Evolutie. Deel XIV

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Op donderdag 15 november 2007 09:53 schreef wijsneus het volgende:
Voor een goede beschrijving van Macro Evolutie en het failliet van ID zou je de getuigenis van Kevin Padian in Kitzmiller v. Dover moeten lezen.

Long read - good stuff.

http://www.sciohost.org/ncse/kvd/Padian/Padian_transcript.html

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Q And using your definition, intelligent design is a scientific theory, correct?

A Yes.

Q Under that same definition astrology is a scientific theory under your definition, correct?

A Under my definition, a scientific theory is a proposed explanation which focuses or points to physical, observable data and logical inferences. There are many things throughout the history of science which we now think to be incorrect which nonetheless would fit that -- which would fit that definition. Yes, astrology is in fact one, and so is the ether theory of the propagation of light, and many other -- many other theories as well.

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Friesen, V.L. et al. (2007) Sympatric speciation by allochrony in a seabird. PNAS, advance online publication

The importance of sympatric speciation (the evolution of reproductive isolation between codistributed populations) in generating biodiversity is highly controversial. Whereas potential examples of sympatric speciation exist for plants, insects, and fishes, most theoretical models suggest that it requires conditions that are probably not common in nature, and only two possible cases have been described for tetrapods. One mechanism by which it could occur is through allochronic isolation—separation of populations by breeding time. Oceanodroma castro (the Madeiran or band-rumped storm-petrel) is a small seabird that nests on tropical and subtropical islands throughout the Atlantic and Pacific Oceans. In at least five archipelagos, different individuals breed on the same islands in different seasons. We compared variation in five microsatellite loci and the mitochondrial control region among 562 O. castro from throughout the species' range. We found that sympatric seasonal populations differ genetically within all five archipelagos and have ceased to exchange genes in two. Population and gene trees all indicate that seasonal populations within four of the archipelagos are more closely related to each other than to populations from the same season from other archipelagos; divergence of the fifth sympatric pair is too ancient for reliable inference. Thus, seasonal populations appear to have arisen sympatrically at least four times. This is the first evidence for sympatric speciation by allochrony in a tetrapod, and adds to growing indications that population differentiation and speciation can occur without geographic barriers to gene flow.

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Op vrijdag 16 november 2007 13:15 schreef ATuin-hek het volgende:
Wellicht ook interessant
http://www.nu.nl/news/131(...)k_op_land_leven.html

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They produce eggs which remain in the bottom mud to survive when their pools dry out, so their eggs can be stored dry at room temperature for many years.

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Op vrijdag 23 november 2007 09:21 schreef SpecialK het volgende:

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http://www.nu.nl/news/132(...)_steeds_kleiner.html

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Op vrijdag 23 november 2007 10:17 schreef Bensel het volgende:

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damn, je was me te snel af..

Vind het trouwens wel een heel mooi voorbeeld hoe dat de natuur nu reageert op de bedreiging die wij als mensen vormen voor andere diersoorten dmv evolutie. Menselijke selectie is in dit geval gelijk aan natuurlijke selectie.

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The cane toads go bump in the night. I hear them banging as they misjudge where my hotel door ends and the forest begins. The force of a large toad knocking wood is substantial. But the force with which the toads, which are native to Central America, have hit Australia is even greater. Brought to Queensland in 1935 to combat beetles infesting sugarcane fields, the toads have spread out from their point of entry like the shock waves of a bomb, warty legs and oversize tongues jettisoned into every conceivable ecological crack.

Recent research by Ben Phillips and his collaborators at the University of Sydney has shown that the toads are evolving as they spread, perfecting their ability to adapt to the Australian landscape. The toads at the front edge of the invasion now have smaller bodies, reduced toxicity and relatively longer legs, apparently because individuals with those traits were having greater success. The native fauna has evolved in response: the mouths of some snake species are getting smaller, for instance, because so many of the snakes with big mouths were eating the poisonous cane toads and dying off.

Such examples are changing scientists’ views of the speed of evolution. The process was long considered to be slow, even lumbering. Increasingly, though, researchers are observing evolution in action. You may be familiar with the examples of the evolution of drug-resistant bacteria or agricultural pests. Microbes and pests may change the fastest, but they are not unique.

