Beginner question regarding evolution

[silenzer]

Hi,

I stumbled on your website when looking for a good place to ask educated professionals.
I'm 16, I have a question on evolution.

Ok so let's say there are these birds on an island with a food source that require long pecks, but these birds have smaller pecks than needed. So after a long time, I'm not sure to say how long, the birds have developed a longer peck, enabling them to reach the food source.
Now, as I understand, mutations happen every day and most of them are harmless, and some of them don't even matter. Perhaps some small mutation in a stomach cell.
I also recall that mutations happen randomly, and not in any particular part of the body for any animal. Just completely randomly.
So how can these birds develop with themselves this long peck, even if they have millions of years to do it? A single, a single part in their body being transformed beneficially? And how come the animals don't have extremely weird shapes (within each species) if mutations happen completely randomly? Why are the ears on the same spot in almost all human beings? I understand that if the human is too weird looking, he might not be able to get a mate. But a little weirder looks would happen if it would happen randomly, right?

Don't think I'm against evolution, this is just something I can't grasp. I'm a pantheist, so I believe in evolution.
Thanks.

 

[jackmell]

The ones with long beaks get more food, more strong, more able to survive and reproduce and thus contribute this trait to the lineage at the expense of the lil' ones that get hungry, weak, and die. It is however about averages and populations as a whole: on average, the long-beak population will be more successful than the small-beaks if the food source is more available to long-beaks, and after many generations, the proportion of long-beaks will start to dominate since these will have had a better chance for survival. And once they begin to dominate, additional factors affect the appearance of the trait such as sexual factors: the female will grow to know longer beaks are a better mate for her offspring, further decreasing the proportion of the small-beak trait. At some point, the population of small-beaks reach a critical point, beyond which the slide to extinction becomes likely.

 

[silenzer]

The ones with long beaks get more food, more strong, more able to survive and reproduce and thus contribute this trait to the lineage at the expense of the lil' ones that get hungry, weak, and die. It is however about averages and populations as a whole: on average, the long-beak population will be more successful than the small-beaks if the food source is more available to long-beaks, and after many generations, the proportion of long-beaks will start to dominate since these will have had a better chance for survival. And once they begin to dominate, additional factors affect the appearance of the trait such as sexual factors: the female will grow to know longer beaks are a better mate for her offspring, further decreasing the proportion of the small-beak trait. At some point, the population of small-beaks reach a critical point, beyond which the slide to extinction becomes likely.

Thanks for answering! But what about the latter part of the question, about the similar appearance of all humans?

 

[jackmell]

That's not very clear what you're asking. Ears are at the same spot because that spot was selected as an advantageous trait in our evolutionary history. Genetic machinery guides this process and those genes were selected by the favorable advantage to survival and reproductive success imparted by that location.

Look at any trait in any species, and at some point in its evolutionary history, the trait was an advantage to survival and/or reproductive success.

Live and evolution is all about survival and reproduction.

 

[dgtech]

But people seem to fail to account that those mutations, at least as proposed by mainstream evolution, are random and in both ways, they can be positive and negative.

Then, they are settle, and let's say one species evolves its beak to be 0.1 mm bigger, that would hardly give it such an edge compared to other species, nor does it mean all species with 0.1 mm shorted beaks will become extinct.

Then, that one unit that has its beak 0.1 mm bigger will mate with another unit that has its beak 0.1 smaller, and hops... there goes the advantage

And finally, what if evolutionary changes are not random, but susceptible to determination to a certain level, by the actual species? That would allow for accumulating positive features much easier than a settle random process that goes both ways and is effectively canceled out, as its effects are too settle to make a big difference over one or even a few generations?

Does the bigger beak evolve randomly, against common logic, or does it evolve bigger because the species need it?

 

[silenzer]

But people seem to fail to account that those mutations, at least as proposed by mainstream evolution, are random and in both ways, they can be positive and negative.

Then, they are settle, and let's say one species evolves its beak to be 0.1 mm bigger, that would hardly give it such an edge compared to other species, nor does it mean all species with 0.1 mm shorted beaks will become extinct.

Then, that one unit that has its beak 0.1 mm bigger will mate with another unit that has its beak 0.1 smaller, and hops... there goes the advantage

And finally, what if evolutionary changes are not random, but susceptible to determination to a certain level, by the actual species? That would allow for accumulating positive features much easier than a settle random process that goes both ways and is effectively canceled out, as its effects are too settle to make a big difference over one or even a few generations?

Does the bigger beak evolve randomly, against common logic, or does it evolve bigger because the species need it?

And I thought I had it all figured out :( I hope someone answers this question aswell

 

[dgtech]

If you want a good grade, you'd better stick to what you are being told at school. You can explore other possibilities, but the educational system is unlikely to reward you for it :) You can still present the mainstream version in tests, and work out alternatives for your own intellectual benefit :)

The idea is those random mutations give such an edge to the species it affects, that they get way more competitive and push out the rest who don't have that mutation
It doesn't make much sense considering what I wrote in my first post here, but that's the way things are.. for now. I sure wish evolution was the only aspect of science I find rather unconvincing :) Keep in mind it is an old theory, and even Darwin had his doubts, which are reflected in his journals.

