Biology Question.

[Boyish-Tigerlilly]

I am reading a book, but it seems not to explain some elements of biology in a lot of detail.

1. Evolution. It says that Evolution is basically a process of Natural Selection, and through breeding, modifications acculumlate over time. Both beneficial as well as negative/neutral modifications take place. The most beneficial and the least damaging negative traits help the indivudals/species live long enough to reproduce. By reproducing they pass on these traits to their young. These traits help them obtain the limited resources, survive diseases, and survive predators, but...

What happens that actually makes different species adapt to their surroundings? For example, there are creatures with vestigal eyes, but cannot see. Their environment, I would assume, doesn't need eyes, so they slowly became a useless neutral trait that doesn't adversely effect the creature, so they are not eliminated fully. What is it, however, that makes the eyes turn useless and instead give the organism something else to meet the environment. Where does it come from if traits are passed on from parents and in increasing gene pool?

Basically, I mean...can an organism create an adaptation to an environment, if that trait possibility is not already in the gene pool for said species? It makes it seem that organisms have sex, and traits they already have by the time of reproduction are passed on to the next generations...but if the environment changes, how do the genes change with it? Did SOME member of that species already have the trait that might become useful later? When it becomes usefull for the environment, the creature probably will survive to reproduction and pass it on???



II. Gregor Mendel was a geneticist, right? He created Mendelian Genetics which merged with Darwin's Theory of Evoultion to create Neo-Darwinism which takes his Natural Selection and adds the concept of mutation to it. I didn't get that. I hope it is not too much trouble, but it seemed interesting. Thanks.

I did read all this, but the book is somewhat vague on certain particular points.

[Rye]

I am reading a book, but it seems not to explain some elements of biology in a lot of detail.

1. Evolution. It says that Evolution is basically a process of Natural Selection, and through breeding, modifications acculumlate over time. Both beneficial as well as negative/neutral modifications take place. The most beneficial and the least damaging negative traits help the indivudals/species live long enough to reproduce. By reproducing they pass on these traits to their young. These traits help them obtain the limited resources, survive diseases, and survive predators, but...

What happens that actually makes different species adapt to their surroundings? For example, there are creatures with vestigal eyes, but cannot see. Their environment, I would assume, doesn't need eyes, so they slowly became a useless neutral trait that doesn't adversely effect the creature, so they are not eliminated fully. What is it, however, that makes the eyes turn useless and instead give the organism something else to meet the environment. Where does it come from if traits are passed on from parents and in increasing gene pool?

It's all in the genes, mutations essentially, gene shuffling and other natural processes mix up the genes to change the way they code for proteins and thus how the whole organism grows. Selective pressures then cumulitively create complex gene systems over the generations.

Basically, I mean...can an organism create an adaptation to an environment, if that trait possibility is not already in the gene pool for said species? It makes it seem that organisms have sex, and traits they already have by the time of reproduction are passed on to the next generations...but if the environment changes, how do the genes change with it? Did SOME member of that species already have the trait that might become useful later? When it becomes usefull for the environment, the creature probably will survive to reproduction and pass it on???

They can't do it consciously, it just happens due to the imperfect way genes copy and embryoes form. Each person has around 300 mutations by the time they're born that will differentiate them from their parents, iirc.

[Shortie]

I: Genetic variation mostly comes from mutations (*) and meiosis (**). Natural selection acts on that variation over time. IOW, while offspring pass on their characteristics to their offspring they are not perfect copies, even for asexual organisms (ignoring environmental effects for the moment).

A organism cannot control these changes, which is why evolution takes time, and why there are no goals for it. Since even fairly simple organisms can have pretty large genomes and the envionment acts on that to create their phenotype (actual appearance and characteristics) it's possible for a potentially useful trait to be 'hidden' and only show up when needed, without being created at that moment. But it's not planned, if traits are kept they're either fairly neutral or useful (for a purpose which can change over time).

II: There have been a lot of people working on the evolution of living beings, and a bunch of different names used for their theories. Darwin and Mendel both did some very impressive work when the scientific method was just taking off in biology, so we remember them, but their theories were rather incomplete. Don't worry a whole lot about the sub-theories, they're always changing names and orthodoxy.


* - Mutations are alterations to the genetic code of an organism, caused by chemicals, radiation or just screw-ups in copying. The vast majority of them are either irrelevant or harmful. OTOH, for a complex organism the majority of harmful ones are irrelevant because it's just one cell. There are very few which effect a whole organism (or it's offspring) in a potentially useful way.

