Speciation
Posted on: February 13, 2011 - 2:34am
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Speciation
I find it odd that Richard Dawkins talks about some lizards that were let out on an island and evolved new organs I find this kinda riduclous because dogs have been around forever and most breeds can still mate I would like to think dawkins is mistaken about this theres no way we can witness new organs being formed in the body with even several lifetimes.
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yalmsteen,
Here's an article explaining fur color change in rabbits. It happened relatively recently and was relatively quick (15 thousandish years).
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8225000/8225219.stm
It's good that you are attempting to understand. Try to answer the questions butterbattle is asking you, if we can see what you know about evolution already, then we can fill you in on the parts you don't know yet.
His question is about how a new trait appears.
If you have a population of dark skinned people, of course you can always select for individuals with the lightest skins out of that population. But, in that case, you could only have people with skin as light as the lightest of those in the original population. The question is how can you eventually have people with lighter skin than any of those in the original population?
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
To me these differences seem far to minor to be beneficial and if the mutations were drastic I should see these haappen like a deer having offspring that are much faster and say blend in with the forest say they have a greenish color yet they are always brown and white(white tail deer anyway) and a little black(I wonder what that was for) so its hard to see that animals alive today didnt look anything like this 2,000,000 years ago but I digress.
Why are minor changes not considered beneficial? Any animal has a set of genes that are unique. If it's genes give it an increased chance for survival (no matter how small), then there is a correspondingly higher chance that it will get to pass its genes off. The offspring of this animal will also have an increased chance at survival. Here's an example.
Dawkins explained an experiment that took place quite a few years ago. The experiment started with culturing a strain of bacteria in its ideal environment. Once the bacteria had been given the chance to multiply, the colony was transferred into a new vial that contained a chemical that was toxic to the bacteria. The chemical was diluted so it only represented 1% of the total solution.
Some of the colony could not survive due to the chemical in the environment, but the majority of the bacteria divided. After multiplying, the colony was transferred into a new vile that contained a solution of 10% of the toxic chemical. After the surviving bacteria were allowed to replicate, they were transferred to a vile with a solution containing 20% of the toxic chemical.
Within a very small amount of multiplications (if memory serves me right it was between 50-100), the resultant colony was able to survive in a 100% solution of the chemical. Within a controlled experiment, scientists were able to coax bacteria to become immune to a toxin that would normally kill it.
I know that bacteria are used in this example instead of a more traditional animal. Regardless, what really sticks out to me is the result: the strongest bacteria survived in each instance, and eventually the direct descendants of bacteria that could not withstand a toxin could thrive in a 100% solution of it.
Does this help at all? If it doesn't, why not?
Good questioning skills
I guess this is where Ill have to say I am having trouble comprehending how these mutations being so minor can play anyrole I completely understand how the population can go from looking one way and then looking another way. If every creatures offspring has little changes than other offspring have changes they will combine and eventually as long as their healthy and can continue they will keep changing indefinetly, I understand why there is no reason for animal to stay the way it is(because the genes are never perfect thats why none us look exactly like our parents , the one thing creationists dont seem to understand.) I just think its too damn convientient that the fur would change color to match the enviroment I mean would a rabbits fur turn blue if it would survive better(yeah why arent horses colors like blue and green but birds are?)
Okay. Let's say aliens came to Earth and "somehow" made wood and chlorophyll blue. In that case, I do think that many prey animals would start looking more blue or die.
Wild rabbits usually have a brownish grayish fur, which is a pretty good color for blending into their environment. So, it is at least obvious that essentially all animals have a color that seems to be suited to wherever they live, even if we don't know how they got those colors in the first place.
Eh, are you not sure that new characteristics can appear or are you just confused about how this happens?........
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
Color is a combination of proteins and refraction. Evolving new proteins for new colors takes a very long time evolutionarily. And, we know most mammals lost those proteins as fish, reptiles and birds all have them. So mammals may have had them at one time (some monkeys have famously colored skin but not hair). Once a critter has lost the genes for a particular characteristic, they will not reappear in the exact same genetic pattern. I think there were some insects that evolved to lose their wings. They now have environmental pressure to regain wings, but the new wings are nothing like the wings of their ancestors. We know this from comparing fossil imprints with the modern version.
Really, wiki is your friend. http://en.wikipedia.org/wiki/Feather
Horses, rabbits and other mammals have lost this ability to have these colors because shadows are usually not blue or green - the exception being extreme snow regions. Instead, shadows are dappled, sort of mouse colored, and so hiding from predators or prey is easier if you match the shadow colors. Notice that even though the snow shadows are blue, the arctic hare only manages to be white, it just doesn't have the chemical forms or the refractive properties for its fur to be blue.
More examples of protective coloration at http://en.wikipedia.org/wiki/Protective_coloration#Non-military_applications
-- I feel so much better since I stopped trying to believe.
