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Author Topic: Science Disproves Evolution  (Read 409453 times)
oldmike
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« Reply #2235 on: 03 December 2017, 4:09:36 AM »

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As to your evidence free assertion that chickens are the descendants of dinosaurs, the fact is:  

Here is the evidence:

How Dinosaurs Shrank and Became Birds

Modern birds appeared to emerge in a snap of evolutionary time. But new research illuminates the long series of evolutionary changes that made the transformation possible.
19

As dinosaurs morphed into birds, they shrank dramatically and adopted a more babylike skull shape. Shown left to right: Velociraptor, a dinosaur of the class that gave rise to birds; Archaeopteryx, often called the first bird; and a modern chicken and pigeon.
As dinosaurs morphed into birds, they shrank dramatically and adopted a more babylike skull shape. Shown left to right: Velociraptor, a dinosaur of the class that gave rise to birds; Archaeopteryx, often called the first bird; and a modern chicken and pigeon.
Katherine Taylor for Quanta Magazine
Modern birds descended from a group of two-legged dinosaurs known as theropods, whose members include the towering Tyrannosaurus rex and the smaller velociraptors. The theropods most closely related to avians generally weighed between 100 and 500 pounds — giants compared to most modern birds — and they had large snouts, big teeth, and not much between the ears. A velociraptor, for example, had a skull like a coyote’s and a brain roughly the size of a pigeon’s.

For decades, paleontologists’ only fossil link between birds and dinosaurs was archaeopteryx, a hybrid creature with feathered wings but with the teeth and long bony tail of a dinosaur. These animals appeared to have acquired their birdlike features — feathers, wings and flight — in just 10 million years, a mere flash in evolutionary time. “Archaeopteryx seemed to emerge fully fledged with the characteristics of modern birds,” said Michael Benton, a paleontologist at the University of Bristol in England.

To explain this miraculous metamorphosis, scientists evoked a theory often referred to as “hopeful monsters.” According to this idea, major evolutionary leaps require large-scale genetic changes that are qualitatively different from the routine modifications within a species. Only such substantial alterations on a short timescale, the story went, could account for the sudden transformation from a 300-pound theropod to the sparrow-size prehistoric bird Iberomesornis.

The ancient archaeopteryx (left) has a snout and teeth, like dinosaurs. Modern chickens have large brains and eye cavities in the skull, as well as a long beak.
The ancient archaeopteryx (left) has a snout and teeth, like dinosaurs. Modern chickens have large brains and eye cavities in the skull, as well as a long beak.
Katherine Taylor for Quanta Magazine
But it has become increasingly clear that the story of how dinosaurs begat birds is much more subtle. Discoveries have shown that bird-specific features like feathers began to emerge long before the evolution of birds, indicating that birds simply adapted a number of pre-existing features to a new use. And recent research suggests that a few simple changes — among them the adoption of a more babylike skull shape into adulthood — likely played essential roles in the final push to bird-hood. Not only are birds much smaller than their dinosaur ancestors, they closely resemble dinosaur embryos. Adaptations such as these may have paved the way for modern birds’ distinguishing features, namely their ability to fly and their remarkably agile beaks. The work demonstrates how huge evolutionary changes can result from a series of small evolutionary steps.

A Phantom Leap

In the 1990s, an influx of new dinosaur fossils from China revealed a feathery surprise. Though many of these fossils lacked wings, they had a panoply of plumage, from fuzzy bristles to fully articulated quills. The discovery of these new intermediary species, which filled in the spotty fossil record, triggered a change in how paleontologists conceived of the dinosaur-to-bird transition. Feathers, once thought unique to birds, must have evolved in dinosaurs long before birds developed.

Sophisticated new analyses of these fossils, which track structural changes and map how the specimens are related to each other, support the idea that avian features evolved over long stretches of time. In research published in Current Biology last fall, Stephen Brusatte, a paleontologist at the University of Edinburgh in Scotland, and collaborators examined fossils from coelurosaurs, the subgroup of theropods that produced archaeopteryx and modern birds. They tracked changes in a number of skeletal properties over time and found that there was no great jump that distinguished birds from other coelurosaurs.