 

[silenzer]

Thanks for all the answers! I'm definitely going to ask here again if I have any problems.

 

[jackmell]

And I thought I had it all figured out :( I hope someone answers this question aswell

But people seem to fail to account that those mutations, at least as proposed by mainstream evolution, are random and in both ways, they can be positive and negative.

Mutations are random and are either positive, negative, or neither.

and let's say one species evolves its beak to be 0.1 mm bigger, that would hardly give it such an edge compared to other species, nor does it mean all species with 0.1 mm shorted beaks will become extinct.

Then, that one unit that has its beak 0.1 mm bigger will mate with another unit that has its beak 0.1 smaller, and hops... there goes the advantage

Can't say that. 1/10 mm could have an advantage. But maybe it wouldn't. But mutations are not all like that: one mutation could cause the beak to be several inches difference with just one birth. And there is still chance nothing would come of this individual but also chance it would mate with it's smaller-beak comtemporaries and could cause the off-spring to have a much larger beak than the parent with the smaller beak. And if it's a very successful trait leading to easier access to food, then these individuals would have an advantage over other small-beak individuals. But again, they could mate with small-beak partners or even another large-beak and still have off-spring with small beaks. It depends on how the gene is expressed and how successful it is in confering advantage to it's owner. And really we need to view this in terms of a population and not just one or two individuals. It's the population as a whole that evolves, not the individuals.

And finally, what if evolutionary changes are not random, but susceptible to determination to a certain level, by the actual species?

No. Mutations are random. Use "subtle" not settle.

Does the bigger beak evolve randomly, against common logic, or does it evolve bigger because the species need it?

It evolves because it has a selective advantage towards survival and reproduction. Species don't "need" anything. Rather they have random changes in their DNA which is then presented to nature which then selects or de-selects the trait based on it's ability to affect survival or reproductive success.

 

[dgtech]

You said it - mutations can go both ways. Chances are 50/50 and cases of rapid and well pronounced mutations are very, very rare. You have mutations going both way in one population - you will get those advantages compensated by disadvantages. And as I said, one generation of "subtle" mutation could not possibly make an individual stand out, as there are many other factors. For example one unit can develop a little bigger beak, but be a little less agile and that could render the beak advantage useless.

Crossbreeding patters over generations can however result in species that have an edge, but they will also be carriers of bad genes that could potentially bring an end of their successful lineage as generations shift.

Truth is we cannot know for sure, as those changes happen in very long periods of time.

There are MANY observations that support my view, for example in forest fires butterfly population seems to mutate to change its camouflage so it doesn't stand out on burned out tree trunks and thus become easy prey. There is no process of some butterflies changing to "burned tree color" while others are changing to PINK, YELLOW or any RANDOM color. The "mutation" is not random, it is exactly what that species needs badly to survive.

 

[jackmell]

You said it - mutations can go both ways. Chances are 50/50 and cases of rapid and well pronounced mutations are very, very rare. You have mutations going both way in one population - you will get those advantages compensated by disadvantages. And as I said, one generation of "subtle" mutation could not possibly make an individual stand out, as there are many other factors. For example one unit can develop a little bigger beak, but be a little less agile and that could render the beak advantage useless.

I agree that useful mutations are rare.

There are MANY observations that support my view, for example in forest fires butterfly population seems to mutate to change its camouflage so it doesn't stand out on burned out tree trunks and thus become easy prey. There is no process of some butterflies changing to "burned tree color" while others are changing to PINK, YELLOW or any RANDOM color. The "mutation" is not random, it is exactly what that species needs badly to survive.

I suspect more likely the population of butterflies had a diverse range of coloring to begin with and the change in environment only selected from that population, the darker-colored ones by giving them an advantage to predation. I do not believe they changed suddenly in response to the darker trees. However I am familiar with the moth population in England which because of the industrial revolution, gradually changed from white to a dark color which gave them a survival advantage on the soot-covered trees. These however were still caused by one or more random mutations with the gene frequency in the population for that trait increasing gradually over many generations giving rise to the predominant darker color.

 

[dgtech]

Do you have any plausible ways of proving that evolution is random and its direction is not being determined by the actual needs of species?

Life seems to rapidly adapt to change of conditions, and that can be driven by the actual species requirements. When conditions change, species cannot afford to wait millions of years for small random mutations to build up to ensure their survival. Also, as you said it - RARE

For example, did the giraffe long neck evolved as a random mutation, or their predecessors were constantly stretching their heads up to reach vegetation, and their genetic material has adapted ALL giraffes to evolve longer necks? Or you suggest there were also short neck giraffes that died out because they couldn't compete?

Why is it so scientific to believe in chance and coincidence, rather than the unique adaptability of life, which is in plain view so often?

