ability to fight what we have. It is like when when we develop a new plane that is invisible to radar, someone will find a way to seeit , then we have redesign another way to hide and round and round we go. Humans for the past 20 millions years or so, have had little need to adapt to the environment. We have been healthy, dominant organisms and hence have not really had to evolve. There are signs of our previous selves in our bodies. In our genetic makeup there are thousands of genes that make us, but only a certain precentage of those genes are expressed. In some parts of fetal development, humans have gills where their ears are now. These etrananeous genes could possibly be the leftovers, from our past evolution to what we are today. It is entirely possible with the way that we, as humans, are killing the environment that there may be another evolution of us to better adapt to what we are doing to ourselves. This of course is my opinion, I am not holding that all this is true, so do ot get mad at me for expressing my interests here. :) Thanks for listening and have a great day.

Have a bit of a problem with:Humans for the past 20 millions years or so, have had little need to adapt to the environment. We have been healthy, dominant organisms and hence have not really had to evolve I do think that considerable adaptation has been required during the mentioned time period though, admittedly, little evolution.

Glad you referred to stages of fetal development. In the earlier stages it is virtually impossible to identify the species the fetus belongs to if I'm not mistaken.

Oh, and welcome to Sciforums.

I have to admit I'm a bit of a Neo-Darwinist, I believe that evolution has occured and just because a jigsaw piece "seems" missing doesn't mean it didn't exist at some point.

When geneticists looked at the geneological roots of our ancestry and seemingly can't find our exact route, it might be possible they overlooked something no matter how small it is.

I'm just going to sidestep here to try and explain how I mean.
called
==Source: "Chaos" by James Gleick ===
A man called "Edward Lorenz" discovered something remarkible.
At the time he was working on programming a Cray (computer) to mimic weather conditions, as the reasearch at the time was to develop an accurate method of predicting weather patterns through the use of computer algorythms.

He would input data from weather forecasts and measurements and play them over again and again, and the patterns would follow near enough the same path.

Then one day he decided to start his pattern off from somewhere within it's middle, with the correct number inputted the pattern would continue like all the other simulations, just this time he rounded off the decimal place.

With that one small change, his entire pattern evolved to something completely different from what it was suppose to follow, just due to the decimal places being rounded.

This was the first clue to the renound "Butterfly Effect".
=========================

I mention the above, because that one small calculation threw what was expect out of the window.

I mention this because there is something that seems to be neglected when a mention of evolution is concerned, and that is Bacteria and Virii.

When you get ill your body is attacked by a bacteria or a virii (at least in most cases) and your body has to develop a method of adapting to combat that disease or ailment.

In doing so you might or will defeat the disease but your body now has intergrated into it's design those antibodies, and if that happens to be a womans antibodies they get passed to the offspring.

Now genetics is known to pass the genes of the mother and father along, but what also gets passed along is those antibody patterns, and over time if a creature/race is strong enough a whole disease can be erradicated.

This of course leads onto the problem, that with radiation one of these antibodies could be re-catalysed into a mutant version of it's former disease, in an offspring down the descendant chain, without that disease actually being present in "the wild".

The small antibody changes, weather you had mumps or chickenpox as child acts just like Lorenz's rounded decimal places, and suddenly what would be a direct path you are looking for seems to divert considerably although it is actually present.

Chagur,

You are right in that there has been some evolution of humans, and I think the figure of 20 million is a little to big. I guess that what I was saying is that there really have not been any major changes, i.e. hands turning into fins, or anything like that. basically, we are well adapted top life on the earth. as land lubbers and that there really has not been any kind of major climactic change or otherwise to push further into another evolution. Thanks for your response. have a good day.

In my opinion....

- the idea of a DNA change rate going on so steady that it can be seen as a clock is quite silly. Contrary to 'clocks of the passed' such as the C14 method, in DNA 'good' mutations tends to be favored. At least that's my interpretation of evolution. My DNA is constantly being repaired as well.

- disproving the DNA clock does not mean you need to believe in Divine Creation.

- the basic ideas of DNA and evolution are not depending on this DNA clock.

- i think the evolution theory is still the most detailed explanation.

- Divine Creation is not falsifiable (you can never prove it is wrong, cause 'the Divinity's ways are mysterious') and as such discussion about it does not end up anywhere.

There has a discussion between a Gladstone and a Huxley around 1885 whether the order of creation mentioned in Genesis could be whispered into the writer's ear by God , as it seems to be similar to the geological record (said Gladstone) . Huxley then goes into detail on whether all plants species are really all evolved/created before all mammals, which he claims by fossil records is not so. Etcetera, see chapter 27 Genesis and Geology in Stephen Jay Gould's book 'Bull for Brontosaur'.