Arkhat Abzhanov, a biologist at Harvard University, with a partial skeleton of a Deinonychus, a birdlike dinosaur that likely had feathers.
Arkhat Abzhanov, a biologist at Harvard University, with a partial skeleton of a Deinonychus, a birdlike dinosaur that likely had feathers.
Katherine Taylor for Quanta Magazine
“A bird didn’t just evolve from a T. rex overnight, but rather the classic features of birds evolved one by one; first bipedal locomotion, then feathers, then a wishbone, then more complex feathers that look like quill-pen feathers, then wings,” Brusatte said. “The end result is a relatively seamless transition between dinosaurs and birds, so much so that you can’t just draw an easy line between these two groups.”

Yet once those avian features were in place, birds took off. Brusatte’s study of coelurosaurs found that once archaeopteryx and other ancient birds emerged, they began evolving much more rapidly than other dinosaurs. The hopeful monster theory had it almost exactly backwards: A burst of evolution didn’t produce birds. Rather, birds produced a burst of evolution. “It seems like birds had happened upon a very successful new body plan and new type of ecology — flying at small size — and this led to an evolutionary explosion,” Brusatte said.

The Importance of Being Small

Though most people might name feathers or wings as a key characteristic distinguishing birds from dinosaurs, the group’s small stature is also extremely important. New research suggests that bird ancestors shrank fast, indicating that the diminutive size was an important and advantageous trait, quite possibly an essential component in bird evolution.

Like other bird features, diminishing body size likely began long before the birds themselves evolved. A study published in Science last year found that the miniaturization process began much earlier than scientists had expected. Some coelurosaurs started shrinking as far back as 200 million years ago — 50 million years before archaeopteryx emerged. At that time, most other dinosaur lineages were growing larger. “Miniaturization is unusual, especially among dinosaurs,” Benton said.

While most other dinosaur lineages were growing, the line that gave rise to birds began to shrink nearly 200 million years ago.
While most other dinosaur lineages were growing, the line that gave rise to birds began to shrink nearly 200 million years ago.
Olena Shmahalo/Quanta Magazine. Sources for dinosaur silhouettes: Tetanurans, Coelurosaurs, Paraves. More info.
That shrinkage sped up once bird ancestors grew wings and began experimenting with gliding flight. Last year, Benton’s team showed that this dinosaur lineage, known as paraves, was shrinking 160 times faster than other dinosaur lineages were growing. “Other dinosaurs were getting bigger and uglier while this line was quietly getting smaller and smaller,” Benton said. “We believe that marked an event of intense selection going on at that point.”

The rapid miniaturization suggests that smaller birds must have had a strong advantage over larger ones. “Maybe this decrease was opening up new habitats, new ways of life, or even had something to do with changing physiology and growth,” Brusatte said. Benton speculates that the advantage of being pint-size might have emerged as bird ancestors moved to trees, a useful source of food and shelter.

But whatever the reasons may be, small stature was likely a useful precursor to flight. Though larger animals can glide, true flight powered by beating wings requires a certain ratio of wing size to weight. Birds needed to become smaller before they could ever take to the air for more than a short glide.

Baby Face

In 2008, Arkhat Abzhanov, a biologist at Harvard University, was elbow deep in alligator eggs. Since alligators descend from a common ancestor with dinosaurs, they can provide a useful evolutionary comparison to birds. (Despite their appearance, birds are more closely related to alligators than lizards are.) Abzhanov was studying alligators’ vertebrae, but what struck him most was the birdlike shape of their heads; alligator embryos looked quite similar to chickens. Fossilized skulls of baby dinosaurs show the same pattern — they resemble adult birds. With those two observations in mind, Abzhanov had an idea. Perhaps birds evolved from dinosaurs by arresting their pattern of development early on in life.