"We are entitled to our own opinions. We're not entitled to our own facts"- Al Franken
"If death isn't sweet oblivion, I will be severely disappointed" - Ruth M.
Even a small but persistent 'bias' in favor of some characteristic can still have an effect, given enough generations. There is no reason that if it was below some level it would have no effect.
The random nature of 'background 'mutations, ie the ongoing level of mutations which are mostly neutral, actually helps to ensure that a mutation with even a small net benefit can still have some effect, in the same way that an object sitting on a slightly sloping plank will still overcome friction and slowly move down the slope if the plank is subject to some modest level of vibration. It would have to be in a dominant gene, of course.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
Why do birds have more variety of colors then and that doesnt tell me why dogs cats rabbits etc cant have pink fur because why would a flemingo have pink fur thats obvisous and what about zebras whats will there stripes what purpose does it serve and what would any benefical mutation look like on them?
A beneficial mutation for a zebra occured... that's why they have stripes. Dogs/cats/rabbits CAN have pink fur but they don't because that's not the way their species survived. Changes of an entire species aren't random. Random mutations happen to individual members and if it is beneficial, it results in an increased chance that the mutation will become part of the species as a whole.
Think of natural selection as a force. The environment the animals are in (including the area they live in as well as the predators around, temperature of climate, etc) drive the evolution of a species. I really don't want to give up trying to explain this to you... but I don't think you are grasping it very well. If our answers are not helping, I'd suggest finding a book on evolution. It's bound to have more in-depth answers than what you'll find here.
You need to just focus on one species for the sake of comprehending the fundamentals instead of switching from lizards to cats and rabbits and dogs and subtle human differences and the stripes of zebras all the while asking the same questions over and over on multiple threads.
The mechanisms of evolution are all the same. On one side are pressures from predators and the environment. But there are also pressures of biological economy. Life always tries to do the most with the least energy expenditure - think the DNA double helix spiral. This means that creatures balance what they invest in defenses against the cost of making those changes. The key to evolution is breeding success, not the selection of rabbits the size of sabre tooth cats. The result of predation is that rabbits have huge litters, not huge fangs.
Because no one seems to be getting through to you, could you do me a favour and turn your questions in another direction for a moment. Ask with the same vigour how does creation work? What are its mechanisms? What are its proofs? If you need so much proof to believe what's in front of you and what's demonstrable as consistent with material reality, how much proof do you need for inexplicable events like creation?
Where is the evidence for any of these supernatural events outside of the rank assertions and threats of violence in the bible that were hurled at you as a child? Can you find any proof of creation that does not represent a fallacious argument from complexity - IOW "I don't understand how it happened so god must have done it". And if you can find some proof of creation and its mechanisms, could you please tell us what that is?
You should ask yourself what motivates you to believe in things for which no proof exists. Really ask yourself. You are saying to us that your confusion over the nature of evolutionary theory means you are just going to accept as equally valid something that has no supporting data whatever. Why are you doing that?
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
Well, let's think about the possibilities. Perhaps birds usually don't need as much camouflage because they can fly. Ergo, it might be more important for them to have colors that effectively attract mates. The most colorful birds live in rainforests, so perhaps those environments can be colorful? In principle, dogs, cats, and rabbits can all have pink fur; just because the trait hasn't evolved doesn't mean the trait can't evolve. Flamingos are pink because of what they eat. Zebras' stripes are camouflage.
You are never going to know the steps by which every single trait on every single organism appeared. This is a really futile quest; what's important is to understand what the theory of evolution proposes and how these traits can appear.
That said, do you understand the basic mechanisms and evidence for evolution? If not, why do you believe it? What are some reasons that you believe in evolution?
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
Let me ask you a question. Why do you get the impression that I believe in creation? It sounds like what youre saying is beacuse one competing idea(not really) has no proof or reason what so ever I should accept unquestionable one that has say a tiny bit of evidence to support.
By the way I Believe evolution is true despite not understanding natural selection, going on random mutations and fossils is enough to see that it is something worth learning about and I dont think after all these years of constant study of the subject that scientists are stubborn and dont want to let it go.
as a theist does but you nevertheless seem to credit it as a plausible alternative. Now, there may be an alternative to evolution but it is not supernatural creation.
And then there's this. Because you don't comprehend evolution you keep talking as if evolution has "a tiny bit of evidence supporting it".
Evolution does not have a tiny bit of evidence supporting it. In fact no scientific counter evidence has ever been found to evolutionary theory since it was proposed. Never, ever, ever.
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
I am an atheist and how did you not see where I said I believe evolution is true and you said youre self there may be an alternative to evolution(I dont think so) but its not supernatural and I totaly agree with you
Well, lions hunt mostly at night when color is of sharply reduced importance. They don't even have shadows to work with. So the most effective visual clues will be the animal's overall shape. Hence the stripes break up the appearance of the shape. To a lion, they just appear as white stripes in the moonlight and since they travel in herds, one zebra standing in front of others breaks up the outlines even more.
