• Evolution in Action: Lizard Moving From Eggs to Live Birth
    121 replies, posted
[b]Evolution in Action: Lizard Moving From Eggs to Live Birth[/b] [url]http://news.nationalgeographic.com/news/2010/09/100901-science-animals-evolution-australia-lizard-skink-live-birth-eggs/[/url] [quote][img]http://images.nationalgeographic.com/wpf/media-live/photos/000/254/cache/skink-evolves-live-birth-eggs_25436_600x450.jpg[/img] [b]A yellow-bellied three-toed skink carrying embryos, visible as light orbs inside its body.[/b] Evolution has been caught in the act, according to scientists who are decoding how a species of Australian lizard is abandoning egg-laying in favor of live birth. Along the warm coastal lowlands of New South Wales (map), the yellow-bellied three-toed skink lays eggs to reproduce. But individuals of the same species living in the state's higher, colder mountains are almost all giving birth to live young. Only two other modern reptiles—another skink species and a European lizard—use both types of reproduction. Evolutionary records shows that nearly a hundred reptile lineages have independently made the transition from egg-laying to live birth in the past, and today about 20 percent of all living snakes and lizards give birth to live young only. But modern reptiles that have live young provide only a single snapshot on a long evolutionary time line, said study co-author James Stewart, a biologist at East Tennessee State University. The dual behavior of the yellow-bellied three-toed skink therefore offers scientists a rare opportunity. "By studying differences among populations that are in different stages of this process, you can begin to put together what looks like the transition from one [birth style] to the other." [b]Eggs-to-Baby Switch Creates Nutrient Problem[/b] One of the mysteries of how reptiles switch from eggs to live babies is how the young get their nourishment before birth. In mammals a highly specialized placenta connects the fetus to the uterus wall, allowing the baby to take up oxygen and nutrients from the mother's blood and pass back waste. In egg-laying species, the embryo gets nourishment from the yolk, but calcium absorbed from the porous shell is also an important nutrient source. Some fish and reptiles, meanwhile, use a mix of both birthing styles. The mother forms eggs, but then retains them inside her body until the very last stages of embryonic development. The shells of these eggs thin dramatically so that the embryos can breathe, until live babies are born covered with only thin membranes—all that remains of the shells. This adaptation presents a potential nourishment problem: A thinner shell has less calcium, which could cause deficiencies for the young reptiles. Stewart and colleagues, who have studied skinks for years, decided to look for clues to the nutrient problem in the structure and chemistry of the yellow-bellied three-toed skink's uterus. "Now we can see that the uterus secretes calcium that becomes incorporated into the embryo—it's basically the early stages of the evolution of a placenta in reptiles," Stewart explained. [b]Evolutionary Transition Surprisingly Simple[/b] Both birthing styles come with evolutionary tradeoffs: Eggs are more vulnerable to external threats, such as extreme weather and predators, but internal fetuses can be more taxing for the mother. For the skinks, moms in balmier climates may opt to conserve their own bodies' resources by depositing eggs on the ground for the final week or so of development. Moms in harsh mountain climates, by contrast, might find that it's more efficient to protect their young by keeping them longer inside their bodies. In general, the results suggest the move from egg-laying to live birth in reptiles is fairly common—at least in historic terms—because it's relatively easy to make the switch, Stewart said. "We tend to think of this as a very complex transition," he said, "but it's looking like it might be much simpler in some cases than we thought."[/quote] How do people still deny evolution?
Ignorance isn't an excuse, but they sure love using it.
take that, creationists.
[QUOTE=Biotoxsin;26324838]Ignorance isn't an excuse, but they sure love using it.[/QUOTE] They will just say God wanted it and the cycle will repeat.
:science:
Not evolution... God clearly created this snake and made it have live births...
Live birth? We're one step closer to Argonians walking the earth.