Conditions on the planet have been changing so dramatically over the course of history that life could hardly endure if it wasn't adaptable and had to solely depend on chance and random and minuscule mutations, which are usually so slow they could never save spices from extinction.

IMO there is a certain degree of intelligence to evolution. There are also random mutations, but I don't think it is them who drive the direction of evolution.

One thing I learned thou - the b in subtle is mute - 10x for that correction

 

[jackmell]

Do you have any plausible ways of proving that evolution is random and its direction is not being determined by the actual needs of species?

I think any Biologist you ask would tell you evolutionary change is entirely random and subject to chance. In fact, I saw Stephen Gould shortly before he died. He used the term "massively contingent" in that talk to describe the randomness of evolution. I've used the term often ever since.

Life seems to rapidly adapt to change of conditions

Do it quick enough it won't.

When conditions change, species cannot afford to wait millions of years for small random mutations to build up to ensure their survival. Also, as you said it - RARE

Usually the changes are moderate except during one of the several massive extinctions in history in which cases they do not change and most die. At one time, the human population had almost become extinct with estimates of only a few thousand left at that time. We recovered.

For example, did the giraffe long neck evolved as a random mutation, or their predecessors were constantly stretching their heads up to reach vegetation, and their genetic material has adapted ALL giraffes to evolve longer necks? Or you suggest there were also short neck giraffes that died out because they couldn't compete?

Know what, I don't know exactly how it got so long. I suspect is was a combination of chance mutations, and selective pressures and I suspect it was gradual over many thousands of years although as I said I do not know for sure.

Conditions on the planet have been changing so dramatically over the course of history that life could hardly endure if it wasn't adaptable and had to solely depend on chance and random and minuscule mutations, which are usually so slow they could never save spices from extinction.

It didn't endure millions of times in evolutionary history. I'm sure you realize billions of species have become extinct since the origin of life. Sink or swim.

IMO there is a certain degree of intelligence to evolution. There are also random mutations, but I don't think it is them who drive the direction of evolution.

You're just humanizing a natural phenomenon. There is no intelligence what so ever behind evolution.

Interesting talk. I like evolution. Makes sense to me. But I'm older than you and have studied it longer. Twenty years from now, you'll look back and say, "Jack was right. He was being solid with me." :)

 

[dgtech]

I asked about a plausible proof, not about what every person, milled through the educational system will tell me. I know what the textbooks say ;) If you are into writing I guess there is no point of explaining the meaning of the term "conformity" then? :)

Being able to make "decisions" (figuratively said) based on your surrounding environment is not strictly a human attribute. So no, I am not humanizing anything.

I think it is about 95% of all species ever lived that are extincted today. But most of them were extincted in the major extinction events with very few exceptions. Plus some changes in conditions are way too rapid for life to adapt. You won't grow fur overnight if the climate changes to cold. But species tend to adapt to the cold fairly quickly, which is a natural process, it's not like they are waiting for some random mutation that is rare and might take millions of years so they grow more fur.

Evolution is a theory that has not been set in stone, sadly few people have the privilege of being taught by professors who share that fact with students. There are way to many inconsistencies for evolution to be fully accepted scientifically, now if you are a "believer" that's a totally different story :)

 

[jackmell]

Evolution is a theory that has not been set in stone, sadly few people have the privilege of being taught by professors who share that fact with students. There are way to many inconsistencies for evolution to be fully accepted scientifically, now if you are a "believer" that's a totally different story :)

I see you have doubts. Evolution however for me is absolute; I have no doubt about it and if you keep studying life, you'll get there too. Something else will happen. Sorry, can't explain it. In time you'll see what I mean if you keep an open mind. :)

 

[dgtech]

It is strange, considering even the father of evolution had his share of doubts. I guess you are a believer then, my mind is open to all possibilities, which spawned this interesting discussion, it seems that it's your mind that is shut to everything besides the mainstream :)

It is in our nature to question, especially when there is evidence suggesting controversies. However, as I advised the starter of the threat - if you are after recognition from the mainstream, you'd better conform to it.

My approach to studding life is more Polymatic, I found connecting the dots between the scientific and the artistic to be way more beneficial to me.

 

[jackmell]

I'm sorry. I thought you were the original poster and if I implied you're younger than me and are not then I apologize.

 

[dgtech]

No need to apologize, plus I am probably younger than you anyway, your longer career suggests that :)

 

[D H]

Keep in mind it is an old theory, and even Darwin had his doubts, which are reflected in his journals.

Evolution is a very new science, about 150 years old. Darwin was the start, not the end. Even though it is a young science it has been turned upside down at least twice in its short history. Darwin didn't know about genetics or about DNA.

Do you have any plausible ways of proving that evolution is random and its direction is not being determined by the actual needs of species?

You, dgtech, are the one making extraordinary (and extremely outdated) ideas. The burden of proof is upon you to justify these claims.