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Because I do understand the basic mehcanisms of evolution in fact the theory is so sound that it would be crazy for it not to be true?
I want to when I get the chance go and study biology in school for my self.
the one thing I am having trouble with people who support evolution is they give answersthat are overly simple just like someone on here said zebras have stripes because it was beneficial that doesnt explain how they came about or what the function of strips are they seem preety easy to spot or why tigers have stripes even though they are a predator.
And I know you say evolution is true but you are obviously not convinced evolution works as a mechanism. Anyway, I did not want to stop you talking about evolution to attempt to convince me you comprehended the theory.
The point I'm making that you agree with is that evolution must be a process that takes place in the material world as organic life is selected for fitness, the mystery of abiogenesis notwithstanding.
We agree there are no alternative explanations for the diversity of life on this planet?
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
I'm cheering for the "no stupid questions" camp myself. When you ask the same question repeatedly, however, and fail to respond to verify your understanding; you loose the right to complain about "answers that are overly simple". I'm leaning in the "a lot of inquisitive idiots" camp at this point.
You need to take a step back, start a new thread and list all the facts that you understand, and all the facts that you need clarification on. We're all guessing and suggesting which may seem simplistic to equate the questions tone.
"Don't seek these laws to understand. Only the mad can comprehend..." -- George Cosbuc
Zebras - stripes - 2 reasons - 1) Lions do not see the zebras as well if they have stripes. Why don't lions see the striped zebras? That I don't know. Maybe because there is other lion prey that is easy to see and catch, so they don't really need zebras in their diet.
2) Tsetse (teetzee) flies do not see striped zebras. This is really important. Tsetse flies carry sleeping sickness which can infect all mammals as well as humans. The tsetse fly has plenty of other mammals it can bite (it lives on blood like horseflies do) so it doesn't have to be able to see zebras to survive. The zebras are given a great advantage for survival if the competitors for the grasslands - antelope and so on - are dying off from sleeping sickness.
We can't always guess why a particular trait evolved. We do know some mutations are neutral. That is, they appear to be not particularly beneficial nor particularly harmful. So that trait will persist in the population, never being dominant - never quite going away.
-- I feel so much better since I stopped trying to believe.
"We are entitled to our own opinions. We're not entitled to our own facts"- Al Franken
"If death isn't sweet oblivion, I will be severely disappointed" - Ruth M.
Also, in a herd it's difficult to determine where one individual starts and where one ends. It creates an optical illusion for the lion, that makes it more difficult to spot the weaker individuals.
"Don't seek these laws to understand. Only the mad can comprehend..." -- George Cosbuc
stripes evolved to confuse the lions who prey on zebras. The background of stripes makes it harder for lions to select an individual animal for dinner, as well as making it harder to judge distances between lion and lunch due to optical illusions created by a moving striped background. Tigers coats are designed to blend into the light and shadow striations of a jungle environment. Fish use stripes for the same reasons and if you think of military clothing, tank and warship paintjobs, so do we.
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
Meh, if you say so. Perhaps you understand it well enough to recognize it as sound; I'll buy that.
Well yeah, it's easy for us humans to spot the zebras, but we're not their predators. Lions are a predator, and lions are colorblind. It's possible that their vertical stripes allow them to blend with the tall grass and with other zebras.
Not only prey animals have camouflage. Many predators, even the ones at the top of the food chain, have camouflage. Being hidden from their prey will allow them to catch their prey by surprise. Some predators, like the snapping turtle or angler fish, have more interesting methods of camouflaging themselves and catching their prey. Whatever works......works. You just have to think about it.
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
I can certainly vouch for the lion's coloring being extremely effective in its typical environment.
I was on a photo safari in Kenya, and I very distinctly remember my surprise when a lion suddenly appeared about 30-40 feet away from our vehicle.
It must have been laying down in the long, dry grass, and decided to get up onto its feet. The color of its coat was a great match to the color of the grass. The grass was not quite long enough to hide this guy - he was a big mature animal - even lying down.
We also saw plenty of zebras, and the point about their stripes breaking up their outline and making it harder to distinguish individual animals in a group also is consistent with what I remember.
I also observed how well the spotted pattern of the cheetah worked when they were under a leafy bush or tree with a dappled pattern of sunlight coming through the leaves. Not surprisingly, they seemed to be often under such vegetation when resting.
I think tigers were assumed to have inhabited areas with different vegetation than that of the open savannah, which is why selection seems to have favoured their pattern, which is more like some patterns which have been used to camouflage military vehicles in certain environments. I remember a photo in a wild life book I had as a kid that showed a tiger walking through some vegetation, a bit like a coarser form of grass with broader leaves, and it dd seem to be a good match.
