Anyone care to answer this?

reply to post by Zenithar


You seem to be making the mistake of assuming that the first organisms were very similar to 'modern' cells. This is extremely unlikely to the point of absurdity. The video below describes the work of Dr. Jack W. Szostak in relation to abiogenesis (first life). The first 2:40 or so is an answer to Creationists that confuse abiogenesis with evolution and think that the first cell had to 'pop' into existence fully formed in all its exquisite complicated wonderfulness. After 2:40 it gets really interesting. Abiogenesis is just physics and chemistry and inevitable in the environment as it existed at the time the first life 'started'.

To quote the comments from the poster of the video:

This video summarizes one of the best leading models. Yes there are others. Science may never know exactly how life DID start, but we will know many ways how life COULD start.

Dr. Szostak's ideas are still 'just' hypotheses so far. His work, and that of many others, is, of course, being run through the meat grinder of biochemical debate, experiment, peer review, argument, and synthesis as science works towards a theory. Never-the-less it is a very convincing demonstration of how abiogenesis could have proceeded, and indeed would have been inevitable given the conditions existing at the time.



Now to address some of your specific questions:

okay so there first organissm dont need blood clotting(thats of course a guess from you and scicen i presume)
so...when it evolves a circulatory system, surely it would not have a ready made clotting system in place also, it would be far too coincidental,,

Remember that a blood cell is just a cell, even if a highly specialized cell. Blood wasn't required for many many many many many many, etc... generations after the first multicellular organisms. The first organism with 'blood' very likely did not have a clotting mechanism, why would it? But the first organism with both blood and clotting would have had an advantage over their cousins that had only blood without clotting. That little advantage, to be able to survive damage with out leaking to death, would have ensured that those individuals who had the ability would have multiplied and spread that benefit to their more abundantly offspring. That is natural selection - evolution at work.

also, surely the first organisms had dna or some sort, and surely that dna was susceptible to mutations, even more so!!

Not DNA, no, but nucleotides of some sort. A high mutation rate would be critical for throwing up lots and lots and lots of trials, the ones that worked would multiply and keep mutating and evolving, the ones that didn't work would not multiply (at least not as well). The simpler the organism, the greater the effect of mutations. The extreme variety of one celled organisms today is testament to this. That is natural selection - evolution at work. .

soooo, how did that dna ever survive without a repair mechanism? surely you cant belive it was in place from the beginning!!

You are right, like blood clotting, it wouldn't have been in place from the beginning. Organisms without a DNA repair system would be subject to high mutation rates, and high replication error ('birth' defect) rates. At some point down the track a random mutation threw up the DNA repair mechanism and possessors of that mutation would have a decided advantage over their cousins with out it. Organisms that carried the repair mechanism would be automatically more stable as a species and would out survive organisms without it. That is natural selection - evolution at work.

Interestingly, speaking of the need to repair and protect chromosomes, Dr. Szostak (of the video above) and his team earned the 2009 Nobel Prize for Physiology or Medicine for his work on telomeres and the discovery of how they serve to protect chromosomes.

'In the beginning' the lack of an error replication mechanism is an advantage for building up a large gene pool, that is, for producing a large variety of different organisms that can find their 'niche' in a variety of habitats. Each time something comes along that gives an advantage to one organism over another in any particular niche, the newcomer will come to dominate the population. The first organisms didn't have DNA, but something much simpler (remember the video above). Topoisomerase allows an organism to have longer more complicated DNA strands. Organisms don't require topoisomerase necessarily, but without it they are restricted to being quite simple organisms. Blood clotting allows an individual organism to survive minor damage without leaking to death.

Protection from damage, and the ability to repair damage when it does occur, are extremely advantageous to organisms that have that ability. Lack of these features do not automatically make an organism unviable, just more fragile, less stable.

reply to post by Zenithar


That was a serious reply it was funny to stop the writer getting bored mindless over the same old attitudes from the punters - beam me sideways Spotty ...

reply to post by Zenithar

you go on to say..."the giraffes heart and neck would have evolved together throughout the centuries as a mean to accomplish its tasks." this sentence is crazy imo, firstly can you prove this?

It makes no sense to ask for 'proof' in this context. The giraffe exists, it has a long neck, and a heart that is capable of pumping blood to the brain. Obviously, a couple of "pre-giraffes" with short necks didn't mate and give birth to the first giraffe with a long neck and a specialized heart in one generation. That idea is absurd, and the 'proof' that the heart and the long neck evolved in tandem is in the simple fact of their existence.

