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Darwin: Šta je frka u evoluciji?

Started by scallop, 25-11-2009, 09:47:05

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scallop

Danas se pojavio zanimljiv tekst Olivije Judson na www.nytimes.com.

Na temu: It is worth remembering that evolution fails more often than not.

Diskusija ove dame se svodi na činjenicu da se vrše eksperimenti koji potvrđuju evoluciju, a ne oni koji je proveravaju. Zašto? Zato što su ovi drugi obavezno neuspešni, a ko bi vršio eksperimente koji ne daju rezultat?

Pitanje koje muči istraživače je vrlo pragmatično: Jesmo li sposobni da se adaptiramo na tekuće promene u našem okruženju? Izgleda da nismo, jer su promene brže od brzinskog kapaciteta evolucije! (Brzinski kapacitet evolucije je moja interpretacija teksta.)

Dakle?
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

mac

Precizniji link: http://opinionator.blogs.nytimes.com/2009/11/24/an-evolve-by-date/

Ja ovde ne vidim problem. Kad se okruženje promeni neki će da izumru, a neki ćemo i da preživimo.


scallop

Mac, mogao bi da ga zapaziš. Ovako postavljeno, čini se da je na prilično zdravim nogama (izvinjavam se za virtuelne noge, meni je to vuklo na Paramecijuma). Ako je evolucija, zapravo, crawling proces, onda se može polako sagledati da što je DNK složeniji adaptacija (vrlo pragmatično zapažanje Kufera) je sporija. To bi značilo da u tekućim promenama jednostavniji organizmi imaju veću šansu od složenijih. O onima koji baziraju samo na RNK da ne govorimo. Tako dolazimo do suštine panike: čovek je najsloženija forma i suočavamo se sa leming efektom: sami jurimo ka ivici provalije. Jedina prednost nam je što nemamo specijalizovanu ishranu što nije bogznakakav pomak u odnosu na rakuna ili međeda, a ono rezerve mozga nikako da nam proradi. Mogao bi da zaključiš da ni to nije neka novost, ali se prvi put ukazuje na neke relativno merljive veličine. Brzina devastacije okoline je uporedljiva sa evolucionim potencijalom preko vremenske komponente. Možemo da izračunamo koliko kasnimo. Otkako se ne bavim naukom veoma rado se upuštam u naučnofantastične procene. xrotaeye
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

lilit

Uh Skalope,

Tacno je da naucnici u vezi mnogo cega nemaju isto misljenje, ali postoji neka granica dokle doseze naucna komunikacija a preko koje to prestaje da bude. Banalan primer: moze biti neslaganja i rasprave oko energetskih nivoa u molekulu H2O, ali svako ko bi hteo danas da raspravlja da li je voda uopste H2O ili nije, je li to molekul ili nije, moze to da cini samo kod Ivone Zivkovic i sl ( http://www.znaksagite.com/diskusije/index.php?topic=8371.0 ), jer to jednostavno danas vise nije predmet naucne diskusije.

Ljudi danas vole da istrazuju i citaju, i to je super pozitivno, ali onda neretko imaju utisak da je nesto mnogo jednostavnije nego sto jeste, padaju u zamku oversimplification, i izvlace zakljucke koji nisu nuzno tacni. S druge strane, OK, jasno mi je da "popularnu nauku" nije ni malo lako pisati, narocito u prirodnim naukama.

To bi bio uvod vezan za autorku NYTimesa xrofl, a konkretno, vezano za evoluciju, naravno da se ne rade eksperimenti koji "proveravaju evoluciju", a sa ciljem koji si naveo, upravo zato sto se zna da je evolucija, sa stanovista individue prilicno neuspesan proces. Sama autorka teksta je "sokirana" cinjenicom da je bakterijama potrebno 31.000 generacija da steknu sposobnost da koriste drugu vrstu secera (ne navodeci da je brzina deobe bakterija u proseku od 20 minuta i nije bas potrebno previse da se stigne to tog broja od 31.000 generacija. Sa aspekta planete, sta znaci 31.000 generacija (definisano za bakterije sto ne znaci nuzno da je isti taj broj primenljiv i na homo sapiens sapiensa ili na mrave)? 2 centimetra na skali. http://hypertextbook.com/facts/1997/TroyHolder.shtml

Autorka takodje zanemaruje cinjenicu, koja glasi da je i covek takav kakav je, sa svim svojim vrlinama i manama produkt iste te evolucije i da sve ovo sto danas radi takodje moze da se strpa u vid evolucije. Posebno imajuci u vidu da ce ljudi, za razliku od drugih bica, verovatno biti spremniji da izbegnu zamke tipa: "it the environment continues to change as rapidly as it is at the moment". Plus, ono sto nauka danas zna o genomu je na prilicno jadnom nivou. Zna se nesto o mutacijama na nivou egzona (http://en.wikipedia.org/wiki/Exon) koji kodiraju (najbanalnije receno) gene, a skoro nista se ne zna o funkciji i ulozi introna (http://en.wikipedia.org/wiki/Intron).

Takodje, neke vrste koje su postojale pre 10.000 godina, ne postoje danas i vice versa.  A da prezivi i 31.000 od 6 i kusur milijardi, sasvim dovoljno za dalji "napredak" i mnogo lakse za planetu.  :mrgreen:
That's how it is with people. Nobody cares how it works as long as it works.

mac

Uspešno smo odbili ptičiji grip, uspešno se borimo protiv svinjskog gripa, napadamo problem globalnog zagrevanja (koji smo mi podstakli, ali kažu da se i prirodno dešava). Ima nas ko mrava od Aljaske do Australije, preko Sibira i Sahare. Polako idemo na Mesec i Mars. Nećemo izumreti.

