dendroica

ecowatchorg:

Evidence Finds BP Gulf Oil Disaster Causing Widespread Deformities in Fish

Crude oil from the 2010 Deepwater Horizon disaster causes severe defects in the developing hearts of bluefin and yellowfin tunas, according to a new study by a team of National Oceanic and Atmospheric Administration (NOAA) and academic scientists.

The findings, published in the Proceedings of the National Academy of Sciences on the 25th anniversary of the Exxon Valdez oil spill, show how the largest marine oil spill in U.S. history may have affected tunas and other species that spawned in oiled offshore habitats in the northern Gulf of Mexico…

Read more: Ecowatch

liquidnitrogenteethplay
A three-day-old human embryo is a collection of 150 cells called a blastocyst. There are, for the sake of comparison, more than 100,000 cells in the brain of a fly. If our concern is about suffering in this universe, it is rather obvious that we should be more concerned about killing flies than about killing three-day-old human embryos… Many people will argue that the difference between a fly and a three-day-old human embryo is that a three-day-old human embryo is a potential human being. Every cell in your body, given the right manipulations, every cell with a nucleus is now a potential human being. Every time you scratch your nose, you’ve committed a holocaust of potential human beings… Let’s say we grant it that every three-day-old human embryo has a soul worthy of our moral concern. First of all, embryos at this stage can split into identical twins. Is this a case of one soul splitting into two souls? Embryos at this stage can fuse into a chimera. What has happened to the extra human soul in such a case? This is intellectually indefensible, but it’s morally indefensible given that these notions really are prolonging scarcely endurable misery of tens of millions of human beings, and because of the respect we accord religious faith, we can’t have this dialogue in the way that we should. I submit to you that if you think the interests of a three-day-old blastocyst trump the interests of a little girl with spinal cord injuries or a person with full-body burns, your moral intuitions have been obscured by religious metaphysics.

Sam Harris, on stem cell research.

(via we-are-star-stuff)

Why Shark embryos Gobble Each Other Up In Utero
by Tia Ghose
Shark embryos cannibalize their littermates in the womb, with the largest embryo eating all but one of its siblings.

Now, researchers know why: It’s part of a struggle for paternity in utero, where babies of different fathers compete to be born.
The researchers, who detailed their findings today (April 30) in the journal Biology Letters, analyzed shark embryos found in sand tiger sharks (Carcharias taurus) at various stages of gestation and found that the later in pregnancy, the more likely the remaining shark embryos had just one father…
(read more: Live Science)            (photo: mp CZ - Shutterstock)

Why Shark embryos Gobble Each Other Up In Utero

by Tia Ghose

Shark embryos cannibalize their littermates in the womb, with the largest embryo eating all but one of its siblings.

Now, researchers know why: It’s part of a struggle for paternity in utero, where babies of different fathers compete to be born.

The researchers, who detailed their findings today (April 30) in the journal Biology Letters, analyzed shark embryos found in sand tiger sharks (Carcharias taurus) at various stages of gestation and found that the later in pregnancy, the more likely the remaining shark embryos had just one father…

(read more: Live Science)            (photo: mp CZ - Shutterstock)

Turtle Genome Analysis Sheds Light On Turtle Ancestry and Shell Evolution
by Science Daily staff
Apr. 28, 2013 — From which ancestors have turtles evolved? How did they get their shell? New data provided by the Joint International Turtle Genome Consortium, led by researchers from RIKEN in Japan, BGI in China, and the Wellcome Trust Sanger Institute in the UK provides evidence that turtles are not primitive reptiles but belong to a sister group of birds and crocodiles. The work also sheds light on the evolution of the turtle’s intriguing morphology and reveals that the turtle’s shell evolved by recruiting genetic information encoding for the limbs…
(read more: http://www.sciencedaily.com/releases/2013/04/130428144848.htm)
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reference:
Zhuo Wang, Juan Pascual-Anaya, Amonida Zadissa, et al. The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan. Nature Genetics, 2013; DOI: 10.1038/ng.2615