For example, did the giraffe long neck evolved as a random mutation, or their predecessors were constantly stretching their heads up to reach vegetation, and their genetic material has adapted ALL giraffes to evolve longer necks? Or you suggest there were also short neck giraffes that died out because they couldn't compete?

You are talking about Lamarkian evolution, which is an outdated idea. You need to read up on population dynamics.

 

[dgtech]

Evolution is a very new science, about 150 years old. Darwin was the start, not the end. Even though it is a young science it has been turned upside down at least twice in its short history. Darwin didn't know about genetics or about DNA.You, dgtech, are the one making extraordinary (and extremely outdated) ideas. The burden of proof is upon you to justify these claims.You are talking about Lamarkian evolution, which is an outdated idea. You need to read up on population dynamics.

Your points are valid, but the assumption that I went into exploring alternatives before studding the mainstream theory is a hasty one. I accidentally used the giraffe, which is a typical Lamarkian example, but my idea wasn't that the actual giraffe is passing characteristics, but that the actual process of evolution might be environment aware, after all the organisms is a collection of interconnected systems and is also connected to the environment, so changes in the environment create changes in the organism which can be translated into genetic changes. It is a chain reaction, and with such a large portion of our DNA being regarded as JUNK no one can claim to know for sure if that is plausible or not. It is an open chapter.

I have a lot to say in order to support my view, but that would simply bring me more infraction points, and I have plenty ;) Plus no one would even benefit from the information I provide, as you will likely erase the post.

 

[cesiumfrog]

There are MANY observations that support my view, for example in forest fires butterfly population seems to mutate to change its camouflage so it doesn't stand out on burned out tree trunks and thus become easy prey. There is no process of some butterflies changing to "burned tree color" while others are changing to PINK, YELLOW or any RANDOM color. The "mutation" is not random, it is exactly what that species needs badly to survive

Where are these observations you speak of? It sounds like you're confusing the circumstances of the textbook example of moths (a species in which the adaptation to obvious environmental changes was evidently not caused by a new mutation).

You won't grow fur overnight if the climate changes to cold. But species tend to adapt to the cold fairly quickly, which is a natural process, it's not like they are waiting for some random mutation that is rare and might take millions of years so they grow more fur.

Please, cite the evidence that you have for the length of time that it takes a species to adapt to a different climate.

I guess you are a believer then, my mind is open to all possibilities, which spawned this interesting discussion, it seems that it's your mind that is shut to everything besides the mainstream :) [...] My approach to studding [sic] life is more Polymatic [sic], I found connecting the dots between the scientific and the artistic to be way more beneficial to me.

Arrogant to try to label yourself polymath. There's a name for your artistic approach to science: fiction writing.

 

[dgtech]

First of all you don't know my areas of expertise, and second - your post is way more arrogant and also ignorant of the reasons I stated for not being able to discuss that matter in a forum that forbids non publicly recognized and supported by the mainstream theories.

 

[zomgwtf]

First of all you don't know my areas of expertise, and second - your post is way more arrogant and also ignorant of the reasons I stated for not being able to discuss that matter in a forum that forbids non publicly recognized and supported by the mainstream theories.

If you don't like the fact that this forum is for education in the mainstream theories or discussions of such theories then why do you continue to come here? Every post I've seen you part of you claim the exact same thing.

You should either do some actual work in the fields you profess to know more than the scientists about, in order to prove yourself correct (cosmology, biology etc.) or quit complaining.

Like the guy from zombieland said: Nut up or shut up. Applies quite nicely here.

 

[cesiumfrog]

[STRIKE]dgtech[/STRIKE]? Shame. Thing is, the mainstream is always open to new evidence, so there should be no excuse if you're unable to find expert-reviewed data.

 

[ViewsofMars]

The OP asked about mutations and is curious about evolution. A nice stroll through the online pages of The International Darwin Day Foundation is also helpful. The Mechanisms of Evolution is important to learn. One can also further study "The Role of DNA and Genetic Mutations" as DH earlier mentioned from the following link.
http://www.darwinday.org/learn/evolution.html

Regarding mutations, the quote below was found by linking onto one of the websites from the link above.

Mutations
In the living cell, DNA undergoes frequent chemical change, especially when it is being replicated (in S phase of the eukaryotic cell cycle). Most of these changes are quickly repaired. Those that are not result in a mutation. Thus, mutation is a failure of DNA repair.

[Please read on . . .]
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mutations.html

 

[Antiphon]

Some traits are not expressed as direct genetic changes but as environmentally dependent expressions of existing genes. For example take the cute little piglet, source of joy and bacon to millions of us. If they are released into the wild (and this happens by accident all the time on farms. The little guys get away), they will within one generation grow large tusks, thick coats of fur and revert completely into ubdomesticated wild boar. Clearly there's no time for any form of natural selection to be at work here.

Biological adaptation is a lot more complex and less well understood than genetics.

 

[ViewsofMars]

Biological adaptation is a lot more complex and less well understood than genetics.

One thing we know for sure here on planet Earth is that under the influence of gravity all biological species evolved.