A quote from the article you refer to:
" The evolutionary trees shown in biology textbooks are simply theory, not science. "

That's quite possibly true. The school textbooks are known to copy each other and simplify the if's and but's in every step. Also the simple examples of single genes giving a fenotype rely heavily on a handful of examples, like eye color, hair color and pea plant hairyness. A PhD student i know wanted to use real-life examples of single-gene expressions. She could not find any: most [sorry, can't find the word, i'm not a native english speaker, capacities? ] rely on a number of genes.
This is why I believe many of the dreams biotechnology wants us to dream are false. I read recently that people believed we could help the 3rd world by putting the 'anti drought gene' from a cactus in crops. Utterly ridiculous of course. As most of them empty promises of biotechnology.
Someone else on this forum wants the tomato to make THC (the working stuff in cannabis (marihuana)). I don't think that can be done either, i don't think the tomato has a similar biochemical pathway. Also some biotechnology students in Delft, when i told them about the problems of vitamin A rice, believed they could make a multi-vitamin and all-amino-acid rice. Knowing what i know of genetic engineering I cannot believe that.

But even if the examples in the textbooks are not always presented that well, i think the general idea is quite close to the truth.

I do advise the very readable books by Stephen Jay Gould. Also acceptable to creationists i think.

Hi. Iamhamster not a biologist. But hamsters do get exposed to this stuff. So here goes…

Chrisy, you are obviously right about critical DNA. (Excuse me if you already know this stuff.) A mutation in critical DNA leads to death. Very short clock indeed. However higher organism DNA also contains large regions of so called “junk” DNA. Lots of unused stuff lying in there, including some inactive viral code. In the process of building a protein from the DNA template the “junk” DNA is snipped out. Thus a mutation in the “junk” DNA doesn’t affect the organism one way or the other.

You are also right about DNA being constantly repaired. However the repair process isn’t perfect. (I wouldn’t be here typing if it were.) An average mutation rate for “junk” DNA can and has been measured for various species. This “tick” rate was applied to determine how many years passed since related species shared an ancestor. The times didn’t match up with other dating methods. The molecular DNA clock seems to tick erratically. (Don’t think they know why yet. Could be associated with occasional population collapses that reduce DNA variability.) I have read similar controversy concerning the use of maternal mitochondria mtDNA to determine lineage.

Leviiathan, the best answer I have for you is that the world always seems to be a little more complicated than we first imagine. The molecular clock is more complicated than first expected. Theories must be refined as new facts come to light. Science evolves.

Another criticism you may run across is no evidence of speciation. This one isn’t answered by bacteria adapting. (What does it mean to be different species when you reproduce asexually?) The criticism is that there doesn’t seem to be an observed case of one species evolving into another. That is, the offspring could no longer mate and produce viable offspring with member from the earlier species. If memory serves (doubtful these days) several months ago a regulatory gene (Associated with the histo-compatibility complex? Anyone please feel free to jump in and correct me.) has been discovered that may play a role in speciation. A single mutation in this gene could lead to a new species. (Would the gene have to be recessive? Wouldn’t do any good to have a new species with only one member.)

Xev, some of the science taught in school or presented in the lay press is simplified to the point of being fiction. It’s prettied up and sanitized and presented as gospel truth. The evolutionary trees seen in texts don’t show the gaps or left-over pieces that don’t fit. Nor do they show the alterations that must be made as new evidence comes to light. Real science lives and breathes and is messy. Not easy to teach in school.

Researchers who used the clock concept for the most part always knew it was an assumption. The rate of mutation if you believe in evolutionary theory shouldn't be constant even for the same gene in two populations exposed to different environments. The different conditions would preference positively the selection of some genes, which actually lower the selective pressures on all others. So even for a gene not being selected, there would tend to differences. Plus as pointed out organisms all have differences in their DNA repair programs and living conditions (which can lead to different types of mutations as well as rates).

This doesn't even really have anything to do with the validity of evolutionary theory.

DNA based trees probably have the distances wrong, but the topology is not necessarily that far off. It isn't an accurate assmption, but it is useful and anything fancy is most likely going to be as bad if not worse and a whole lot more work.

The real reason I would say we aren't evolving in the way it is traditionally thought of is because we have so much control over our environment. However, the frequency of certain genes in our gene pool is going to change anyway due to behavioral differences which are correlated with certain genes. Evolution only requires different frequencies of child bearing nothing more.

I am a biologist and my expertise is in conservation and evolutionary genetics. There appears to be some confusion here about evolutionary theory, molecular clocks and scientific theory. Instead of posting unsolicited responses to misconceptions that I've read here, I'll just offer explanations in regards to evolutionary theory to whoever has questions. Ask away if you wish.

I was jsut curious as to the misconceptions you were talking about?

Well, for example,

evolution is a continuous process, it doesn't turn on and off when the environment changes, but natural selection may. Populations evolve, individuals don't.

scientific theories ARE science, therefore phylogenetic trees are science

Molecular clocks are not silly, they are extremely useful for phylogenetic reconstruction. They match up quite well with the fossil record. Of course, it's not an exact clock as we use clocks, but in geological terms, it's a very good clock.

humans, as H.sapiens, have been around about 10,000 years, certainly no more than 50,000 years.

There are many examples of single gene expressions, but many genes are duplicated.