A buva o neiskorišćenosti mozga je samo buva, http://en.wikipedia.org/wiki/10%25_of_brain_myth

lilit

Quote from: mac link=topic=8433.msg218642#msg218642 date=1259149600

A buva o neiskorišćenosti mozga je samo buva,
url=http://en.wikipedia.org/wiki/10%25_of_brain_myth]http://en.wikipedia.org/wiki/10%25_of_brain_myth[/url]

To valjda znamo i nismo pokusali da negiramo.
That's how it is with people. Nobody cares how it works as long as it works.

mac

Osvrnuo sam se na ovaj detalj:

Quote from: scallop on 25-11-2009, 13:30:35... a ono rezerve mozga nikako da nam proradi.

lilit

ma to je skalopova metafora, rekla bih, al da ne glumim drvenog advokata.  :)
That's how it is with people. Nobody cares how it works as long as it works.

Lord Kufer

Čovek je simbioza jednoćelijskih organizama. To što mi konvencionalno gledamo na čoveka kao na "jedinku" nema nikakve veze s fiziološkom evolucijom čoveka. Promene se dešavaju i na ćelijskom i na individualnom nivou.

S treće strane, ljudsko društvo je takođe bitan faktor u "selekciji" (o čemu zapravo teorija evolucije i jeste), pošto se u ljudskom društvu vrši selekcija tako što se favorizuju poslušni a neposlušni se eliminišu. Pa, prema tome, imamo još i taj nivo evolucije, koji je sigurno u koliziji s ovim drugim.


mac

Kakvi sad poslušni i neposlušni, otkud se to stvorilo? Dajmo malo ozbiljnosti.

scallop

Baš lepo. Moram da priznam da vrlo rado upadam u oversiplification. Tim pre što ni overcomplication nije produktivna. To vam je kao sa definicijama, suviše jednostavna zahvata prevelik prostor, previše detaljna je sigurno pogrešna. ;) Mogu ja kao i sa Taranom: zakomplikujem zapršku, pa od svega hoće gorušica. Evolucija je adaptacija! Sad bi neko mogao da kaže da je Kufer previše pojednostavio, ali ako se vratimo do Darwina videćemo da je on, zapravo, od adaptacije zeba (?) i krenuo, što i nije evolutivna promena, kao što to nije ni kod kergelenske muve. Da manje duvaju vetrovi na Kergelenu, muvama bi ponovo narasla krila. Međutim, genetsko prilagođavanje ljudi na upotrebu kravljeg mleka je radikalno srezalo genetski okvir ljudske populacije u Evropi i danas svi bez posledica koriste mleko za ishranu. To nije slučaj i kod nekih drugih populacija na Zemlji. Da ne postoji crawling efekat evolucije kod ljudi ne bi neka genetska istraživanja porekla čoveka upućivala na Džingis Kana i na jedno malo urođeničko selo u severozapadnoj Africi. Teorija o Adamu je priča o evoluciji gde svi drugi ljudski potencijali nisu preživeli neko od iskušenja u prošlosti.

Ja svake godine doživljavam evolutivni udar kad odem u SAD i kad se posle nekoliko meseci vratim. To vidim na svojoj koži, na desnima, na fizičkoj konstituciji u celini. Ne smatram da ću dati neki doprinos nauci, ali volim da potaknem na razmišljanje. U suštini sam antidogmata i analogonac, volim da vidim i drvo i šumu. Može mi se. I ne prijaju mi poređenja sa Ivonom Živković, ko god da je. U mojoj tintari ima mnogo toga, a moglo bi da bude i bolje sređeno i iskorišćeno. Da imam Vanaksov memoreks i da mogu da sve presložim videli biste vi koliko bi neiskorišćenog prostora ostalo. xrotaeye

Pardon, možda ima nečega u Kuferovoj opasci koliko god da je na prvi pogled politizovana. SAD su gradili uz velika iskušenja i preživeli oni koji su se izborili. Zato su danas na delu njihovi nasilni potencijali, jer drugih nema, mada ih dođoši malo razvodnjuju.
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

Lord Kufer

Ja sam došao do zaključka da je u Amerikanaca strah od smrti posledica evolucije. Naime, oni nemaju svece da ih sačekaju tamo, kad umru.

Jednostavno su evoulirali u pravcu ideje preživljavanja, koja je potpuna deluzija (obmana), jer na ovom svetu zaista niko neće preživeti. Usmeravanje svih potencijala k tom cilju je zapravo čista degeneracija, da ne kažem de-mutacija.


lilit

@scallop,

Ma vidi, daleko od toga da sam htela da te poredim s Ivonom Zivkovic, ne znam odakle si to izvukao (a da sam htela, to bih i napisala). Plus, nemam sta da dodam na tvoj poslednji post, osim da nije bilo potrebno da se smeni 31.000 generacija da bi se ljudi adaptirali na kravlje mleko.
I naravno da sam uvek za razumljivo pisanje o, na prvi pogled, nerazumljivim stvarima, ali mi je tekst koji si linkovao ipak malo...onako...oversimplikovan:D

xremyb
That's how it is with people. Nobody cares how it works as long as it works.

Lord Kufer

S druge strane, znam šta smeta macu... Teorija evolucije, kao i svaka druga teorija, nije sredstvo istine, već je bitno da je operativna. To znači da teorija evolucije ne treba da objašnjava "ciljeve" već da uočava veze između promena, na mikro i makro planu. Ukoliko bi samo nametala svoju "istinu", a to je ono što se čini u mnogim društvenim sredinama, naravno, išla bi protiv sebe - to jest, u praksi, to se zove negativna selekcija.


