Summations Only

What macro-evolution is has been questioned throughout this thread, but it seems to me that macro-evolution is simply an artifact that depends on what is being observed; it is humans looking at two critters from a lineage that are each temporally and generationally distant.It is just the sum of a long series of micro-evolutionary changes caused by repeated mutation and selection.It seems to me that it really is that simple.

Hi Jar, Well that is the heart of the question isn't it? There are so many definitions both from science and from non-science (particularly creationists) that it is easy to be confused or for two people to be talking about two different things. It is an artificial artifact of our making merely to make a label to use in conversation. Yes, it is evolution accumulated from adding up the single generation observations of microevolution. 1+1+1+1+1+1+1+1+1+1=10 rather than 1+1=2.Enjoy.

So would you say that Mendels work helps to define microevolution?
Mendel did his work on green/yellow peas and smooth/wrinkled peas and showed that these specific traits don't become diluted from one generation to the next but that rules apply to their transfer to the next generations. If we assume that bulk microevolutionary events constitute macroevolution we might aswell determine that yellow peas are a different species to green peas. Every single microevolutionary change results in a new species and therefore you and I are different animals!

Well, no, because species essentialism is wrong. We don't define species as a certain specific genetic configuration, but as a reproductive community. Conceivably there's a sequence of events by which you and Percy might find yourselves in isolated reproductive communities as a result of successive microevolutionary change, which would constitute a macroevolutionary speciation event. That's how bulk microevolution leads to macroevolution.

If all you're seeking is how a photoreceptor could arise in an organism without photoreceptors, then the answer is one that you'll probably find a bit trite - mutation.This may seem like a copout, but I'm unclear what more you're searching for. Let's look at a photoreceptor protein. The one I've picked is the Photoactive Yellow Protein PYP. It's a protein found in the bacterium Halorhodospira halophila that repsonds to blue light (meaning that it looks yellow - the blue light is absorbed rather than reflected). Here's the sequence of the protein. Each letter stands for an amino acid residue, the building blocks of proteins, and this shows you the order they fit together to make this particular protein:MEHVAFGSEDIENTLAKMDDGQLDGLAFGAIQLDGDGNILQYNAAEGDITGRDPKQVIGK
NFFKDVAPCTDSPEFYGKFKEGVASGNLNTMFEYTFDYQMTPTKVKVHMKKALSGDSYWV
FVKRVNow, there are any number of ways an organism could build this protein, since the genetic code is full of synonyms. For example, the protein sequence above starts with Methionine (M), then Glutamic Acid (E), then Histidine (H). The sequence of DNA coding for this bit in H. halophila is 'ATGGAACAC' (where each letter stands for one of the four nucleic bases which make up DNA), but exactly the same protein would be produced if it instead started 'ATGGAACAT', for example, or 'ATGGAGCAC'.It also wouldn't need to be exactly the same protein. There are many different photoreceptor proteins found in nature, and there are probably many more that could potentially work, but which we don't see around us.The basic point is that there are many different ways for a photoreceptor protein to appear. There are many different potential proteins, and many different ways to code for each specific protein. What, exactly, are you looking for here?Edited by caffeine, : ABE: changed sub-topic

If by "bulk microevolutionary events" you mean a huge number of mutations within a single generation, then I don't think anyone on the science side would assume this as playing any significant role in evolution. Most, including myself, would probably think it extremely unlikely unless the population was living inside a uranium mine. If "single microevolutionary change" is actually referring to your idea about "bulk microevolutionary events" from the previous sentence, then I've already said this seems very unlikely. Death, with the effect that the organisms fail to contribute to the next generation, seems the likely outcome of huge numbers of simultaneous mutations.But if "single microevolutionary change" refers to the normal mutation rate, then a new species will never be the result. Microevolution across a single generation never causes speciation. It's in the definition of microevolution, which is evolution within a species.--Percy

I never mentioned mutations once. Where did this spring from? Mendel talks about dominant and recessive alleles. The particles that are governed by the rules of heriditry. Your line of logic leads me to conclude that you don't accept that Mendel established how microevolutionary changes occur.If we can't define microevolution how will we ever define macroevolution?