In regards to biotechnology using genes in economically important species is not ridiculous and it's been done and it works.

Just some examples.

I see your stand on molecular clocks and the like, I was not discounting that one at all. I do know that evolution is ongoing process, my point was, that in the past 50,000 years, there has been very little in the respect to human evolution as a population. I also know that there are huge advance being made in the feild of gene therapy and I think it is a fantastic feild.

If I may ask, what is it you do? Are you a researcher in the feild of evolution? Are you a professor?

I have a Ph.D. in zoology, my graduate expertise is in Conservation genetics, evolutionary genetics, systematics. I'm not a professor, although I have taught classes in genetics, cell biology, biometry, human anatomy, marine biology at the university level as a graduate assistant.

H.sapiens is evolving continuously, although i agree that phenotypically humans haven't changed much, if at all in the last 10,000 years.

It seems that you are also a biologist. Do you currently have a position in a biological field?

Best, Paul

paulsamuel

evolution is a continuous process, it doesn't turn on and off when the environment changes, but natural selection may. Populations evolve, individuals don't.

In your opinion, how is the Earth's now rapidly changing biosphere affecting our evolution?

I do have a BS in biology from the University of Maryland. I actually did a bit of research with plant genetics in college and then moved into toxicology for a bit. Now I am actually in the Sales and Marketing field as an inside sales manager. So I have run the gamut of things in the biological field, soon to move into the booming phara field, hopefully. :-) I am looking to go back to grad school and get my MBA in management and healthcare.

To answer your other question, I feel with the onset of global warming and the over population of so much of the world, that natural selection will begin to equalize the ecosystem. With advent of a heating of the natural environment things will start to change and evolution will continue. I dont reall think that there will be a large scale "natural selection" of humans, but something will occur to change things. Of course, you and I will not see it happen. So everything is only speculation.

By the way, you into March Madness? :-)

There's a couple of different topics in this question.

Our biosphere isn't changing that much. But there is evidence of global warming and humans are affecting the environment. This wil affect evolution of all organisms. There is a recent book out by S.R. Palumbi on this topic.

Although human evolution continues, Human technology and culture protect humans from natural selection. but humans are still affected by disease and environmental toxins.

I have to disagree. Natural selection occurs even on organisms that control their environment. The main issue in evolution is the grouping and proportions of various genes. All this requires is differential reproduction rates and seletive breeding. Both of which occur in human populations.

Morphologically people haven't changed much, but penotype isn't the same as morphology. Medecine has drastically affected evolution of many non-morphological phenotypes. Consider vision defects and diabetes especially.

Everyone has misconceptions including me, please don't put forward your experience as a criteria for accepting yours. You should assert your beliefs and ideas so we can pick the ones that make sense, but not simply tear down that which is imperfect as everything we know was built through mistakes.

I agree, natural selection occurs in all organisms including humans, but humans are protected from natural selection as well, both culturally and through advances in technology. You rightly cite two examples that support this.

I know phenotype isn't the same as morphology, anyone with a dictionary knows the difference. That is why I said phenotype (morphology is a subset of phenotype).

Your statement "Medecine has drastically affected evolution of many non-morphological phenotypes," is imprecise. But if you're talking about medical corrections of genetic defects, then you are agreeing with me. Humans are protected from selection by technological advances. (BTW, if the vision defects your talking about are near-sightedness or far-sightedness or astigmatism, these are morphological).

Finally, if you have followed the thread, and know evolutionary biology, then you would have read the misconceptions posted here. As I wrote in my original post, I would not offer unsolicited comments, and I have only responded to direct questions (and now, this attack). There are two reasons I did this. 1) Discussions of evolution can run in circles and lead nowhere without an understanding of the fundamentals, which I can offer and 2) I only offered to respond to specific questions because I did not want to, in your words, "assert [my] beliefs and ideas." I will assert nothing of the kind because evolutionary biology is not my beliefs and ideas, it's a natural phenomenon. Also, there's plenty of material out there without me running an evolutionary biology course here.

The last two sentences in your post are uncalled for and reflect either a lack of effort on your part to read the entire thread, or an inability to understand what you've read.

RE: March Madness. Go Bows!!

Paul,
I would never intentionally attack anyone. If you construed my post as an attack, can you tell me why (so I can avoid making you feel this way in the future)? I simply disagreed. I don't see how the last two lines are uncalled for. I simply meant to ask (politely with please) that you not simply assert truth without reasoning as to why its true. Maybe I was unclear, but I think answers without explanation are often misleading.

I also admit that I didn't give any more substantiation then you, but I assumed that you would interpret my comments in a contemplative rather than dogmatic and defensive fashion. To be clear, even elimination of selection for a certain trait alters the selective pressures on a species and therefore is effectively a selective pressure of its own (ie one could argue that removing a constraint could speed spread of a closely linked, but improved version of a gene. Essentially an effective pressure for the new and improved version).

