When does microevolution turn into macroevolution?

Gonna try to explain it without a lot of jargon.Micro-evolution is evolution on a small scale, typically within a species. Think, advancement of one particular trait.So, here would be an example:Pre-lawn mowers dandelions all grew very tall so they could get above the grass.
Post-lawn mowers there was a very powerful selective force in favor of short flat dandelions.The arrival of short flat dandelions is a good example of micro-evolution.It's micro-evolution because, to the best of my knowledge (Im not a botanist) short dandelions and tall dandelions can still cross breed with each other.Macro-Evolution is generally considered to occur when enough micro-changes have come up so that the original species and the new adaptation are different enough that they can no longer interbreed.Using the dandelion example and projecting into the future -- Again, NOT a botanist, just giving examples based on plants and animals we are all familiar with.Let's say that dandelions typically rely on honey bees for pollination, and that short dandelions, while significantly better at surviving lawn mowers, are not easily spotted by honey bees.However, short dandelions are easily discovered by bumblebees.Let's say that the smell the flowers is what attracts one type of bee over another. And for simplicity sake, lets say that bumblebees and honeybees don't like the same smells. (in reality this is a heck of a lot more complex, but I'm boiling everything down to make an example).Any short dandelions in a yard that are attractive to honey bees will reproduce, but any short dandelions that are attractive to bumblebees stand an even better chance - since the bumblebees can more easily find the flowers than the honey bees.So, now there is a selective force in favor of flowers which smell good to bumble bees.Meanwhile, a silimiliar but opposite selective force is in play for tall dandelions making them smell good to honey bees.As time goes by, short dandelions which smell good to bumble bees out produce their counterparts. And tall dandelions which smell good to honey bees out produce their counterparts.What we end up with are two kinds of plants, both still very similiar, but with completely different smelling flowers. As a result, the honey bees stick to the tall plants and the bumblebees stick to the short ones.Because the bees are not carrying pollen from the tall flowers to the short flowers and viceversa, the two types of plants do not (can not) interbreed - they are therefore different species.That's macro-evolution.Both are relatively small changes, One just creates the barrier between species.Now, in mammals, it may require more than one little change to create that barrier, therefore "macro" evolution can refer to an entire host of changes - (ie the numberous small differences which seperate foxes and dogs).Hope this clears things up a bit.As for "snardy remarks" - microevolution is easily demonstrated in labs and even the fundamentalists can not deny that it exists. Therefore the reason the two terms are at play is that they accept micro-evolution, but do not believe in macro-evolution.

I'm a little confused by the term "span of all life".Do you mean, how can we observe macro-evolution taking place over all of history?For that we look to the fossil record. As changes mount up, we eventually say - these two are seperate species.If you look at my dandelion example, you'll note that there would be almost no fossil record for the changes I'm describing - yet macro-evolution is taking place.In all likelihood, we've overlooked a great number of species splitsWe may consider fossils of three very phyiscally similiar birds to be the same species, even though, in practice, their feather coloration (which would not get preserved) prohibits them from interbreeding since the various types of females are simply not attracted to the different types of plummage.

Dr A gave a good example.Here's another one. There are many many different "species" of jumping spiders which are, from a mathematical stand point, genetically identical.However, since these different "species" have different mating dances, even if you put two 99.999% identical spiders together, they can not get in the mood to get it on.If you were to artificial mix the materials, they could produce offspring, but in the real world, they simply can not.Hence, since they can not naturally interbreed successfully, they are different species.Now, keep in mind, we are basically dividing things up using a system we've agreed on to be more organized. Nature is not so organized.Hence, whales and dolphins are different species (lots of different species) but every once in a while you get a wholphin popping up 'cuz horny is as horny does.