Another thing which may not have been mentioned is that some of these skin or fur colors are dramatically effected by simple enabling or disabling or modification of one or two genes, which probably control the production of the fur or skin pigment substance. Even small changes to the structure of a molecule can dramatically affect its color.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
Yes I agree there are no other alteranatives I guess since you cant see my emotion in the questions I ask you might think I am attacking evolution but I know evolution is true about random mutations and natural selection(in concept) Its just I guess I want to know the details about how specific traits are useful and how they can come about specificly over time because when I look around at us and dogs for example you dont see anything happening for survivals concern.
All these answers are really helpful I didnt think about the lions having different vision then we do and the lions do have good camaflouge for their surroundings. Here is what im asking what did this process look like I know we werent there but im saying if we understand it we could easily speculate like what did zebras look like before they had thier stripes and what were lions doing before they were predators
I thought we were going to have a back and forth with you asking questions and making sure I understood, have you called it off?
I think you guys misunderstand me, let me explain. My mom was arguing for gods existense and said that you can't see air but you know its there. I replied with we can't see air but we can observe its effects and it explains so many things like wind, sound, breathing, pressure, heat. We can experiment with it. So it doesnt matter that we can't see it we arent relying on sight only and thats what you are not understanding. So anyways the details of phenomena involving sound for example I dont fully understand I dont get how low frequencies travel farther than higher frequncies I dont understand how someone can have the bass so loud in a car that the doors are flexing yet this doesnt puture your ear drum or how sound and wind can happen at the same time( I kinda get it). So with evolution the concept of random mutations and the smiliar traits that some creatures have that we can link them to when they seperated on the evolutionary tree explains alot .Natural selection I vaguley understand like I get what you guys are saying like a giraffes neck is long so it can reach tall leaves and if didnt it would have eithe found another way or died off but this doesnt explain how it happened this all seems to gimmicky were the trees growing with there necks as well or what. Also I can see how their necks could be slightly longer than others just like humans easy to grasp but why doesnt a brown horse occasianly have a strand of
blue hair somewhere on its body, this is not the same as saying a dog giveing birth to a cat and mixing animals together doesnt count beacuse they are mixing their genes. So I understand random mutations especially since we al look different but you would think these mutations would have to be more prominent to have any real affect of the world of survival .
Also about the air I am saying that I dont need to know everything about air to know thats its true so same with evolution I know it is a real phenomena(well I want it to be anyway) but I just can't make sense of all I see around me.
Ah, sorry. No, I just kind of missed it.
Well, now you're starting to ask some really tough questions.
For the most part, I just have a good understanding of how evolution works, in principle, and have some knowledge of many categories of evidence for it. Outside of that, I know very little about specific evolutionary histories or how phylogenetic analysis etc. works. So, my short answer to your question is, I actually don't know. I don't know the details about how zebras or lions evolved. I know zebras are an ungulate that's closely related to the horse or the quagga. I know lions are a big cat closely related to other big cats. That's about it.........I'm surprised I even remembered "quagga."
The history of a large, well known mammal like a zebra or lion has been explored quite a bit now by evolutionary biologists etc. So, they have a wealth of information about it. Ergo, it seems like cop-out from a certain perspective, but the best we can do is refer you to google or wiki. I hope you appreciate how much observation and research it requires for people to assemble just the last few million years of any one such species that currently exists.
I'll pick a couple ostensibly good sources for each and see if that helps.
Zebra evolution
Zebra evolution 2
Lion evolution
Lion evolution 2
Right. The details are always ridiculously complex, but the premise is simple. Obviously, as you noted, the giraffe's neck doesn't get longer because it "stretches it" and "tries to get the leaf." What gets passed on to the next generation is genes, and what the organism does in its lifetime to affect it's physical body doesn't change its genes. So, instead, the average giraffe's neck gets longer because the giraffes with longer necks are more likely to get the leaves on the tree. All it takes is for the giraffes with the longest necks to fare somewhat better than the giraffes with the shortest necks. Even then, we wouldn't be limited by the length of the giraffe with the longest neck, because their offspring are not perfect copies. Two giraffes with long necks could mate and have a kid with a slightly longer neck.
Trees use their leaves to catch sunlight and produce energy with chlorophyll. So, clearly, it would be bad if all of their leaves were eaten. By making their leaves high in the air, they avoid many animals that would eat them or adapt to eat them or just trample and/or damage the leaves and branches by moving among them. In a forest, trees also have to grow tall for the main reason that there is fierce competition for sunlight. Trees that don't grow fast enough or tall enough are blocked from the sun by other trees and die a slow death. It's possible that trees grew slightly taller in response to giraffes, if the giraffes ate enough leaves to dramatically harm many trees.
Lol. Maybe there were or are a couple of horses with random blue hairs on their body. I don't know. According to researchers, grey horse is already a mutation.
http://www.hillcountryaviaries.com/color_mutations.htm
http://www.youtube.com/watch?v=ZY15BKZ5O60
Animal Color Mutations
What counts as prominent? Even a small difference in color might help an organism survive to reproduce.
