As I said on a previous thread when I had to correct many, many of your totally false claims about evolution, you guys should *really* try reading some science journals for a change and not just keep parroting nonsense from those creationist pamphlets. You're only wasting your own time, and ours, by repeating nonsense, fallacies, and lies.
You also might want to actually *respond* to rebuttals for a change, instead of just ignoring them totally and then hopping to a different thread to post more ignorant nonsense, such as your current "contribution":
1: Random mutations of DNA are supposed to cause all changes.
Not totally, no, and DNA mutations are not always "random" either, but close enough for a junior-high-school level of understanding.
Because they are completely random, there can be no environmental pressure, thus, it is 100% impossible for anything actually needed to develop.
Wow, this is an *incredibly* ignorant comment, and reveals a total lack of even the most rank beginner's knowledge of biology. Sorry, son, but the fact that mutations are random in no way means that "there can be no environmental pressure", since environmental pressure affects n the *results* of mutations, even though it doesn't work on the *production* of mutations. Sheesh, man, where did you "learn" about evolutionary biology, a comic book? Or a creationist pamphlet? But I repeat myself.
Here, educate yourself and try to get a clue before you spout off again without knowing what in the hell you're talking about:
Introduction to Evolutionary Biology
Furthermore, when something is needed you cannot survive millions of years without it.
Nonsense, for the obvious reason that you can "need" something which you can still survive without. Gazelles "need" to run faster to have higher odds of surviving attacks by predators, but won't all die en masse and go extinct if they don't run faster *immediately*.
Evolution works via upping the *chances* of successful survival/reproduction, not by introducing something that you'll instantly die without.
Again, try cracking open a science book for a change. You have a ludicrously cartoon idea about biology, and yet you're arrogant enough to try to "lecture" us all on the topic and "explain" why career biologists have been "wrong" for 100+ years of research. Do you realize how ridiculous you sound?
If you evolve a trait that you do not need, it should be filtered out through natural selection.
See above, kid. You can gain a trait which *enhances* your survival, even if it's not at the moment *critical* for your survival.
And it will take a near-infinite number of mutations to actually produce anything unique to the subsequent species and not the ancestor.
Nonsense. The genetic difference between humans and chimps, for example, is a median figure of two nonsynonymous substitutions per gene (and there are only about 30,000 genes), not "a near-infinite" number of them. Go visit a library.
2: Macroevolution means an upward change in viability and complexity of lifeforms.
No it doesn't. Care to try again?
Microevolution means a horizontal change in the traits of a lifeform, with no bearings of viability or complexity.
Wrong again!
Come on, not even the usual creationist wingnuts get things this wrong. Are you trolling on purpose or something?
You can also expand the definition of microevolution to include natural selection. Natural selection eliminates harmful traits from a gene pool indirectly, by killing off creatures who were unlucky enough to have unnecessary traits prominent.
Wrong again, or at least there are several inaccuracies in this one. Natural selection can weed out harmful traits from a population without "killing off" anything, just due to differential reproductive success over several generations. Again, ever heard of a library? Try learning something about a topic before you start "lecturing" about it.
Thus, natural selection is the loss of information to specialize a species to a certain environment.
If you're going to count the removal of detrimental alleles as a "loss of information", then you're going to have to be honest enough to admit that the amplification of other alleles (including beneficial ones) by natural selection is at the same time a *gain* of information.
Sort of "forgot" about that one, eh?
Natural selection is more of an event, which leads to microevolution as these minor limitations lead to what can be perceived as alterations.
...and cumulative "alterations" over time lead to the large-scale alteration that is called "macroevolution".
Evolutionists fervently screech that natural selection is evidence for macroevolution. This is an outright lie.
Actually, the only "lie" is your misrepresentation. "Evolutionists" aren't confused enough to think that the existence of natural selection alone is "evidence for macroevolution", so they don't claim that, nor do they even "screech" it. THIS is evidence of macroevolution, son:
[From: http://www.talkorigins.org/faqs/comdesc/]And don't make the mistake of thinking that the short descriptions on these handful of web pages encompasses the totality of the evidence -- it's just an overview. Go follow any of the hundreds of citations provided, and you'll find your entry to the primary research literature, containing *vast* amounts of rigorous research and evidence, and a web of citations leading to literally *millions* of other papers which embody the evidence for evolution.