To test that theory, Abzhanov, along with Mark Norell, a paleontologist at the American Museum of Natural History in New York, Bhart-Anjan Bhullar, then a doctoral student in Abzhanov’s lab, and other colleagues, collected data on fossils from around the globe, including ancient birds, such as archaeopteryx, and fossilized eggs of developing dinosaurs that died in the nest. They tracked how the skull shape changed as dinosaurs morphed into birds.

Over time, they discovered, the face collapsed and the eyes, brain and beak grew. “The first birds were almost identical to the late embryo from velociraptors,” Abzhanov said. “Modern birds became even more babylike and change even less from their embryonic form.” In short, birds resemble tiny, infantile dinosaurs that can reproduce.

This process, known as paedomorphosis, is an efficient evolutionary route. “Rather than coming up with something new, it takes something you already have and extends it,” said Nipam Patel, a developmental biologist at the University of California, Berkeley.

The bird beak can take very different forms, such as this long delicate ibis beak (top) and the stubbier chicken beak.
The bird beak can take very different forms, such as this long delicate ibis beak (top) and the stubbier chicken beak.
Katherine Taylor for Quanta Magazine
“We’re seeing more and more that evolution operates much more elegantly than we previously appreciated,” said Bhullar, who will start his own lab at Yale University in the fall. “The umpteen changes that go into the bird skull may all owe to paedomorphosis, to one set of molecular changes in the early embryo.”

Why would paedomorphosis be important for the evolution of birds? It might have helped drive miniaturization or vice versa. Changes in size are often linked to changes in development, so selection for small size may have arrested the development of the adult form. “A neat way to cut short a developmental sequence is to stop growing at smaller size,” Benton said. A babylike skull in adults might also help explain birds’ increased brain size, since baby animals generally have larger heads relative to their bodies than adults do. “A great way to improve brain size is to retain child size into adulthood,” he said.

(Indeed, paedomorphosis might underlie a number of major transitions in evolution, perhaps even the development of mammals and humans. Our large skulls relative to those of chimpanzees could be a case of paedomorphosis.)

What’s more, paedomorphosis helped to make the skull a blank slate on which selection could create new structures. By erasing the snout, it may have paved the way for another of birds’ most important features: the beak.

Birth of the Beak

The problem with studying something that occurred deep in evolutionary time is that it’s impossible to know exactly what happened. Scientists can never precisely decipher how birds evolved from dinosaurs or which set of features was essential for that transformation. But with the intersection of three fields — evolution, genetics and developmental biology — they can now begin to explore how specific features might have come about.

One of Abzhanov’s particular interests is the beak, a remarkable structure that birds use to find food, clean themselves, make nests, and care for their young. He theorizes that birds’ widespread success stems not just from their ability to fly, but from their amazing diversity of beaks. “Modern birds evolved a pair of fingers on the face,” he said.

Armed with their insight into bird evolution, Abzhanov, Bhullar and collaborators have been able to dig into the genetic mechanisms that helped form the beak. In new research, published last month in Evolution, the researchers show that just a few small genetic tweaks can morph a bird face into one that resembles a dinosaur.

In modern birds, two bones known as the premaxillary bones fuse to become the beak. That structure is quite distinct from that of dinosaurs, alligators, ancient birds and most other vertebrates, in which these two bones remain separate, shaping the snout. To figure out how that change might have arisen, the researchers mapped out the activity of two genes that are expressed in these bones in a spectrum of animals: alligators, chickens, mice, lizards, turtles and emus, a living species reminiscent of ancient birds.

Bhullar collects eggs from an alligator nest. Like birds, alligators guard the nest and take care of the young.
Bhullar collects eggs from an alligator nest. Like birds, alligators guard the nest and take care of the young.
Arkhat Abzhanov
They found that the reptiles and mammals had two patches of activity, one on either side of the developing nasal cavity. Birds, on the hand, had a much larger single patch spanning the front of the face. The researchers reasoned that the alligator pattern could serve as a proxy for that of dinosaurs, given that they have similar snouts and premaxillary bones. The researchers then undid a bird-specific pattern of gene expression in chicken embryos using chemicals to block the genes in the middle of the face. (For ethical reasons, they did not allow the chickens to hatch.)

