Now, I Certainly Don't Understand Most Of This, BUT...

[Rhal]

 

[PtldPlatypus]

The micro-/macro- line is something that creationists have co-opted in an effort to try and muddy the waters. The evolutionary process isn't different for each. When examples of macro- are brought up, they call them examples of micro- (moving the goalposts). It's akin to the way creationists insist that evolution is just a "theory" without realizing the scientific connotations of the term. Deliberately misleading in both cases.

That's an interesting claim. What exactly is the proper distinction between macro- and micro-? And can you give an example of a macro- process that has been explained scientifically and then marginalized as micro- by creationists?

 

[crandc]

Let me see. A evangelical Christian web site whose purpose is to promote biblical literalism posts two paragraphs, without context, from a chemist, not an evolutionary biologist or geologist or anyone else with training in the field and BRAVO! they have disproven the last 150 years of biology!

How many times have we seen that?

 

[speeds]

That's an interesting claim. What exactly is the proper distinction between macro- and micro-? And can you give an example of a macro- process that has been explained scientifically and then marginalized as micro- by creationists?

There is a good chance this discussion will devolve into purple nonsense but I'll try my best. Maybe if I were an eminent chemist I would have a better grasp of evolutionary biology.

I was probably a bit glib in saying that creationists move the goalposts with regards to examples of macroevolution but I'll try and explain what I meant. Creationists don't adhere to the concept of macroevolution full-stop. I'll provide some examples but to answer your question, these creationists have dismissed every example of macro- out of hand and only grudgingly accept some types of evolution as occurring, labeling it all micro-.

So it's unusual that macroevolution, as a term, is much more important to pseudoscientific creationists than it is to the scientific community at large. Micro- and macro- are, essentially, evolution, the difference being scale (above or below species, more on that in a minute). Creationists wish to use the term macro- to describe evolutionary phenomena that can't be observed and as such are an impossibility. In very simple terms they insist that complex changes don't take place while minor changes (eg. Darwin's finches) can.

This sect of creationism doesn't dismiss common ancestry or evolution per se, it wishes to group animals into "kinds" in an effort to disassociate certain kinds from others, the end result being a rejection of the possibility of humans evolving from simple primates and all species evolving from simple life forms (universal common descent). This creationist idea is called Baraminology and while it might be something you can study(?) at a Christian college, it is not accepted by the scientific community due to lack of testing and extreme bias. It's something like the scientific equivalent of quote mining.

Macro- and micro- are just evolution, the difference being scale. An above species/macroevolution example is the evolution of feathers, the development of which brought about Aves (birds)--an evolutionary event (spread over a long period of time beginning with a feathery reptile) which led to the introduction of a new species. Another is the increase in cranial capacity of hominids over the last 3-million years: fossil records demonstrate an increase of nearly 500%.

Scale doesn't necessarily infer massive changes over a massive period of time, either. A classic example of macroevolution is the Evening Primrose (Oenothera gigas). Dutch botanist & geneticist Hugo de Vries observed new varieties of the flower occurring naturally and collected seeds for lab testing, finding that he was able to produce even more variety.

 

[PtldPlatypus]

Micro- and macro- are, essentially, evolution, the difference being scale (above or below species, more on that in a minute).

This has always been my understanding, so I'm glad we're on the same page here.

An above species/macroevolution example is the evolution of feathers, the development of which brought about Aves (birds)--an evolutionary event (spread over a long period of time beginning with a feathery reptile) which led to the introduction of a new species.

So, in keeping with the article in the the OP, has there been a biological/chemical explanation for the development of feathers from reptilian biology, or is the primary evidence of this development the fossil record of what creationsts refer to as "transitional forms"?

 

[Denny Crane]

http://www.pbs.org/wgbh/evolution/library/03/4/l_034_01.html

Scientists now view Archaeopteryx, which lived about 150 million years ago, as the earliest known (or most basal) member of the lineage of modern birds, but it still retained many features of small dinosaurs. These small, two-legged dinosaurs called theropods scurried around something like today's roadrunners. Many characteristics that typify birds were present in the theropods before birds evolved, including hollow bones, a wishbone, a backward-pointing pelvis, and a three-toed foot. In the course of theropod evolution, the forelimbs and hands became progressively longer. In some theropods, the bones of the wrist took on a shape that allowed the joint to flex sideways. This would have allowed these animals to whip their long hands forward in a swift snatching motion, perhaps to catch prey. The wishbone in theropods served to anchor the muscles that pulled the forelimb forward in this grabbing movement -- a motion that functional analysis shows to be almost identical to the flight stroke of modern birds. Theropods, though, probably remained largely on the ground.

Despite the increasingly clear picture of the evolution of birds from theropod dinosaurs that has emerged, a few scientists are still unconvinced. No alternative hypothesis has been offered to explain the multiple similarities between birds and theropods, however, and there is scant evidence to support a link to any of the other animals that have been suggested as possible ancestors or relatives. Meanwhile, the evidence connecting birds and theropods continues to accumulate.

For a long time, feathers were regarded as a uniquely avian feature. But recent fossil evidence suggests that feathers, too, evolved in theropods before birds. Whether they evolved for warmth, for display, or served some other function is not yet known. But in a small, lightly built bipedal predator leaping into the air to catch insect prey, even primitive feathers could have given a small amount of lift. Larger feathers would have increased lift until it was possible to stay airborne for short distances. The evolution of feathers with an asymmetrical shape, like those of Archaeopteryx, further enhanced the flight capabilities of early birds.

 

[speeds]

Trying to explain everything through chemistry is just what Tour is about. It's not exactly the way biologists are developing their understanding of evolution.

Prum & Brush (2003) have an interesting take on the development of feathers you might want to have a look at.

http://www.yale.edu/eeb/prum/pdf/Prum_n_Brush_2003.pdf

 

[Nikolokolus]

Apropos of nothing, it's always interesting to me when I see hints of Lamarckism in articles and discussions centered around evolution ... not that I'm accusing anybody here of that exactly.

 

[PtldPlatypus]

Apropos of nothing, it's always interesting to me when I see hints of Lamarckism in articles and discussions centered around evolution ... not that I'm accusing anybody here of that exactly.

What exactly is that--unwillingness to play in the post?

 

[SlyPokerDog]

What exactly is that--unwillingness to play in the post?

http://en.wikipedia.org/wiki/Lamarckism

 

[PtldPlatypus]

http://en.wikipedia.org/wiki/Lamarckism

Should've gone with the green font...