Clearly a an individual of some species of 'normal' necked animals (the 'not' giraffes) gained some advantage over its brothers and cousins because it had a bit of a longer neck due to some random mutation. The advantage meant that it could breed or protect itself better that it rivals, so the mutation spread through the population. Each succeeding generation found and advantage with longer and longer necks. At some point, the neck would be too long for the 'original' heart. Individuals in the 'medium length' neck population (the 'almost' giraffes) who had a mutation for a stronger heart would then have an advantage over those without. The descendants of the 'almost giraffes' with the strong heart could continue lengthening the neck and evolve into 'real' giraffes.

second, the faith required to assume this co evolution could occur through random mutations etc is just immense

There is no 'faith' involved what-so-ever. There is only observation: giraffes exist, long necks pose problems for blood circulation; and explanation: long necks provide advantage over rivals with short necks, strong hearts allow long necks, individuals with strong hearts can maintain longer necks and gain more advantage than those individuals that are limited by their hearts; prediction: there should be evidence of the "not-giraffe" and the "almost-giraffe"; and confirmation: a goodly list of not-giraffe's and almost-giraffes is known - climacoceras, Palaeotragus, samotherium, honanotherium, etc. The okapi is a surviving descendant of the "almost-giraffe" that perhaps didn't have the 'strong heart' mutation to enable it to gain a long neck.

Here are some links for your enjoyment:

Investigating Giraffe Evolution!
Edyta's Research Paper: Evolution of the Giraffe Neck Via Sexual Selection
Transitional Vertebrate Fossils FAQ part 2c
Animal Corner: Giraffe Anatomy

Perhaps the best link is: Skeptic Wiki: Neck of the Giraffe which offers this explanation:

It is perfectly true that the neck of the giraffe would be fatal if the giraffe had a small heart, or that the blood pressure produced by the heart of the giraffe would be fatal if the giraffe had thin arteries. However, evolutionary theory does not say that evolution does its work first on one feature of an animal, and then on another: it says the very opposite. Obviously random mutations do not form an orderly queue, with those extending the length of the neck going first, those increasing the blood pressure going second, and so forth. Instead, a slightly longer neck gives a selective advantage to a slightly stronger heart, which gives a selective advantage to slightly thicker arteries. So long as there is environmental pressure for slightly longer necks, there is also a selective pressure for these coadaptations, and mutations for them will be favored. It is rather depressing to think that nearly 150 years ago, Darwin gave the same answer to the same grotesque misunderstanding of his theory concerning the same animal, and that it is necessary to repeat it:

"With animals such as the giraffe, of which the whole structure is admirably co-ordinated for certain purposes, it has been supposed that all the parts must have been simultaneously modified; and it has been argued that, on the principle of natural selection, this is scarcely possible. But in thus arguing, it has been tacitly assumed that the variations must have been abrupt and great.[2]"

With this theoretical error, the Creationists compound a crass factual error: supposing that the particular features named are unique to the giraffe. Not one of them is.

* The giraffe has elasticated arteries? So do you, I trust. Hardening of the arteries is an undesirable medical condition: all arteries are by nature elastic.

* The giraffe’s cerebrospinal fluid produces a counter-pressure to prevent rupture or capillary leakage? This again is true of all mammals, and is a matter not of design nor of evolution, but basic physics.

* The giraffe has valves in the veins of its neck? So do all mammals. You too have a jugular valve.

* Giraffes have pressure sensors in their neck arteries? Again, so do all mammals.

* The giraffe has a rete mirable? So do most of its relatives: The function of the rete mirabile is to regulate the flow of arterial blood towards the cerebrum as well as the thermal regulation of the brain preventing it from overheating; the arterial system of the cerebrum in ruminants […] is equipped with a safety system. [3]

* The giraffe has a shunt between the carotid and vertebral arteries? So do many of its relatives, including its closest relative, the okapi, which has a short neck.

In summary, the mechanisms which the giraffe uses to control its blood pressure are all either common to mammals in general, or common to the species most closely related to the giraffe.

reply to post by KilgoreTrout



I know, I never saw it mentioned in a biology textbook in school, just recently came across it listening to Richard Dawkin's An Ancestor's Tale.

I don't know how recent the discovery is, though, he mentioned it but the problem with audio books is you can't underline key points.

