Daarom Evolutie #11

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Op zondag 10 september 2006 12:19 schreef stinkyduiker het volgende:
Mutaties ontstaan door "foutjes" in het repliceren van DNA (toch?) en mutaties zijn veel vaker slecht dan goed voor het organisme. Als je hier verder op ingaat zal een organisme met een systeem wat minder "foutjes" maakt een selectief voordeel krijgen.
Het lijkt me dat er steeds minder mutaties plaats gaan vinden en dat evolutie dus eigenlijk steeds langzamer wordt, klopt dit?

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Early Bird Used Four Wings to Fly

The earliest known bird had flight feathers on its legs that allowed it to use its hindlimbs as an extra pair of wings, a new study finds.

The finding, detailed in the current issue of the journal Paleobiology, supports the theory that early birds learned to glide and parachute from trees before achieving full-fledged flight.

"This paper puts forward some of the strongest evidence yet that birds descended from arboreal parachuters and gliders, similar to flying squirrels," said study author Nick Longrich, a doctoral student a the University of Calgary in Canada.

The missing link
Archaeopteryx was a crow-sized animal that lived about 150 million years ago and which looked like a cross between a bird and a dinosaur. It had feathers and a wishbone like birds but also reptilian features like a long bony tail, claws and teeth.

When the first Archaeopteryx fossil was discovered in 1861, it caused a sensation because it was the kind of transitional animal that the British naturalist Charles Darwin predicted in his theory of evolution only a few years earlier.

In 1877, a second Archaeopteryx specimen discovered in Germany showed a curious feature: long feathers covering its hindlimbs. For more than a century, the feathers were dismissed by most scientists as being simple, albeit unusual-looking, insulating body feathers--called "contour" feathers--that didn't play a role in the animal's flight.

But then, beginning in 2002, paleontologists began finding four-winged dinosaurs in China with hindlimb feathers that appeared to be important for gliding and perhaps even flying. In light of the new findings, Longrich decided it was time that Archaeopteryx was reexamined.

Flying with four wings

Longrich examined hindlimb feathers on five Archaeopteryx fossils using a dissecting microscope and found that the feathers had features typical of flight feathers in modern birds, including curved shafts, a self-stabilizing overlap pattern and vane asymmetry, in which the parallel row of barbs that make up the feather are longer on one side than the other.

Next, Longrich used standard mathematical models for flight to calculate how an extra pair of wings would have affected Archaeopteryx's flight. He found that hindlimb feathers would have allowed Archaeopteryx to fly slower and to make sharper turns.

Sharper turns would have improved Archaeopteryx's abilities to maneuver in pursuit of prey, to escape predators and to fly through the cluttered branches of trees and bushes. And the ability to fly slower meant Archaeopteryx had more time to avoid obstacles and to make safer landings.

Longrich speculates that the hindlimb feathers might have served other roles in addition to flight. Like modern pigeons, kittiwakes and vultures, Archaeopteryx's hindlimb feathers might have acted as airbrakes, or perhaps stabilizers, control surfaces or flaps, Longrich writes.

Scientists don't know when in their evolutionary history birds switched from a "four winged" design to a two-wing one, but it's thought that hindlimb wings were sacrificed in order to free up legs for other functions, such as running, swimming and catching prey.

"The idea that a multi-winged Archaeopteryx has been around for more than a century, but it has received little attention," Longrich said. "I believe one reason for this is that people tend to see what they want or expect to see. Everybody knows that birds don't have four wings, so we overlooked them even when they were right under our noses."

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Michael Shermer: Darwin on the Right
Why Christians and conservatives should accept evolution

According to a 2005 Pew Research Center poll, 70 percent of evangelical Christians believe that living beings have always existed in their present form, compared with 32 percent of Protestants and 31 percent of Catholics. Politically, 60 percent of Republicans are creationists, whereas only 11 percent accept evolution, compared with 29 percent of Democrats who are creationists and 44 percent who accept evolution. A 2005 Harris Poll found that 63 percent of liberals but only 37 percent of conservatives believe that humans and apes have a common ancestry. What these figures confirm for us is that there are religious and political reasons for rejecting evolution. Can one be a conservative Christian and a Darwinian? Yes. Here's how.

