There are also temporal changes (i.e. changes over time) within the same population. We can’t use gene flow to determine if the populations are separate from one another since they are often separated by thousands or millions of years. In this case, the accumulation of micro-changes within a population can accumulate over time and produce change over time. The division between micro-evolution and macro-evolution in this example is somewhat arbitrary.
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How are you defining “macro-evolution”? It seems that you may define it as “lots of change”, which is not the definition I would use. And if the definition includes the word “species”, how are you defining “species”?
It depends on the context. If we are talking about extant species then gene flow is the best criteria for defining sexual species. But how do we define fossil species since we can’t measure gene flow in this situation? The best we can do for fossil species is an arbitrary measure of “lots of change”. The same would apply to asexual species.
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So you are more or less going with the biological species concept for extant, obligate-outcrossing taxa and the morphological species concept for everything else. That’s fine with me as long as nobody conflates the two, which unfortunately happens often. One problem is that under the morphospecies concept there may be “speciation” without splitting, just change within a single population. Of course in such a case, macroevolution really is nothing more than microevolution added up.
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Confusing the two concepts is a problem in these types of conversations. I will gladly agree on that point.
Absolutely agree. There is still a lot of debate on how to classify hominid fossils, as one good example.
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