Originally posted by RuneSpider
reply to post by KilgoreTrout

 

I know, I never saw it mentioned in a biology textbook in school, just recently came across it listening to Richard Dawkin's An Ancestor's Tale.

I don't know how recent the discovery is, though, he mentioned it but the problem with audio books is you can't underline key points.

I work at the cutting edge of plant breeding/biology and I have never heard the term used. That's the problem with theories, they're seldom applied critically to all life. Same with evolution, it is just another theory, one that can sometimes be used to answer a simple question, but it, being the standard, is overly applied and so answers none of the niggles. The little theories, like Ring Species, don't get the press so other branches of specialised study don't know to apply it.

Interestingly, though off topic, there is a study in progress at the moment where I work, not my department, investigating 'pseudo-domestication'. There is a very real fear developing within plant science that we don't understand the mechanisms of plant evolution at all, and that it is going to bite us very firmly on the arse in the course of climate change. We, as a species, are entirely dependent on a very, very, very small cache of plant based food sources, all of them domesticated and bred for very specific conditions.

reply to post by KilgoreTrout

We, as a species, are entirely dependent on a very, very, very small cache of plant based food sources, all of them domesticated and bred for very specific conditions.

Yeah, think maize for example - sweet corn is an entirely artificial artifact (I know: redundant) that would disappear without human intervention.

Likewise dates and other staples. How many rice varieties would disappear with out human aid?

The answer is....let me think this one out and the answer will come into existence...hmmmm!

Originally posted by rnaa
reply to post by Zenithar

 

You seem to be making the mistake of assuming that the first organisms were very similar to 'modern' cells. This is extremely unlikely to the point of absurdity. The video below describes the work of Dr. Jack W. Szostak in relation to abiogenesis (first life). The first 2:40 or so is an answer to Creationists that confuse abiogenesis with evolution and think that the first cell had to 'pop' into existence fully formed in all its exquisite complicated wonderfulness. After 2:40 it gets really interesting. Abiogenesis is just physics and chemistry and inevitable in the environment as it existed at the time the first life 'started'.

I assure you I am not making the mistake, if you had read through my previous answers and thread you would no that i am neither a creationist nor do i confuse evolution with abiogenisis, I am talking about the first oganissm THAT HAD these systems, not where or when they originated, we know that at some point, single celeld organisms would replicate many millinos of time, im simply saying that if dna repair was not there, there dead, and if it is there, and the enzyme topoisimerase is not at the same time, its dead,.. so surely its a belif system to think these components were present at this right time!

now i think its you making assumptions " inevitable in the environment as it existed at the time the first life 'started'. " now this is a crazy statement, firstly that whol enviroment is hypothetical, and second, it is not inevitable at all, that is nonsense, what can i say, if you want to belive that its inevitable then thats your way.


To quote the comments from the poster of the video:

This video summarizes one of the best leading models. Yes there are others. Science may never know exactly how life DID start, but we will know many ways how life COULD start.

Dr. Szostak's ideas are still 'just' hypotheses so far. His work, and that of many others, is, of course, being run through the meat grinder of biochemical debate, experiment, peer review, argument, and synthesis as science works towards a theory. Never-the-less it is a very convincing demonstration of how abiogenesis could have proceeded, and indeed would have been inevitable given the conditions existing at the time.

Now to address some of your specific questions:

okay so there first organissm dont need blood clotting(thats of course a guess from you and scicen i presume)
so...when it evolves a circulatory system, surely it would not have a ready made clotting system in place also, it would be far too coincidental,,

Remember that a blood cell is just a cell, even if a highly specialized cell. Blood wasn't required for many many many many many many, etc... generations after the first multicellular organisms. The first organism with 'blood' very likely did not have a clotting mechanism, why would it? But the first organism with both blood and clotting would have had an advantage over their cousins that had only blood without clotting. That little advantage, to be able to survive damage with out leaking to death, would have ensured that those individuals who had the ability would have multiplied and spread that benefit to their more abundantly offspring. That is natural selection - evolution at work.

how would those without clotting survive so many generations of "waitign for blood clotting to arive"
and what about when they multiplied, without topoisimerase present, supercoiing prevents the informatino bieng
read,,,

also, surely the first organisms had dna or some sort, and surely that dna was susceptible to mutations, even more so!!