** - Cells divide to make new cells for an organism to grow & reproduce. If the result is two (diploid) cells identical to the original one it's mitosis. If the result is two (haploid) cells each with just half of the genetic material of the original, it's meiosis. Sexual reproduction is when two haploid cells combine to form a diploid one, and a new organism. Anyway, the process isn't just a simple bisection, there's various crossing over and such of the chromosomes which fundamentally alters their genetic makeup.

[Alyrium Denryle]

What happens that actually makes different species adapt to their surroundings?

Basically what happens is, when say... an eye is useless, harmful mutations are n longer selected against. And they accumulate. Once to many defects build up, they eye becomes incapable of performing its original function.

can an organism create an adaptation to an environment, if that trait possibility is not already in the gene pool for said species?

Yes, but it cannot do it to themselves... what I mean is tthat an animal cannot say "I need better eyes" however, a random mutation could occur after several generations that gives sharper vision and that positive mutation will be passed down.

Did SOME member of that species already have the trait that might become useful later?

SOmetimes they do, sometimes they dont, usually the trait is already existing somewhere, but in the case of something completely new, a few(many) generations are needed until a benificial muttion pops up at random.

[Trytostaydead]

What the giant pumpkin said. Basically mutations, however that's rather simplistic. If we're talking mutations of a complex organism, not EVERYTHING can adapt to its environment.. hence, extinctions. It takes a large combination of characteristics, traits, and favorable blind fool luck for a species to evolve. Mutation rates, or at least mutation rates that are kept and passed down to their offsprings are incredibly small. The process with which DNA is checked and replicated is unparalleled by anything man-made is capable of doing right now.

So you have to assume that the genetic mutation would be FAVORABLE to the species, and most mutations are quite decidely NOT. Second of all, not everything changes within one mutation, it takes a long series so you have to factor in that the species can reproduce and its offsprings likewise survive and reproduce. The latter, reproduction might also be difficult as the mutation may have changed a trait their fellow mates may look for in a mate as well.

As for a species adapting to their own envionment conciously. There are degrees of adaptation, such as camoflague. Though the closest would probably be single celled organisms that can pretty much adapt within a generation or two to various degrees of environments and sustainability,

[Ted C]

What happens that actually makes different species adapt to their surroundings? For example, there are creatures with vestigal eyes, but cannot see. Their environment, I would assume, doesn't need eyes, so they slowly became a useless neutral trait that doesn't adversely effect the creature, so they are not eliminated fully.

More or less correct. The process by which DNA copies itself isn't perfect, so mutation is contantly introducing variations into the genetic material of a population. Furthermore, sexual reproduction mixes DNA from more than one animal in the descendant. The mutation process is actually independent of the selection process, in which variations that aid survival become dominant while variations that hinder survival become less common. Variations that do neither might become more or less common depending on how they're tied to other traits.

What is it, however, that makes the eyes turn useless and instead give the organism something else to meet the environment. Where does it come from if traits are passed on from parents and in increasing gene pool?

The environment is what determines whether a given trait is valuable. In the case you describe, eyes are useless to fish populations that live their entire lives in lightless caves. Consequently, mutations that reduce visual ability become harmless, so natural selection doesn't eliminate them. Similarly, mutations that improve vision don't improve suvivability and reproduction, so natural selection doesn't favor them.

Basically, I mean...can an organism create an adaptation to an environment, if that trait possibility is not already in the gene pool for said species?

Basically, no. Mutation has to introduce a new trait into the gene pool before natural selection starts to operate on it.

It makes it seem that organisms have sex, and traits they already have by the time of reproduction are passed on to the next generations...but if the environment changes, how do the genes change with it?

The genes don't change, but the prevalance of particular genes in a population changes as the associated traits become more or less beneficial to the population.

Did SOME member of that species already have the trait that might become useful later? When it becomes usefull for the environment, the creature probably will survive to reproduction and pass it on???

Yes, the trait already existed in the species. The environment determines whether the trait becomes very common in the species (because it has a strong beneficial effect), less common in the species (because it has a strong detrimental effect), or randomly distributed (because it has no particular effect on survival and reproductive success).