I never denied there were misconceptions, I asserted it. You are certainly right that to some extent minor changes in eye shape are morphological defects, but I think my point that genetic change is inevitable and even accelerated by medecine would have been apparent. If not one can certainly stick with diabetes and other diseases (which might in some cases be be due to morphological abnormalities in internal organs leading to systemic issues although the situation is not obvious - my main point was that phenotype on a molecular scale is often not apparent to casual observation like the typical examples given in textbooks.)

Not to be argumentative, but to discuss our apparent difference in views, can you give a definition of fitness that isn't circular? Specifically in the feature that the true measure has to explain the change in genetic composition over time?

Please don't attack me in the future, I don't really appreciate it. Whether I can understand what is written or not , it is either mean to say so or not true. In general I don't think you want to be mean or spread misconceptions. If you can clear up any misconceptions of mine please do so, but don't simply question my intelligence. That isn't very productive.

What I took offense to in your post was your assertion that I was using my "experience," by which I guess that you mean my education, as a criteria for accepting my misconceptions (Your quote: "Everyone has misconceptions including me, please don't put forward your experience as a criteria for accepting yours."). Sounds like an attack to me. You also suggest that I not correct misinterpretations of evolutionary biology. Well, that was my intention all along, as I stated in my first post. I pointed out that there were misconceptions, that I could correct, but I would not do so unsolicited. I there fore thought that you either didn't read my post, or that you misunderstood it. I can think of no third alternative.

Lack of selective pressures or loss of selective pressures from environment or species interaction can lead to loss of gene function (loss of selective constraint on a gene will allow it to freely mutate). Examples are pseudogenes and some genes of the MHC. This loss of function is evolution. I can think of no examples where the following happens:

Your quote:
"To be clear, even elimination of selection for a certain trait alters the selective pressures on a species and therefore is effectively a selective pressure of its own (ie [sic] one could argue that removing a constraint could speed spread of a closely linked, but improved version of a gene. Essentially an effective pressure for the new and improved version)."

If you have examples of this (real ones, i.e. published) please pass them on.


Fitness is a relative term. Simply, it is the amount of one's genetic composition passed on to the next generation relative to the rest of the population. In most eukaryotes, this means reproduction, but there are exceptions (e.g. inclusive fitness).

I didn't attack you or question your intelligence, but as I stated, you either didn't read my first post or didn't understand what I meant.

I hope that I did not start something bad here with all the arguing. I just love science and especially evolution and I like to here views on that.

Also, I have picked the Bows in March Madness!! Lets go Terps!!

Nah, you didn't start anything.

Well I just like to talk...as you can tell. I am interested in learning more about the evolutionary processes. I just bought Darwin's book about it and want to read that soon.

There's lots of great books out there. You know the Gould ones, which are great for non-specialists (and specialists, I read and re-read them all the time).

Also;

The Structure of Biological Science, Rosenberg
and
The Growth of Biological Thought, Mayr.

Best

paulsamuel

Our biosphere isn't changing that much.

If the definition of our biosphere is the part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life, then I'll have to disagree. And so would others...

http://astrobiology.arc.nasa.gov/roadmap/objectives/o14_ecosystem_response.html

http://earthobservatory.nasa.gov/Newsroom/MediaResources/Changing_Global_Land.pdf

http://terra.nasa.gov/FactSheets/LandSurface/

A doubling of the air's CO2 content could well double agricultural production in many areas of the world by merely eliminating the adverse effects of but one air pollutant, i.e., ozone. Then, consider the fact that by the mid-point of the current century, we will likely face a food production crisis of unimaginable proportions...

The biosphere will continue to exist, but not as we know it; for most of its wild diversity of life will have been extinguished by mankind's mad rush to appropriate ever more land and water to grow the food required to feed itself

http://www.co2science.org/edit/v4_edit/v4n43edit.htm

I appreciate the titles of the books. I am going to track them down and read them. Still want to read Darwin first and then get the other ones.

Oh goodness Terps, the 'Origen' is very dry and confusing. (Sheesh, Charlie goes on and on and on about pigeons)

I recommend reading 'Darwin's Ghost' by Steve Jones as a companion.

PaulSamuel: If you don't mind, what is the University of Hawaii like, biology department wise? I'm rather interested in genetics and microbiology especially, and I will probably go to the U of Michigan....but I'm still toying with different universitys.

Thanks.

Xev...what do you do? Are you heading into grad school at Univ of Mich?

Paul welcome to SciForums. Many members of this forum are very interested in the mechanisms of evolution. Member backgrounds vary widely which makes assuming knowledge or lack of knowledge a problem.

“I am a biologist and my expertise is in conservation and evolutionary genetics. There appears to be some confusion here about evolutionary theory, molecular clocks and scientific theory. Instead of posting unsolicited responses to misconceptions that I've read here, I'll just offer explanations in regards to evolutionary theory to whoever has questions. Ask away if you wish.”

This hamster believes you meant this as a generous offering. By not clarifying what posts contained the “confusion” and “misconceptions” the impression left is that all the posts were lacking. The only evidence provided was the authority of your degree.