Not DNA, no, but nucleotides of some sort. A high mutation rate would be critical for throwing up lots and lots and lots of trials, the ones that worked would multiply and keep mutating and evolving, the ones that didn't work would not multiply (at least not as well). The simpler the organism, the greater the effect of mutations. The extreme variety of one celled organisms today is testament to this. That is natural selection - evolution at work. .

soooo, how did that dna ever survive without a repair mechanism? surely you cant belive it was in place from the beginning!!

You are right, like blood clotting, it wouldn't have been in place from the beginning. Organisms without a DNA repair system would be subject to high mutation rates, and high replication error ('birth' defect) rates. At some point down the track a random mutation threw up the DNA repair mechanism and possessors of that mutation would have a decided advantage over their cousins with out it. Organisms that carried the repair mechanism would be automatically more stable as a species and would out survive organisms without it. That is natural selection - evolution at work. Interestingly, speaking of the need to repair and protect chromosomes, Dr. Szostak (of the video above) and his team earned the 2009 Nobel Prize for Physiology or Medicine for his work on telomeres and the discovery of how they serve to protect chromosomes. 'In the beginning' the lack of an error replication mechanism is an advantage for building up a large gene pool, that is, for producing a large variety of different organisms that can find their 'niche' in a variety of habitats. Each time something comes along that gives an advantage to one organism over another in any particular niche, the newcomer will come to dominate the population. The first organisms didn't have DNA, but something much simpler (remember the video above). Topoisomerase allows an organism to have longer more complicated DNA strands. Organisms don't require topoisomerase necessarily, but without it they are restricted to being quite simple organisms. Blood clotting allows an individual organism to survive minor damage without leaking to death. Protection from damage, and the ability to repair damage when it does occur, are extremely advantageous to organisms that have that ability. Lack of these features do not automatically make an organism unviable, just more fragile, less stable.

edit on 26/10/2010 by rnaa because: I like correcting myself. Its therapeutic.

you say... At some point down the track a random mutation threw up the DNA repair mechanism

this is wherer the faith comes in for me, i mean, most of what you described above is obvious, its simply what would happen IF those proposed circumstances actually happend, we cannot simply accept it did. i am a searcher of knowledge and never take this kind of thing on authority but dig in and form my own opinion,
you say "Lack of these features do not automatically make an organism unviable"
can you demonstrate this to me? i mean , it dosent matter that much in terms of my argument but id be very interested to see a currently living organism of this type.
those cells that did not have blood clotting in the early earth, how would they survive all those replications without dna repair? wouldnt it be a lot more likey that they would all die, infact the supposed atmosphere of that tiem would ravage anything not adapted, dna repair was surely teh least of a small cells worries!
anyway

you say "Not DNA, no, but nucleotides of some sort"
one of the many assumptions above, nothign wrong with an inference but evolution goes too far in trying to explain certain "designed" featurse in the natural world


as it stands for me, from my reseach, the mechanisms proposed to produce the astonishing adaptions around us just does not add up al all imo

reply to post by Zenithar

I assure you I am not making the mistake, if you had read through my previous answers and thread you would no that i am neither a creationist nor do i confuse evolution with abiogenisis,

I didn't mean to imply that at all, I was pointing out that the first bit of the video was aimed at those people, that is why I directed you to the interesting part.

I am talking about the first oganissm THAT HAD these systems, not where or when they originated, we know that at some point, single celeld organisms would replicate many millinos of time, im simply saying that if dna repair was not there, there dead,

But you are wrong. If DNA repair is not there, then the population may be unstable but individuals still exist and live out whatever life they live out, but when they reproduce, the offspring may be radically different from parents, and there may be a huge mortality rate. This is not a difficult concept to understand, millions of human sperm are produced to fertilize one egg, the high mortality rate for sperm is not only not a problem, it allows for the vast majority of uncorrected replication errors to be 'filtered' out (defective sperm are usually slow swimmers). The FACT, not belief, FACT, that life survived this problem is self authenticating proof.

and if it is there, and the enzyme topoisimerase is not at the same time, its dead,.. so surely its a belif system to think these components were present at this right time!