The result: The treated embryos developed a more dinosaurlike face. “They basically grew a bird embryo back into something that looked more like the morphology of extinct dinosaurs,” said Timothy Rowe, a paleontologist at the University of Texas, Austin, who has previously collaborated with Abzhanov.

The findings highlight how simple molecular tweaks can trigger major structural changes. Birds “use existing tools in a new way to create a whole new face,” Abzhanov said. “They didn’t evolve a new gene or pathway, they just changed control of an existing gene.”

Like the studies of Brusatte and others, Abzhanov’s work challenges the hopeful monster theory, and it does so on a genetic scale. The creation of the beak didn’t require some special evolutionary jump or large-scale genetic changes. Rather, Abzhanov showed that the same forces that shape microevolution — minor alterations within species — also drive macroevolution, the evolution of whole new features and new groups of species.

Specifically, small changes in how genes are regulated likely drove both the initial creation of the beak, which evolved over millions of years, and the diverse shape of bird beaks, which can change over just a few generations. “We show that simple regulatory changes can have a major impact,” Abzhanov said.

Bhullar and Abzhanov plan to dig deeper into the question of how the beak and bird skull evolved, using the same approach to manipulate different features of skull and brain development. “We have just scratched surface of this work,” Bhullar said.

Correction June 3, 2015: The original article stated that alligators descended from dinosaurs. In fact, alligators and dinosaurs share a common ancestor. The article has been revised to reflect this.

June 4, 2015: The dinosaur silhouettes in “The Incredible Shrinking Bird” graphic are based on the following illustrations: Monolophosaurus by Jordan Mallon, Deinonychus by Emily Willoughby, and Velociraptor by Matt Martyniuk.

This article was reprinted on ScientificAmerican.com.


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oldmike
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« Reply #2236 on: 03 December 2017, 4:10:19 AM »

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 Why did you ignore my question? So how long did the blood sit around waiting for the heart to evolve? And what did it do while it waited?  