Lord Kufer

Što se tiče adaptacije na mleko, treba imati u vidu da je upravo naš probavni trakt simbiotička tvorevina, da u njemu ima otprilike kilo i po bakterija koje obavljaju posao varenja a one nisu prirođeni deo našeg organizma.

lilit

Quote from: Lord Kufer on 25-11-2009, 14:41:00
Što se tiče adaptacije na mleko, treba imati u vidu da je upravo naš probavni trakt simbiotička tvorevina, da u njemu ima otprilike kilo i po bakterija koje obavljaju posao varenja a one nisu prirođeni deo našeg organizma.


Mislim da se tu pre radi o tome da neki ljudi, uglavnom neEvropljani, imaju smanjenu produkciju laktaze, enzima koji razlaze laktozu na galaktozu i glukozu. A opet su u igri mutacije.

The normal mammalian condition is for the young of a species to experience reduced lactase production at the end of the weaning period (a species-specific length of time). In humans, in non-dairy consuming societies, lactase production usually drops about 90% during the first four years of life, although the exact drop over time varies widely.[9]

However, certain human populations have a mutation on chromosome 2 which eliminates the shutdown in lactase production, making it possible for members of these populations to continue consumption of fresh milk and other dairy products throughout their lives without difficulty. This appears to be an evolutionarily recent adaptation to dairy consumption, and has occurred independently in both northern Europe and east Africa in populations with a historically pastoral lifestyle.[10] Lactase persistence, allowing lactose digestion to continue into adulthood, is a dominant allele, making lactose intolerance a recessive genetic trait. A noncoding variation in the MCM6 gene has been strongly associated with adult type hypolactasia (lactose intolerance)[4].
That's how it is with people. Nobody cares how it works as long as it works.

Lord Kufer

Ono što je stvarno problem, po mom mišljenju, jeste ta aristotelijanska potreba da se vrše klasifikacije i generalizacije. Minorne razlike jednostavno ne prihvatamo kao bitne, e da bi opstala vrsta. Naravno, na političkom nivou svaka, pa i najmanja razlika, biološka ili kulturna, može se zloupotrebiti, kao što je i slučaj u praksi.

Mozak je u čoveka pre 150.000 godina bio veći nego danas.
Šta to dokazuje?


mac

Da je trošio više energije, i da je više zanosio pri trčanju.

scallop

Bilo je potrebno 160.000 godina da mu se utuve vijuge. Kad to vijuge pritegnu, mozak je manji.
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

scallop

Quote from: lilit_depp on 25-11-2009, 14:38:37
I naravno da sam uvek za razumljivo pisanje o, na prvi pogled, nerazumljivim stvarima, ali mi je tekst koji si linkovao ipak malo...onako...oversimplikovan:D

Pa, nisam ga našao u naučnoj literaturi. :shock: Naravno, kod nas i o razumljivim stvarima pišu nerazumljivo. Evo, i Kufer se već fatio Aristotela.
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

Lord Kufer

Trošili su više energije ondak nego sadak? To kad bi se zezali  xjap

scallop

Pa, naravno da je trošio više energije nego sada. Dumao je o vatri kojih desetak hiljada godina dok nije utuvio da se to može šibicom. Koliko mu je trebalo da shvati da se biljka može i posaditi, da se životinja može odgajiti, da ne mora da tegli na leđima, da može da se obuče u životinju, jer životinji nije ladno, a njemu jeste, da otkrije da se deca ne rađaju iz žira ili u kupusu, te da ga žene drndaju jer je jak a glup... Toliko toga da se ne može porediti sa današnjim čovekom koji ni knjigu ne mora da lista, a kamoli da oštri guščije pero. Svako takvo otkriće nova kvrga među vijugama, a mozak sve lakši i ne zanosi na krivini. Mac ti je goli homo tehnikus pa štedi reči, a ja sam homo proliferatus pa se kod mene preliva. xrotaeye
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

Lord Kufer

E, stvarno dobar argument  xrofl

Kao oni vajni naučnici koji su razvili tezu da je homo erektus imao jaču vilicu jer je morao da žvaće živo meso. A s običnom ručnom sekirom (kamenčinom) je mogao da napravi tatarski biftek i od nosoroga...


scallop

Vajni naučnici smatraju da je kamena sekira služila da se nosorogu skine nos da ne povredi jer je tatarski biftek pravljen tako da predak sedne na njega i bulji u Mesec dok ne izračuna njegovu orbitu. Takav bio recept.
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

Lord Kufer

Ma najveći je problem u tome što mnogi učitavaju u evoluciju nekakav smisao ili krajnju svrhu "usavršavanja", što je potpuno bezveze. Ako se uslovi pogoršavaju, vrsta će ili da ogrubi, da se pojednostavi ili da odumre.

Drugi problem je upravo ta pretpostavljena postupnost, kao da stvarno neki paramecijum ima za cilj da postane delfin, pa se sad milionima godina polako pretvara u delfina i rastu mu peraja. Ima živih primera, kao oni papagaji u Škotskoj što su odjednom svi do jednog posiveli ko vrapci - prilagodili se novom okruženju. Nije tu bilo nikakvog postupnog posivljavanja niti bilo kakve selekcije. Tesilo se u trenu.

mac

Verovatno ima i toga, da se papagajima jedne sezone više svidela siva od šarene, pa su ženke više davale sivljacima.

lilit

That's how it is with people. Nobody cares how it works as long as it works.

scallop

Quote from: mac on 26-11-2009, 01:57:04
Verovatno ima i toga, da se papagajima jedne sezone više svidela siva od šarene, pa su ženke više davale sivljacima.