Turtle Genome Analysis Sheds Light On Turtle Ancestry and Shell Evolution

by Science Daily staff

Apr. 28, 2013 — From which ancestors have turtles evolved? How did they get their shell? New data provided by the Joint International Turtle Genome Consortium, led by researchers from RIKEN in Japan, BGI in China, and the Wellcome Trust Sanger Institute in the UK provides evidence that turtles are not primitive reptiles but belong to a sister group of birds and crocodiles. The work also sheds light on the evolution of the turtle’s intriguing morphology and reveals that the turtle’s shell evolved by recruiting genetic information encoding for the limbs…

(read more: http://www.sciencedaily.com/releases/2013/04/130428144848.htm)

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reference:

Zhuo Wang, Juan Pascual-Anaya, Amonida Zadissa, et al. The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan. Nature Genetics, 2013; DOI: 10.1038/ng.2615

Dinosaur Growth Spurt.
By studying fossilized embryonic femur bones at different stages of development, scientists can learn how Lufengosaurus grew up to be a giant.
Nearly 200 million years ago, some of the earliest dinosaurs on Earth laid their eggs in modern Yunnan Province in southern China, only to have one nest after another destroyed by floods. Today, the remains of those lost eggs—and the embryonic dinosaurs that they contained—are helping scientists understand how their relatives grew up to be giants…
(read more: Science NOW)
(Credit: D. Mazierski; Debivort; D. Mazierski and D. Scott From Photos by A. Le Blanc)

Dinosaur Growth Spurt.

By studying fossilized embryonic femur bones at different stages of development, scientists can learn how Lufengosaurus grew up to be a giant.

Nearly 200 million years ago, some of the earliest dinosaurs on Earth laid their eggs in modern Yunnan Province in southern China, only to have one nest after another destroyed by floods. Today, the remains of those lost eggs—and the embryonic dinosaurs that they contained—are helping scientists understand how their relatives grew up to be giants…

(read more: Science NOW)

(Credit: D. Mazierski; Debivort; D. Mazierski and D. Scott From Photos by A. Le Blanc)

World’s Oldest Dinosaur Embryo Bonebed Yields Organic Remains

Apr. 10, 2013 — The great age of the embryos is unusual because almost all known dinosaur embryos are from the Cretaceous Period. The Cretaceous ended some 125 million years after the bones at the Lufeng site were buried and fossilized.
Led by University of Toronto Mississauga paleontologist Robert Reisz, an international team of scientists from Canada, Taiwan, the People’s Republic of China, Australia, and Germany excavated and analyzed over 200 bones from individuals at different stages of embryonic development.
"We are opening a new window into the lives of dinosaurs," says Reisz. "This is the first time we’ve been able to track the growth of embryonic dinosaurs as they developed. Our findings will have a major impact on our understanding of the biology of these animals."
The bones represent about 20 embryonic individuals of the long-necked sauropodomorph Lufengosaurus, the most common dinosaur in the region during the Early Jurassic period. An adult Lufengosaurus was approximately eight metres long…
(read more: Science Daily)          (Artwork by D. Mazierski)
Journal Reference:
Robert R. Reisz, Timothy D. Huang, et al.  Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains. Nature, 2013; 496 (7444): 210 DOI: 10.1038/nature11978

World’s Oldest Dinosaur Embryo Bonebed Yields Organic Remains

Apr. 10, 2013 — The great age of the embryos is unusual because almost all known dinosaur embryos are from the Cretaceous Period. The Cretaceous ended some 125 million years after the bones at the Lufeng site were buried and fossilized.

Led by University of Toronto Mississauga paleontologist Robert Reisz, an international team of scientists from Canada, Taiwan, the People’s Republic of China, Australia, and Germany excavated and analyzed over 200 bones from individuals at different stages of embryonic development.

"We are opening a new window into the lives of dinosaurs," says Reisz. "This is the first time we’ve been able to track the growth of embryonic dinosaurs as they developed. Our findings will have a major impact on our understanding of the biology of these animals."

The bones represent about 20 embryonic individuals of the long-necked sauropodomorph Lufengosaurus, the most common dinosaur in the region during the Early Jurassic period. An adult Lufengosaurus was approximately eight metres long…

(read more: Science Daily)          (Artwork by D. Mazierski)

Journal Reference:

Robert R. Reisz, Timothy D. Huang, et al.  Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains. Nature, 2013; 496 (7444): 210 DOI: 10.1038/nature11978

Waves Clone Coral Embryos

by Jennifer Welsh

Ever wanted an identical twin? A clone to do your chores? If you were a coral embryo, you could just break in two and make yourself a body double, new research suggests.