1. Evolution fits well with good theology. Christians believe in an omniscient and omnipotent God. What difference does it make when God created the universe--10,000 years ago or 10,000,000,000 years ago? The glory of the creation commands reverence regardless of how many zeroes in the date. And what difference does it make how God created life--spoken word or natural forces? The grandeur of life's complexity elicits awe regardless of what creative processes were employed. Christians (indeed, all faiths) should embrace modern science for what it has done to reveal the magnificence of the divine in a depth and detail unmatched by ancient texts.

2. Creationism is bad theology. The watchmaker God of intelligent-design creationism is delimited to being a garage tinkerer piecing together life out of available parts. This God is just a genetic engineer slightly more advanced than we are. An omniscient and omnipotent God must be above such humanlike constraints. As Protestant theologian Langdon Gilkey wrote, "The Christian idea, far from merely representing a primitive anthropomorphic projection of human art upon the cosmos, systematically repudiates all direct analogy from human art." Calling God a watchmaker is belittling.

3. Evolution explains original sin and the Christian model of human nature. As a social primate, we evolved within-group amity and between-group enmity. By nature, then, we are cooperative and competitive, altruistic and selfish, greedy and generous, peaceful and bellicose; in short, good and evil. Moral codes and a society based on the rule of law are necessary to accentuate the positive and attenuate the negative sides of our evolved nature.

4. Evolution explains family values. The following characteristics are the foundation of families and societies and are shared by humans and other social mammals: attachment and bonding, cooperation and reciprocity, sympathy and empathy, conflict resolution, community concern and reputation anxiety, and response to group social norms. As a social primate species, we evolved morality to enhance the survival of both family and community. Subsequently, religions designed moral codes based on our evolved moral natures.

5. Evolution accounts for specific Christian moral precepts. Much of Christian morality has to do with human relationships, most notably truth telling and marital fidelity, because the violation of these principles causes a severe breakdown in trust, which is the foundation of family and community. Evolution describes how we developed into pair-bonded primates and how adultery violates trust. Likewise, truth telling is vital for trust in our society, so lying is a sin.

6. Evolution explains conservative free-market economics. Charles Darwin's "natural selection" is precisely parallel to Adam Smith's "invisible hand." Darwin showed how complex design and ecological balance were unintended consequences of competition among individual organisms. Smith showed how national wealth and social harmony were unintended consequences of competition among individual people. Nature's economy mirrors society's economy. Both are designed from the bottom up, not the top down.

Because the theory of evolution provides a scientific foundation for the core values shared by most Christians and conservatives, it should be embraced. The senseless conflict between science and religion must end now, or else, as the Book of Proverbs (11:29) warned: "He that troubleth his own house shall inherit the wind."

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Op dinsdag 3 oktober 2006 23:01 schreef Autodidact het volgende:

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Op woensdag 4 oktober 2006 12:49 schreef speknek het volgende:

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Hij valt in de Sociaal Darwinisme valkuil.

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Op woensdag 4 oktober 2006 12:53 schreef Autodidact het volgende:
Hoezo? De evolutietheorie verklaart sociale verschijnselen zoals moraal...

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Scientists find more bones of big camels

DAMASCUS, Syria - Hunters stalked giant camels as tall as some modern-day elephants in the Syrian desert tens of thousands of years ago and archaeologists behind the find are wondering where the camels came from and what caused them to die off.

The enormous beasts existed about 100,000 years ago and more of the bones, first discovered last year, have been found this year in the sands about 150 miles north of the capital, Damascus.

The animal, branded the "Syrian Camel" by its Swiss and Syrian discoverers, stood between three and four yards high — about twice the size of latter-day camels and the height at the shoulder of many African elephants.

"The camel is a dromedary but extremely big and extremely tall — about double the size of a modern day camel," said Jean-Marie Le Tensorer, who led the Swiss side of the team.

The camels did not appear to have been bred by humans as beasts of burden, the scientists said, raising questions about its provenance — and disappearance.

"What we want to know now is: where did it come from, and why did it disappear never to be seen again? Was it migrating from Asia to Africa?" said the team's Syrian leader, Heba al-Sakhel.

Le Tensorer said humanoid bones were discovered at a nearby site and stone tools used by early humans were found with the camel's bones, which are thought to be up to 100,000 years old.

"The bones — a fragment of an arm and a tooth — are, of course, of the hunter of the giant camel. He probably stalked his prey to a water spring where he came to drink," said Le Tensorer.