Izvini što se mešam u tvoje učitavanje u evoluciju, ali pravilno je - sivonjama.

Ne znam odakle, Kuferu, ideja o učitavanju smislenosti i "viših ciljeva" u evoluciju? Oni koji učitavaju "više ciljeve" i nisu tako skloni evoluciji. Ipak, evolucija i nije tako besmislena. Igra nastanka i ekstinkcije je identična metodu proba-greška. A, ta metodologija se pokazala veoma smislenom u prostoru nefundamentalnih nauka, pa i onim fundamentalnim kad se prodire u nepoznato. "Viši ciljevi" postaju jasni tek ako se dostignu.

Nauka još nije sigurna da je evolucija proces, a kamoli da li se da kotrolisati. Ako se izvesnost da je to proces postavi kao hipoteza deluje prilično primamljivo ideja o selekciji i kontroli. Svedoci smo da istraživanja idu i u tom pravcu. Naravno, znatno je teže prihvatiti tu hipotezu kao postulat, jer onda je put zacrtan bez mogućnosti da se skrene sa njega. Rešenja često leže pored puta. Danas znamo da su selekcije moguće unutar vrste, ali da je hibridizacija prilično nepouzdana i nereproduktivna. Ako nateramo mulu ili mazgu da imaju potomstvo, onda smo dokazali evoluciju i tada smislenost definitivno nadrasta haotičnost. Tu stojimo i možda ćemo tu i ostati, ali to ne znači da treba odustati. Čovek je u svojoj evoluciji pregazio tu granicu i nema povratke, osim ako je ta granica ujedno i prag na kome počinje ekstinkcija.

Recimo, Monsanto je u sortu krompira Russet ugradio bakterijski genetski materijal koji biljku čini otrovnom i odbojnom za krompirovu zlaticu. Budući da se pokazao reproduktivnim, Monsanto je registrovao ovaj krompir kao preparat za zaštitu bilja, jer se krompir ne može pravno zaštititi. Ako seljak hoće da gaji taj krompir, a taj krompir nema rizik propadanja useva, mora da kupi seme kao preparat. Ako ga sledeće godine zaseje bez kupovine kod Monsanta, Monsanto će ga tužiti! Velike kuće kao Mc Donalds troše ogromne količine krompira i tragaju za stabilnim isporučiocima. Sa strane biznisa je sve u redu, a moguće neželjene posledice se ne razmatraju, jer lova je lova. Codex Alimentarius će pozdraviti dalje genetsko uplivisanje na prehrambene proizvode i sutra će nove genetski potpuno izdvojene vrste preplaviti Zemlju. To podstiče one koji veruju da se evolucija da kontrolisati i da je smisleni proces. Tu se otvaraju i svi drugi istraživački pravci postuliranja evolucije. Tema nije ni jednostavna ni naivna. Mi je samo tako učitavamo pabirčeći po informativnom prostoru, bez kritičkog poriva da razlučimo informaciju od dezinformacije.

Da ne davim više. Poricanje i sprdanje nas ne mogu voditi kroz ovu priču. Ubeđenost da se o njoj dovoljno zna, takođe.
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

lilit

Quote from: scallop on 26-11-2009, 10:55:44
Ako ga sledeće godine zaseje bez kupovine kod Monsanta, Monsanto će ga tužiti! Velike kuće kao Mc Donalds troše ogromne količine krompira i tragaju za stabilnim isporučiocima. Sa strane biznisa je sve u redu, a moguće neželjene posledice se ne razmatraju, jer lova je lova. Codex Alimentarius će pozdraviti dalje genetsko uplivisanje na prehrambene proizvode i sutra će nove genetski potpuno izdvojene vrste preplaviti Zemlju. To podstiče one koji veruju da se evolucija da kontrolisati i da je smisleni proces. Tu se otvaraju i svi drugi istraživački pravci postuliranja evolucije. Tema nije ni jednostavna ni naivna. Mi je samo tako učitavamo pabirčeći po informativnom prostoru, bez kritičkog poriva da razlučimo informaciju od dezinformacije.

Cini mi se da su dva osnovna problema vezana za genetski modifikovane biljke: 1) opasnost od rezistencije patogena i pojava gladi kao posledica; 2) sirenje na racun prirodne populacije.

I mislim  da s njima treba postupati jako oprezno. One ugrozavaju autohtone vrste (domace), koje poseduju visoku genetsku varijabilnost (i samim tim veliku mogucnost adaptacije). Monokulture su generalno problem upravo zbog te smanjene varijabilnosti (pojavi se rezistentni patogen i pobije sve bez razlike, dok se u genetski varijabilnoj populaciji onda odigrava proces selekcije, pa neko ipak ima neke sanse makar i minimalne), a GM sojevi su vestacki stvoreni da budu otporniji i zato u trenutnoj postavci stvari nose kompetitivnu prednost u odnosu na prirodnu populaciju. Ali, na dugorocnoj skali, strah od realne prirodne katastrofe u kojoj ce neki mutirani patogen unistiti sve te genetski identicne jedinke sa sposobnoscu adaptacije nula je veoma realan.

Nece se niko pretvoriti u paradajz ako pojede GM paradajz, ali dugorocne potencijalne opasnosti uvodjenja su prilicno jasne u naucnoj javnosti (skalope, nemoj da me streljas :) ), ali dzaba lobiranje za zdravu hranu, gajenje organic proizvoda i sl kada novac ide na drugu stranu...A i ono sto se negde prodaje ko "organic", cesto ne zadovoljava sve propise.