This hamster, whose area of expertise is not biology, noticed this apparent rudeness. Scilosopher is very well versed in evolutionary biology. (This hamster has greatly appreciated Scilosopher’s postings on biology and evolution on this forum.) This hamster believes Scilosopher’s posts to you were a suggestion that you accord other posters the respect you would give a peer, i.e. don’t assume they are wrong. If they are wrong, explain your reasoning. Then everyone learns.

This hamster hopes to learn from both Paul and Scilosopher.

Here’s part of a discussion on aging that seems relevant to the topic of selection occurring in modern humanity.

“Julia Moravcsik wrote:

Mitochondria age as a person gets older. And yet the mitochondria that we had in our original ova are in the same direct line as our mother's mitochondria (and her mitochondria are in the same direct line as our grandmother's, etc.). It is basically like having mitochondria from the same, very old, organism (who happens to get very small (ova-sized) and then very big (human-sized). So why are the mitochondria of a young person "younger" than the mitochondria of an old person.

Aubrey de Grey replied:

Well, a one-phrase answer is "selection of the fittest": same as one's ova themselves must be no older then one's mother's ova were at the same age. Somatic cells (everything except ova and sperm and the cells that they come from) can age, because they don't lead to cells in one's progeny; hence, the constituents of those cells (such as mitochondria) can age too. Mechanistically, there are various tricks that the body uses to select the healthiest ova (which, among other things, means the ova with the healthiest mitochondria), including atresia, quiescence of ova until ovulation, and clever stuff in oogenesis to make sure that if an ovum is unhealthy then it's very unhealthy (so won't be fertilised).”

The hurdles an egg must pass from fertilization to birth is a selection process that weeds out some harmful mutations.

Paul,
The Hamster summed up my intent well. I just don't like "expertism" in general where somone puts themselves forward as holding the correct view on a given topic. I didn't mean to question the usefulness of your insights, but more the manner in which you presented your role. I agree that you didn't force your views on the thread, but I'm still just not a big fan of that kind of situation. I didn't intend to offend.

Nobody understands evolution that much is clear. Any evolutionary theory accepted or not will therefore have some misconceptions (at least in terms of missing pieces and how they alter the picture) buried within it. Including the views I hold. The fact that I said the same held true for me, makes me wonder why you considered it an attack. Especially since I said please.

Rather than discussing the details of our misunderstanding, please accept my apology (I'm sorry) and let's discuss some ideas. I look forward to hearing your perspectives. I'm much more versed in genetics, developmental, and molecular biology than evolutionaray theory, but any study of biology is greatly enriched by considering evolutionary aspects and I have certainly thought about them a lot. I'm sure my views may be crosswise at odds with certain evolutionary theories because of my mechanistic view of the system in question.

I might not have explained it well, but I believe I read something by Chip Aquadro that suggested hitch-hiking and related effects exist on closely linked genes (especially in regions of low recombination). I quickly browsed the abstracts in pubmed, but couldn't remember which one. There were statistics that supported him in the assertion as well if I'm remembering correctly (I read it over a year ago). I think its reasonable to expect that such effects could exist and significantly alter selective pressure on nieghboring genes both positively and negatively.

I would put forward that humans are more sensitive to natural selection than other organisms as by controlling our environment extensively (especially in medical/nutritional fixes to genetic defects), we alter selection which can feed into more modifications to our environment (ie increased dependence on medecine and research into fixes). We are essentially exposing ourselves to amplified natural selection. Allowing certain genotypes that could never have existed before is clearly imposing selection not buffering from it.

As we are increasing the proportion of some portion of the populace with an otherwise negative trait we are making certain individuals more fit and thereby selecting for the trait. If fitness and thereby natural selection is simply the differential transimission of certain genes or genotypes then we can't buffer ourselves from natural selection w/o explicitly attempting to maintain a specific genetic composition.

If I make any comment you find unclear or imprecise let me know. I will try and clarify, but generally there is a limitation to how much one wants to type and polish the wording of statements in a forum intended mainly for fun. I find that if one can state the difficulty seen with a brief idea/statement it is much more efficient. Often interesting details pop up, whereas a complicated precise statement requires a more complicated and precise response and can lead to an energetic barrier to interactive discussion.

Imahamster,
Interesting, the same considerations go for the germline in general (which is handled more by selection of progeny - and maybe zygotes in general). It makes me think about the maintenance of organization and how selection in some way seems to do work (in a thermodynamics/statistical mechanics sense) on a population. I'm having a hard time figuring out the flows of energy and where to draw the system boundaries as far as what exactly is doing work on what. Maxwell's demon comes to mind - all he did was to select.

Terpsrule:

Gracious, no. I'm 18, much too young for grad school. I've been going to a small community college for the last two years, and it's around time to transfer to a university and start on my.....well, I really don't know what.....

I shall spend the summer trying to accumulate money and figure out just what I want. So, I'm more interested in general information about, well, any school with good biology programs and department.

Any information would be appreciated....but I don't want to hyjack this thread. Thanks.

