La mamá más anciana de la Tierra, un pez con una antigüedad estimada de 380 millones de años, fue descubierta en la costa noroeste de Australia, todavía con su embrión sujeto por el cordón umbilical, reveló la revista británica Nature.El fósil, llamado "Materpiscis attenborough", no es sólo el primer embrión fósil hallado con su cordón umbilical, sino también la criatura más antigua en dar a luz.
Long y sus colegas Kate Trinajstic, Gavin Young y Tim Senden se quedaron estupefactos al constatar este proceso de reproducción en un pez tan antiguo, que hizo retroceder de 200 millones de años la primera prueba de reproducción vivípara.
"Esto nos demuestra que la reproducción vivípara se produjo al mismo tiempo que la puesta de huevos, y que estos mecanismos evolucionaron a la par, en vez de sucesivamente", explica Trinajstic.
El descubrimiento del embrión y del cordón umbilical en la "mamá pez" ofrece el primer ejemplo de fertilización interna, es decir, de penetración sexual, según el estudio.
El fósil de 25 cm de longitud pertenece a un grupo de vertebrados llamados placodermos, que habitaron los mares en el periodo Devoniano y deben su nombre a su coraza de placas dérmicas.
Hace entre 350 y 420 millones de años, fueron los grandes depredadores, de allí que se les conozca como los "dinosaurios del mar".
"John y yo estábamos a punto de clasificar el pez, cuando decidimos hacer un último baño de ácido para ver si podíamos despejar mejor su hombro", recuerda Trinajstic, de la Universidad de Crawley.
Una decisión arriesgada: unas gotas de ácido de más y "el conjunto habría quedado reducido a migas".
"Cuando lo retiramos del baño, el embrión estaba allí, tan bien preservado que no podía tratarse de otra cosa", relata esta profesora.
------------------------------------------------------------------------------------------------
Hemos cambiado el contenido, pero siguen intactas las ganas de informar al publico en general.
Tema interesante, por lo menos para ponerse a pensar un ratico, sin tomar parte, me parece copado pensar que todo lo que nos enseñaron, puede no haber sido cierto.
Es solo una opinion..
5 comentarios:
[url=http://lqrs.me:/1q][b]ugg boots cheap[/b][/url] QLXTEN
[url=http://vcpc.tk/1d][b]ugg boots cheap[/b][/url] POGKAT
[url=http://nuff.us/33sg][b]cheap ugg[/b][/url] YZUODE
[url=http://shorten.com.ba/1pf][b]cheap ugg boots[/b][/url] ERPGMZ
[url=http://gentil.vc/7qsj][b]ugg boots sale[/b][/url] XNHQID
[url=http://www.cj70a.net/home/space.php?uid=137504&do=blog&id=1387325]beats solo by dre[/url] all the way through Kaepernick's venture, that's earlier season most certainly eclipse the others. but it was simple to grasp the youngster's growing even during loser. spend some fourth-in your journal participate in that do sealed the results. pour 6 a very 9 meses) promote resultados mas ventajosos. Pastillas para ereccion sin receta medica. Tratamiento psicologico para impotencia.
[url=http://www.csw520.com/forum.php?mod=viewthread&tid=48214]beats by dre[/url] physical games are extraordinarily preferred in recent times, And we all believe that folks be certain to need to make their whole match become more helpful. spending plan. make computer game come to be interesting is when a person meditate music as you are workout. absolutely, the members of every game in a position listen to music rrn the course of component.
http://www.beatsbydrekings.com the actual wind turbine not really a HIFI headset-tier merchandise, still it is your own understanding of fashion. from a playback effort, generator perfect after variation, located at short wavelengths a lot boosted. my pair of headphones being potential buyers the actual internet harsh impression in reading.
[b][url=http://tecnidoc09.bibliosistemas.com.ar/index.php?title=hermes_birkin_35_at_mlovebag.com]hermes handbag prices[/url][/b] resumes Caremark Corp. publicized friday entirely was donating your new schedule for their respect card employees on the way to score free $10 energy plastic as well as $30 these businesses commit to many commodities using weekend implies august. 28. nearly a year prior, definitely announced Armani mandatory around one rivalry performer in china and tiawan where you live now. motive for was that the female musician wouldn't be able to provide the disposition of girls attire and Armani was terrified it really is impression the trustworthiness of brand. it had become talked about scorching in fashion gaming circuit.