You have to understand that only DNA damaged individuals are at risk. If there are millions of individuals in the population, high mortality rates can be absorbed with little or no impact on the population as a whole. DNA errors don't strike every individual, it is only when the populations get quite small that an unrepaired fatal DNA mutation would cause problems.

now i think its you making assumptions " inevitable in the environment as it existed at the time the first life 'started'. now this is a crazy statement, firstly that whol enviroment is hypothetical,

I clearly stated that this is one of many possible models. The described 'hypothetical' environment is not really very hypothetical, it is based on solid evidence, but it is true that it is not certain. As the disclaimer I quoted states, we'll never know exactly how life started, but we will know many ways it could have started. If we identify all (an impossible absolute, of course) possible pre-existing situations and show how life would have started in each, then we may not know for certain which one was operative, but we certainly know that it could have started in some way.

and second, it is not inevitable at all,

In the environment described the chemistry and the physics would make the processes described inevitable. It is simple, well understood, organic chemistry and physics. Even though the exact conditions of that environment is uncertain, the physics and organic chemistry would work in a wide range of possible pre-biotic environments. Some of those environments exist even today; although life has radically changed the chemical composition of the oceans, the environment near sea vents are quite similar to what could have been expected in the pre-biotic ocean.

how would those without clotting survive so many generations of "waitign for blood clotting to arive"

By not getting damaged at least until they had reproduced? Or by not having a circulatory system that suffers a fatal leak when damaged? Does a 'ciculatory system' necessarily imply a 'modern' tube system driven by a pump?

Or maybe the clotting capability did come first and made it possible for tubes and pumps to evolve later.

and what about when they multiplied, without topoisimerase present, supercoiing prevents the informatino bieng
read,

Only if the strands are long enough to coil. And only if they are 'modern' DNA nucleotides.

You seem to have a blockage that two dependent processes could only have been evolved in parallel. Today an automobile could not exist without a steering wheel, but the first cars didn't use a steering wheel. And the wheel was invented millenia before the automobile. Things don't necessarily happen in lock step in evolution either.

you say... At some point down the track a random mutation threw up the DNA repair mechanism

this is wherer the faith comes in for me, i mean, most of what you described above is obvious, its simply what would happen IF those proposed circumstances actually happend, we cannot simply accept it did.

We must accept the fact of existence, there is no faith involved in existence, it either is or it isn't. Since it is, then there are few possibilities: supernatural creation of full blown complicated DNA with error correction enzymes in place, evolution of DNA without error correction enzymes present, synthesis of error correction enzymes separate from and prior to DNA serendipitously in place for when DNA happens along. The first is faith based on the existence of a supernatural force, the other two can (in theory) be demonstrated with out reliance on faith.

i am a searcher of knowledge and never take this kind of thing on authority but dig in and form my own opinion,

An honorable ambition. Be careful not to fall into the trap of thinking that one person in one lifetime can reproduce the entire knowledgebase of the human race. Also remember that scientists don't form opinions on this stuff, they observe and experiment and extrapolate and argue and disagree and synthesize theories from hypotheses.

When an hypothesis has been demonstrated to successfully describe a phenomena and make successful predictions it becomes recognized as a theory. When that happens, scientists can accept it as a building block for further work, and not have to return to first principles for everything that is already well understood. Yes new findings sometimes identify holes in existing theory and corrections are required, but when the correction is being formulated, the work that went into the original theory does not have to be revisited, only that part that is affected by the new data. Einstein didn't overthrow Newton. Pool tables and inclined planes still work the same way they always did. Einstein just solved more problems than Newton could and showed where Newton's limits lay.

you say "Lack of these features do not automatically make an organism unviable"
can you demonstrate this to me? i mean , it dosent matter that much in terms of my argument but id be very interested to see a currently living organism of this type.

Well, I am not personally familiar with any specific examples of species existing today with a circulation system and without a blood clotting mechanism if that is what you want. However I can point you to human hemophiliacs that survive quite well as long as they don't get damaged. This is not a satisfactory answer to your question, but it does make a point. The important thing in evolution is the population, not the individual. You have to get beyond the individual to the population. If there are millions of individuals in a generation, a high mortality rate is easily absorbed. Turtles lay hundreds of eggs in a generation, but only a few individuals survive. It is the population that counts, not the individual.

Furthermore, I can point out that even with DNA repair mechanisms in modern cells, not every DNA error is corrected, thus evolution continues. Some of these errors produce drastic birth defects. Not all birth defects are fatal at birth and individuals live for many years, even normal lifespans, and even reproduce. DNA damage to an individual is clearly not necessarily fatal to the individual, and obviously not to the population as a whole.