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
How do the trees know that they are being harmed? I know they don't actually know they are being harmed and even animals being aware still wouldn't dictate them having better more efficient offspring. If you say its because the ones that were growing are more likely to survive, than are you saying that if there were no animals they would not get taller? I get when we select animals for breeding cause we know what traits are beneficial and try to get them to happen more often by favoring certain traits and trying to expand upon them but all of nature shaping all the life we see today is just unfathamoble to my brain.
I can understand something having slighlty more of an advantage than something else, say a person stronger legs and winning a race. For an animal though like say a wolf has a longer toe than another how does this effect anything right at the moment. Now I can understand something evolving in a certain direction for a long time and then all the sudden some kind of new situation forces some animals to change there typical routine and the ones that have the most beneficial traits survive. The enivornment however dictating thier progress step by step seems unlikely. I hope this helps everyone understand why I can't fathom how crocodiles amd sharks can remain unchanged. If I could get over this obstacle evolution would make more sense to me.
Correct. If there were no tall (long legs, long necks) animals eating the leaves higher up, there would be less environmental pressure for the trees to grow tall. The competition for sunlight would still select for taller trees. I would think it would be more likely the competition for sunlight is driving trees, and the need to reach the leaves is driving giraffes. Remember, they started the same height. Then the weather changed, causing more trees to grow taller, and the giraffes had to change or go extinct. They were able to change enough to survive.
Competition for sunlight only happens when there is enough precipitation (rain, snow) for there to be a large number of plants/trees. If you hang out in the desert - where I grew up - the trees are very short. They have lots of sun and very little water. No tree browsers larger than mule deer, because they don't need to be taller than that.
The environment doesn't "dictate" change. Changes in the environment may or may not force a change in a population of organisms. The changes that do occur must fit within the existing genome of that population. For example, bacteria won't - because they don't have the genes - suddenly sprout eagle eyes. They don't have the basic "eye" genes in their genome. They do have enough in their genome to be photosensitive. That is, some bacteria do track light and move towards it.
Sharks and crocodiles have changed very little because they are in environments that have changed very little since they first evolved. But if you really look at ancient fossils, there are different species of shark and crocodile that no longer exist - because they were unable to adapt to change in the environment they were living in.
Remember just the difference between the top of a hill and the valley between hills right next to each other can be enough difference that the species on the hill are different than in the valley. Modern sharks and crocodiles are the ones that live in environments that are very similar to their ancestral environments and they were able to adapt to any (probably) small changes.
A wolf having a longer toe is probably a neutral mutation. I have mentioned neutral mutations before and so has Bob Spence. A mutation that neither harms nor assists reproductive success is neutral. It will persist in the population at a low level just because there is no reason for it not to persist. It will not become dominant in the population because there is no advantage for those with that gene.
Finally, "progress". There is no "progress" in evolution. There are only grandchildren. The successful population will have grandchildren. A bacteria is just as successful as a human. No difference. Each leaf of the evolutionary tree is evolved enough to reproduce and the population survives. No one has ever found a population that has evolved to match their environment "perfectly".
Why grandchildren and not children? The grandparents must have children who are capable of reproducing. The population does not survive if they are only capable of having one generation.
-- I feel so much better since I stopped trying to believe.
"We are entitled to our own opinions. We're not entitled to our own facts"- Al Franken
"If death isn't sweet oblivion, I will be severely disappointed" - Ruth M.
Look if a different group of people live on one island and another group elsewhere and after millions of years they will not look the same and I am saying this based on our living conditions there is no environmental pressure but they change anyway because they are random they can not stay the same random does not mean consistent there is nothing we can do to stop our off spring from looking different.
Is something wrong with the statement above besides the grammar and punctuation?
No, nothing wrong - that is what probably happened in a lot of cases. The "founder's effect" is because the original settlers of the island are limited in genetic diversity. If they are truly isolated. No passing sailors. No shipwrecked sailors. No way to get off the island to visit cousin Rosy down the island chain. Then, yeah, it is possible that in a few million years, you will have a distinct species of humans on that island.
But we have very little evidence that has happened. Maybe the short Indonesian islanders - the ones they called Hobbits? -but they weren't isolated for long enough to become a different species. If humans can reach the island once, they can reach it again. And so we don't have any evidence for that "founders effect" happening for humans.
What about the common chimp / human ancestor? That was probably founder's effect - but - no islands. And no boats. What we can see from the fossil record is there were a lot of large primates in Africa. Some were larger and seem to have looked vaguely human like. Some were large and seemed sort of like gorillas. Or about the same size and looked sort of like chimps. Or smaller. Anyway, not just chimps, gorillas and human ancestors.
I will bet - though no one knows for sure - that some of the early mutations could have interbred with chimp ancestors. But part of the becoming human population was isolated enough that they could no longer interbreed. No boats. No shoes. No fire. Maybe some sticks for tools. (For the nitpickers - I am thinking pre-paleolithic - that is, before stone tools and controlled fires.) So a river or a ridge may have been enough separation for speciation to occur. We don't know for sure. All we can tell is that speciation happened - because we are a separate species from chimpanzees.
