Evolution
- Thread starter omega 616
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You mean 25 years ago the world wasn't baren and in the 4 years before my birth things just evolved at super speed? Now I get it!Mr.K. said:
Sorry, just joking.
I know it never happened over night, what I am getting at is how did it start? In my head there is a bunch of single celled organisms that are going to form horses, rabbits, tigers, rhino, ants etc how did it start?
Sure it's easy to go "horses grew into geraffs 'cos the longer necked ones got more food, so lived", but what about before the horse? How did the one cell go "in 3 billion years time I am going to be a horse!".
Man, am I finding this hard to articulate!
Say you had two single cells, one called Frank, Frank wants to eat plants, how does that start? There are no out side influences to start Frank into eating plants. Does he get a decent size and just start sucking on leaves, then finds something that looks like him and mate with it and teach his children to suck on leaves, then during a million years of sucking leaves mutations happen that allow Frank to chew leaves?
Surely Frank never came out with a full set of gnashers, perfectly formed to chew on leaves.
All the people who have commented on this thread seem to be going from the half way mark of "we have animals and this happend to form what we have now".
lol It's ok mate, nothing in science is ever complete that's one of the best things about it, always more to learn.Glademaster said:
As I say i'm just very quick to jump into attack mode when I see "it's only a theory". To be fair you said as a theory it's badly put across in modern society, you are dead right there man no arguments here. Hope I didn't come across as too much of an ass.
Well I think you're vastly simplifying the issue. The scientific definition of the word "evolution" is fairly simple. Change over time. Very, very, VERY slow change over a very, very, VERY long time. And allow me to dispel any misconceptions about "crawling out of primordial ooze" right now. Again, a vast over simplification. Life likely arose as, at least in the beginning, extremely simple collections or self-replicating organic molecules, (that's organic in the scientific terms) something along the lines of RNA as we understand it today. Not DNA for very complex reasons I haven't the time or patience to explain here.
As far as your understanding of a mutation goes, you're way off. Never has any creature given birth to it's offspring to find that they have some vast morphological deviation on the scale of the famous (and ludicrous) "crocoduck". The fact is, that major genetic mutations are extremely rare. Most mutations are referred to as "neutral", meaning that the change in the nucleotide sequence of the genetic material (RNA or DNA) has no effect of the organism's life or function. This could be for several reasons that are, again, much too complex to be explained here.
Remember, though, that even this is only a brief, and extremely simplified look into the science of evolution be natural selection. As others have, I would recommend Richard Dawkins' "The Selfish Gene", and "The Greatest Show on Earth" if you're interested to know more.
As far as your understanding of a mutation goes, you're way off. Never has any creature given birth to it's offspring to find that they have some vast morphological deviation on the scale of the famous (and ludicrous) "crocoduck". The fact is, that major genetic mutations are extremely rare. Most mutations are referred to as "neutral", meaning that the change in the nucleotide sequence of the genetic material (RNA or DNA) has no effect of the organism's life or function. This could be for several reasons that are, again, much too complex to be explained here.
Remember, though, that even this is only a brief, and extremely simplified look into the science of evolution be natural selection. As others have, I would recommend Richard Dawkins' "The Selfish Gene", and "The Greatest Show on Earth" if you're interested to know more.
To TS:
Maybe this is more easy to understand if you attack it from a different direction, namely the source: genes.
All evolution requires something that can copy itself and occasionally creates variations of themselves. This applies not only to genes (animals) but for example ideas (memes) as well.
Following is the heart of evolution. The notion that some genes causes itself to be more prune to be copied and/or become numerous. Genes causing the animal to outrun predators will make it live longer and hence have more opportunities to breed (copy its genes).
From this perspective, other things become explainable. Have you ever wondered why humans are so compassionate even to the extreme of ending ones life in favour of another? The egoistic view can't explain this as the survival of oneself is the most important. On a gene level the origins of altruism (notion of caring for others) comes from the fact that when man was young, we lived in small groups of mainly relatives. Chances are good many carry the same genes and hence it would benefit the gene to cause us to care for not only us.
Maybe this is more easy to understand if you attack it from a different direction, namely the source: genes.
All evolution requires something that can copy itself and occasionally creates variations of themselves. This applies not only to genes (animals) but for example ideas (memes) as well.
Following is the heart of evolution. The notion that some genes causes itself to be more prune to be copied and/or become numerous. Genes causing the animal to outrun predators will make it live longer and hence have more opportunities to breed (copy its genes).
From this perspective, other things become explainable. Have you ever wondered why humans are so compassionate even to the extreme of ending ones life in favour of another? The egoistic view can't explain this as the survival of oneself is the most important. On a gene level the origins of altruism (notion of caring for others) comes from the fact that when man was young, we lived in small groups of mainly relatives. Chances are good many carry the same genes and hence it would benefit the gene to cause us to care for not only us.