"Ordinary camels appeared in the (Middle East) region some 6,000-7,000 years ago and, for the first time, we have a wild form and very, very old," he said.

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Mich. board OKs curriculum on evolution

LANSING, Mich. - The State Board of Education on Tuesday approved public school curriculum guidelines that support the teaching of evolution in science classes — but not intelligent design.

Intelligent design instruction could be left for other classes in Michigan schools, but it doesn't belong in science class, according to the unanimously adopted guidelines.

"The intent of the board needs to be very clear," said board member John Austin, an Ann Arbor Democrat. "Evolution is not under stress. It is not untested science."

Some science groups and the American Civil Liberties Union had worried that state standards would not be strong enough to prevent the discussion of intelligent design as the course expectations developed over the summer.

The guidelines approved Tuesday detail what the state expects school districts to teach in their science classes. If a district or teacher chose to include intelligent design in a science class, they could face a court challenge from opponents of teaching intelligent design.

Intelligent design's proponents hold that living organisms are so complex they must have been created by a higher force rather than evolving from more primitive forms.

Some want science teachers to teach that Darwin's theory of evolution is not a fact and has gaps.

Gregory Forbes, a community college biology instructor, said it appears the "doors have been shut" on those in Michigan who support the teaching of intelligent design as a viable scientific alternative to evolution.

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Op dinsdag 3 oktober 2006 23:01 schreef Autodidact het volgende:

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Scientist finds 100 million-year-old bee

PORTLAND, Ore. - A scientist has found a 100 million-year-old bee trapped in amber, making it possibly the oldest bee ever found.

"I knew right away what it was, because I had seen bees in younger amber before," said George Poinar, a zoology professor at Oregon State University.

The bee is about 40 million years older than previously found bees. The discovery of the ancient bee may help explain the rapid expansion and diversity of flowering plants during that time.

Poinar found the bee in amber from a mine in the Hukawng Valley of northern Myanmar, formerly known as Burma. Many researchers buy bags of amber from miners to search for fossils. Amber, a translucent semiprecious stone, is a substance that begins as tree resin. The sticky resin entombs and preserves insects, pollen and other small organisms.

Also embedded in the amber are four kinds of flowers. "So we can imagine this little bee flitting around these tiny flowers millions of years ago," Poinar said.

An article on his discovery will appear Friday in the journal Science, co-authored by bee researcher Bryan Danforth of Cornell University.

In the competing journal Nature this week, there is an article about the unraveling of the genetic map of the honeybee. The recently completed sequencing of the honeybee genome already is giving scientists fresh insights into the social insects.

Poinar's ancient male bee, Melittosphex burmensis, is not a honeybee and not related to any modern bee family.

The pollen-eating bee has a few features of meat-eating wasps, such as narrow hind legs, but the body's branched hairs are a key feature of pollen-spreading bees.

The bee — about one-fifth the size of today's worker honeybee — has a heart-shaped head.

But the ancient bee was probably an evolutionary dead end and may not have given rise to modern bees, scientists said.

"It's exciting to see something that seems so different from what we think of as modern bees," Danforth said. "It's not an ancestor of honeybees, but probably was a species on an early branch of the evolutionary tree of bees that went extinct."

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Mirror test implies elephants self-aware

WASHINGTON - If you're Happy and you know it, pat your head. That, in a peanut shell, is how a 34-year-old female Asian elephant in the Bronx Zoo showed researchers that pachyderms can recognize themselves in a mirror — complex behavior observed in only a few other species.

The test results suggest elephants — or at least Happy — are self-aware. The ability to distinguish oneself from others had been shown only in humans, chimpanzees and, to a limited extent, dolphins.

That self-recognition may underlie the social complexity seen in elephants, and could be linked to the empathy and altruism that the big-brained animals have been known to display, said researcher Diana Reiss, of the Wildlife Conservation Society, which manages the Bronx Zoo.

In a 2005 experiment, Happy faced her reflection in an 8-by-8-foot mirror and repeatedly used her trunk to touch an "X" painted above her eye. The elephant could not have seen the mark except in her reflection. Furthermore, Happy ignored a similar mark, made on the opposite side of her head in paint of an identical smell and texture, that was invisible unless seen under black light.