Paul welcome to Sciforums:

I am not a biologist. This is an interesting thread. I read this here and there, and then search for basic information, so maybe I will understand the essential of the thread. More doubts...I read it again. I am learning ...everyday.

Paul/Scilo/Hamster/Q: please continue sending information.

Thanks for your post. I guess I misunderstood your original post. I didn't mean to imply that the biosphere is static, that is obviously not true. What I meant to say is that the vagaries of the environment have not changed much in the last 50,000 years (since humans have been around).

For example, a quote from one of the links that you posted, "Yet, scientists cannot say what, if any, long-term impacts these changes will have on global climate systems."

This is what I was talking about. I am under the impression that large long-term changes in the global climate have not been documented since humans have been around. Of course this is hard to test. They've been using core samples in the Antarctic ice sheets to determine ancient climates.

I concur that deforestation, loss of biodiversity and large influxes of CO2 from the use of fossil fuels are affecting local environments, but it is hard to determine if these will have long-term global climate effects.

However, even short-term localized environmental changes will affect evolution.

My contention for human evolution is that, at least in technological human populations, natural selection is SOMEWHAT suspended. What do humans die from that would prevent their passing of genes to the next generation? Disease, but you have to subtract the selective pressures of diseases that manifest themselves after reproductive years.

Let's try to think of, and name other selective factors.

Best

Terpsrule, Origin is a hard read, but well worth it. It's amazing how correct many of his insights were, even though nothing was known of genetics at the time.

Xev, I love living in Hawaii. Best place I've ever lived. It will be hard to leave, but job opportunites for me are limited. The genetics department is good. In fact, Rebecca Cann, one of the originators of the "Original Eve" hypothesis of human evolution (The search for Eve. Science. 1992 Apr 3;256(5053):79.) is here. I know one prof. in micro, Ned Ruby, who's pretty famous (symbiosis of Vibrio in squid) but don't know much else.

Good Luck

You stated

"This hamster believes you meant this as a generous offering."

You are right, and thank you.

Then you said,

"Scilosopher is very well versed in evolutionary biology."

I never said he wasn't.

And,

"This hamster believes Scilosopher’s posts to you were a suggestion that you accord other posters the respect you would give a peer, i.e. don’t assume they are wrong. If they are wrong, explain your reasoning. Then everyone learns."

I never accorded anyone with disrespect and never made any assumptions about them. I do believe that unsolicited interventions are rude, so I won't do them. I've only responded to questions and/or statements made directly to me.

Best

Ok, apology accepted. Just a couple clarifying points that may have led to our misunderstanding. You said,

"Any evolutionary theory accepted or not will therefore have some misconceptions (at least in terms of missing pieces and how they alter the picture) buried within it."

I was not talking about evolutionary theories that are (or were) controversial or could be wrong. I was talking about those posts that were unfamiliar with the theory or theories, so misinterpreted them in their posts. I listed some of those in a prior post. To attack a theory that one thinks is wrong is good for science. But to attack a theory because one has misunderstood what the theory was, or was unfamiliar with the theory or concepts behind it, then that's wrong, and fruitless. I am not denigrating those who are unfamiliar with the theories (one can't know everything), which is why I offered clarification on any of those unfamiliar theories. Also, because I know a theory and can explain it, doesn't mean that I am saying that it's true. All I'm saying is that that is the theory. And, I like theories (scientific ones, that is) that are at odds with accepted theories. It was only 50 years or so ago that plate tectonics was scoffed at.

Gene hitch-hiking is well documented. If you use "hitch-hiking" in PubMed search engine (this is the link for those who are interested <http://www.ncbi.nlm.nih.gov/>) you'll come up with a bunch of refs. Hitch-hiking is a type of linkage disequilibrium but a loss of selective pressure would not prevent a loss of genetic function in a hitch-hiking gene. What can happen is a "bad gene" (i.e. one that has negative selection on it) can be maintained in a population if it's tightly linked to a "good gene" (one under positive selection). Is this what you mean? (Anyone with questions on this topic, I'll be glad to try and answer them.)

When you say,

"I would put forward that humans are more sensitive to natural selection than other organisms as by controlling our environment extensively (especially in medical/nutritional fixes to genetic defects), we alter selection which can feed into more modifications to our environment (ie increased dependence on medecine and research into fixes). We are essentially exposing ourselves to amplified natural selection. Allowing certain genotypes that could never have existed before is clearly imposing selection not buffering from it."

we are talking at cross purposes but, I think saying the same thing. In humans (at least those in a technologically advanced society), virtually all humans survive to pass on their genes to the next generation. To me that means selection is relaxed (all survive, no selection). I think you're saying the same thing but you're calling it amplified selection. If this is true, we're arguing semantics, which I won't do.


You say,

"As we are increasing the proportion of some portion of the populace with an otherwise negative trait we are making certain individuals more fit and thereby selecting for the trait."

We are not actively selecting for that trait. That would require us to breed for that allele at the expense of the other. I do agree however that the proportion of that allele increases in the population and we are increasing the fitness of that individual.