I did not ignore your question, I answered it.
t
The Evolution of the Heart
The evolution of the heart has enabled oxygen and nutrients to be pumped efficiently to body tissues, enabling the oxygen greedy brain to develop….
Invertebrate animals have a simple circulatory system, as opposed to a heart. Many do not even have blood, but rather are filled with fluids that receive its nutrients through body cells. More complex invertebrates use an open circulatory system, which has a few, if any blood vessels. A pumping mechanism (muscle contraction..) pumps the blood and fluids throughout the tissues, and filters back to the pumping mechanism, for example earthworms have small muscular areas that contract and pump blood throughout the earthworms body. The origins of the heart pump are believed to have started with the pumping of a jellyfish.
The next evolution of a heart saw the development of a fish heart, the simplest type of heart. Primitive fish do have the beginnings of a four-chambered heart, but the chambers are arranged sequentially, unlike mammal and bird four chambered hearts. In the adult fish, the four chambers are arranged in an S-shape, with the latter two chambers lying above the former two. These examples saw the development of a closed circulatory system, with two chambers to separate the blood being pumped away, and the blood returning for reoxygenation. The top chamber is called the atrium, the bottom chamber is called the ventricle. It has one vessel that directs blood into gills for reoxygenation.
A double circulatory system saw the ability for more efficient oxygen distribution throughout the body. This change in morphology coincided with the development of lungs and can be found in terrestrial organisms.
In living amphibians, a three chambered heart has developed. Frogs have two atria, yet still only one ventricle. Two atria ‘s allow oxygenated and deoxygenated blood to be separated. The single ventricle is large and strong, so it is able to pump oxygenated blood throughout the body. The less efficient three chambered heart is adequate for these organisms to survive, as they still respire through the skin, allowing a less degree of oxygenation mechanisms within the blood system.
Reptile hearts vary, with some, such as turtles, having a variation of three and a half chambers. There is a septum that goes halfway into the ventricle. Blood still mixes in the ventricle, but the timing of the pump minimizes mixing of the blood. There has been observations that this pump timing and septum size is actually means that there is no mixing of oxygenated and deoxygenated blood.
Archosaurs (crocodilians and birds) and mammals all portray a complete separation of the heart into two pumps and four heart chambers. It is believed that archosaur hearts, and mammal hearts developed independently of each other. The crocodilians have a small opening, (the foramen of Panizza) at the base of the arterial trunk, so some degree of mixing can occur, usually during an underwater dive. Only in birds and mammals are the two streams of blood, permanently kept separate by a barrier.
The mammalian heart has a fully formed septum that separates the atria and the ventricles. Deoxygenated blood enters the right atrium, which is then pumped to right ventricle, of which is then pumped to the pulmonary artery to be reoxygenated by the lungs. It then returns to the left atrium and leaves through the left ventricle, and pumped using the largest artery in the body, the aorta.
In mammals, the right side of the heart collects de-oxygenated blood, into the right atrium from the body and pumps it via the right ventricle into the lungs. This is called the pulmonary circulation. that Carbon dioxide is dropped off and oxygen picked up by a passive process of diffusion allowing the gas exchange to occur. The left side collects oxygenated blood from the lungs into the left atrium, where it is pumped throughout the body via the aorta.
The heart is effectively a syncytium, a multinucleate cell that results from multiple cell fusions of unicellular cells, using an electrical messaging system to control the complex yet efficient circulatory system.
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« Reply #2237 on: 03 December 2017, 4:14:48 AM »

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As to your evidence free assertion that chickens are the descendants of dinosaurs, the fact is:  

Here is the evidence:

How Dinosaurs Shrank and Became Birds

Modern birds appeared to emerge in a snap of evolutionary time. But new research illuminates the long series of evolutionary changes that made the transformation possible.
19

As dinosaurs morphed into birds, they shrank dramatically and adopted a more babylike skull shape. Shown left to right: Velociraptor, a dinosaur of the class that gave rise to birds; Archaeopteryx, often called the first bird; and a modern chicken and pigeon.
As dinosaurs morphed into birds, they shrank dramatically and adopted a more babylike skull shape. Shown left to right: Velociraptor, a dinosaur of the class that gave rise to birds; Archaeopteryx, often called the first bird; and a modern chicken and pigeon.

What evidence. All of that is sheer supposition. I am still waiting for your answer to my question: So how long did the blood sit around waiting for the heart to evolve? And what did it do while it waited? 
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oldmike
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« Reply #2238 on: 04 December 2017, 20:39:56 PM »


As to your evidence free assertion that chickens are the descendants of dinosaurs, :
What evidence. All of that is sheer supposition.

You have made statements like this on numerous occasions. I have provided evidence sufficient to convince any open minded person time and again, but clearly your mind is closed.
Speaking of evidence free assertions, the creationist assertion that the rates of radioactive decay 6000 years ago were thousands of times what they are now, is not only evidence free, but flatly contradicts the evidence.

 I am still waiting for your answer to my question: So how long did the blood sit around waiting for the heart to evolve? And what did it do while it waited?
 Your question, which I have answered twice, shows your complete ignorance of what evolution teaches.
I will try to be more simple:
The first life forms were certainly single cells which had no circulatory system. The simply absorbed nutrients from their surroundings. Animals without backbones have a simple circulatory system, as opposed to a heart. Many do not even have blood, but rather are filled with fluids that receive its nutrients through body cells.
 More complex invertebrates use an open circulatory system, which has a few, if any blood vessels. A pumping mechanism (muscle contraction.) pumps the blood and fluids throughout the tissues, and filters back to the pumping mechanism.
In other words, blood, or a fluid which did the same job as blood, was around before the heart was developed. This may have been the case for millions of years, for all I know.