Sean B. Carroll, Ph.D. gave a lecture back in 2005 entitled "Evolution: Constant Change and Common Threads." Here is a snippet from Lecture Four—From Butterflies to Humans:

21. Evolution acts by gain and loss due to chance mutations (22:55)
So what we understand here is the process of evolution involves both gain and loss. In the case of the spotted fruit flies a new switch has evolved that draws a new pattern. It's expanded the role, expanded the number of jobs of a toolkit gene. In the case of the reduced pelvic sticklebacks a job has been abandoned. The pitX gene is no longer used for hind fin development in the species that have adapted to these lakes and lost their pelvic skeleton. The gene still exists and other switches still exist for that gene, but the switch has been inactivated in the sticklebacks. So this is the broad picture of evolution we get from understanding these switches and understanding how genes are used. Gains and losses are happening. Evolution is not a steadily progressive process. Pieces of genetic machinery, pieces of routines that are used in building animals are set aside or abandoned other new ones evolve. So whether we're talking about sticklebacks or butterflies or in fact virtually any other animal in the kingdom, the message is the same gains and losses are happening in the course of descent with modification. So, wondering where do these new tricks come from we have to reinforce the message of yesterday. The animal does not conceive of this new trick. Mutations arise at random that will create variation in form. Mutations in switches arising at random. Nature, either in the form of a mate or a predator nature acts as the art critic that selects the better forms and patterns.

http://www.hhmi.org/biointeractive/dvd/transcripts/Evolution%20Lecture%204%20Transcript.pdf

 

[cesiumfrog]

If they are released into the wild [.. sus domesticus] will within one generation grow large tusks, thick coats of fur and revert completely into [sus scrofa].

Do you have evidence to support this?

 

[Moonbear]

Ok so let's say there are these birds on an island with a food source that require long pecks, but these birds have smaller pecks than needed. So after a long time, I'm not sure to say how long, the birds have developed a longer peck, enabling them to reach the food source.
Now, as I understand, mutations happen every day and most of them are harmless, and some of them don't even matter. Perhaps some small mutation in a stomach cell.
I also recall that mutations happen randomly, and not in any particular part of the body for any animal. Just completely randomly.
So how can these birds develop with themselves this long peck, even if they have millions of years to do it? A single, a single part in their body being transformed beneficially?

There's a basic, and very common misunderstanding that is causing your confusion. The birds don't develop longer beaks because of their food source. Those that happen to have longer beaks have a better chance to get that better food source. If they couldn't get at the food at all, the species would be extinct. A better example of the process would be a group of birds that start out with a range of beak sizes (the same as people can be a large range of heights and all be "normal.") Now, the easy to reach food gets scarce, and only the food deep in crevices is left. The ones with the short beaks don't survive, while those with long beaks do. With enough generations of all the offspring with short beaks dying young and not reaching an age to reproduce, the alleles for short beaks dwindles from the gene pool and all the birds have long beaks.

And how come the animals don't have extremely weird shapes (within each species) if mutations happen completely randomly?

I'm not sure what you mean by extremely weird, but of course mutations can result in unusual features. Some examples in humans would be someone born with extra fingers or toes (polydactyly), or with webbing between their fingers or toes. Some might be born without arms or legs, or be born with an extreme form of dwarfism that leaves them shorter than a toddler as an adult. Lots of weird things happen all the time with mutations.

Why are the ears on the same spot in almost all human beings? I understand that if the human is too weird looking, he might not be able to get a mate. But a little weirder looks would happen if it would happen randomly, right?

That has more to do with how ears develop. Ears are in essentially the same location on all animals. The face actually develops in two halves the fold together and fuse in the middle.

Don't think I'm against evolution, this is just something I can't grasp. I'm a pantheist, so I believe in evolution.
Thanks.

No problem. I think a lot of high school level textbooks explain the subject very poorly. They try to make it simple for the age level of the students, but instead make it more confusing by leaving out too much of the explanation. It's good to ask questions like this to understand it better.

 

[silenzer]

There's a basic, and very common misunderstanding that is causing your confusion. The birds don't develop longer beaks because of their food source. Those that happen to have longer beaks have a better chance to get that better food source. If they couldn't get at the food at all, the species would be extinct. A better example of the process would be a group of birds that start out with a range of beak sizes (the same as people can be a large range of heights and all be "normal.") Now, the easy to reach food gets scarce, and only the food deep in crevices is left. The ones with the short beaks don't survive, while those with long beaks do. With enough generations of all the offspring with short beaks dying young and not reaching an age to reproduce, the alleles for short beaks dwindles from the gene pool and all the birds have long beaks.

Thanks for this.

No, I erased this misunderstanding a while ago - I know that evolution is about the survival of the fittest. What I cannot grasp is that, let's say, these birds would have very similar beaks. Some would eventually get the "a bit longer beak" trait, but what are the odds of that happening? If mutations vary from a single gene in a cell located in the foot and to an extra limb being attached, what are the odds of getting a beneficial trait? Aren't they extremely small?