II. Gregor Mendel was a geneticist, right? He created Mendelian Genetics which merged with Darwin's Theory of Evoultion to create Neo-Darwinism which takes his Natural Selection and adds the concept of mutation to it. I didn't get that. I hope it is not too much trouble, but it seemed interesting. Thanks.

Gregor Mendel was a monk who paid attention to what was happening in his garden and kept good notes. He also taught natural science.

Reference

[Darth Wong]

If an alien species came along and executed every adult human who stood taller than 5 feet tall, this would be an example of selection. The surviving humans would naturally tend to carry the genes for shorter people, so the human race as a whole would become shorter in the next generation.

This is basically how evolution works; some people are taller and some people are shorter; this is just variation. But if you kill off all the tall people, you have essentially selected the short ones, and only their genes will propagate to the next generation.

[Stravo]

If an alien species came along and executed every adult human who stood taller than 5 feet tall, this would be an example of selection. The surviving humans would naturally tend to carry the genes for shorter people, so the human race as a whole would become shorter in the next generation.

This is basically how evolution works; some people are taller and some people are shorter; this is just variation. But if you kill off all the tall people, you have essentially selected the short ones, and only their genes will propagate to the next generation.

What about people carrying the recessive trait for tallness? (unless tall is a dominant trait) Tall people will always crop up here and there just alot less of them.

[Howedar]

Yes, there will always be outliers in a population (especially in this scenario since the kill-off was apparently a one-time thing). But the average human will be shorter.

[Darth Wong]

What about people carrying the recessive trait for tallness? (unless tall is a dominant trait) Tall people will always crop up here and there just alot less of them.

Of course, since genetic variation is part of the concept. That's what would make it possible for humans to slowly evolve to be taller again, once the environment becomes conducive to that (ie- the aliens go away).

[Futoque]

So you have to assume that the genetic mutation would be FAVORABLE to the species, and most mutations are quite decidely NOT.

I have always thought of favorable mutations as something that helps with one of 3 things.
1. It helps you more easily get food
2. It helps you more easily not be food
3. It helps you more easily reproduce

Yes this is a very simplistic way of looking at it because there are some mutations that are beneficial, but carry with them some negative side affects. It really depends on how beneficial that mutation is and if it is able to compensate for the negative side affect. For example, the human throat is very well shaped for speech, but because of that shape we are much more likely to choke on food than a lot of other species. Obviously speech was much more important for the survival of our ancestors than a few of them choking to death.

[Darth Wong]

So you have to assume that the genetic mutation would be FAVORABLE to the species, and most mutations are quite decidely NOT.

That is a fucking stupid thing to say. There is no such thing as absolutely "favourable". Some traits are favourable in one environment, but unfavourable in another. And the vast majority of mutations have no significant effect on survivability or reproducibility. Hair colour is a mutation. You're thinking of mutations in terms of sudden, shocking changes.

[Boyish-Tigerlilly]

Thanks. Now I get it. So it really is an almalgmation of already present genes, and the occasional mutation that adds to the gene pool. This happens and allows species to evolve sometime; other's in which this doesn't happen die off.

It is more like chance and pressure to survive.

[Trytostaydead]

So you have to assume that the genetic mutation would be FAVORABLE to the species, and most mutations are quite decidely NOT.

That is a fucking stupid thing to say. There is no such thing as absolutely "favourable". Some traits are favourable in one environment, but unfavourable in another. And the vast majority of mutations have no significant effect on survivability or reproducibility. Hair colour is a mutation. You're thinking of mutations in terms of sudden, shocking changes.

I agree with your first statement (after the fucking stupid thing to say), the most traits are favorable in one type of environment or condition. But when we're talking about adaption (as the OP asked), the mutation should be selected for, not against nor did I say absolute.

My point was that for ADAPTATION through genetic mutation, you'd need favorable traits that can be successfully passed down through their offsprings. It can of course be a benign mutation such as maybe a change in the codon that writes for the same thing and then latter another mutation hits it and then alters the protein. But I was using an umbrella that the general direction should be favorable for that organism for adaptation (key word being adaptation).

And yes, there are tradeoffs that occur. When an organism adapts to an environment, it is often at the expense of another function. The most startling examples are the ones that change within a generation or two where they so quickly adapt to the environment, it'll die in the environment it was just taken from a generation ago.

Secondly, in regards to survivability and reproduction. What do you think evolutionary adaptation is all about? The net sum is that the organism has to be conferred a greater success at surviving and reproducing in its environment.