Coral embryos, which are complex marine animals with differentiated cell layers and tissues, are able to reorganize their bodies, even if they’ve broken in half, to form anew. This means that when even a gentle wave comes along and a coral embryo is damaged, it just ends up turning into two smaller, identical twins.

This ability “helps to explain how coral maximize their chances of finding a suitable habitat in which to settle and survive,” study researcher Andrew Heyward, of the Australian Institute of Marine Science, said in a statement. “This is another example of the complexity of these incredible animals and suggests that there may be more to learn about the lives of corals.”…

(read more: Live Science)     (photos: Heyward & Negri, AIMS )

Embryonic Turtles Communicate to Coordinate Hatching
By Olivia Solon, Wired UK
Murray River turtles communicate with their siblings while they are still in their shells, buried under the soil, in order to  coordinate when they hatch.
Achieving this synchronicity isn’t easy. Although the eggs are always  laid at the same time in the same nest, those at the top of the nest  near the sun-drenched soil develop much faster than those buried deeper  in the cooler soil. However, Murray River turtles are able to tell  whether their fellow hatchlings are more or less advanced and adapt  their pace of development accordingly, allowing the slow-coaches to play  catch-up.
Ricky-John Spencer from the University of Western Sydney has been studying the  turtles for years. In 2003 he collected dozens of batches of wild turtle eggs,  split them into two groups and incubated them at either 25C or 30C. He  then reunited the eggs and discovered that they still hatched together.  At this point he wasn’t sure whether the colder batch were hatching  prematurely or speeding up their development…
(read more: Wired Science)
(Image: Judy Cebra-Thomas & Scott Gilbert/Swarthmore College/NSF)
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You can read the study, titled: Embryonic communication in the nest: metabolic responses of reptilian embryos to developmental rates of siblings
(* thanks to http://sonorensis.tumblr.com/ for letting us know about this)

Embryonic Turtles Communicate to Coordinate Hatching

By Olivia Solon, Wired UK

Murray River turtles communicate with their siblings while they are still in their shells, buried under the soil, in order to coordinate when they hatch.

Achieving this synchronicity isn’t easy. Although the eggs are always laid at the same time in the same nest, those at the top of the nest near the sun-drenched soil develop much faster than those buried deeper in the cooler soil. However, Murray River turtles are able to tell whether their fellow hatchlings are more or less advanced and adapt their pace of development accordingly, allowing the slow-coaches to play catch-up.

Ricky-John Spencer from the University of Western Sydney has been studying the turtles for years. In 2003 he collected dozens of batches of wild turtle eggs, split them into two groups and incubated them at either 25C or 30C. He then reunited the eggs and discovered that they still hatched together. At this point he wasn’t sure whether the colder batch were hatching prematurely or speeding up their development…

(read more: Wired Science)

(Image: Judy Cebra-Thomas & Scott Gilbert/Swarthmore College/NSF)

___________________________________

You can read the study, titled: Embryonic communication in the nest: metabolic responses of reptilian embryos to developmental rates of siblings

(* thanks to http://sonorensis.tumblr.com/ for letting us know about this)

apteryxrowi

Why don’t our arms grow from the middle of our bodies? 
The question isn’t as trivial as it appears. Vertebrae, limbs, ribs, tailbone … in only two days, all these elements take their place in the embryo, in the right spot and with the precision of a Swiss watch… During the development of an embryo, everything happens at a specific moment. In about 48 hours, it will grow from the top to the bottom, one slice at a time — scientists call this the embryo’s segmentation. “We’re made up of thirty-odd horizontal slices,” explains Denis Duboule, a professor at EPFL and Unige. “These slices correspond more or less to the number of vertebrae we have.”Every hour and a half, a new segment is built. The genes corresponding to the cervical vertebrae, the thoracic vertebrae, the lumbar vertebrae and the tailbone become activated at exactly the right moment one after another. “If the timing is not followed to the letter, you’ll end up with ribs coming off your lumbar vertebrae,” jokes Duboule. How do the genes know how to launch themselves into action in such a perfectly synchronized manner? “We assumed that the DNA played the role of a kind of clock. But we didn’t understand how.”When DNA acts like a mechanical clockVery specific genes, known as “Hox,” are involved in this process. Responsible for the formation of limbs and the spinal column, they have a remarkable characteristic. “Hox genes are situated one exactly after the other on the DNA strand, in four groups. First the neck, then the thorax, then the lumbar, and so on,” explains Duboule. “This unique arrangement inevitably had to play a role.”…
(read more via Science Daily: From blue whales to earthworms, a common mechanism gives shape to living beings)