(hm, ako coveka i ono sta on radi uvrstimo u "evolutivnu tvorevinu", mozemo li onda i njegovo eksperimentisanje sa GM takodje strpati u tu ladicu?)

That's how it is with people. Nobody cares how it works as long as it works.

scallop

Ne mogu sad da ti odgovorim, moram još jednom u policiju po pasoš i ličnu kartu. Šta ćeš, nisam rezistentan na idiotsku birokratiju. Sa'će nam ponovo da merkaju podatke da vide da li je eksperiment izdavanja biometrijskih dokumenata uspešan i u našem slučaju. Grrrrr! xuss
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

lilit

That's how it is with people. Nobody cares how it works as long as it works.

Lord Kufer

Da te je Monsanto patentirao, bio bi zaštićen od birokratije  :twisted:

scallop

Ima jedan psovački topik, dole, na Deponiji. Tamo se istresemo u ovakvim slučajevima.

Taman mi na vrata, a dođe poštar. Uruči mojoj ženi od suda da je njena izjava pred sudom, (zbog stana iz koga 60 godina ne može da istovari uljeze, tri generacije i sad i neki unuci koji imaju decu čuvaju stan za babu koja je u Domu i koja se vraća čim joj bude bolje, a mojoj ženi umro deda koji je kuću zidao, umrla majka koju su iz tog stana isterali kad je moja žena imala oko 10 godina, naša deca se rasula po svetu ili podstanare) pomerena od 9-og decembra za 23 februar. A mi odložili priliku da budemo za Thanksgiving sa Indijancima, idemo 14-og i vraćamo se (sic!) 9-og marta! Opsujem ja i evoluciju i one koji ovako uspešno preživljavaju i odemo u Policiju. Naravno, tamo nam prošao red (otvorili još jedan šalter pa ubrzali) tako da smo jedva objasnili da naše vreme i dalje postoji u nekom paralelnom svemiru i da nije potreban veliki napor da se vrati, jer niko ne gubi svoje vreme koje je slučajno došlo ranije nego što su očekivali. Zabezeknem se kad je dama na šalteru rekla OK, a niko sa strane nije imao daha da navali na nas. Još jednom provere da li tehnologija identifikacije radi (!), sve sa mojim prstom i kompjuterom i - završimo.

Izvinjavam se što sam se istresao ovde, a ne tamo, računam da kao evolucionisti znate za crawling efekat.

Dakle, kad bismo znali da zaustavimo vreme, odmah bismo primetili da evolucija teče kraj i oko nas. Dosadna novembarska muva letucka naokolo, već je smestila ona jaja iz kojih će krenuti generacija muva 2010, čeka da mi se smuči i da konačno krenem muhotepalicom na nju. Znate kako je, ili muva nije u sobi ili je muhotepalica u kuhinji. Gledam je i mislim kako je trebalo da je ulovim uzvodno, kao lososa. Sad je kasno i likujući ostavljam da crkne od muke.

Kad Monsanto ugradi u čoveka bakteriju koja sikteriše muve i komarce, a taj trenutak nije daleko, onda će i na nas udariti štambilj i odlučivati ko može u krevet i s kim. Bene Geserit to već radi i na njihovim proizvodima je utisnuta oznaka brenda.

Ne mogu ozbiljno. Jedva čekam Ameriku, pa kad mi se tamo ukažu njihove genetske deformacije, da zavolim ponovo Beograd. Mrdaj, evolucijo, vi'š da sam nestrpljiv!
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

Lord Kufer

Mokrim dlanovima lako se hvataju i muhe i komarci, a suhim ne.

lilit

Quote from: scallop on 26-11-2009, 15:37:09
Dakle, kad bismo znali da zaustavimo vreme, odmah bismo primetili da evolucija teče kraj i oko nas.
Am Ende, dodjosmo do zakljucka da nam fali Hiro Nakamura!  :lol:
That's how it is with people. Nobody cares how it works as long as it works.

Mica Milovanovic

Dakle, kad bismo znali da zaustavimo vreme, odmah bismo primetili da evolucija teče kraj i oko nas. Dosadna novembarska muva letucka naokolo, već je smestila ona jaja iz kojih će krenuti generacija muva 2010, čeka da mi se smuči i da konačno krenem muhotepalicom na nju. Znate kako je, ili muva nije u sobi ili je muhotepalica u kuhinji. Gledam je i mislim kako je trebalo da je ulovim uzvodno, kao lososa. Sad je kasno i likujući ostavljam da crkne od muke.

Pišeš ko da ti je Koni Vilis mama, a ne tri godine mlađa koleginica...
Mica

scallop

Tehnolog, a? Jel' mi onda Brus tata? Ja sam vrlo mlad pisac, možda mi je uzor. Da se ne zezamo, da li je to nešto dobro ili loše po mene?
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

scallop

Dosađujem se jutros. Gledam vesti, a tamo nešto cvrče po Monsantu. Pade mi napamet da sam negde, jednom, prerano kukurikao o genetskim modifikacijama, o Monsantu i tako to. Uvek ja prerano, pa moram da podsećam Mehu ili se jedim kad mi zakovrnu da je to Kepler pre mene napisao ili Čerčil rekao. Potražim po starim postovima, kao što neki drugi ovde, zalidni, rade i nađem ovaj topik, prerano nastao i prerano crkao. Pročitam sve i još jednom zaključim: "Bože kako sam ja pametan!" Šta ćete, ogledalce je đavolska tvorevina, što napisao Borhes.


Dakle, mogli bi pametni da budu još malo pametni, ja bih mogao da malo protresem svoje rečenice i uzbunim istanjenu elokvenciju, a neki, kao Lilit, da prodrmaju ganglije, a ne da se troše na površnost.