A couple of issues with your post -- No, an African American and a turnip look completely different. An African American and a Japanese American look very much alike. If I have a these two guys and a turnip in a line, you would have absolutely no trouble picking out the two humans.Now, what you can say is something along these lines: There are many characteristics which seperate African Americans from Japanese Americans (skin tone, height, hair placement and style, vocal range, etc.)But both of these are the people are the same species, and as you correctly pointed out, stripping away everything but the skeleton we'd lose sight of a great number of the so called differences.I don't see how this is a problem though? They are both human. And, judging from their remains we would concluded correctly that they are both human. I think you misunderstand what I was saying above. I'm not saying that fossil evidence doesn't demonstrate macro-evolution. What I am saying is that macro evolution can occur outside of evidence in the fossil record.The fossil record, in other words, gives us evidence for macro evolution in and of itself. But the sum total of macro-evolutionary changes that have actually happened are not all recorded in the fossil record.I'll try to make up an example:
If there is a muddy bank of a river and a bear walks on it it leaves footprints. If that mud then hardens and becomes stone, those footprints are preserved. That is evidence that at some point a bear walked on that spot. However, we can assume that in the past many many things have walked on the spot - it's just that circumstantially, only the bear left footprints.My pointing out that not all things which walk always leave foot prints does not in anyway lower the evidentiary value of the foot prints we do have. If a person only saw short dandelions, you would be correct. however, if an observer came upon a field of short dandelions, noted it, then came upon an area of tall grass and discovered tall dandelions, they would have additional data.If they saw a lawnmower cut down the tall grass, they'd have even more data.If they found paintings from a time before the invention of a lawnmower and only saw images of tall dandelions, they'd have even more data.If they tested the genetics of dandelions living today and of dandelion pollen found in sedament from thousands of years in the past, they'd have even more data.As they continue to dig deeper, they get more and more information. As they picture fills in, they get a better grasp of what actually happened in the past, even if they were not there to observe it.Remember, it's not like scientists found one fossilized dino bone and came out the complete field of paleontology as you see it today. Lots and lots of info has been collection, conclusions have been deduced from the facts. You wouldn't. Perhaps I wasn't clear enough. My point was this -
Though we do see evidence of macro-evolution in the fossil record, there is undoubtably MORE macro-evolution happening than is recorded in the fossil record.In other words, it happens, we see it. But sometimes it happens and we don't see it. However, just because we don't have evidence for every time it happens, doesn't mean that the evidence we do have doesn't prove it's existance.Example -
If you touch something, you leave a fingerprint. If someone dusts for fingerprints a couple days later, they will find some but not all of your fingerprints. They can prove that you were at the location, even if they can't prove how many different things you touched there.

I know I'm drifting off topic by posting this here but...Guys! You wanna know why Fundies never come around? YOUR discussion is why.I see it on EVERY thread here.Fundy: "I don't understand the concept of X"
Evo1: "Okay, let me try and explain it to you. blah blah blah."
Evo2: "Actually evo1, you missed out on sub-sub-sub-point 7. You said blah, but really its bllah"
Evo3: "You are both wrong. Recent studies show that "bllah" is mearly "balh"
Evo1: "Fine, but that doesn't address what I was saying"
Evo2: "Well, the implications of sub sub sub point 7 are that if bacteria blah blah blah"
Evo3: "Here we go again about bacteria. Once again I want to address your issue with minute detail 23."
Fundy: "Geez, there's no concensus among the Evos they much all be wrong about everything."STOP trying to impress one another and focus on the issue at hand - A fundy wants information. They don't have an advanced degree in Bio-genetics, don't treat them like they do. Keep it simple, and keep the nitpicking to the nitpicking threads.

He asked a very simple question. It deserves a simple response.There is no "proving it to be false" because he's not asking for a falsifiable statement. He just wants to better define the two terms.I'm not saying you should gloss over the truth, what I am saying is that this sort of scientific dick measuring HURTS the cause.If two people who speak Spanish are arguing over a minor dispute - all I can tell you is they are arguing, because I don't speak Spanish. The Fundies don't speak science. When you guys dicker about sub-issue 33, all they hear is disagreement.The entire reason there is even a debate going on politically about Creationism and Evolution boils down to one EXTREMELY simple fact.The Fundies can walk in lock step. They all say the exact same thing, quote the exact same source.100 people shouting the same thing can very easily be wrong, but they get heard over 100 people shouting different things each one of which is correct.

In regards to this debate - Fundies are supporters of YEC and ID (and no there really isn't any difference between the two theories).Is the Pope a fundy? Nope. Pope supports evolution.

a better understanding for you of for others? Because what you are doing is causing a greater lack of understanding among the people who we most need the knowledge. Of course it isn't. Just like trig is more complicated than addition. By this thinking, we should start with trig in pre-school so as to prevent the kids from thinking that math is based on simply understood concepts. Mod! You've been here for 2 years! How can you not know this?! YES! The fundamentalists DO NOT SEE that scientific debate occurs. They hear that there is a debate between "steady state" and "punctuated equilibrium" and conclude that scientists disagree that evolution exists. ABSOLUTELY!Why? Because I KNOW that the fundies don't get past "polarized" - the rest of the sentence is Spanish to them.So when a fundy asks "Is the sky blue" and we reply "yes", it allows us to start from a foundation. We have the fundy agreeing that there is a "sky" and that it is "blue".From there we can build.Instead, if you respond with: 'The reason the sky is blue is because the blue frequencies are polarized by electron-positron interaction at the quantum level which deexcites the rest of the spectrum temporarily.'The Fundy stops reading and says - even the scientists don't believe the sky is blue.Game over.

Gonna start a new thread