Why don’t our arms grow from the middle of our bodies?

The question isn’t as trivial as it appears. Vertebrae, limbs, ribs, tailbone … in only two days, all these elements take their place in the embryo, in the right spot and with the precision of a Swiss watch…

During the development of an embryo, everything happens at a specific moment. In about 48 hours, it will grow from the top to the bottom, one slice at a time — scientists call this the embryo’s segmentation. “We’re made up of thirty-odd horizontal slices,” explains Denis Duboule, a professor at EPFL and Unige. “These slices correspond more or less to the number of vertebrae we have.”

Every hour and a half, a new segment is built. The genes corresponding to the cervical vertebrae, the thoracic vertebrae, the lumbar vertebrae and the tailbone become activated at exactly the right moment one after another. “If the timing is not followed to the letter, you’ll end up with ribs coming off your lumbar vertebrae,” jokes Duboule. How do the genes know how to launch themselves into action in such a perfectly synchronized manner? “We assumed that the DNA played the role of a kind of clock. But we didn’t understand how.”

When DNA acts like a mechanical clock

Very specific genes, known as “Hox,” are involved in this process. Responsible for the formation of limbs and the spinal column, they have a remarkable characteristic. “Hox genes are situated one exactly after the other on the DNA strand, in four groups. First the neck, then the thorax, then the lumbar, and so on,” explains Duboule. “This unique arrangement inevitably had to play a role.”…

(read more via Science Daily: From blue whales to earthworms, a common mechanism gives shape to living beings)

The Evolution of Snake Fangs (2008)
by James Owen
The diverse and deadly array of venomous snakes living today all arose from a single fanged ancestor, a new study suggests.    Vipers, cobras, and other snakes that have fangs at the fronts of their  jaws surprisingly begin life like snakes that have poisonous fangs at  the back of their jaws, said a team led by Freek Vonk of Leiden  University in the Netherlands.
The discovery suggests venomous fangs—the lethal evolutionary invention  that led to snakes becoming so successful—arose only once about 60  million years ago. The origins of venom-injecting snakes have long been the source of  scientific controversy, because the contrasting fang positions of  diverse snake groups pointed to independent evolution.
But a study of the embryos of eight front- and rear-fanged species has  found that fangs always first appear at the back of the upper jaw before  migrating forward in vipers and cobras.   This previously unidentified transformation in the unborn young occurs  due to “rapid growth of some parts of the upper jaw relative to the  others,” Vonk explained…
(read more: National Geo)     (image: Gaboon Viper, by Brian MacKay)

The Evolution of Snake Fangs (2008)

by James Owen

The diverse and deadly array of venomous snakes living today all arose from a single fanged ancestor, a new study suggests. Vipers, cobras, and other snakes that have fangs at the fronts of their jaws surprisingly begin life like snakes that have poisonous fangs at the back of their jaws, said a team led by Freek Vonk of Leiden University in the Netherlands.

The discovery suggests venomous fangs—the lethal evolutionary invention that led to snakes becoming so successful—arose only once about 60 million years ago. The origins of venom-injecting snakes have long been the source of scientific controversy, because the contrasting fang positions of diverse snake groups pointed to independent evolution.

But a study of the embryos of eight front- and rear-fanged species has found that fangs always first appear at the back of the upper jaw before migrating forward in vipers and cobras. This previously unidentified transformation in the unborn young occurs due to “rapid growth of some parts of the upper jaw relative to the others,” Vonk explained…

(read more: National Geo)     (image: Gaboon Viper, by Brian MacKay)