29+ Evidences for Macroevolution
The Scientific Case for Common Descent
Version 2.85
Copyright © 1999-2004 by Douglas Theobald, Ph.D.[Last Update: April 15, 2005]Permission is granted to copy and print these pages in total for non-profit personal, educational, research, or critical purposes.
Introduction
volution, the overarching concept that unifies the biological sciences, in fact embraces a plurality of theories and hypotheses. In evolutionary debates one is apt to hear evolution roughly parceled between the terms "microevolution" and "macroevolution". Microevolution, or change beneath the species level, may be thought of as relatively small scale change in the functional and genetic constituencies of populations of organisms. That this occurs and has been observed is generally undisputed by critics of evolution. What is vigorously challenged, however, is macroevolution. Macroevolution is evolution on the "grand scale" resulting in the origin of higher taxa. In evolutionary theory it thus entails common ancestry, descent with modification, speciation, the genealogical relatedness of all life, transformation of species, and large scale functional and structural changes of populations through time, all at or above the species level (Freeman and Herron 2004; Futuyma 1998; Ridley 1993).
Common descent is a general descriptive theory that concerns the genetic origins of living organisms (though not the ultimate origin of life). The theory specifically postulates that all of the earth's known biota are genealogically related, much in the same way that siblings or cousins are related to one another. Thus, macroevolutionary history and processes necessarily entail the transformation of one species into another and, consequently, the origin of higher taxa. Because it is so well supported scientifically, common descent is often called the "fact of evolution" by biologists. For these reasons, proponents of special creation are especially hostile to the macroevolutionary foundation of the biological sciences.
This article directly addresses the scientific evidence in favor of common descent and macroevolution. This article is specifically intended for those who are scientifically minded but, for one reason or another, have come to believe that macroevolutionary theory explains little, makes few or no testable predictions, is unfalsifiable, or has not been scientifically demonstrated.
Outline
- Universal Common Descent Defined
- Evidence for Common Descent is Independent of Mechanism
- What Counts as Scientific Evidence
- Other Explanations for the Biology
- How to Cite This Document
The kind of incredible ignorance which leads an embarrassingly large number of anti-evolutionists to mouth such shockingly stupid statements as "there is no evidence for evolution, blah blah blah" is just mind-boggling. And make no mistake -- millions of Americans *are* familiar with the evidence for evolution, at least to some degree, and when so-called conservatives make such blindingly moronic comments as "there's no evidence", it's *entirely* obvious to informed Americans that the speaker is a dolt, and this does *not* reflect well on conservatism in general. I personally know *dozens* of people who would otherwise be predisposed to consider themselves conservatives or vote Republican, who are utterly repulsed from the idea because they've seen too many conservatives bleat idiocy like this, and it scares them away -- in exactly the same reason that lots of liberal-leannig folks have run screaming from the Democrats because of the nutball rantings of some of the more fringe liberals.
Proof of natural selection proves natural selection,
Thank you, Mr. Redundant.
and N.S. is a process that slows down if not completely halts macroevolution.
ROFL! Why, because you say so? Sorry, but 100+ years of biological research reveals that you're sadly mistaken. Go get an education before you try again.
Macroevolution requires additions to the gene pool,
...which are those "mutations" you mentioned at the start of your post and then promptly forgot about.
while N.S. takes away traits available.
...AS WELL AS amplifies other, more beneficial traits, which as a consequence spread through the population and accumulate with other beneficial traits across generations. "Forgot" about that again, eh?
Microevolution plus time does not equal macroevolution.
...because...? Stamping your foot and holding your breath until you turn blue does not make your false statements any more true.
Small changes building up does not lead to more viability or complexity.
Sure it does. Each small change increases viability, so accumulated small changes increase viability to an even greater degree. Duh. And the acquisition of dozens of new "small traits" increases the complexity of the organism over what it was at the start. Duh again.
I like how you contradict yourself without even realizing it.
Making scales on a lizard longer and thinner alters existing traits, through random mutations and coping mistakes (a fallen world), with no increase in complexity or viability. These longer and thinner scales will not turn into feathers if they keep getting longer and thinner.