Thirdly, actually the vast amounts of mutation never get through the checkpoints.

[Boyish-Tigerlilly]

I am making a basic biology/evolution page for a hobby. Is it ok if I use this conversation in a FAQ, or if I cite research from Wong's page alongside my books?

[Trytostaydead]

I am making a basic biology/evolution page for a hobby. Is it ok if I use this conversation in a FAQ, or if I cite research from Wong's page alongside my books?

Best to cite journals and if need be, books.

If you go to a university, your school internet proxies should allow access to a goldmine of PRIMARY literatures that you can cite and get straight from online without the hassle of going through the library to find them, If you cite textbooks or science books you're still citing it through second or third sources. Getting sources from a BBS forum is just getting hackneyed.

[Boyish-Tigerlilly]

Best to cite journals and if need be, books.

If you go to a university, your school internet proxies should allow access to a goldmine of PRIMARY literatures that you can cite and get straight from online without the hassle of going through the library to find them, If you cite textbooks or science books you're still citing it through second or third sources. Getting sources from a BBS forum is just getting hackneyed.

I am using them too, but some of the phraseology he used was nice. I didn't mean I would cite this particular forum. I meant his personal webpage on evolution.

[Boyish-Tigerlilly]

I might be able to use Ebscohost. Is that a good source for science? I know it was really good for Literature and English.

[Admiral Valdemar]

It'd be worth noting that mutations occur all the time. You yourself may have incurred mutation in a cell or cells, but because evolution has gifted us with one hell of an advanced proof reading system, such instances where a mutation, be it benign, beneficial or harmful. If we weren't so good at stopping such errors, we'd be a useless organism and the failure rate is astoundingly low.

If you want to read some more good books on the subject, I suggest anything by Dawkins. The man is a genius and probably the best modern biologist author since Gould. He shows the flaws in Creationism, explains evolution in simple terms and gives great examples of work he has done and his colleagues.

[Son of the Suns]

Best to cite journals and if need be, books.

If you go to a university, your school internet proxies should allow access to a goldmine of PRIMARY literatures that you can cite and get straight from online without the hassle of going through the library to find them, If you cite textbooks or science books you're still citing it through second or third sources. Getting sources from a BBS forum is just getting hackneyed.

I am using them too, but some of the phraseology he used was nice. I didn't mean I would cite this particular forum. I meant his personal webpage on evolution.

It might be a better idea to cite people that are actually involved in the field of evolutionary biology.

[Boyish-Tigerlilly]

Yea, perhaps. I need somewhere simple, because I am not a very good science person. I always tend to get confused with the little things. Sentences seem to drag on forever and sometimes I actually don't know what I am reading This is why history is so much better for me lol.


It is still interesting though.

[Boyish-Tigerlilly]

I might as well forget trying to learn biochemistry and things like that. It would take a miracle.

[Trytostaydead]

I might as well forget trying to learn biochemistry and things like that. It would take a miracle.

Learning science is easy, understanding it is difficult. Most people feel overwhelmed by science because it throws a lot at you using big words. You have to take each thing slowly, make sure you have it all then move on to the next page.

Understanding science is a different matter, that's why you have a lot of people running around with Bachelor's in science, some masters and fewer PhDs. And even with journals, you have mainly articles that make observations but precious few that analyzes some new insight.

[Boyish-Tigerlilly]

I dont't know. I was never good at math and science. I get a headache very quickly with it. I liked biology, but I never liked the biochem part or the molecular sections. I like history and rhetoric best. The latter class was awesome

[Elfdart]

If an alien species came along and executed every adult human who stood taller than 5 feet tall, this would be an example of selection. The surviving humans would naturally tend to carry the genes for shorter people, so the human race as a whole would become shorter in the next generation.

This is basically how evolution works; some people are taller and some people are shorter; this is just variation. But if you kill off all the tall people, you have essentially selected the short ones, and only their genes will propagate to the next generation.

What about people carrying the recessive trait for tallness? (unless tall is a dominant trait) Tall people will always crop up here and there just alot less of them.

There are some gazelles that still carry the recessive trait for being slower runners. They are usually the first ones to get passed through the cheetah's digestive system. Most domestic pigs lack the huge, sharp tusks of their wild brethren, since the tusks were bred out of them. But sometimes a set of tusks will crop up on the farm. If the animals go feral, the tusks come back within a few generations. The same is true of horns on domestic rams. The traits are still in the animals' systems.