so all this irreducable complexity nosnese gave me and idea for a cool new thread. how did it evolve. here we will discuss ways certain complex systems can come about. im going to pick an easy one, since my head hurts and im sick, an- blabla anyway the wing: lets say a creature developed a flap of skin under its armpits. maybe its used as some sort of heat synk, like how elephants ears work. now lets say other creatures found this sexy for whatever reason. and bigger was better. so now whats going to happen is the flap will spread an grown, eventually connecting to the legs (flying squirrel anyone?) now the smart little bugger realized it can use the flaps to glide. animals are actually pretty smart. well, now they have entered a new relm, and natural selection takes a new turn. now they can glide from tree to tree and get food and avoid predators much more easily. now another mutation happens. reduced bone density. normally this would be a harmfull mutation, but for these cute litle hypothetical animals, it made the lighter, so they can glide further. eventually this flap of skin will evolve into a full fledged wing, and from gliding, will come flying. interstingly this hypotheitcal could suggest that intelligence played a role in evolution long before humans came about
Why would a creature find a flap of skin under an arm more attractive in any way? How did skin evolve? Also how did teeth evolve? Every single tooth has a predetermined shape written in the DNA before they even begin to grow. Every single tooth in the mouth perfectly compliments all surrounding teeth. How would randomly growing bone know what shape the other teeth surrounding it will be shaped like?
huh? evolution doesnt work through mutations of genes spreading via natural selection and other factors throughout a population? i think thats exactly what evolution is. my example was more abridged obviously, but its still exactly how evolution works. sorry if i left out all the eco system and predator parts in my example. mutation occures, if it is good (its passes to young, and doesnt get weeded out) evolution occures
Ah, I see that you were oversimplyfying it on purpose. Had to re-read your post and noticed you said your head hurts. Sorries.
You're misunderstanding genetics and evolution. Ancient DNA didn't start out with each tooth and area of skin mapped out and predetermined as they appear in us now. There was no code in early man say, for the capacity for speech, it developed little by little in response to various factors, it wasn't inherent in man at the beginning. Our teeth weren't always the same, nor was our skin. MelT
On the matter of wings, perhaps wingless birds (or the derived creature) found that they weren't suited for land or water. Conditions pushed them into developing a way to take to the air. Although that is pretty intelligent, should I believe that the wing was developed without imperfect "trial" wings being produced along the path? Does biology already know how to produce a wing before a wing is needed?
Remember that the wing didn't begin as a wing, but a hand and arm (this is true for bats too and others). There were no useless half wings, all through the development of the wing, birds were using their 'hand' claws to help them climb, and as a weapon. Even today birds use their wings like clubs when fighting other birds, and it's this ability that may have led to flight. Feathers had already evolved to a great degree in non-flying dinosaurs before birds came along. http://en.wikipedia.org/wiki/Bird_flight#Evolution_of_bird_flight MelT
I could explain the evolution of feathers and flight if you'd really like. The evolution of birds is my favorite subject and I'm going to MSU to become a paleontologist where this will be my subject of focus.
Please do Do you think that feathers developed on earlier non-flying dinosaurs as a decorative/mating signal, or for warmth, or other reasons? MelT
I'm fairly certain that's not how it exactly works. A mutation doesnt occur for a specific purpose, such as warmth. Instead, when the DNA is being replicated in the cell, something just goes wrong, for example instead of the codon being CCG it could mutate to CGG. It's pure chance that a certain mutation will lead to a development that is beneficial. And if that mutation happens to be beneficial enough, it will attract more mates/last longer to reproduce more/whatever. At least, I think that's kinda how it works. Its been a while since AP Bio....
I understand the genetics, it isn't all mutations, but obviously natural selection too. The tail of the Lyre bird for instance is useless for anything other than signalling to mates. Mutations as you describe them do take place, but it isn't the sole mechanism for evolution in organisms. MelT
well of coarse the entire point of this threat is to hypothesize how certain complex organs can form. so please by all means share we all know that the wing did in fact evolve from an arm like limb, this thread is for exploaring how it came about, not arguing with silly creationists that we already know are dumb
Okay, we know pretty much how the wing came about and we have a good couple of theories regarding the development of flight. How about something else instead? Why do our hands have five fingers? Will we eventually lose our little fingers and toes? MelT
well yea, thats the point, i just used flight as my op example, but we can talk about anyhting. ill try to restart this thread with another example. the penis sexual reproduction is what jump started evolution. its what gave life the ability to mutate quickly, and also protect good mutations. but how did it come about? here is one way, a primitive mutlicellular organism may have developed a thing that stuck out, perhaps to inject dna similar to a retro virus. over time as it became more complex. and other animals defended against it, it became less compatible, and required the hoast to be more similar to the origion organism. then over time a symbiotic relationship develops, and two species assimilate into one, revolving around sex
Let's jump off from an appropriate point: Evolution of sexual reproduction - Wikipedia, the free encyclopedia The cannibal theory sounds pretty weak to me
I know that you intentionally oversimplified some aspects of this, so forgive me if I try to correct you on something you already know. Most of this post is pretty well stated. A couple of things- the initial reproductive success of the individuals with the small skin flaps under their arms most likely had nothing to do with them being viewed as more attractive or desirable as mates by the opposite sex, but that these skin flaps gave them a survival advantage, allowing them to live longer on average, giving them the chance to have more offspring on average. Also, the gliding most likely wasn't due to intelligence or reasoning/experimenting. Maybe some of the individuals with the developed flaps were a bit more bold, taking longer leaps from branch to branch, and just by naturally extending their arms to reach the next branch, they were able to glide and jump further. These individuals would be better at escaping predators/aggressive enemy critters. The better at gliding they are, the longer they survive, etc etc etc. I already covered the attractive skin flaps. Skin is a modified scale, developed from our reptilian ancestors. The scales molded together and became softer and semipermeable. Teeth have a clear evolutionary history just like everything else. And no, bones don't know what shape to grow. They don't know anything. They don't have brains, silly. Please rejoin this discussion when you have a better understanding of biology. This has the potential to be an interesting thread. For the sake of maintaining the intelligent discussion and avoiding flame wars, let's try to keep it respectful. This is a good question. I'm not sure there's any particular reason we have 5 fingers, rather than 4 or six. Some aspects of evolution are somewhat random. Our early ancestors just happened to have 5 phalanges, and it worked pretty well, so there wasn't any change. We will not lose our little fingers or toes. For that to happen, little fingers and toes would have to somehow reduce your chances of reproduction, which will most likely never be the case. This is an excellent question, and at the risk of sounding like a fucking freak- there is a lot of really fascinating evolutionary history behind the penis. But as far as initial development- sexual reproduction originally took place outside the body. The female lays eggs, then the male sprays his brogurt on it to fertilize. When life began to move onto land, this became somewhat less effective. Some animals began fertilizing eggs as the female was laying them. Eventually this lead internal fertilization and the evolution of the penis.