 

[jackmell]

this is just something I can't grasp.
Thanks.

Lots of good popular books out there. Need to try and get a few and read them. Authors that come to my mind are Richard Dawkins, E.O. Wilson, and Steve Gould. Many others.

Beneficial mutations are rare.

 

[D H]

No, I erased this misunderstanding a while ago - I know that evolution is about the survival of the fittest. What I cannot grasp is that, let's say, these birds would have very similar beaks. Some would eventually get the "a bit longer beak" trait, but what are the odds of that happening? If mutations vary from a single gene in a cell located in the foot and to an extra limb being attached, what are the odds of getting a beneficial trait? Aren't they extremely small?

The odds of a beneficial mutations are indeed very small. Suppose the very existence of a population depends on some newly born member having just the right mutation. That most likely is not going to happen. The population will cease to exist.

Suppose a population of birds is released on a remote island that only has one food source for those birds. If none of the birds can eat that food, the answer is simple: They will all die. This is a contrived example. More realistic would be a population with some variation already in it. All finches look alike to you because you aren't a finch. All finches do not look alike to other finches.

Some member of the population would be able to eat that food, perhaps readily. Some would have a harder time, maybe being able to get at a small fraction of that food source; there is inevitably going to be some variation in that food source. Some wouldn't be able to eat at all. Those poor birds might well die. On the other hand, they might well find some other source of nutrition that you didn't think of. In a few generations the natural genetic distribution in this population will have drifted considerably.

Mutations do not happen at will, or even by need. They are random. Just because the underlying mechanism is random does not mean that evolution is completely random. Evolution moves a population toward a local optimum by means of population drift. New mutations add to the genetic variation within a population. Whether that local optimum is a global optimum is a different question. Ofttimes it is not. Species can evolve some strange stuff that are locally beneficial but are very much suboptimal in a bigger context. Example: the deer with the biggest antlers get to mate.

 

[silenzer]

The odds of a beneficial mutations are indeed very small. Suppose the very existence of a population depends on some newly born member having just the right mutation. That most likely is not going to happen. The population will cease to exist.

Suppose a population of birds is released on a remote island that only has one food source for those birds. If none of the birds can eat that food, the answer is simple: They will all die. This is a contrived example. More realistic would be a population with some variation already in it. All finches look alike to you because you aren't a finch. All finches do not look alike to other finches.

Some member of the population would be able to eat that food, perhaps readily. Some would have a harder time, maybe being able to get at a small fraction of that food source; there is inevitably going to be some variation in that food source. Some wouldn't be able to eat at all. Those poor birds might well die. On the other hand, they might well find some other source of nutrition that you didn't think of. In a few generations the natural genetic distribution in this population will have drifted considerably.

Mutations do not happen at will, or even by need. They are random. Just because the underlying mechanism is random does not mean that evolution is completely random. Evolution moves a population toward a local optimum by means of population drift. New mutations add to the genetic variation within a population. Whether that local optimum is a global optimum is a different question. Ofttimes it is not. Species can evolve some strange stuff that are locally beneficial but are very much suboptimal in a bigger context. Example: the deer with the biggest antlers get to mate.

That was a very good answer, thank you. But since the odds of a beneficial trait are so small, do they match the number in which they occur?

 

[minorwork]

The question to resolve about morphologic change of a population over time is whether or which changes in a population are genetic and which epigenetic or even just the result of variation in human contrived taxonomic systems. Better, to resolve the inter-relationship of each in a specific population as was being studied on the islands of Pod Mrčaru and Pod Kopište on a population of wall lizards. http://www.scitechexplained.com/2010/02/evidence-for-evolution-lizards-from-pod-mrcaru/"

Just keep in mind that these are doctoral dissertation topics and not exactly beginner material. Do what it takes to pass your undergrad classes "instantly"and take a little more time to work out the "impossible" stuff post grad. Metaphorically, you should master what is known about genetic inheritance before tackling the complexities of epigenetic influences which will require knowledge of many fields of discipline; molecular biology, bio-informatics, math, physics, chemistry, statistics, philosophy of science, etc. Time is short. There is little sense in re-inventing things.

 

[Antiphon]

Do you have evidence to support this?

http://en.m.wikipedia.org/wiki/Wild_boar?wasRedirected=true

"Domestic pigs quite readily become feral, and feral populations often revert to a similar appearance to wild boar; they can then be difficult to distinguish from natural or introduced true wild boar (with which they also readily interbreed). "

 

[Monique]

Yes, if you mate with a wild boar your offspring is going to look like a wild boar!

 

[mitchell porter]

What I cannot grasp is that, let's say, these birds would have very similar beaks. Some would eventually get the "a bit longer beak" trait, but what are the odds of that happening? If mutations vary from a single gene in a cell located in the foot and to an extra limb being attached, what are the odds of getting a beneficial trait? Aren't they extremely small?