"It seems to verify for us she definitely recognized herself in the mirror," said Joshua Plotnik, one of the researchers behind the study. Details appear this week on the Web site of the Proceedings of the National Academy of Sciences.

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Op dinsdag 31 oktober 2006 09:43 schreef Autodidact het volgende:

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Op dinsdag 31 oktober 2006 09:56 schreef Autodidact het volgende:
Baby's herkennen zichzelf en hun ouders in de spiegel, geloof ik.

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Op dinsdag 31 oktober 2006 10:00 schreef Alicey het volgende:

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Da's interessant. Het zit er dan dus eigenlijk al heel vroeg in dat mensen zelfbewust zijn.

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Op dinsdag 31 oktober 2006 10:07 schreef Autodidact het volgende:

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Nou, dat zit complexer. Baby's kunnen bijvoorbeeld heel slecht causale verbanden leggen...daar zijn ook leuke spelletjes omtrent verzonnen hè. Als een baby een auto op straat ziet, even zijn even ogen sluit, opent en weer naar de straat kijkt terwijl de auto weg is, kan hij de relatie niet leggen dat de auto dús weggereden is. Hij ziet gewoon een nieuwe wereld die de vorige niet was. Dan lijkt het me, dat hij die causale verbanden in zichzelf ook slecht kan leggen. Ik weet eigenlijk niet in hoeverre.

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Op dinsdag 31 oktober 2006 10:24 schreef Autodidact het volgende:
Ik heb het niet zo zeer over dat de auto wegrijdt, maar dat het weg is. Dat beseft een klein kind niet.

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Op dinsdag 31 oktober 2006 10:27 schreef Alicey het volgende:

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Okee.. Maar komt dat dan niet omdat het kind geen auto kan herkennen, omdat het het concept nog niet kent? Onderscheid maken tussen voorwerpen en omgevingen is toch iets wat we leren door kennis over voorwerpen?

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Op dinsdag 31 oktober 2006 09:47 schreef Alicey het volgende:
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Ik vraag me daarbij ook af of het een willekeurig dier niet te leren is zichzelf te herkennen. Ook kan ik me voorstellen dat wanneer een mens nooit leert over zich zelf en ook nooit een spiegel ziet, dit ook zal moeten leren...

Of maak ik nu een fundamentele denkfout?

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Op woensdag 6 september 2006 11:45 schreef Knipoogje het volgende:
Vraag: hoe zijn de man en de vrouw ontstaan? Ik neem aan dat het gros van de organismes op deze aarde uiteindelijk zijn evolved uit organismen die zich voortplantten door een soort fusie-methode ipv zichzelf te delen.

Probleem is alleen dat een anti-evolutionist zegt dat man en vrouw nooit via evolutie kan zijn ontstaan en 'vermoedelijke verklaringen' niet accepteert. Hebben we iets van hard bewijs omtrent de evolutie van mannelijke en vrouwelijke organismen?

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Op vrijdag 13 oktober 2006 14:39 schreef PvtRyan het volgende:
Ook het idee dat God evolutie heeft gepland of heeft geholpen vind ik een nutteloze aanname. Evolutie oogt niet gepland of 'ontworpen'. Ik zie evolutie en God als incompatibel, evolutie is een geleidelijke proces van trial en error, voor elk dier dat nu leeft zijn er miljoenen onsuccesvol geweest. Zeggen dat God dit bestuurt is zeggen dat ie maar wat aanmoddert. Zeggen dat God prima in een evolutionistisch wereldbeeld past, is zeggen dat God helemaal geen almachtige creator is. Verder kan evolutie prima op zichzelf staan, de aanname van God is overbodig en derhalve volgens Occam's Razor waarschijnlijk ook niet de juiste.

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Op dinsdag 31 oktober 2006 20:27 schreef Monolith het volgende:

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Dit is precies de antropomorfische denkwijze die Gilkey aanhaalt als kritiek op het creationisme. Het kenmerk van een God is nou juist dat menselijke denk- en handelwijzen daar nou jiust niet op te projecteren zijn.

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Het kenmerk van een God is nou juist dat menselijke denk- en handelwijzen daar nou jiust niet op te projecteren zijn.

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Op woensdag 1 november 2006 00:16 schreef Iblis het volgende:

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Waarom niet? We zijn toch in Zijn beeld geschapen?
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