-- I feel so much better since I stopped trying to believe.
"We are entitled to our own opinions. We're not entitled to our own facts"- Al Franken
"If death isn't sweet oblivion, I will be severely disappointed" - Ruth M.
I'll add to cj's posts.
As already said, there is still competition for sunlight between plants. But, I am fairly certain that many trees would not be as tall as they are. Note though, that there is a complex relationship between plants and animals in the ecosystem, so I believe it is a gross oversimplification to just say that the trees would be shorter.
What's crucial is that in both scenarios, there persists a non-random selection of genes. The organisms' genes correspond to their observable traits, and some of those traits will inevitably be preferred over others. Organisms with preferred traits will have a higher chance of reproducing and thus, passing on their genes. Since the selection is non-random, succeeding generations will automatically be different from preceding generations; given more generations, there will be a bigger difference. If a different "agent" does the selecting, the speed of change (as in, change per generation) and what the change is might be different, as this new "agent" will "prefer" something different. But, ultimately, there is change.
Let's say humans decided that they wanted rabbits with thicker fur. Naturally, they decide to breed the rabbits with the thickest fur. Rhetorical question, what prevents rabbits from evolving thicker fur in the wild? If their environment suddenly becomes colder, then rabbits will thicker fur will probably have a higher chance of surviving to reproduce. Hence, in later generations, the average rabbit will have thicker fur.
Well, maybe it doesn't affect anything right at the moment. Not every little trait or mutation significantly affects the "fitness" of an organism.
Why?
Neither of them are completely unchanged. Some organisms are more different than their ancestors. Some less. Crocodiles and sharks are just near the end of the "less" side. There are still differences between populations today and those of millions of years ago.
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
I am glad you brought this up this is perfect for what I have been trying to say. That makes since but what if if no mutation ever produces thicker fur. Thats what I have been trying to say why is it that there is an external pressure and convinetly there is always a random mutation to combat it?
Because that would mean it is was some kind of entity dictating what stays and what goes.
Mutations are random. That means they can do in all possible directions. There will be all possible variations occurring across a population.
If it gets colder, there will still be some offspring with thinner fur, as well as others with thicker fur. The number either way will NOT change 'conveniently'.
Its just that those lucky enough to have slightly thicker fur will likely survive and reproduce a bit better than those with thinner fur. Many genrations later, they will probably dominate.
Can you still not see this?
There is not always a 'convenient' mutation to address some change in the environment, and then, guess what, the species may even die out in that region.
There is no 'plan', no direction, evolution has no foresight, sometimes a 'family' line gets lucky, other times it doesn't, and like the vast majority of species that have appeared through history, it goes extinct.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
Well, then they die.
No. Absolutely not. Almost all of the species that ever existed are now extinct.
Ah, okay, that is a problem with the language. We like to describe things in these convenient, anthropomorphic ways.
Don't think of the "environment" as "dictating" progress then. The environment is not even an "entity." It's just whatever might affect the organism.
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
I guess I need to understand how the first living thing functioned, what it needed to continue to be living.
Like instead of gur for the rabbits why not just be unaffected by the cold? This is probably where I need to understand some biology on why we have to be at certain temperatures.
Every living thing has to be giving energy to stay alive, so what is it about food that supplies living things with energy and other animals that eat other animals and get energy?
How did the survival of the fittest get started> I know that there is no goal and there is no progress, but look at the dinosaurs apparently once it gets started everything just keeps getting bigger but I suppose they requried alot more energy for their systems to function is this right?
Could any other animals get as big as the dinosaurs?
"Survival of the fittest" is not a good phrase for natural selection. Darwin didn't like, it was proposed by Herbert Spencer, a contemporary of Darwin.
Natural Selection is survival of those most successful at reproducing, which is not quite captured by the term 'fittest'.
Anyway, natural selection is simply a natural principle which is always around, and automatically applies to anything which is self-reproducing and subject to some degree of variation, so it applied to the very first self-copying molecules.
What evolves is what happens to work, and what can be easily formed by small step-by-step genetic changes. Fur works, it doesn;t require as much adjustment of the way the body works, especially in mammals, which rely on keeping their inner body temperature within a small range. Large mammals are better able to handle the cold.
Everything doesn't necessarily 'just get bigger', they can go in any direction which the environment can support.
Here is a good link on the size of dinosaurs and how and why they got that big: http://www2.scholastic.com/browse/article.jsp?id=4766
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
The amount of energy that goes into answering questions like the ones above blows my mind. Try http://www.wikipedia.org good resource...
"Don't seek these laws to understand. Only the mad can comprehend..." -- George Cosbuc
Because that is impossible. Energy travels from warmer to cooler spaces automatically as heat. A rabbit "unaffected" by the cold would be a rabbit "unaffected" by thermal physics. So, that is biology + physics.