No one said that they did. But *other* kinds of genetic modifications do indeed increase viability and complexity. So it's rather dishonest of you to pretend that "longer thinner scales" are the *only* kind of genetic mutation, while *ignoring* the ones that torpedo your false claims. Nice try, did you think no one would notice?
Big changes like scales-to-feathers or legbones-to-wingbones require a massive reversal of current genetic progress as well as a decrease in complexity and viability until a new type of animal arrives.
ROFL! You have a habit of making the most amusing claims, with complete confidence, no matter how transparently false and fallacious they are. Admit it, you *are* a troll, aren't you? No one could be this clueless for real, could they?
So, a legbone will become a bad legbone before it becomes a good wingbone.
Uh huh. Sure, whatever you say, kid:
Now, where in there did you see "a legbone becoming a bad legbone before it becomes a good wing"? Oh, right, it didn't -- it kept *increasing* in utility throughout the sequence.Theropod dinosaur to bird evolutionary transition:
The cladogram for the evolution of flight looks like this:
(Note -- each name along the top is a known transitional fossil; and those aren't all that have been discovered.) Here's a more detailed look at the middle section:
Fossils discovered in the past ten years in China have answered most of the "which came first" questions about the evolution of birds from dinosaurs.
We now know that downy feathers came first, as seen in this fossil of Sinosauropteryx:
That's a close-up of downy plumage along the backbone. Here's a shot of an entire fossil
Sinosauropteryx was reptilian in every way, not counting the feathers. It had short forelimbs, and the feathers were all the same size. Presumably, the downy feathers evolved from scales driven by a need for bodily insulation.
Next came Protarchaeopteryx:
It had long arms, broad "hands", and long claws:
Apparently this species was driven by selection to develop more efficient limbs for grasping prey. One of the interesting things about this species is that the structure of the forelimb has been refined to be quite efficient at sweeping out quickly to grab prey, snap the hands together, then draw them back towards the body (mouth?). The specific structures in question are the semilunate carpal (a wrist bone), that moves with the hand in a broad, flat, 190 degree arc, heavy chest muscles, bones of the arm which link together with the wrist so as to force the grasping hands to spread out toward the prey during the forestroke and fold in on the prey during the upstroke. Not only is this a marvelously efficient prey-grabbing mechanism, but the same mechanism is at the root of the wing flight-stroke of modern birds. Evolution often ends up developing a structure to serve one need, then finds it suitable for adaptation to another. Here, a prey-grasping motion similar in concept to the strike of a praying mantis in a reptile becomes suitable for modifying into a flapping flight motion.
Additionally, the feathers on the hands and tail have elongated, becoming better suited for helping to sweep prey into the hands.
Next is Caudipteryx:
This species had hand and tail feathers even more developed than the previous species, and longer feathers, more like that of modern birds:
However, it is clear that this was still not a free-flying animal yet, because the forelimbs were too short and the feathers not long enough to support its weight, and the feathers were symmetrical (equal sized "fins" on each side of the central quill). It also had very reduced teeth compared to earlier specimens and a stubby beak:
But the elongation of the feathers indicates some aerodynamic purpose, presumably gliding after leaping (or falling) from trees which it had climbed with its clawed limbs, in the manner of a flying squirrel. Feathers which were developed "for" heat retention and then pressed into service to help scoop prey were now "found" to be useful for breaking falls or gliding to cover distance (or swooping down on prey?).
Next is Sinornithosaurus:
Similar to the preceding species, except that the pubis bone has now shifted to point to the back instead of the front, a key feature in modern birds (when compared to the forward-facing pubis bone in reptiles). Here are some of the forearm feathers in detail:
Long feathers in detail:
Artists' reconstruction:
Next is Archaeopteryx:
The transition to flight is now well underway. Archaeopteryx has the reversed hallux (thumb) characteristic of modern birds, and fully developed feathers of the type used for flight (long, aligned with each other, and asymmetrical indicating that the feathers have been refined to function aerodynamically). The feathers and limbs are easily long enough to support the weight of this species in flight. However, it lacks some structures which would make endurance flying more practical (such as a keeled sternum for efficient anchoring of the pectoral muscles which power the down-stroke) and fused chest vertebrae. Archaeopteryx also retains a number of clearly reptilian features still, including a clawed "hand" emerging from the wings, small reptilian teeth, and a long bony tail. After the previous species' gliding abilities gave it an advantage, evolution would have strongly selected for more improvements in "flying" ability, pushing the species towards something more resembling sustained powered flight.