Takođe, kako stoji evolucija čoveka u poređenju sa našim leming sindromom i hoćemo li crći pre nego što nas evolucija izbriše. xrotaeye



Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

Meho Krljic

Al evo sad šta je dalje bilo:
180,000-Year-Old Mutation Allowed Humans to Become Vegetarians and Move Out of  Africa


Quote

Early humans were able to move from Africa after a single genetic mutation  allowed them to become vegetarians, scientists claim.
The switch, which allowed humans to process vegetables, meant that humans  were able to move away from water sources and spread across the continent.
A team of geneticists compared DNA sequences from a variety of people around  the world to see how different populations relate to one another and when they  have gone their separate ways. The scientists found that a key genetic variant  gave humans the ability to convert fats from plants into essential nutrients for  the brain.
The study, published in the journal Public Library of  Science (PLOS), suggests that the gene mutation would have  allowed Homo sapiens to leave the bodies of water in central Africa where they  ate fish.
A team of scientists from the Wake Forest Baptist Medical Centre in North  Carolina, the Johns Hopkins University School of Medicine in Baltimore and the  University of Washington School of Medicine, Seattle analyzed the genes of 1,092  individuals representing 15 different human populations that were sequenced as  part of the 1000 Genome Project and 1,043 individuals from 52 populations from  the Human Genome Diversity Panel database.
Homo sapiens first appeared 180,000 years ago but stayed around bodies of  water in central Africa for almost 100,000 years. Researchers explained that the  location was critical because it had a ready supply of fish and shellfish that  provided the necessary fatty acid Docosahexaenoic acid (DHA) necessary for brain  development.
"This may have kept early humans tethered to the water in central Africa  where there was a constant food source of DHA," study author Doctor Floyd  Chilton, professor of physiology and pharmacology and director of the Centre for  Botanical Lipids and Inflammatory Disease Prevention at Wake Forest Baptist,  said in a statement.
"There has been considerable debate on how early humans were able to obtain  sufficient DHA necessary to maintain brain size and complexity. It's amazing to  think we may have uncovered the region of genetic variation that arose about the  time that early humans moved out of this central region in what has been called  the 'great expansion,'" he added.
The change meant that humans no longer had to rely on just one food source,  fish, for brain growth and development.
Lead researcher Joshua Akey of the University of Washington said that the  conversion was particularly important because the genetic variation happened  before there was organized hunting and fishing, which could have provided more  reliable sources of necessary fats. "The power of genetics continually  impresses me, and I find it remarkable that we can make inferences about things  that happened tens of thousands of years ago by studying patterns of genetic  variation that exist in contemporary populations," he added.
In 2011, researchers found that people of African descent have a  significantly higher frequency of the gene that converts plant-based fatty acids  to polyunsaturated fat. This gene causes inflammation, which may be why African  Americans have higher rates of hypertension, type 2 diabetes, stroke, coronary  heart disease and certain types of cancer.
"The current observation provides another important clue as to why diverse  racial and ethnic populations likely respond differently to the modern western  diet," Chilton said.


scallop

To je još jedan dokaz kako se diriguje istraživanjima u SAD. Davalac grantova i nosioci projekta mora da su zadrti vegetarijanci. Ovo istraživanje znači da su ljudi pre 180.000 godina bili vegetarijanci i glupi, a onda su uz vodene površine (kao da drugi uslov za opstanak nije blizina vode) počeli da jedu ribu i školjke (to ide u prilog Bobanovim teorijama) i postali toliko pametni da su opet mogli da postanu vegetarijanci. xrotaeye  Zapravo, da su orangutani počeli da jedu meso i oni bi postali čovek. Čini mi se da je evolutivni tok bio više posledica evolucije naših ljubljenih bakterija (to sad ide u Kuferov kufer), koje su izvele sopstvenu promenu da bi proširile svoj jelovnik. :-|


Međutim, mene je više zanimalo događanje oko Monsanta. Treba se zabrinuti, jer mi pre mesec dana rekoše u Makedoniji da se odnosi sa EU komplikuju. Više nisu obavezni samo da kupuju seme za povrtarstvo u Holandiji, nego im sada šalju i bolji (i lepšiji) paradajz na prepakivanje i distribuciju po svetu. Eh, gde su vremena kad su slali samo vino iz Tikveša na prepakivanje i afirmaciju slovenačkih robnih marki, a EU slala meso na prepakivanje u Bujanovac! Brine me što smo i mi već potpisali sranja koja će nas dovesti u sličnu situaciju, kao Bolonjska deklaracija. Dok mi saznamo Džek više neće smeti da peče svoju jabukovaču, da ne govorim o hiljadama pecara po Srbiji, a ješćemo povrće čiji genetski potencijal može sutra da crkne. To što će to prvi osetiti vegetarianci me ne teši, neće bolje proći ni proizvođači čvaraka i kavurmi. Kupovaćemo ih od Meksikanaca. :-|
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

lilit

liliti su ganglije poslednjih dana na 3%, srećom je tu meho da izvadi stvar!

(jbt, kako sam nekad zvučala pametno! da ne veruješ! xrofl)
That's how it is with people. Nobody cares how it works as long as it works.

scallop

Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

lilit

That's how it is with people. Nobody cares how it works as long as it works.

scallop

Moram da ti rastresem te gangllije. Od cinca-marinca sa zoskom nema fajde.
Never argue with stupid people, they will drag you down to their level and then beat you with experience. - Mark Twain.