I can refer you to CB 200.2: Blood Clotting and Irriducible Complexity for a critique of the notion that circulation and clotting are 'designed'.

Several references are provided at that page thay may be helpful to you in your knowledge search. It appears that Dolphins and Pufferfish survive quite well without all the recognizable components of blood clotting mechanism.

How about plants? Plants have a circulation system and not all of them 'clot' and humans take advantage of that fact to gather the sap of the rubber tree and the maple tree.

those cells that did not have blood clotting in the early earth, how would they survive all those replications without dna repair?

What does blood clotting have to do with DNA repair? I'm not sure which question you want answered.

Organisms with a circulation system but without a clotting mechanism would only be in trouble when they were damaged. Not every individual gets cut and bleeds to death, and remember, the individual only has to survive to reproduce anyway. It is the population that has to survive, not the individual.

DNA errors in an individual does not affect the entire population, only the individual. Not every reproduction results in 'errors' in DNA, not every DNA 'error' is fatal, some DNA 'errors' are beneficial. If a DNA 'error' is beneficial to the individual's reproduction capability, that individual will pass it into the population via its descendants so that the population as a whole will gain the benefit. If a DNA 'error' is detrimental to an individual's reproduction capability, it won't pass into the population because there will be fewer or no descendants to carry it.

wouldnt it be a lot more likey that they would all die,

No, it would be extremely unlikely that they would all die. Only individuals that got cut somehow would die. As long as enough individuals survived to reproduce, the population would continue. They are in the ocean, what is going to cut them? Is the entire population going to bounce off rocks?

infact the supposed atmosphere of that tiem would ravage anything not adapted,

Since this was going on in the ocean, the atmosphere wouldn't make any difference to this problem. By the way, the atmosphere is as we know it today because life has made it that way; life didn't adapt to the atmosphere, life adapted the atmosphere to life!

dna repair was surely teh least of a small cells worries!

DNA repair would have been detrimental to early life, by my way of thinking. Even though the mortality rate may have been higher for individuals, a high mutation rate would increase the gene pool quickly. Stabilizing DNA acts to slow down the mutation rate.

DNA and RNA would have to be working together from the beginning. They´re very complex structures in our cells. To believe otherwise, would be fantasy. DNA is necessary to produce proteins, and proteins are necessary to produce DNA. Which one came first?

reply to post by spaceship100

DNA and RNA would have to be working together from the beginning.

Sorry, this just isn't true.

RNA was clearly around doing its thing before DNA. There is a large body of work in abiogenesis concerning the "RNA World" hypothesis. Different types of RNA can do everything DNA can do including store information, build proteins, and reproduce. DNA is more efficient and more stable than RNA, so natural selection favored it and virtually all known life today uses DNA. But RNA was first, and DNA came later.

Wikipedia has a good summary of the the RNA World Hypothesis (NOT theory) including its pros and cons.

reply to post by Zenithar


Don't let your mind be so open that your brain falls out. Critical thinking and application of logic is not being "close-minded."

Originally posted by KilgoreTrout
The neck is not a big deal, it is proven. Brachiasaurus, Diplodocus, has incredibly long, flexible necks. But they were cold blooded and very small brained (proportionately), so the heart may not have needed to have been as big, and therefore, they would not have needed the value system in the neck to control the pressure of the blood flow. But either way, without those adaptations, the long neck, combined with a mammalian brain, wouldn’t be feasible without the huge heart and ‘neck’ valves.

Well, first, dinosaurs were not cold-blooded. A sauropod probably had a relatively cool temperature, because it's huge, and retains heat easily, but it was endothermic, just like all dinosaurs.

Second, the sauropods did not hold their necks upright like a giraffe does - at least they didn't all the time. Sadly we don't have relevant sauropod soft tissues - they may have had valves, or a gigantic heart, or maybe their arteries were muscular and used a system like peristalsis. We don't know.

Therefore, long necks, large hearts, and valves are all regularly occurring mutations. For those mutations to then succeed and become a ‘feature’ of success, they have to both occur with enough frequency to allow the pairing of the necessary genes, but infrequently enough for it to be given a preference in sexual selection. There must also, most importantly be a ‘drive’, either sexual or dietary, that leads to that trait being passed onto successive generations. That is, it is no accident, it is driven by a desire, in this case, to reach higher, the Giraffe forces it’s own evolution.