Then you say,

"If fitness and thereby natural selection is simply the differential transimission of certain genes or genotypes then we can't buffer ourselves from natural selection w/o explicitly attempting to maintain a specific genetic composition."

Fitness is not the same as natural selection. Natural selection will maintain genetic composition (some genes have been driven to monomorphism through natural selection). We buffer ourselves from natural selection by lessening negative selection on some genes. Again, we may be arguing semantics.

Best,

This hamster’s take on Scilosopher’s point is that mutation “A” might have been disadvantageous without access to modern technology. Hence gene combinations including “A” might be disadvantageous. With technology, “A” in association with other genes is now a viable possibility. The range of viable gene combinations has been extended by technology.

Human technology has not stopped selection. It has only shifted the dominant selection forces. Removing one constraint allows others to dominate. Selection still occurs. (Parent survival is no longer a dominant selection factor in the US. Number of children is a significant factor. This hamster believes this is more selection of family culture rather than genes.)

This hamster believes that most human genetic selection occurs before birth. The selective competition among millions of eggs and sperm is intense. Gametes having only half the genetic material should further increase the selection pressure. Only after survival as a single fertilized egg does further selection at the multi-cellular level occur. Selection as gamete, selection as zygote, selection as embryo, selection as fetus, and finally selection as adult. Significant selection has occurred before a baby is born. To date most attention has been placed on selection after birth. This may be because the tools and science needed to study earlier phases has not existed.

Xev,

I can tell you right now that the UNiv of Maryland is a great school to go to. One thing, you are close to Washington DC and Baltimore, where there are lots of gov't type of jobs and you would be near of the biggest biotech centers in the country, besides California and Boston. IF you want more info email me at terpsrule1@lycos.com.

This thread is getting very good. Looks like we are addressing the issues well and I am enjoying them alot. Paul, can you email the titles of those books you were talking about? Thanks.

I don’t know if this is any help or not. But to the response of the man who commented on the possibility of injecting a gene that produces THC into tomatoes. You said its probably impossible because of there genetic diversity. I would figure if you knew the amino acid sequence of THC you could manufacture an mRNA strand (the codons that code for a particular amino acid are in reference books and nearly universal for all walks of life). if this strand was read by the RNA polymerase and THC was produced it a good bet that its a useable gene. Unfortunately transformation into the tomato would be VERY difficult because little is known about eukaryotic gene regulation, and what is known is sketchy. I would recommend using bacteria such as E. Coli because transformation is quite easy and genes are by default expressed. As far as producing THC that is useable for human consumption much more is needed. Several attempts at the biological synthesis of a chemical have resulted in consumer disasters. In one experiment I believe they were making tryptophan. They synthesized mRNA and included it into the genome of bacteria. When the levels of tryptophan became extremely high in the cytoplasm the cell made a material called 1-ethylidine-bis-L-tryptophan or EBT. EBT causes horrible side effects in humans. Due to poor lab procedure the tryptophan/EBT concoction was ingested causing many to get sick. The reason the bacteria reverted to producing EBT is still unknown. Moral of the story, anything can be modified to make your desired end product but isolation of the end product is key to safe a manufacturing procedure.

Does anyone have anyone have any notable material on the subject? I am very interested.

THC isn't a protien. There's a whole pathway that would need to be transfected for it to work.

I think transgenics in tomatoes works ok, though admittedly tobacco is the best studied plant for transgenics, but that wouldn't make any sense ...

As you pointed out you would probably want the production to be regulated, but that might be difficult as the promoters from plants don't necessarily work in other species (though some probably do ... especially in closely related species).

Speaking of which hops is the plant most closely related to herb. I just say stick with natures gifts if tomatoes were supposed to get you blazed they would.

If what these researchers say is true, that the theory of a molecular clock is hopelessly flawed, scientists have some real reorganization on their hands.

No they don't. This seems to me to be a marginal theory to begin with. Creationists like to think that evolution, or any scientific theory for that matter, is a three-legged stool: you discredit one or a few scientific theorems or experiments and therefore the whole thing is bunkum. This in no way invalidates evolutionary thought as a whole.

le coq

the real genetic evidence for evolution is not the rate of change in DNA, but gene homology...

why do we all share similar genes?

Why are the genes of some species more similar than others (because they are more related).

That there is some disagreement about the rate of changes between two species is interesting but hardly makes a problem for evolution

good point, I wasnt thinking. THC isnt a protien. As far as the gene regulation goes, if your going to use tobacco you could PROBABLY use some sort of plasmid (assuming that tobacco accepts plasmids) to inject the pathway. if the pathway is too long however the the sticky ends of it (assuming pathway genes are sequencal) probably wont bind, even if you find the proper digestion enzymes. write back with thoughts

I am a biologist, well im still in school :(

Evolution is real folks! The evidence it mind boggling!

I think the problem here is that people are afraid that evolution kills god. This is simple not true. Evolution does not require a god but that not to say there is not one? To put it bluntly science could NEVER disprove god! So you can keep your deities and eat your cake too.