Its little wiggly arms are both gross and cute. Evolution is aesthetically confusing.
it's not evolution because the skinks created the bananas that we all know and love [img]http://2.bp.blogspot.com/_7Se7iswAanA/S7yZLR8WweI/AAAAAAAALIY/-MuQnUDpUEA/s1600/banana.JPG[/img] how can you atheists be so goddamn stupid
[QUOTE=Kalibos;26324902]it's not evolution because the skinks created the bananas that we all know and love [img_thumb]http://2.bp.blogspot.com/_7Se7iswAanA/S7yZLR8WweI/AAAAAAAALIY/-MuQnUDpUEA/s1600/banana.JPG[/img_thumb] how can you atheists be so goddamn stupid[/QUOTE] but pineapples are sharp why would god create things that hurt us [img]http://static.howstuffworks.com/gif/what-makes-a-good-pineapple-1.jpg[/img]
I said the SKINKS created the bananas not GOD for fuck's sake [editline]26th November 2010[/editline] although god created the skinks so I guess he created the bananas too [editline]26th November 2010[/editline] you know what ham shut up you heathen atheist nonbeliever goddamn scum you're going to burn in hell goddamn evolutionist piece of shit
God-fucking-damn. That thing is cute.
[QUOTE=ham!;26324920]but pineapples are sharp why would god create things that hurt us [img_thumb]http://static.howstuffworks.com/gif/what-makes-a-good-pineapple-1.jpg[/img_thumb][/QUOTE] God created knives
The only logical conclusion here is surely that skinks are, in fact, God. Duh.
[QUOTE=GunFox;26325150]The only logical conclusion here is surely that skinks are, in fact, God. Duh.[/QUOTE] Jesus was an Illuminati lizard man like George Bush and the Queen? It all makes sense now.
I want one of these skinks, they are pretty awesome looking. maybe if I expose them to radiation they will evolve into robot dinosaurs
[QUOTE=Penguiin;26325307]I want one of these skinks, they are pretty awesome looking. maybe if I expose them to radiation they will evolve into robot dinosaurs[/QUOTE] I doubt they'd make good pets.
[QUOTE=Penguiin;26325307]I want one of these skinks, they are pretty awesome looking. maybe if I expose them to radiation they will evolve into robot dinosaurs[/QUOTE] No, they'd just turn into a massive blob of cancer and die.
I wonder if that guys who owns Conservapedia will get into a fight with these guys like he did with Professor Lenski and his bacteria that evolved.
[img_thumb]http://images1.memegenerator.net/ImageMacro/3888806/ARGUE-ABOUT-EVOLUTION-I-AM-A-SCIENTIST.jpg?imageSize=Large&generatorName=TypicalFacepunchUser[/img_thumb] Everyone that has posted or will post in this thread. [highlight](User was banned for this post ("trolling" - Lithifold))[/highlight]
[QUOTE=Ashten;26325681][img_thumb]http://images1.memegenerator.net/ImageMacro/3888806/ARGUE-ABOUT-EVOLUTION-I-AM-A-SCIENTIST.jpg?imageSize=Large&generatorName=TypicalFacepunchUser[/img_thumb] Everyone that has posted or will post in this thread.[/QUOTE] Is that a picture of yourself?
What rubbish, everyone knows God created Man in his image and animals as they were, none of this evolution nonsense.
[QUOTE=Ashten;26325681][img_thumb]http://images1.memegenerator.net/ImageMacro/3888806/ARGUE-ABOUT-EVOLUTION-I-AM-A-SCIENTIST.jpg?imageSize=Large&generatorName=TypicalFacepunchUser[/img_thumb] Everyone that has posted or will post in this thread.[/QUOTE] Wow you're a douchebag
Is that a snake with arms?
[QUOTE=Ashten;26325681][img_thumb]http://images1.memegenerator.net/ImageMacro/3888806/ARGUE-ABOUT-EVOLUTION-I-AM-A-SCIENTIST.jpg?imageSize=Large&generatorName=TypicalFacepunchUser[/img_thumb] Everyone that has posted or will post in this thread.[/QUOTE] You look better than usual in that photo. :raise:
[QUOTE=Psychokitten;26325770]You look better than usual in that photo. :raise:[/QUOTE] thx i been workin out yaknow
[img]http://images.nationalgeographic.com/wpf/media-live/photos/000/254/cache/skink-evolves-live-birth-eggs_25436_600x450.jpg[/img] [b]"Wanna scrap, bitch?'[/b]
inb4 the church responses with: "GOD WILLS IT!!!"
[QUOTE=Miskatonic;26324878]Live birth? We're one step closer to Argonians walking the earth.[/QUOTE] Argonians lay eggs.
D'aaw. This is awesome!
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