It might help to think about how DNA works and why mutations have effects.

DNA is a very long molecule stored in the cell nucleus. Sections of DNA (the genes) get copied and moved out of the nucleus to other parts of the cell, where small molecules called "transfer RNAs" which have amino acids attached to them, line up along the copy of the DNA sequence. This is how proteins are assembled from a DNA blueprint. Those proteins then go and do whatever they're supposed to do.

A mature multicellular organism has the same DNA sequence in every cell, but different cells are expressing different parts of that sequence, and that is why some are brain cells, others are muscle cells, others are blood cells, and so on. There's a genetic cause for everything.

A mutation is a change in the DNA. This can be a small change in one gene that affects the shape and other properties of the protein that it codes for, or it can be a big change like the complete deletion of a gene, or the duplication of a gene. Duplication events are good raw material for evolution because one copy of the gene can mutate while the other copy preserves the original function. Let's say you have a gene that produces an important digestive enzyme. If it mutated you might lose the ability to digest certain substances and that would be bad for your survival prospects. But if the gene is duplicated, now evolution has a chance to experiment on one copy while the other one still keeps you alive.

In the human genome (and other species) there is actually a lot of redundancy, a lot of old genes that are no longer used but not yet completely deleted, and so on. The human body and the genes that build it are extremely intricate, but they are not perfectly streamlined in how they work. It's even likely that the genome has evolved to be a little sloppy, precisely so evolution can occur. Some species mutate much more than others. This has advantages and disadvantages, and comparative advantage is what evolution is all about.

Anyway, what actually happens when a mutation makes a bird with a longer beak? First, the mutation has to happen in a "germ cell", like an egg cell, so the offspring will inherit it and manifest it. The direct cause of the mutation might be a toxic molecule that damages the DNA a little, or it might be a rearrangement or duplication of several genes caused by the machinery that normally copies genes for readout or checks for errors. Some genes contain repetitive subsequences ('repeats'), and if they correspond to protein structure, duplication of repeats can literally change the shape of the protein that the gene produces. That will change the way the protein interacts with other proteins, and ultimately it can add up to a big change of form. For example, if the protein controls how much growth hormone gets produced, a change in the protein may mean that it stimulates the production of growth hormone much more, which in turn means that certain tissues will grow bigger. That is the sort of mutation that produces a longer beak. The size and shape of organs is due to the way that their constituent tissues grow, and that growth consists of cell divisions, and cell divisions are controlled by internal and external signals like the growth hormone, which in the end is just another protein produced from a specific gene or two.

So I'm trying to sketch how it is that a change in the DNA turns into a change in the offspring. You can see variation in human beings all the time - height, weight, strength, as well as less visible qualities like personality, intelligence, or the way you respond to diet and environmental conditions. There is a basic human genetic blueprint, more or less, and then all the individual people are variations on that blueprint. The variations we see are mostly produced by sex, and the way that the child's chromosomes are a mix of the parents'. But maybe you can see how a mutation in that genetic system is not so different to sexual recombination - it's another way of playing with the blueprint. If the variation is really bad, then the fetus won't even develop properly and there will be a natural abortion. But if the mutation is mild enough to lead to an organism that can live and function in the world, then the new quality has a chance to prove itself in the world of survival and reproduction.

There are genes which control really basic things like the number of limbs. Mutations there are responsible for the big changes to what is called the body plan, the general organization of the organism. Again, most mutations like that (two heads, one eye, etc) are simply fatal, or at least not life-enhancing. Nonetheless, the basic supposition is that the history of evolution over *millions* of years consists mostly of small variations on a settled blueprint, with most big mutations being lethal or maladaptive, but very occasionally getting an extra limb, losing a limb, or rearranging a limb really does allow an organism to do something new and useful in its environment, and it's those events which add up to the big differences in the tree of life - between a worm, a fish, a rat and so on.

What I just wrote is not exactly scientific quality discussion, but I hope it conveys some more of the details.

 

[ThomasEdison]

Hi,

I.

Why are the ears on the same spot in almost all human beings? I understand that if the human is too weird looking, he might not be able to get a mate. But a little weirder looks would happen if it would happen randomly, right?


Thanks.

Mutation does happen in humans all of the time and in some very extreme ways (more extreme than missing ears or extra ears (and i'll bet those do happen.))
As far as ears go, a cat was actually born with four ears in Germany and humans would not be a surprise.
http://creation.com/a-cat-with-four-ears-not-nine-lives

We may not call them 'mutations' per se they might even be labeled genetic abnormailities or even birth defects or genetic differences. Perhaps it is only a semantic distinction. In some cases the mutations like the continued lactose digestion for adult humans have great advantages. Not all humans can digest lactose properly but the ability to do so as an adult probably started as mutation. In my opinion it's a very important adaptation considering it relates to the domestication of animals (the start of civilization) Its an adaptation directly relating to technology no different than say the eye or skin changing this century in office workers to better adapt to flourescant light. The point I make though is that not all humans share this trait of lactose digestion and its a major one-- a huge adaptation. We are not as homogenous as we like to assume and that is probably controversial. We are not that different than your scenario where some birds have longer beaks than others within the same species and in the same niche.