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« Reply #2239 on: 07 December 2017, 5:29:31 AM »


As to your evidence free assertion that chickens are the descendants of dinosaurs, :
What evidence. All of that is sheer supposition.

You have made statements like this on numerous occasions. I have provided evidence sufficient to convince any open minded person time and again, but clearly your mind is closed.
Speaking of evidence free assertions, the creationist assertion that the rates of radioactive decay 6000 years ago were thousands of times what they are now, is not only evidence free, but flatly contradicts the evidence.

There is no evidence chickens evolved from dinosaurs.

Quote
I am still waiting for your answer to my question: So how long did the blood sit around waiting for the heart to evolve? And what did it do while it waited?
 Your question, which I have answered twice, shows your complete ignorance of what evolution teaches.
I will try to be more simple:
The first life forms were certainly single cells which had no circulatory system. The simply absorbed nutrients from their surroundings. Animals without backbones have a simple circulatory system, as opposed to a heart. Many do not even have blood, but rather are filled with fluids that receive its nutrients through body cells.
 More complex invertebrates use an open circulatory system, which has a few, if any blood vessels. A pumping mechanism (muscle contraction.) pumps the blood and fluids throughout the tissues, and filters back to the pumping mechanism.
In other words, blood, or a fluid which did the same job as blood, was around before the heart was developed. This may have been the case for millions of years, for all I know.

So you are asserting that simple life forms evolved into humans. Where is your evidence for that?
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« Reply #2240 on: 07 December 2017, 14:44:24 PM »

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So you are asserting that simple life forms evolved into humans. Where is your evidence for that?
   

I have posted the evidence on numerous occasions.
There are none so blind as those who will not see.Once again, I recommend that those who are interested in the subject read
" David Attenborough's First Life" by Matt Kaplan. Available on Kindle.
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« Reply #2241 on: 08 December 2017, 2:47:55 AM »

Let’s stick with transitional fossils for a minute, just because I think they’re cool.

Instead of spamming us with nonsense from a creationist propaganda website why don’t you explain (in your own words would be nice) why you deny the existence of transitional fossils?
Because none have been found.  

Quote
We could start with transition from primitive jawless fish to sharks, skates, and rays if you like.  Or primitive jawless fish to bony fish.  From primitive bony fish to amphibians, or just list the transitions among the amphibians:

Temnospondyls, e.g Pholidogaster (Mississippian, about 330 Ma) -- A group of large labrinthodont amphibians, transitional between the early amphibians (the ichthyostegids, described above) and later amphibians such as rhachitomes and anthracosaurs. Probably also gave rise to modern amphibians (the Lissamphibia) via this chain of six temnospondyl genera , showing progressive modification of the palate, dentition, ear, and pectoral girdle, with steady reduction in body size (Milner, in Benton 1988). Notice, though, that the times are out of order, though they are all from the Pennsylvanian and early Permian. Either some of the "Permian" genera arose earlier, in the Pennsylvanian (quite likely), and/or some of these genera are "cousins", not direct ancestors (also quite likely).
   
Dendrerpeton acadianum (early Penn.) -- 4-toed hand, ribs straight, etc.

Archegosaurus decheni (early Permian) -- Intertemporals lost, etc.

Eryops megacephalus (late Penn.) -- Occipital condyle splitting in 2, etc.

Trematops spp. (late Permian) -- Eardrum like modern amphibians, etc.
   
Amphibamus lyelli (mid-Penn.) -- Double occipital condyles, ribs very small, etc.

Doleserpeton annectens or perhaps Schoenfelderpeton (both early Permian) -- First pedicellate teeth! (a classic trait of modern amphibians) etc.)

We could carry from amphibians to amniotes, from synapsid reptiles to mammals, from diapsid reptiles to birds... throw in a few primates for good measure…

I suspect I am wasting my time here as you are claiming that none of these exist.



Where is evidence of transitions in your list?
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