Its no problem it is the internet and tone of voice can't be expressed here. As I said I probably could of rephrased what I originally said better. I know there can be a lot of ignorance and trolls on the internet.TheDist said:lol It's ok mate, nothing in science is ever complete that's one of the best things about it, always more to learn.Glademaster said:
As I say i'm just very quick to jump into attack mode when I see "it's only a theory". To be fair you said as a theory it's badly put across in modern society, you are dead right there man no arguments here. Hope I didn't come across as too much of an ass.
If it were fact, the logic surrounding it wouldn't change, but it does, showing that people do not know evolution to be a fact. Realistically, much of science is not fact because our understanding of it keeps changing, but we take it for granted, so you could technically say that much of science is actually faith.Loop Stricken said:
Ugh, please, don't bring faith into this. Science has nothing to do with faith. This really is no place for science-philosophy, there's absolutely no harm in seeing the theory of evolution as an absolute fact because at the moment to us it is. Whether or not it'll be completely reworked in 10 years is irrelevant.Don said:
EURGH! i hate sematics.Chrono212 said:
Science actually cannot prove anything; hence the term theory. we can only disprove hypotheses till our eyeballs pop and all other alternatives have been disproven.
the evidence is really NOT circumstantial. its very substantial in fact. and the fact that we call it a theory means that it is accepted by the scientific community.
Well I'm not sure about the horses, but my guess would be that they fill their own little niche that giraffes ignore because they have access to the much more nutricious leaves and fruit. Actually do horses share an environment with giraffes? Daddy long legs probably don't need a strong venom (just looked up their diet, they're pretty clever). They don't need it to kill, and they escape predators with their distracting legs.omega 616 said:
Have you ever seen the evidence of the existence of subatomic particles? If not, do you believe in them anyway? If so, that is faith. If believing is not seeing, then that is, arguably, faith.Nimcha said:
I'm sorry but the fact that it's called the theory of evolution and not the Laws of evolution, like the Laws of Motion, means that it is still a theory.kromify said:
A very well thought out and compelling and likely theory, but a theory nonetheless.
You seem to be misunderstanding how evolution works, nothing decided to be anything, they developed that way over billions of tiny changes.omega 616 said:
Let's use the currently accepted theory of the evolution of the eye as an example.
An organism (let's call him frank) has no eyes, in fact no way to discern light at all, one day one of frank's offspring has a minor mutation, he has a small external patch that is sensitive to light, he can't "see" but he can discsern light, over a few thousand genereations that patch of light sensitivity got more complex, at first it merely spread out a bit, but eventually it began to senese the streanght of light, after a while longer it began to discern shapes by noticeing the difference in light between different areas in it's field of "vision", later still the light sesitive part became concave and as such could determine shapes more easily.
Genereation after generation the light sensing organ became more complex, it could determine shape, and eventually distance, as it evolved it allowed Franks desendents to avoid obstacles, search for food and even avoid predertors.
After several billion years of small changes like this a small multicellular organism developed slowly in to a number of different evolutionary paths, some worked and got more complex, some didn't and died out.
A horse is a result of countless different mutations over billions of years.
Finally an important thing to keep in mind:
Evolution does NOT try to explain the origin of life, it DOES however explain how life grew to be so complex and diverse over time.
Horses are alive because they don't need long necks. They eat grass.omega 616 said:
As for how one-celled organisms turned into the multi-celled organisms of today, I don't think we're entirely sure.
The theory I've heard is that several one-celled organisms did at one point form a colony. The different organisms (cells) performed different tasks within the colony, and this was a very effective way of keeping alive. Over time, the different organisms became more and more specialized, to the degree where the colony was no longer a bunch of different one-celled organims, but an organism in itself.
In one way, I guess you can even view yourself as not one organism, but billions of tiny organisms (your cells) co-operating to survive.
Edit: As for daddy longlegs. Is this [http://en.wikipedia.org/wiki/Opiliones] what you think of when you say daddy longlegs?
If so: This one doesn't have poison at all, it catches its prey by other means.
That guy could be a teacher. He really should to, he is better than some of my teachers.Marik2 said:
Not nearly so complicated. The horse with a neck a cm or so longer is able to eat a larger amount of the leaves or fruit hanging from trees. This improves its likelihood to survive, meaning it is more likely to mate.omega 616 said:
So, let's say you have 50% of horses with 12 cm necks, and 50% with 14 cm necks, and the ones with 14 cm necks live an additional year (18 vs 19) They are more likely to actually have offspring. Those offspring will be more than 50/50 likely to have the longer neck. A few generations later, you have 40% 12 cm necks, and 60% 14 cm necks.
Further more, the horses who find the longer necks more attractive are more likely to have long neck offspring, which are more likely to survive. So after a while the sexual preference will also shift towards the longer neck horse.
Of course this takes a LONG TIME to happen.