A non-harmful mutation as an example:
Blue Eyes.
http://www.sciencedaily.com/releases/2008/01/080130170343.htm


There are even people born without irises. Wiki "Eye color" and you will see some strange variances in eye color like red, no iris (black) etc.
If these differences were considered the height of human attractiveness I don't see why they wouldn't become more common.

I will conjecture that the first Blue eyes ever to appear were considered attractive and thus that trait survived. This is a guess.
In my opinion, whatever strays too far from the norm will be shunned, eye color was simply not a great enough difference for the other people in the village to stake and burn the blues.

I just want to make the point that there is great variety in human beings right now and there are people with unique traits who did not inherit them from their parents (this is alluded to in the cat link) some can appear "out of the blue" (a random mutation never before seen to happen) we could call them errors or mutations but in modern society they are probably just called birth defects.

There was a book in the 1970's called something like "Special People" or something or other (sadly I can not remember it.) Within its pages were many vastly different looking humans from short to tall, thin, wide, extra limbs, missing limbs, hirsuite or without hair, a seemingly endless amount of drastic variation. This still happens with humans today but its important to make the distinction that many of the differences mentioned are inherited (like hirsuitism or the many variations of dwarf) and so they are not mutation at all but some of it is random mutation, at other times it can be from a direct source (a defect from a poison like thalidamide) which does not qualify as random mutation or it could be from a disease which makes a person look different or a behavior (like extreme morbid obesity) not a mutation at all... but this does not mean that drastic human mutations are not out there and there were certainly some in that book.

For an inheritable difference it would be the first occurance ever that I would consider the 'random' mutation not the following generations. Like with blue eyes.


Perhaps I simply should have said: "There are people with random mutations walking about even odd ears."

..whew.

 

[bobze]

Hi,

I stumbled on your website when looking for a good place to ask educated professionals.
I'm 16, I have a question on evolution.

Ok so let's say there are these birds on an island with a food source that require long pecks, but these birds have smaller pecks than needed. So after a long time, I'm not sure to say how long, the birds have developed a longer peck, enabling them to reach the food source.
Now, as I understand, mutations happen every day and most of them are harmless, and some of them don't even matter. Perhaps some small mutation in a stomach cell.
I also recall that mutations happen randomly, and not in any particular part of the body for any animal. Just completely randomly.
So how can these birds develop with themselves this long peck, even if they have millions of years to do it? A single, a single part in their body being transformed beneficially? And how come the animals don't have extremely weird shapes (within each species) if mutations happen completely randomly? Why are the ears on the same spot in almost all human beings? I understand that if the human is too weird looking, he might not be able to get a mate. But a little weirder looks would happen if it would happen randomly, right?

Don't think I'm against evolution, this is just something I can't grasp. I'm a pantheist, so I believe in evolution.
Thanks.

I only skimmed the topic, so if this was addressed (I didn't see it anywhere) then I apologize. However I didn't see anyone mention some very important things for understanding evolution.

First evolution cannot happen to individuals. Evolution is a process which can only happen on populations. Make sure you drill that into yourself when studying biology-Its a very common misconception.

Why?

Because, biological evolution is the change in allele frequencies over time. Individuals are born with a set genes, live with those genes and die with them. Populations however are like shifting clouds of alleles. Over time selection drives this cloud in a direction that best fits the population to their environment.

Think about it as an analogy like this;

Think about a population of organism and all their different alleles for each gene as a cloud, which can represent with a color. Over time, that color gradually shifts reflecting which alleles are passed on more than others.

[PLAIN]http://img641.imageshack.us/img641/9906/genepool.jpg

Another thing I'd like to point out, that seems a very big misconception about evolution is it is not a random process. Often times people that mean well trying to explain it say this, but it is not true. You can't have adaptive evolution that is random-The probabilities involved are staggering.

People tend to misunderstand this because evolution does involve some 'chance', namely mutation. However, who lives and reproduces isn't a random event. Some variants in a population are better suited to a given environment, thus more likely to survive and reproduce.

The next misconception seems to be 'most mutations are harmful'. Again, not true. Most of your genome isn't given to coding DNA (DNA which makes proteins). So mutations in these other areas are largely unnoticeable-That is neutral.

Because multiple codons also code for the same amino acids many times mutations which do change amino acids in proteins are again, neutral.

And only specific parts of proteins play their specific roles in their functions. Changes to amino acids outside of these sites are again, neutral.

In biology we use the term 'fitness' to describe an organisms ability to pass on its genes. Remember that the ability to do so isn't random, in other words its not equiprobable that all males in a generation will sire offspring or that all females in a generation will birth the same number of offspring over their life.

Organisms that are less fit, are 'weeded' out by natural selection and their genes don't make it into the next generation, or maybe make it in a lower proportion.