I am going to be more blunt because I'm starting lose a little bit of patience. Once again, if you are going to need to understand every little detail about every organism in order to feel like you understand evolution, then you are never going to feel like you understand evolution, and we will be stuck here for the rest of our lives answering your questions. What is important is for us to help you clarify what evolution proposes and how it works.
Do you understand natural selection? Yes or no? If no, what do you not understand? If yes, explain it in your own words.
You get energy and nutrients from food in the form of chemical compounds. So, that is biology + chemistry.
Probably, once some organic chemicals began copying themselves. This is abiogenesis.
Just because they got bigger, it seems like there was a purpose?
Yes, they require more energy.
There are animals living today that are "bigger" than most of the dinosaurs. Blue whale?
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
You shouldnt be losing patience since you can respond on your on time I am not holding up your time it. But I do appreciate when you do.
I understand as much as the average person would understand it but I dont understand its relationship with random mutations.
I think that would just about be it and I was talking about land creatures since I dont think water conditions have changed over time although that is wierd that sharks used to be bigger kind of makes you suspcious.
No not a purpose for getting bigger but inevitable.
Thanks.
Well, you understand that natural selection can only choose from the genes that currently exist. Mutations are needed to generate genuinely new traits.
Ah. There are some theories about that.
There were much higher levels of oxygen and CO2 in the atmosphere at the time, and it was probably much warmer, so there were probably a lot more nutritious plants, meaning that there were enough resources to sustain many extremely large herbivores. So, it's possible that they grew really big because of an abundance of resources. Maybe some grew tall partly in order to reach the leaves on tall trees, like giraffes. Size may have given them protection against predation. Maybe their size insulated them from temperature changes.
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare
Can someone just tell me how to use the scientific method?
Was a right about the air and how it best explains the phenomena of wind, sound, and pressure? We can't see air so why do you see those diagrams where it shows the air molecules bunch up together to prepresent a sound wave since we can't see them how do they know its accurate to portrait them that way? How do they know trees give off oxygen if they can't see it? Why do you guys say evolution has stronger evidence than any other theory surely there is more evidence for air than evolution? Also gravity is just the atrraction between matter right why is gravity such a mystery I keep hearing about?
I know this is off topic but I need to understand how the scientific method works to understand how evolution was even figured out.
In my vastly simplified way of viewing the world and science, I'll give it a shot. I am not a working scientist, so I may not have all the details.
It begins with an idea, a question, also called a hypothesis. Why do we feel wind? And leaves blow around, and sometimes there are tornadoes, sometimes trees are blown down, roofs blow off. A very long time ago people said god(s) were blowing out. But that still doesn't answer why we feel someone breathing.
As people developed various instruments, they could measure wind speed and direction. It was important to understand if you are trying to sail a ship as the ship moves because of the wind. So you could better sail your ship if you could measure the wind speed and direction. Well, then they discovered how to make a vacuum - a place without air. A heavy glass jar (usually shaped sort of like a bell so they call it a bell jar) sealed around the bottom with grease. They had a pump to remove water from the bottom of those sailing ships, so they used the pump to see if they could remove the air. And they could - and if they put things in the jar and pumped the air out, mice would die, candles would go out, and so on. So there was something positive about air, it wasn't nothing. I did this experiment in the 8th grade.
About the same time, other people were messing around with the idea of batteries. Why, if there is an electrical storm, being hit by lightning when standing in a puddle of water is fatal? Eventually, someone put a positive charge on a piece of metal at one side of a bowl of water and a negative charge at the other side of the bowl. And the water would bubble and gradually go away! What are the bubbles? What is in them? So they tried catching the gas from the bubbles and lighting a match to the bubbles and the effects were different. I did this experiment in my high school chemistry lab. The oxygen molecules are attracted to the positive terminal because oxygen is overall negatively charged. The hydrogen molecules are attracted to the negative terminal because hydrogen is overall positively charged. They hadn't named them hydrogen and oxygen yet, back then. And they didn't know about opposites attract. But they kept experimenting and tracking the results and talking with each other. And they eventually figured out what works and what is consistent and can be replicated between different researchers.
And years later, they had the equipment to analyze air and find out all the different elements in air. And now we talk about air pollution and global climate change because of the pollution and they have really fancy computers to model how that changes air flows. And a lot of other stuff.
The scientific method:
You ask a question.
You try to devise a way to answer the question. (This can be very complex anymore.)
You test and experiment.
Is your question answered?
If no, go back and try to figure out another way to answer the question.
If yes, repeat the experiment to verify that you didn't make any big errors.
Because the next step is to have your paper published and people around the world will try to replicate your results.
And you will hear about it if your results can not be duplicated.
If your results can be replicated, you may win awards and/or some really big money and a lot of prestige. But for many scientists, it isn't about the rewards or prestige, it is about answering their questions.
If the answers to your question can be put together to explain and predict results, then you are said to have a theory. A scientific theory is not a guess like in a detective show. It is a way explain what is happening around us and to predict what might happen in the future. A scientific law is not a theory all grown up. It is a mathematical relationship.