Hi Big Al!I can see now that by "bulk microevolutionary events" you did not mean mutations, but in that case the term has no meaning. Every single gene gets remixed during sexual reproduction, one allele from each parent. Always. In the sense you intended it, there's no such thing as non-bulk microevolutionary events.But again, what has this to do evidence for macroevolution?--Percy

Actually, the answer to your question is "No".Mendel made some observation that involved statistics of hereditary traits, but even he showed that those traits did not ALWAYS hold true. There were cases where the hereditary rules did not hold true and something really unexpected happened.He set all that data set aside as "unexplained".Nothing in Mendel's work explained how things change, that understanding evolved over the next hundred and fifty years.

You have become a master politician it would seem in your role as administrator. I have asked you twice now but you have failed to answer my question directly.I will ask you one final time; do Mendels laws of inheritance constitue the mechanics of microevolutionary change or don't they? A simple yes or no will do for now and perhaps we can then move on.

Would you agree that they largely hold true then?You are suggesting that the exceptions to the rule drive microevolutionary change? That was never my understanding. Exceptions to the rule are like lawless bandits where no real working foundation can be established. The result is confusion, chaos and misunderstanding. That's why I wanted to leave exceptions out of the equation for the time being. However, if you believe exceptions are the foundation of evolution then I was right when I said that we can't even agree on micro-evolution never mind macro-evolution.

Hi Big Al,I'm not trying to avoid your question. It's just that your question reflects a lack of understanding of what Mendel actually discovered, and I don't see the point of a discussion about Mendelian inheritance in a thread about the evidence for macroevolution, but let me give this a try and I'll try to be brief: The short answer is no. The slightly longer answer is that Mendel didn't figure out any mechanics, if by mechanics you mean what was actually going on in the cell. For Mendel genes and alleles were conceptual units - he didn't know what genes or alleles actually were, or even whether they were properties of cells or not. And he didn't know anything about mutations, which play a key role in the macroevolutionary arena.Speciation does not require mutations, but large scale of macroevolutionary change for which evidence is being requested in this thread could not take place without mutations.--Percy

Ok, you believe that Mendel knew nothing of the mechanics of micro-evolutionary change. Therefore, can I ask, do we have a working definition of micro-evolutionary change from an established and respected scientist at the current time? Because I see no reason to discuss macro-evolutionary change without a deep understanding of micro-evolution.If by discussing micro-evolution I am off topic then I must bow out. Good luck!

Hi again Big_Al35 In this case the rule was strict inheritance, and the exception were those cases where the pea plants were modified by mutation and thus did not fit in the neat boxes of Mendel's model.So in this case those exceptions, being mutations, are part of what drives microevolutionary change. Of course, those would be the hereditary traits that are passed from generation to generation and form the homologies observed in patterns of descent.But preservation of homologies are not part of the mechanisms of change, and Mendel's work was focused on the preserved homologies in his experiments.But neither mutations nor preserved homologies are elements of the larger picture that is the macroevolution process, rather they are part of microevolution.The topic is evidence for macroevolution.Enjoy.Edited by RAZD, : add

Yup, Mendel's observations largely hold true, and also the examples where they do not hold true are what drives evolution. I'm not suggesting that, I am stating that as a factual conclusion that is supported by ALL the evidence as well as reason, logic and reality.All exceptions to the rule are not like lawless bandits, most are like slight eccentricities, and some are like precocious children.It is those exceptions to the rule that are then filtered by Natural Selection to remove the "lawless bandits" that are the essence of evolution. You cannot leave out the exceptions since they are one of the major components of evolution.It is not what stays the same that is important but what changes.