You share more traits in common with your siblings than you do with your cousins due to the recent ancestors you share with them, your parents. Deeper down, you share more in common with those in your extended family than you do with neighbors and classmates, etc., people you don’t recognize as part of your biological family. But you must realize that on some level you’re still related. Deeper down, one could likely recognize subtle indications of cultural demes which most people will still agree all descend from one common ancestral lineage –despite their current apparent diversity and unfamiliar ways.
Deeper down, we've seen that new breeds of barnyard birds, domestic pets, livestock, corn, even bananas have to some degree been engineered by human intervention via artificial selection, and new sub-species have occurred in the wild via natural selection. In both cases, these stem from common ancestry, be that hundreds of breeds of dogs coming from one strain of wolves, or dozens of commercial bovines being derived from the now-extinct European Aurochs.
All these reveal that life is a fluid dynamic producing new and subtle variation with every descendant. But evolution only occurs when new alleles are spread throughout a given community. This is where selection comes into play, because the parent gene pool actually does more to inhibit new aberrations than to promote them. A smaller gene pool is much easier to influence. So what you usually get are more significant changes emerging in smaller colonies that have been genetically isolated from the main population. Eventually, they may get to the point where the two groups are distinct, where a trait now held in common by every member of one group is not shared by any member of the other group. This is known as a subspecies, or “breed”. If the two groups resume interbreeding, then all that may meld together again as if it had never been. But if they’re isolated long enough, they will continue to drift further apart both physically and genetically until it becomes difficult to interbreed at all anymore. Eventually they’ll only be able to sire infertile hybrids, if they can still produce anything living. At the point when two sexually-reproductive populations can no longer interbreed with viable offspring, then they have become two different species.
This is the most significant level in the whole of phylogenetics –when the daughter strain is now unrestrained by the once-dominant parent gene pool, and is therefore free to express an even greater variance thus continually widening the gap between them. This is a practical parallel of what creationists call the addition of new “information”. Speciation is the only taxonomic division which is genetically significant, and it is the only one that can be objectively determined. So it is the only possible point of division between the largely unnecessary distinctions of macro and microevolution.
"The theory is perfectly valid at that level;
minor changes that do not produce new kinds of organisms,
and that above all do not add to the genetic information,
...breeders are able to produce change only within boundaries.
Even those dogs are all members of a single biological species,
which are chemically interfertile.
Uh, we don't get dogs getting bigger and bigger indefinitely
–as big as elephants, or whales, much less changing into elephants or whales.
...and the claim that if selective breeding hasn't produced the kind of macro changes,
the kinds of new forms of life, new biolo- complex organs uh, that are needed,
that's only because there hasn't been enough time."
Creationists insist that macroevolution has never been observed, and the excuse they use to deny that it has requires the addition of a bogus condition that simply does not apply. Creationists argue that evolution can only occur within “definite limits”, and then only to subtle variance within their “kind”. They say new diversity is limited to rare and unviable hybrids between those “kinds”, and they usually say that the emergence of new species is impossible.
No “Darwinist” would ever say any of these things. Sorry Stein, but you’ve lost your mind.
In the evolutionary perspective, any single ancestral species can diverge into two or more daughter species, each becoming so distinct that eventually either of the new species would be unable to interbreed with the ancestral and/or sister species anymore. But by ignoring fossil forms, the creationist’s perspective has that completely backwards, insisting instead on an illusory sequence of separately conjured “kinds” which (like “information”) must remain forever undefined, and they imagine that evolutionary diversity can only occur by mixing these “kinds” in hybridization. This is another reason they reject transitional fossils, and instead demand some blend only between current “kinds”. Their perspective has no depth.
Creationists may refuse to acknowledge geologic time scales, and cannot admit that any new organism might be unable to interbreed with the stock from whence it came because their sacred fables say they were “created each after their own kind”. But of course they can’t say what a “kind’ is either, because it’s impossible to identify any point in taxonomy where everything that ever lived isn’t evidently related to everything else. So they largely ignore phylogenetics altogether.
Creationists have to deny macroevolution for the same reason they have to deny transitional species, not because these combined realities can only indicate an animal ancestry, but because either one alone proves that such is at least possible, and creationists are not permitted to admit even that.
If it is possible to walk twenty feet, it’s possible to walk twenty miles. So creationists insist there must be some “definite boundary” blocking the evolution of new “kinds”. But they won’t say where or what that boundary is. Creationists habitually misdefine their terms –if they can be forced to use definitions at all, because they will not be accountable. They can’t be, because they’ve decided in advance never to change their minds even if they’re proven wrong. If they were to find out that macroevolution was ever actually seen and proven to have happened for certain, their cultish faith would still forbid them to admit it. Instead they’d have to redefine their terms, to “move the goalposts” to some higher taxonomic level –but not so high as to have to admit where humans belong in the families of apes.
But now we know there really is no level above species, because every other “grade” in taxonomy is more or less arbitrarily assigned as a construct of human convenience. The Linnaean ranks of family, genus, order, and phyla, are all factually illustrative, but virtually meaningless otherwise because every new taxonomic class that ever evolved began with speciation, the emergence of a distinctly new species, but one that was still just a modified version of whatever its parents were, and who’s eventual descendants will always belong to whatever categories their ancestors did also –no matter how much they may change as time goes on.
The only reason creationists cling to these “micro” and “macro” distinctions is so they can have some excuse to accept “small scale” evolution, which they begrudgingly admit cannot be denied even with the greatest faith; while still denying “large scale” evolution where their exact parameter of “how large” must remain illusive to prevent it ever being disproved. Of course that means “large scale” evolution can mean whatever they want it to at that moment. Frank Sherwin from the Institute of Creation Research recently defined macroevolution as “the origin of every kind of animal”, and later on in the same discussion, he changed his definition to “the origin of all life”. He knows he’s using the terms incorrectly. He simply doesn’t care!
But the fact is he doesn’t get to conveniently redefine what these terms have always meant to the scientists who invented those words in the first place. According to Universities actually teaching this subject, microevolution is variation within species, and macroevolution is variation between species. The different breeds of dogs are an example of microevolution, while the different species of wolves and foxes, panthers and felines, horses and zebras, or llamas and camels –are all examples of macroevolution. Each set is definitely biologically closely-related, but they’re each different species, not different “kinds” of the same one.
Macroevolution is properly defined as the emergence of new taxa at or above the species level. The only time creationists will use the proper definition is when they are as-yet unaware of the fact that speciation has already been directly-observed and documented dozens of times –both in the lab and in naturally-controlled conditions in the field. In fact, we’ve seen it so many times we’ve had to categorize recurrent types of macroevolution we’ve seen so often repeated. Once creationists find out about all this, their first reaction is to use the excuse that some newly evolved species of fruit fly or fish somehow still doesn’t count because it’s “still” a fly or it’s “still” a fish. Well of course it is! Evolution couldn’t permit them to be anything else.
Creationists demand that the new species be so different from their parents that one can’t even tell they’re related. The irony there is that evolutionary theory never suggests that one “kind” of thing ever turned into another, fundamentally-different “kind” of anything, not unless you ignore all the intermediate stages –which of course creationists do.
To comprehend evolutionary Theory, one must first understand that it’s only ever a matter of changing proportions –altering or enhancing existing features to build on what is already there. Developmental biology, genetics, and comparative morphology combine to confirm many of these taxonomic stages such that organs do not seem to have appeared abruptly or fully-formed as if out of nowhere, because there is an implied evolutionary origin evident in every case. Even the transition of fish-to-tetrapods, dinosaurs-to-birds, or apes-to-men are each are just a matter of incremental, superficial changes being slowly compiled atop successive tiers of fundamental similarities. These represent monophyletic clades which will forever encompass all the descendants of that clade. This is why birds are still dinosaurs, and humans are still apes, and both are still stegocephalian chordates.
No matter how much you or your heirs may change, you obviously can’t outgrow heredity. The very concept of common ancestry is a multi-tiered and intertwined complex phylogenetic system which shows why there can’t be any distinctly separate “kinds” to begin with! At the same time, the act of speciation splits the population presenting an eventually impassable boundary between them. We often see this demonstrated live in the form of “ring species”, where different evolutionary stages exist all at once in a geographic rather than chronological distribution. Subspecies (A) may breed with subspecies (B), and (B) may breed with (C), and (C) with (D), but (A) and (D) cannot interbreed because by the time their territories overlap again, they’ve grown too distant genetically, and can’t come back. This is when we see the formation of new features, organs, or skeletal structures, each examples of new genetic “information”. What all these show is that even though a new species of perching bird (for example) is “still” a finch, it is now a different “kind” of finch, a distinct descendant species proving there is no “boundary” against macroevolution.