Next is Confuciusornis:
This species had a nearly modern flight apparatus. It also displays transitional traits between a reptilian grasping "hand" and a fully formed wing as in modern birds -- the outer two digits (the earlier species had three-fingered "hands") in Confuciusornis are still free, but the center digit has now formed flat, broad bones as seen in the wings of modern birds.
Additionally, the foot is now well on its way towards being a perching foot as in modern birds:
It also has a keeled sternum better suited for long flight, and a reduced number of vertebrae in the tail, on its way towards becoming the truncated tail of modern birds (which while prominent, is a small flap of muscle made to look large only because of the long feathers attached).
From this species it's only a small number of minor changes to finish the transition into the modern bird family.
(Hey, who said there are no transitional fossils? Oh, right, a lot of dishonest creationists. And there are a lot more than this, I've just posted some of the more significant milestones.)
There's been a very recent fossil find along this same lineage, too new for me to have found any online images to include in this article. And analysis is still underway to determine exactly where it fits into the above lineage. But it has well-formed feathers, which extend out from both the "arms" and the legs. Although it wasn't advanced enough to fully fly, the balanced feathering on the front and back would have made it ideally suited for gliding like a flying squirrel, and it may be another link between the stage where feathers had not yet been pressed into service as aerodynamic aids, and the time when they began to be used more and more to catch the air and developing towards a "forelimbs as wings" specialization.
So in short, to answer your question about how flight could have developed in birds, the progression is most likely some minor refinement on the following:
1. Scales modified into downy feathers for heat retention.
2. Downy feathers modified into "straight" feathers for better heat retention (modern birds still use their body "contour feathers" in this fashion).
3. Straight feathers modified into a "grasping basket" on the hands (with an accompanying increase in reach for the same purpose).
4. Long limbs with long feathers refined to better survive falls to the ground.
5. "Parachute" feathers refined for better control, leading to gliding.
6. Gliding refined into better controlled, longer gliding.
7. Long gliding refined into short powered "hops".
8. Short powered flight refined into longer powered flight.
9. Longer powered flight refined into long-distance flying.Note that in each stage, the current configuration has already set the stage for natural selection to "prefer" individuals which better meet the requirements of the next stage. Evolution most often works like this; by taking some pre-existing ability or structure, and finding a better use for it or a better way to make it perform its current use.
And if, as you confidently assert, having a body part modified into a not yet fully functional wing capable of powered flight necessarily causes the body part to go "bad", how exactly do you explain the fact that the following creatures all get along just *fine*, contrary to your claim?
Your ignorance of biology is staggering, as is your arrogance in your belief of being able to "refute" an entire field of science without actually knowing the first thing about it.
In short, you're a run-of-the-mill anti-evolutionist. Just about ALL of them are like that.
Evolutionists either fail to answer these fundamental flaws in their religion or just deny they exist, remaining hysterical and screeching "logic" and "science".
Instead of "fail to answer" or "deny they exist", what we *actually* do, as I've done here, is respond to all of the fallacious attacks on evolutionary biology by clueless people who haven't bothered to learn the very first thing about evolutionary biology before they spout off their confused "critiques" of it, and we show exactly how and where these childish attacks are flawed and fly in the face of the reality of biology and the real-world evidence.
Then, what almost always happens is that the anti-evolutionist runs away from dealing with the rebuttal, and then a day or two later (heck, sometimes the *same* day) comes back on another thread and just repeats the same or similar nonsense all over again, as if nothing had happened and his material was never refuted or answered. The intellectual dishonesty of this kind of behavior is mindboggling, but it's typical behavior for anti-evolutionists. They think if they pretend that they haven't seen material which shoots down their "killer" arguments against evolutionary biology, then for all practical purposes it doesn't exist and they can keep making the same claims again.
See ya on the next thread, son.