That's false, actually - Lamarckism. It actually works in the opposite direction - the trait manifests, and then the organism uses it to some advantage; the trait does not appear because the organism needs that advantage. All that leads to traits being passed to successive generations is the sexual success of those individuals bearing the genes for those traits. In theory a successful genetic change will lead to a longer life and either more sex or better reproductive ability, while a detrimental one has the opposite effect.

That is, a giraffe's long neck would only get passed on if the long-necked individuals managed to get laid more. if, by some fluke, long-necked giraffes also had say, weaker sperm cells, then the long neck would lose out to stumpy necks, even if having a longer neck opened up more food resources.

The tongue is specially adapted to wrap around a stem, and strip the leaves and young shoots, off the stem. It primarily favours the Acacia erioloba and I wonder if there is a symbiotic relationship, evolutionary wise in that. The roots and bark of the tree were used by humans to treat headaches, it may have blood thinning properties.

I have a notion that a giraffe will "favor" anything that it can eat. Acacia happen to be the most common available forage in the habitat of the giraffe. Acacia has actually been tested as a blood thinner, and there's no support for the claim; it was traditionally used for treatment of headaches and blood clots, but remember, the Chinese think tiger penis soup is an aphrodisiac. "Folk remedies" either work or they don't - the oens that do are called "medicine."

Giraffes have very good eyesight, the leaves are probably rich in betacarotenes, which the Giraffe then converts into Retinal.

Giraffes also have very large eyes situated on the sides of their head. This has way more impact on their eyesight than any possible gain from their favorite foliage.

Given the markings of the Giraffe, it is likely that they have a surplus of betacarotenes in their diet that allow for the markings.

Easy to test - feed captive giraffes BC-poor diets. I'dwager they develop the same color patterns they would anyway.

It also allows them to see the markings, they most likely have three colour vision.

Highly unlikely they have trichromatic vision. The vast majority of mammals have dichromatic vision, owing to our Class' early origins as nocturnal critters. You don't need color vision if there's no light to see color by. There's no reason for giraffes to be the lone artiodactyl with color vision.

In fact, if they had color vision, we could expect the several species of giraffe, who are almost identical in body shape, to be very differently colored, so they could tell each other apart. It's how birds do it, it's how reptiles do it, it's even how a lot of primates do it. However, the giraffe species don't have different colorations; they're all pretty uniform, brown blotches on beige.

However, those spots are key to differentiating the species - by shape. A giraffe can't see the colors of another giraffe's hide, but they can tell the shape of the spots. It's pretty much what you'd expect!

The tree, has very yellow flowers, which have a sweet scent, the Giraffes have good sense of small. Because of the thorns, which are impressive, the tongue has to reach where the eyes can’t see. Hence the co-evolution. The plant produces betacarotenes that help the animal to see Yellow (and orange), I’d bet my bottom dollar, that the Giraffes are the main pollenators too. And it has yellow, scented flowers, that tell the Giraffe where the young leaves it likes so much are, and the Giraffe is ‘tricked’ into rubbing it’s snout in the pollen.

You'd lose your bottom dollar. Giraffes eat the flowers, which is directly counterproductive to the whole notion of pollination. Rather, the main pollinators of acacia - in Africa, South America, Asia, and everywhere they've been introduced (most such places are noticeably short on giraffes) - are small wasps and beetles.

The scents and colors are there for the benefit of athropods; if the acacia benefited from giraffes eating it, it wouldn't have three-inch spines shooting out of every branch. Filled with ants. Ants that hate you.

the concepts evolution and revolution are misplaced in english language; if an animal was revoluting on an island and its past state was the eve of being on that island im sure its complexity would compensate for its state. is that faith or work? if darwin attempts to state that complexity in life is attained by selection then his being is a work that is selfish as evident by the study of his history; being a feeble and brackish man in the eyes of society who propelled him in the face of complexities for their own sake.

reply to post by LordBucket


The first question that pops into my head about punctuated equilibrium evolution is how long do they think it takes? I suppose that it's short in natural history standards, but still how long? And second of all, how do interdependent systems suddenly evolve? Equilibrium is saying that the same mutations took place but that they took less time to do so if I'm getting this correctly. That seems like more of a stretch. It would make more sense if both forms of evolution happened simultaneously, but both systems require the same faith described by the poster. How does the new theory explain this?

Eh you could've stopped at bacterial flagellum, but I'm not a science expert what do I know?