Meho Krljic

Why IQs Rise

Quote
Are We Getting Smarter?: Rising IQ in the Twenty-First Century by James R. Flynn Cambridge University Press, 310 pp., $22
  IN THE MID-'80s, the political philosopher James Flynn noticed a remarkable but puzzling trend: for the past century, average IQ scores in every industrialized nation have been steadily rising. And not just a little: nearly three points every decade. Every several years, IQ tests test have to be "re-normed" so that the average remains 100. This means that a person who scored 100 a century ago would score 70 today; a person who tested as average a century ago would today be declared mentally retarded.
This bizarre finding—christened the "Flynn effect" by Richard Herrnstein and Charles Murray in The Bell Curve—has since snowballed so much supporting evidence that in 2007 Malcolm Gladwell declared in The New Yorker that "the Flynn effect has moved from theory to fact." But researchers still cannot agree on why scores are going up. Are we are simply getting better at taking tests? Are the tests themselves a poor measure of intelligence? Or do rising IQ scores really mean we are getting smarter?
In spite of his new book's title, Flynn does not suggest a simple yes or no to this last question. It turns out that the greatest gains have taken place in subtests that measure abstract reasoning and pattern recognition, while subtests that depend more on previous knowledge show the lowest score increases. This imbalance may not reflect an increase in general intelligence, Flynn argues, but a shift in particular habits of mind. The question is not, why are we getting smarter, but the much less catchy, why are we getting better at abstract reasoning and little else?
Flynn starts from a position that accepts the idea of IQ—a measure that supposedly reflects an underlying "general" intelligence. Some researchers have objected to this concept in part because of its circular definition: psychologists measure general intelligence by analyzing correlation patterns among multiple intelligence tests; someone with greater general intelligence will perform better on all these subtests. But although he does not quibble with the premise, Flynn argues that an increase in general intelligence is not the full story when it comes to the past century's massive score gains.
If we were really getting smarter overall, scores should be going up across all the subtests, but that is not the case. To understand the score gains, then, we need to set aside issues of general intelligence and instead analyze patterns on the IQ subtests. Doing so opens a window into cognitive trends over time and reveals a far more interesting picture of what may be happening to our minds. This inquiry is at the heart of Flynn's thirty-year career, and it drives his thoughtful (though occasionally tedious) book.
As Flynn demonstrates, a typical IQ test question on the abstract reasoning "Similarities" subtest might ask "How are dogs and rabbits alike?" While our grandparents were more likely to say something along the lines of "Dogs are used to hunt rabbits," today we are more likely to say the "correct" answer, "Dogs and rabbits are both mammals." Our grandparents were more likely to see the world in concrete, utilitarian terms (dogs hunt rabbits), but today we are more likely to think in abstractions (the category of "mammal"). In contrast, the Arithmetic IQ subtest and the Vocabulary IQ subtest—tests that rely on previous knowledge—show hardly any score increase at all.
Why has this happened? The short answer, according to Flynn, is that a convergence of diverse social factors in post-industrial societies—from the emphasis of scientific reasoning in school to the complexity of modern video games—has increasingly demanded abstract thinking. We have begun to see the world, Flynn says, through "scientific spectacles." To put it even more broadly, the pattern of rising IQ scores does not mean that we are comparing "a worse mind with a better one," but rather that we are comparing minds that "were adapted to one cognitive environment with those whose minds are adapted to another cognitive environment." Seen in this light, the Flynn effect does not reflect gains in general intelligence, it reflects a shift to more abstract thinking brought about by a changing social environment. We aren't getting smarter; we are getting more modern.
This interpretation of rising IQ scores was detailed in 2007 in Flynn's book, What Is Intelligence? In Are We Getting Smarter? he both summarizes the previous book and explores a wide new range of possible implications. The chapters are organized into broad categories—"Developing nations," "Youth and age," "Race and gender"—into which he dumps a whole host of observations and speculations. "Death, memory, and politics," makes a passionate plea to consider the Flynn effect when considering IQ scores of inmates on death row. No one who scores at or below 70 (the cutoff for mental retardation) can now legally be executed in the United States, but because inmates are often given old or improperly calibrated tests, their scores may not reflect an accurate measure of their IQ, and a few miscalculated points can mean the difference between life and death. And the problem of miscalibrated scores may extend far beyond the justice system: "we are now aware that a whole range of clinical measuring instruments ... are also suspect because of obsolete norms." The growing number of elderly people diagnosed with memory disorders, for example, may be inflated because tests are administered without taking the Flynn effect into account. Flynn's writing can be a bit rambling and pedantic, and the book feels like more of a sequel than a cohesive new contribution, but woven into the excessive tables of statistics and clunky academic prose are such moments of genuine insight.
Implicit in Flynn's argument that we are becoming "more modern" is that IQ gains are due to environmental factors, not genetic ones. Some of the most successful moments in this book come when Flynn considers IQ data in combination with sociological facts in order to do away with absolutist notions of intelligence. Given the long and troubled history of intelligence science—e.g., eugenics—this stance is significant. He invokes environmental factors, for example, to explain the shrinking male/female IQ gap and debunk notions of innate differences in intelligence between men and women. (If you do not lump current generations of women with past generations and if you separate university from non-university populations, the enormous male advantage disappears.) He uses similar reasoning to explain IQ differences between developed and developing countries. Many developing countries have seen massive IQ gains in recent years and seem to be closing the IQ gap with more developed countries; those that are aren't closing the gap, such as Sudan, are lagging behind because of extenuating environmental circumstances that would stifle any group's IQ scores: natural disasters, disease, hunger. It is also hard for a developing nation to raise overall scores when women do not have access to education. If half your population is uneducated, your country's IQ scores are going to drag.
The focus on environmental factors is where Flynn's book gets interesting: in making the case that the Flynn effect is connected to modernity, the book offers a broader indictment of intelligence research and the field of psychology as a whole. Flynn laments the "failure of the sociological imagination"—the tendency in psychology to overlook environmental factors. "Somehow, psychologists have developed the habit of ignoring social scenarios that explain their results," Flynn writes. "In so far as they attempt to integrate the psychology of human intelligence with another layer of analysis, they choose brain physiology." By focusing in on the brain, Flynn argues, we risk missing the forces that shape it. This is not just another nature/nurture argument; it is a call for a complex, interdisciplinary science of the human mind that sees the individual as an open system constantly reacting to and acting upon her environment. It is also a rejection of the bigotry and the elitism implicit in research that claims to locate innate differences between groups and an appeal for the inclusion of another dimension—time—into the calculus of intelligence research. Neither human intelligence nor culture is static. They change over time, and those changes can offer profound insight into how our minds work, and why.
Flynn's argument that IQ gains open a window into what he has called "the cognitive history of the twentieth century" is persuasive, and his shift away from the "innate" elements of intelligence is welcome. But there is still a value system at work here. He suggests a hierarchy of more-to-less-modern nations: those engaged in tasks of greater "cognitive complexity" are at the fore, and the others are straggling behind. He flatly states that he is "no cultural relativist," and implies that the developed world "represents a higher stage of civilization," a world to which "almost all of the nations on this earth aspire." This is the great paradox of the book: in disassembling one hierarchy, it assembles another.
Despite its flaws, there is a deeper, almost humanitarian, purpose driving Are We Getting Smarter? It urges us—researcher and layperson alike—to take the veiled bigotry of absolute genetic differences among races, genders, and nations off the table. If we can figure out why intelligence measures are different among groups, if we can understand the complex interplay of environmental pressures that affect those measures, then we will be closer to a more nuanced understanding of who we are, where we have been, and where we are going.
Meehan Crist is Resident Writer in Biological Sciences at Columbia University. She is working on a nonfiction book about traumatic brain injury. Tim Requarth is an NIH National Research Service Award Fellow and doctoral candidate in neuroscience at Columbia University. Requarth co-directs and Crist is a founding member of NeuWrite (www.neuwrite.org), a New York-based collaborative writing group of scientists and writers. 