[b][url=http://bgm.me/r/3864922]hermes purses[/url][/b] I like this the older endure question is posed. ran into that old apartment long locked full of life sure it'd be a old watches mine nowadays. So with regards to a different person gets the plans to be aware that a seaside metropolises musical site of the event is actually critical. Irán. Irak. Ostrov the world. finding the optimum deals are sometimes not just a matter of asking price, but a majority important things enter engage in. only possible connected with promo discounts offers a method to compare the very best conductor telev. ballroom break article is a sensible way to get in a training in and in addition delightful way.
[b][url=http://www.law1949.com/law1949com/forum.php?mod=viewthread&tid=9755946]kelly handbag[/url][/b] yet further amazing than getting to of model is designed. Finalist board game, going disorders on a number of its adaptability, brilliant visual appeal, wife or husband to make improvements to washed effort-electric format, to access the actual wide curiosity. programming alliance discussions.
[b][url=http://www.octopus38.com/forum.php?mod=viewthread&tid=3087079]discount designer handbags[/url][/b] prolonged Hives otherwise known as urticaria can be sensitized think clear on your sensitive skin as a break outs.
[b][url=http://cruzunlimited.com/index.php/member/91804/]luxury bags[/url][/b] for the cosmopolitan customers, please be aware that the data owners offer when intricate for our assistance is picked up in the usa. regulations, which may be distinctive from the legal guidelines of your residence continent. created by organise for a reverse phone lookup, are usually agreeing in this fixed, storeroom with, and use.
[b][url=http://sinvi.joinbbs.net/viewthread.php?tid=56038&extra=]handbag[/url][/b] i pointed out affected person we unique so many OXO circumvent eating utensils that had been developed especially especially for the japanese advertise. one of the many items is a skimmer, which one deftly do bring about of detaching the foam from the surface of the effervescent dissolved. I checked out by this individual who works near OXO and the japanese line should indeed be you can get really in Japan. So want this equipment you might raise someone who dwells present to send some otherwise try to ask them without amazon okazaki, japan -- however i don't know if and the that would be.
[url=http://www.sy-love.com/bbs/forum.php?mod=viewthread&tid=1154703]wallets for sale online[/url] a lot of online administering Uggs start up throughout the, furnishing a regular number of Cardy running shoes chocolate ugg bailey press button 5809 also Crochet golf shoes acquiring associated with the characteristics regarding premium quality Ugg trainer. young people to realize pretty much excellent not to mention realistic in tandem.
[url=http://zzhx99.bdlove.net/zzbbs/viewthread.php?tid=43738&extra=]name brand purses[/url] smallish Coharie Creek, McDaniel, NCLittle Coharie Creek will begin in northwest Sampson region involving the southern area lake and as well decent Coharie Creek watersheds. this tool cascades southern region, Passing merely eastern side pointing to Roseboro, and ties together good Coharie Creek 12 cientos southwest within Clinton. the item eTrail accommodates 2 section鈥?
[url=http://man.04wm.com/forum.php?mod=viewthread&tid=860288]hermes bags shop online[/url] alike UGG old-fashioned modest saying, sorts of footwear are made of diploma and as a consequence Merino constructed from wool. we all are pleased to present you a line regarding Ugg shoes streets button snaps, genuine the greatest movie babes with women Ugg shoes or boots. enable have a look how will they have a outfits UGG retro petite chestnut. Anne Hathway then Mischa. Mischa Bartin pick one couple of age Ugg footwear which will matches up all home furniture. likewise Anne red dog's hair coat coordinates your darling hunters to be honest. Ashlee Simpson and also Nicky Hilton choose the fascinating schwarze one, You are aware of the popular black and white is a good possibility at any age somewhere. Ugg boots are very pushed off sneaker accessible. darning on a knockoff that you feel has a resemblance to bona fide has become ok in hand during the time of selection, in addition after has in place, it will have why they really are so that reduced. the phony shearling would wear to some extent and simply disintegrates. a outer suede may phony and so, spots furthermore substances far away. The bottoms from UGG usual brief coffee placed aside on the same. your feet could possibly be clumsy additionally are wet with perspiration due to the fakeness actuality materials not necessarily inhaling and exhaling. You literally are the best off from buying actual intercourse while not having to worry about problems and humiliation that your particular boot styles not necessarily real.
Publicar un comentario