Though the bible that’s just plain false. A book of mythology in my option! Have you ever read these things it say stuff in there like you should eat your children if your under siege and that if a man rapes your daughter you he can get away with it by paying you a ridiculously small amount of money. Jess, that book is scary just plan scary! Genesis though entirely wrong is in no way as bad as some of the other stuff in there!

Originally posted by WellCookedFetus

I think the problem here is that people are afraid that evolution kills god. This is simple not true. Evolution does not require a god but that not to say there is not one? To put it bluntly science could NEVER disprove god! So you can keep your deities and eat your cake too.


Essentially evolution killed god because it pushed mankind out of the center of the universe. We used to be special before evolution was introduced. Man was created in gods image. Man was the center of the universe and everything revolved around man. Then evolution came along and reduced us to mere animals. We were just another insignificant part of nature.

So yes, evolution did kill of god. Yes, you might still think that there is a god because we can't prove that there isn't. But the most important reason to believe in god has been shown to be false. That we are in some way a special creation with a special purpose.

I don't, I'm just trying to devise a way for creationist not to hate me. I don't think that "we are not special" is even provable… your example explains nothing.

Originally posted by WellCookedFetus
I don't, I'm just trying to devise a way for creationist not to hate me. I don't think that "we are not special" is even provable… your example explains nothing.

'we are not special' is proven by evolution.

how?

we are not specially created, but a product of evolution as is every other species on this world. We are not on the top of the tree, but merely another branch on the bush of evolution like every other species.

quote from 'descent of man' by charles darwin:

'It is incredible that all these facts should speak falsely. He who is not content to look, like a savage, at the phenomena of nature as disconnected, cannot any longer believe that man is the work of a separate act of creation. He will be forced to admit that the close resemblance of the embryo of man to that, for instance, of a dog- the construction of his skull, limbs and whole frame on the same plan with that of other mammals, independently of the uses to which the parts may be put- the occasional re-appearance of various structures, for instance of several muscles, which man does not normally possess, but which are common to the Quadrumana- and a crowd of analogous facts- all point in the plainest manner to the conclusion that man is the co-descendant with other mammals of a common progenitor.'

So? I could say we are spacial because we are very intelligent and can develop technology and crush everything in a wake...

any species is special in a certain way (goldfish are probably more remarkable than us in terms of physiological adaptations, etc etc). But before we thought that we were above nature. Then we became part of nature.

It is just that we got used to the concept of evolution and hence we forgot that at one point the whole essence of the debate was about us being part of the whole nature thing, or being a special creation.

So basically people are just pushing forward their definition of special. But the big battle was already lost more than 100 years ago. No it is limited to a few skirmishes. People are special because we are so intelligent, we are special because we use tools, we are special because we have morals...etc etc. We just pick out qualities we know we are good at and make them special. But for all the examples I mentioned they also found animal counterparts. Hence are we that special? no...the only thing we seem to be special at is that we like to deceive ourselves.

well...that's my view on the matter. You may disagree of course.

I don't really disagree i just think that creationist can find way of excepting evolution as true and still believe in there deities.

yep...i totally agree on that. They should read more on the history of this debate. Then they might found out that they are simply nitpicking now, because that is what they are doing. The real battle is history.

There is no empirical evidence supporting macro-evolution whatsoever. Genes have the ability to reorder themselves within a certain threshold, this is micro-evolution. Nowhere is there evidence of new genes being created in "adaptation".

An interesting note,
A lizard's leg would be a bad leg long before it became a good wing, rendering it an inferior specimen... it would be eliminated.

But then, what I think is pretty irrelavent. Jut look out the window.

There is no empirical evidence supporting macro-evolution whatsoever. Genes have the ability to reorder themselves within a certain threshold, this is micro-evolution. Nowhere is there evidence of new genes being created in "adaptation".

Duplication of genes.

For instance:
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=299744
Hox genes play a key role in animal body plan development. These genes tend to occur in tightly linked clusters in the genome. Vertebrates and invertebrates differ in their Hox cluster number, with vertebrates having multiple clusters and invertebrates usually having only one. Recent evidence shows that vertebrate Hox clusters are structurally more constrained than invertebrate Hox clusters; they exclude transposable elements, do not undergo tandem duplications, and conserve their intergenic distances and gene order. These constraints are only relaxed after a cluster duplication. In contrast, invertebrate Hox clusters are structurally more plastic; tandem duplications are common, the linkage of Hox genes can change quickly, or they can lose their structural integrity completely. We propose that the constraints on vertebrate Hox cluster structure lead to an association between the retention of duplicated Hox clusters and adaptive radiations. After a duplication the constraints on Hox cluster structure are temporarily lifted, which opens a window of evolvability for the Hox clusters. If this window of evolvability coincides with an adaptive radiation, chances are that a modified Hox cluster becomes recruited in an evolutionary novelty and then both copies of duplicated Hox clusters are retained.