Meho Krljic

Profesor Gerald Crabtree sa Stanford univerziteta je objavio rad u kome dokazuje da je ljudska inteligencija dostigla vrhunac pre nekoliko milenijuma i da od tada opada!!!


  Our Fragile Intellect

Ne kačim tekst sam jer je u PDFu i loše se prelomi.

Meho Krljic

Mystery Molelike Mammal Survived Dino Extinction 
Quote
A molelike mammal nicknamed the "grave robber" survived the event that killed the dinosaurs, new research finds.
Necrolestes patagonensis, whose name translates in part to "grave robber," was among the mammals that lived through the dinosaur mass extinction. The new study finds that the creature lived 45 million years longer than paleontologists realized.
Necrolestes was first discovered in fossil form in the Patagonia region of South America in 1891, but little was known about the animal, study researcher John Wible, a mammalogist at the Carnegie Museum of Natural History, said in a statement.
"Necrolestes is one of those animals in the textbooks that would appear with a picture and a footnote, and the footnote would say 'we don't know what it is,'" Wible said.
For a century, researchers at different institutions gave Necrolestes their best shot, trying to place it accurately onto the mammal family tree. No one could agree. In stepped Wible and his team, including the University of Louisville's Guillermo Rougier.
"This project was a little daunting, because we had to contradict 100 years of interpretation," Rougier said in a statement.
Part of the confusion involved the animal's mismatched features, which included an upturned snout, compact body, and short, wide legs. All researchers could tell was that its body would have been perfect for digging. Triangular teeth suggested a diet of worms and other squirmy underground creepy-crawlies. [25 Amazing Ancient Beasts]
In 2011, however, Rougier and his colleagues discovered a new South American extinct mammal, part of a now-extinct group that lived in the Late Cretaceous and early Paleocene, about 100 million years ago. The new fossil bore many similarities to the mysterious Necrolestes, including molars with just one root anchoring them to the jaw.
The find cements that both the new and old fossils are Necrolestes and proves that this group did not go extinct as early as believed. Paleontologists call discoveries like this "the Lazarus effect," after the Biblical character who came back from the dead. Once thought to have died with the dinosaurs, Necrolestes is now known to have survived 45 million years longer than its relatives, which mostly perished when the dinosaurs died.
Necrolestes' subterranean lifestyle may explain its lucky fate, the researchers reported Monday (Nov. 19) in the journal Proceedings of the National Academy of Sciences.
"There's no other mammal in the Tertiary of South America that even approaches its ability to dig, tunnel, and live in the ground," Wible said. "It must have been on the edges, in an ecological niche that allowed it to survive."


Albedo 0

Quote from: Meho Krljic on 15-11-2012, 12:49:10
Profesor Gerald Crabtree sa Stanford univerziteta je objavio rad u kome dokazuje da je ljudska inteligencija dostigla vrhunac pre nekoliko milenijuma i da od tada opada!!!


  Our Fragile Intellect

Ne kačim tekst sam jer je u PDFu i loše se prelomi.

pa to je otprilike rekao Tesla prije sto godina, samo što ljudi i dalje ne vjeruju da drugi zakon termodinamike pobija teoriju evolucije.

mac

Aman čoveče, zakon se odnosi na zatvoren sistem, a Zemlja to nije. Sunce i Zemlja zajedno su već druga priča. Već sam te ispravljao u vezi s ovim. Pitaj šta nije jasno, i nauči.