We see rapid evolution most often where some force (often us) has given it a jump start by suddenly and dramatically altering an organism’s environment. Rats have developed smaller bodies when introduced to islands. Trophy fish have also adopted smaller body sizes in response to fishers’ preference for big fish (which, if killed, do not breed). Mayflies in streams where trout were released now forage at night to avoid the fast-swimming predators. Many hundreds of herbivorous species have switched to novel, sometimes toxic, food sources introduced by humans and have come to specialize in consuming those new resources. Various native species have evolved in response to newly arrived competitors. Cedar trees have begun making toxins to protect themselves from being eaten by deer now roaming in their formerly benign habitats. Mussels in New England have evolved the ability to detect invasive green crabs and produce thicker shells where the crabs are present.

Most of these changes appear to have resulted from natural selection: organisms that by chance had some genetic trait that helped them thrive in the face of a new stress were favored, and subsequently they reproduced successfully and spread the helpful trait to future generations. But some evolutionary changes we see may simply be the result of genetic drift (random genetic changes that accrue over time).

The more we look, the more we can observe evolutionary changes that are fast enough to be seen during the course of a single study. A Ph.D. student might, in the five or so years of a dissertation project, realistically see the development of new species, whether in real time or using genetic tools to reconstruct evolutionary history. As house mice and rats have spread with us around the world, they have speciated into forms best adapted to the different regions where they live. In the northeastern U.S., a species of fly has evolved to feed on a species of honeysuckle introduced to North America less than 250 years ago. Although the new fly is a hybrid between two existing species, it can mate with neither one and maintains viable populations of its own.

People tend to imagine evolution as acting only on long-extinct creatures such as the dinosaurs, but the flensing knives of natural selection and the random pushes and pulls of genetic drift are still at work today. We see a red oak tree in our backyard or a cane toad at our hotel-room door, but the names fool us. These species are not the same this year and next. Although the evolution we observe in real time will not suddenly give us dinosaurs, it is still a process to be reckoned with. Give natural selection a few individuals of any species, and it will work the same way in a waste pool as it does in Yellowstone National Park. Nature abhors a vacuum, but nearly anything else will do.

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Op vrijdag 23 november 2007 10:17 schreef Bensel het volgende:

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damn, je was me te snel af..

Vind het trouwens wel een heel mooi voorbeeld hoe dat de natuur nu reageert op de bedreiging die wij als mensen vormen voor andere diersoorten dmv evolutie. Menselijke selectie is in dit geval gelijk aan natuurlijke selectie.

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Op vrijdag 23 november 2007 10:52 schreef Monolith het volgende:

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De mens is in deze natuurlijk ook gewoon een roofdier, dus zo gek is dat niet. Is dit trouwens wel zo recent? Ik probeerde even de wetenschappelijke publicatie te vinden en kwam dit artikel uit 2005 tegen waarin hetzelfde wordt beweerd. Dit artikeltje bekijkt de invloed van de mens in een bredere context en vindt nog veel meer voorbeelden van snelle aanpassing door de invloed van de mens:
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Op vrijdag 23 november 2007 09:21 schreef SpecialK het volgende:

http://www.nu.nl/news/132(...)_steeds_kleiner.html

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Op vrijdag 23 november 2007 13:23 schreef Papierversnipperaar het volgende:

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Dat verklaard waarom er geen fossielen zijn van "tussenvormen"

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Op maandag 26 november 2007 18:13 schreef Autodidact het volgende:

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Wat zeg je nou? Dat er geen fossielen zijn van zgn. tussenvormen?

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Op maandag 26 november 2007 18:24 schreef Papierversnipperaar het volgende:

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Schijnt een kritiekpuntje te zijn van creationisten, dat ze het fossielenbestand niet compleet genoeg vinden.

Maar ondanks dat we niet alle schilderijen van Rembrandt hebben vinden we het toch een goed schilder.

TOCH?!?

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Op maandag 26 november 2007 18:24 schreef Papierversnipperaar het volgende:

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Schijnt een kritiekpuntje te zijn van creationisten, dat ze het fossielenbestand niet compleet genoeg vinden.

Maar ondanks dat we niet alle schilderijen van Rembrandt hebben vinden we het toch een goed schilder.

TOCH?!?

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Op maandag 26 november 2007 20:20 schreef Autodidact het volgende:

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Je neemt nu de de claims van creationisten voor waar aan. Niet doen . Dat was misschien een enigszins geldig argument in Darwins tijd, toen er bijna geen fossielen waren, maar nu niet meer.

Zie bijvoorbeeld de evolutie van de walvis, waarvan de volgende "tussensoorten" bekend zijn. Nu kun je altijd zeggen "we hebben het fossiel van een dier tussen de Takracetus en de Gaviocetus niet&quot. Klopt, maar dan maak je bij elke vondst twee nieuwe "missing links". Maar gelukkig hoef je niet alle fossielen gevonden te hebben voordat de evolutietheorie geloofwaardigheid heeft, net zoals je niet alle mogelijke rekensommen hoeft te maken om te weten dat algebra geldige wiskunde is.

[ afbeelding ]

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Op dinsdag 27 november 2007 15:00 schreef bigore het volgende:

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De stap tussen dalanistus en rodho is wel erg groot eigenlijk

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Op vrijdag 23 november 2007 13:23 schreef Papierversnipperaar het volgende:

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Dat verklaard waarom er geen fossielen zijn van "tussenvormen"

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Op dinsdag 27 november 2007 17:47 schreef boyv het volgende:

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Ik las net toevallig in een schoolboek dat er wel tussenvormen zijn gevonden. Zal het zo even opzoeken en citeren.

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TOPEKA, KS—In response to a Nov. 7 referendum, Kansas lawmakers passed emergency legislation outlawing evolution, the highly controversial process responsible for the development and diversity of species and the continued survival of all life.

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The sweeping new law prohibits all living beings within state borders from being born with random genetic mutations that could make them better suited to evade predators, secure a mate, or, adapt to a changing environment. In addition, it bars any sexual reproduction, battles for survival, or instances of pure happenstance that might lead, after several generations, to a more well-adapted species or subspecies.

Violators of the new law may face punishments that include jail time, stiff fines, and rehabilitative education and training to rid organisms suspected of evolutionary tendencies. Repeat offenders could face chemical sterilization.

To enforce the law, Kansas state police will be trained to investigate and apprehend organisms who exhibit suspected signs of evolutionary behavior, such as natural selection or speciation. Plans are underway to track and monitor DNA strands in every Kansan life form for even the slightest change in allele frequencies.

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"If Earth's species were meant to change over successive generations through physical modifications resulting from the adaptation to environmental challenges, then God would have given them the genetic predisposition to select mates and reproduce based on their favorable heritable traits and their ability to thrive under changing conditions so that these advantageous qualities would be passed down and eventually encoded into the DNA of each generation of offspring," Olathe public school teacher and creationist Joyce Eckhardt said. "It's just not natural."

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"If Kansans want to ban evolution, that is their right, but they must understand that we rely on a certain flexibility in the natural order of things to be able to deliver healthy food products to millions of Americans," said Carl Casale, a vice president with the agricultural giant Monsanto. "We're not talking about playing God here. We are talking about succeeding in the competitive veggie-burger market."

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Gemummificeerde dinosaurus ontdekt
Uitgegeven: 3 december 2007 06:28

WASHINGTON - Een tiener heeft de mogelijk compleetste dinosauriër tot nu toe ontdekt. Het gaat om een gedeeltelijk gemummificeerde hadrosaur. Van het fossiele dier is weefsel bewaard gebleven, misschien zelfs zacht weefsel.

De intacte huid met schubben toont bewijzen van strepen, aldus een wetenschapper van de universiteit in het Britse Manchester maandag na maandenlang onderzoek. De hadrosaur blijkt gespierder te zijn geweest dan was aangenomen.

De destijds 17-jarige Tyler Lyson trof de 67 miljoen jaar oude overblijfselen in 2000 aan op het land van een oom in het Amerikaanse North Dakota.

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Op maandag 3 december 2007 06:57 schreef barthol het volgende:
ANP bericht via Nu.nl:
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Uiteraard zijn er ook iets uitgebreidere (engelstalige) berichten over via Associated Press en Reuters

Hmmm, zou het eventueel de mogelijkheid geven om (een deel van) het DNA van die Hadrosaurus te onderzoeken?

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Time long ago transformed Dakota's soft tissue into mineralized rock, preserving it for the ages.
"It's a dinosaur that was turned into stone, essentially," said Lyson, 24, now a graduate student in paleontology at Yale University.
http://www.washingtonpost(...)80.html?hpid=topnews