Gravity is a law and a theory. Thanks to many researchers starting with Isaac Newton, we have mathematical equations that explain the effects of gravity. These are the laws of gravity. Why when you shoot a cannon ball out of a cannon does it comes down, no matter how much powder you put in or how high you point it? Gravity. And you can figure out how far the cannon ball will go and how high it will go if you use Newton's equations. Gravity is also a theory. Why does gravity exist? What is gravity made of? There is still a lot of research to do to since we don't know every little thing about gravity.
You have a lot of questions, you might enjoy being a scientist. But you will need to go back to school and do a lot of work first.
-- I feel so much better since I stopped trying to believe.
"We are entitled to our own opinions. We're not entitled to our own facts"- Al Franken
"If death isn't sweet oblivion, I will be severely disappointed" - Ruth M.
So how do I apply the scientific method to evolution? If I wanted to see why humans look different from our parents or why some people have darker skin(not from tanning but born that way) what would I do to figure that out?
Also my dad thinks that the rain is caused by god and I wanted to say something when he brought it up? That is an example of not speaking up about to my famiy that we were talking about on the other thread.
You can't just apply the 'scientific method' to determine something as the whole way to determine something.
In the classic sense, you start by coming up with ideas as to what possible explanations there might be. In a some ways that is the hard part.
You should read up on whatever you can find that has already been proposed as explanations, study what has already been found out and well proven, and work out what experiments or studies might help you decide if there is already overwhelming evidence for some existing explanation. Then if you are still not convinced by what explanation is currently accepted, you need to come up with a plausible alternative, and then devise experiments or just specific detailed observations, assisted by whatever scientific instruments you can get access to. It will often be helpful to gather as much relevant historical data as possible.
The main thing that science adds to the old ideas of how to explain things is to not just accept what 'seems to make sense', IOW to NOT accept an explanation until it had been tested as thoroughly as possible, both for how well it actually fitted to all relevant observations, and whether it fitted better than whatever alternatives you or anyone else could come up with.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
If I read what someone else said then I need to have a way to verify it with reality to see if its true or false. Like all the fossils you read about I haven't personally dug up fossils so how do I know that they aren't fake understand. I am not saying the whole of fossils is a fraud but most fossils are rplicated and put in museums so how do I know which ones are legit and which ones are fake( as in discoveries). Also I have seen where they say chimps and humans have 99% the same DNA yet other sites have 97,96,94 etc.. yet I Dont know the first thing about dna to understand who is telling the truth. What do you guys mean when you say credible source if its from a real scientist then so what the only credible source should be your self and what you empirical test about the world. It sounds like you are saying just take the word of people who are experts in their fields. Thats why I wish I was in too science during high school although my brother who is still in high school says they dont teach evolution there.
Also I know this is off topic but my question from earlier about air, how do they know that sound is a compression wave and how do you find out how long a wavelength is or the frequency for that matter?
Since you don't have the background or equipment, you will have to other people's word for it. Just like you are doing now. How do you know I'm not totally full of shit? If you had a PhD in genetics and a state of the art lab to work in, you would be able to find out exactly how the genes work to produce those effects. Since you don't have either one, you will have to accept that and read about what other people have discovered. A good place to find real facts and not wishful thinking is to hit the science and university websites. Don't bother to read any website that includes wishful thinking about a dog/god/s/dess. If they are going on about creationism or intelligent design, don't read them for now. Get the basic scientific information that is available for high school and college students. Learn about genes and DNA and RNA and replication errors before you try to see if the religious crowd has anything useful to say.
It does no good to clutter up your mind with a lot of false information when you can't tell if it is false. The only way you are going to be able to tell true from false is to get some basic science education.
Sites like these:
http://www.nsf.gov/
http://si.edu/
http://www.mnh.si.edu/
http://www.homeworkspot.com/high/science/
How about - if god causes rain, why do weather men get it right occasionally? If god caused rain, it would be totally random and you could never guess when it was going to rain.
-- I feel so much better since I stopped trying to believe.
"We are entitled to our own opinions. We're not entitled to our own facts"- Al Franken
"If death isn't sweet oblivion, I will be severely disappointed" - Ruth M.
http://www.rationalresponders.com/science_dummies
Imo, one of the most important things to understand about the scientific method is that it is not some rigid labyrinth of testing that can only be carried out by people with PhDs in white lab coats. It's just the seemingly best way to think about and find the answers to problems in the real world. You are using the scientific method right now, to an extent, in your questioning.
The diagrams are a convenient way of illustrating the molecules in the air, even if it's not 100% accurate.
We can know they are good diagrams because directly seeing is not the only way to gather information.
We mean that there is stronger evidence for it than for any other theory that attempts to explain the diversity of life.
Because we haven't really identified how it works. Electromagnetism is drastically more developed.
What you are doing right now.........that is how the scientific method works.
Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare