Macroevolution Vs. Microevolution.

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Macroevolution Vs. Microevolution.

 Many times I've heard creationists say that microevolution, or "Evolution within a species" can exist, while macroevolution, or "Evolution between species." cannot.

We all know that this is a stupid conclusion, but I've never heard it explained very thoroughly why it is so stupid.

 

The main issue in this argument is a misconception of meaning. Not the meaning of evolution, but the meaning of "species".

 

What is a species? A species is a category. It is a classification of organisms based on similarities in such things as genetic qualities, adaptive abilities, reproductive habits, etc.

 

Who defines what species are? We do.

Human scientists use accepted criteria to define which organisms belong to which species. A species is a man-made definition.

 

So, evolution can happen within species, but not outside the realms of species? Does genetic mutation really give a d*** about man-made definitions?

The only way that this argument works is if it was declared that evolutionary limits were a known criteria for categorizing species. No such claim has ever been made.

 

So. Here's how it works. A species experiences microevolution over a series of generations. This microevolution accumulates to changes in the species traits. Eventually, there are enough iconic changes in the species that it can then be defined as a new species.

Since we have only relatively recently began naming species, the point where those species were named became an arbitrarily placed 0 on the evolutionary timeline, with future generations going in the positive direction, and past generations in the negative. Not enough time has passed since then for enough genetic mutation to accumulate to the point where we can name something as a new species.

 

Really, we're not waiting for the scientists to make a discovery, we're waiting for the scientists to make the decision. Once they make that decision, we will have then recorded macroevolution.

 

This is the best way I can think of to explain the issue of microevolution vs. macroevolution, assuming that the creationist you use it with accepts microevolution as a valid premise. If not, then don't bother arguing with them. There's no way to help that level of stupidity. Let me know if I've gotten something screwed up with my logic.


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Taxonomy is as

Taxonomy is as self-correcting as any other facet of science.

However, it's just a tool for the theory; not the theory of speciation itself.

There is no GUT of speciation, but there are analyses of parapatric, allopatric, and sympatric speciation that have shown genetic divergence to a new species.

Granted, there isn't enough hard data for divergence of genera... yet. i.e. Lions to pussy cats. However, it forms a good hypothesis.

Take the example of 'Ida' recently. An ankle bone was the deciding factor between lemur and monkey.

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Speciation

Thunderf00t had a good discussion about this subject in The Thunderf00t - Ray Comfort discussion (Part 7) between 5:44 - 9:48.  While Ray Comfort accepts micro-evolution, he seems to discount speciation as infertility!  Of course, this is nonsense because the species can still bread very well among its "own kind."

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Micro vs macro

Micro vs macro is the province of mental ingrates seeking a semantic rock to huddle under. There is no micro or macro in reality. There is just linear evolution in real time.

Think of life as a tree with bacteria at the roots and a bunch of branches at the top representing life adapted to the available niches. Life evolves from the trunk – the common line. It doesn’t evolve from branch to branch. The common ancestor, the concestor, is extinct though it may have currently living relatives. To see it we have to look into the past – into the fossil record. If a potential concestor has not become extinct then we will see it living today, a creature that has retained the same form and remains in the same niche it first adapted to fit. Like saltwater crocodiles. They are related to archosaurs, cousins of dinosaurs, and have retained the same form and niche for about 200 million years. Then there are ants. They are 168 million years old and are very closely related to each other and to the cousins of their winged forebears, which was a species of wasp. Ants have a modern evolutionary path that mirrors the evolution of flowering plants. And we know what flowering plants are, don't we? They are environmental niches to be exploited by the creatures best suited to survive in them. 

Theists, with their anthropomorphic fixation, love to drone about the non evolution of people but humans are not a great example because we’re a young species and are so closely related that our genome argues that we are actually the same race. This supports a theory that we are in fact all members of the same small, extended ancestral family that alone survived through some population trauma about 100,000 years ago. Looking at evolution from the human perspective is too limiting. You have to consider fossils with us. There are more than 20 ancestral hominids we know about and we have fossil evidence of hundreds of individuals stretching back 5 million years. This includes H floresiensis, a homind that died out a mere 14,000 years ago. That means H floresiensis shared space with H sapiens. Even given the brevity of our recent evolution we still show adaptations that have been pressed upon us by our environment since that bottleneck. Skin colour, sweat gland size, eye shape, nostril size, height, body hair, body shape and muscularity all vary based on the geography of human populations.
 
We don’t need the great leaps between species that theists cling to so they won't have to conceptualise the viewable evolution that takes place in microbes like bacteria as being possible in multi-celled creatures. But its those tiny changes that count over the long term in a process that sees a species or a branch of a species under survival pressure from a new or changing environment morphing into something new, incrementally. Theists see species as a sort of fixed law but this is erroneous. All species are in a constant state of flux in response to the pressure of survival in their environment.

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AnotherPen

AnotherPen wrote:
microevolution vs. macroevolution

 

Hmm. How complicated can this be?

The way I have understood it, microevolution is about what is happening within a species, whereas macroevolution is about how the entire environment changes due to its interaction with numerous, often "competing" microevolutionary processes.

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AnotherPen wrote:What is a

AnotherPen wrote:
What is a species? A species is a category. It is a classification of organisms based on similarities in such things as genetic qualities, adaptive abilities, reproductive habits, etc.

 

Who defines what species are? We do.

 

Human scientists use accepted criteria to define which organisms belong to which species. A species is a man-made definition.

 

OK, that is valid. However, of some note, the whole idea of a species predates Darwin by a century and was introduced in a time when nobody seriously questioned the idea of “each by it's own type”. So what constituted a species was largely the idea of two populations being cross-fertile. Of course, while the idea of a species remains of some use, that use is really not a major focus of evolutionary biology today.

 

One important concept that is much more current is that of a cline. A cline is a group of geographically separate populations where closely spaced groups are cross fertile with each other but more distantly separate populations lose fertility with increasing distance. A great example are the seagulls of the northern hemisphere.

 

Basically, the gulls from Ireland can interbreed with the gulls from Eastern North America which can breed with (for brevity) Alaskan gulls>Eastern Siberian gulls>Central Russian gulls>North European gulls. Where this becomes really notable is that the gulls from Scandinavia have overlapping territory with the Irish gulls but the two populations are not cross fertile. Such a group of populations begs the question “Where does one draw the line between the two different species?”

 

Another important point to note is that it is not always clear that a specific species should even be classified as such. Since the beginning of molecular biology about 30 years ago and with DNA sequencing in the past 15 to 20 years, many of what was considered to be identified species have been “moved” from one place in the tree of life to another.

 

One example here is that it has only been about 25 years since it became generally accepted that penguins are birds. Sure, they lay eggs and have feathers. However, some biologist suggested the while birds may have originated from velociraptors, the line that led to penguins might have originated from a species that was only related to velociraptors.

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James Shapiro

 I was also of the impression that macroevolution and microevolution were only creationist ways to create a problem where there was none. Then I saw James Shapiro's notes for his Evolution in the 21st Century lecture, and started to think otherwise. I don't see a clear cut way to define "small" and "big" change, and all creationists I can recall couldn't either, with the difference that they thought they could. Still, we should be able to agree that the development of a whole organ, such as the heart, is somehow different from a variation in fur colour or bone shape in dog breeds. Proving the later can happen through simple selection of DNA replication errors doesn't directly prove the former.

 Shapiro is not your typical ID crazy. He has a PhD in genetics (as opposed to the many scientists for ID who are actually computer scientists) and is a professor in a major University (of Chicago). His idea is not creationist per se. He just believes intelligence rises much earlier than mankind, and is to be observed in the cellular machinery itself. He believes evolution is somewhat directed, planned, by this cellular intelligence. At least this is what I think I got from the little I read from him. Incidently, while googling for Shapiro, I found the transcript of a judicial hearing  in which Behe argues against rushed attempts to dismiss his criteria of ireducible complexity for the coagulation process. The transcript is in Talk Origins, of all places, and for a moment looked quite convincing to me. 

 


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What's next are we going to

What's next are we going to have micro and macro mountain formations in the theory of plate tectonics? After all we have never seen it form a big mountain.

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