Second Confirmed Shark "Virgin Birth"

As a follow up to this post from last year, scientists have confirmed the second-ever case of a 'virgin birth' in a shark, further confirming that female sharks can reproduce without mating and that many female sharks may have this incredible capacity. The scientists have proven through DNA testing that the offspring of a female blacktip shark named 'Tidbit' contained no genetic material from a father.

The phenomenon of 'virgin birth' occurs when a baby is conceived without male sperm having first fertilized the female's eggs, and has been proven in some bony fish, amphibians, reptiles, and birds. In the type of parthenogenesis seen in these sharks, known as automictic parthenogenesis, the newly forming pup acquires one set of chromosomes when the mother's chromosomes split during egg development.

But instead of uniting with similarly split chromosomes from sperm, as occurs in sexual reproduction, the mother's set is paired with a copy of itself. This results in offspring of reduced genetic diversity who may be at a disadvantage for surviving in the wild.



Source article here.

Video of Embryo at Cellular Level

For the first time, it is possible to actually watch the initial 24 hours of the life of an embryo at the cellular level. With a newly developed microscope, scientists were able to track the complex cellular organization of a zebrafish embryo as it grows from a single cell to 20,000 cells.

The montage video below is of three-dimensional images taken at 10-minute intervals and shows cells dividing and moving around the embryo to form specialized tissues.



Source article here.

"Deepest Ever" Living Fish Filmed

Scientists believe they have discovered the "deepest ever" living fish. The team found the surprisingly active fish at depths of 4.8 miles in the Japan Trench in the Pacific, and captured them on film. The scientists have been using remote-operated landers designed to withstand immense pressures to comb the world's deepest depths for marine life. The fish, known as Pseudoliparis amblystomopsis, can be seen darting about while scooping up shrimps.

Click on the link to the article to view video of the fish.

Scientists note that the fish are about 12 inches long and are "surprisingly cute." Nobody has really looked at these depths before, and the scientists indicated that one day fish will likely be seen living much deeper. The previous record for any fish to have been spotted alive was thought to have stood at about 4 miles.

Scientists note there are several obstacles to overcome in living at such depths. The first is food supply, which is very remote and has to come from 5 miles above. There is also very high pressure. They have to have all sorts of physiological modifications, mainly at the molecular level. The third obstacle is that these deep trenches are in effect small islands in the wide abyss and there is a question of whether these trenches are big enough to support thriving endemic populations.

Because the fish live in complete darkness, they use vibration receptors on their snouts to navigate and to locate food.

Original article here.

Visualizations of Science

Presented in this post are several examples of winners of the 2008 International Science and Engineering Visualization Challenge.

The awards are given to the best photographs, illustrations and interactive media that visualize science and technology.

The full gallery can be seen here.

The image on the right won the "illustration" category. It shows the key components of the human circulatory system at 10 different magnifications. Click on the image to see the full size.

Below is "The Glass Forest," winner of the photography prize, which depicts a community of microscopic diatoms - unicellular algae with a peculiar glass-like cell wall - attached to a marine invertebrate (Eudendrium racemosum). The image was captured with a scanning electron microscope.



Next is "Squid Suckers: The Little Monsters That Feed the Beast," which was awarded an Honorable Mention in Photography. It is a false-color microscope image of the suction cups on the arm of the Loligo pealei squid. The 400 micrometer suckers have chitin "fangs."



Next is an extract from "Stream Micro-Ecology: Life in a Biofilm," a large poster explaining the ecology of microbial biofilms. It was awarded an Honorable Mention in Informational Graphics. Better known as slime, these complex communities of many different micro-organisms are found in many watery environments and thought to be crucial to aquatic ecology. The poster shows the main organisms found in a biofilm from a stream, and explains their interactions and ecological roles.



Original article here.

Giant prehistoric geese the size of small plane

Scientists have discovered that giant prehistoric geese the size of small aircraft once flew over Britain.

Dasornis, which had a 16 ft wingspan and sharp teeth, lived 50 million years ago and was related to present-day ducks and geese. Once it skimmed the waters which covered what is now London, Essex and Kent, snapping up fish and squid with its bony-toothed beak. Scientists announced the discovery of one of the best preserved Dasornis fossil skulls buried in clay on the Isle of Sheppey.

Dasornis was in many ways similar to the modern albatross, which has the largest wingspan of any living bird, but research has shown that its closest cousins are ducks and geese. Perhaps the strangest thing about them is that they had sharp, tooth-like projections along the cutting edges of the beak.

No living birds have true teeth - which are made of enamel and dentine - because their distant ancestors did away with them more than 100 million years ago, probably to save weight and make flying easier. But the bony-toothed birds, like Dasornis, are unique among birds in that they reinvented tooth-like structures by evolving these bony spikes. These spikes would have enabled them to skim across the surface of the sea while snapping up fish and squid.

Original article here.

World's Oldest Rocks Found, with Signs of Life

Earth's most ancient rocks, with an age of 4.28 billion years, have been found on the shore of Hudson Bay, Canada. The sample of Nuvvuagittuq greenstone is 250 million years older than any rocks known.

It may even hold evidence of activity by ancient life forms. If so, it would be the earliest evidence of life on Earth.

The rocks contain geological structures which might only have been formed if early life forms were present on the planet. The material displays a banded iron formation - fine ribbon-like bands of alternating magnetite and quartz. This feature is typical of rock precipitated in deep sea hydrothermal vents - which have been touted as potential habitats for early life on Earth. These ribbons could imply that that 4.3 billion years ago Earth had an ocean with hydrothermal circulation. Some scientists believe that to make precipitation work, you also need bacteria. If true, then this would be the oldest evidence of life.

Original article here.

Peacock Mantis Shrimp

The peacock mantis shrimp calls the waters of Bali, Indonesia home (Odontodactylus scyllarus). The shrimp feeds by smashing open its prey until it can feed on its tissue.

Biologists on the Verge of Creating New Form of Life

A team of biologists and chemists is close to bringing non-living matter to life.

A lab led by a Harvard Medical School molecular biologist is building simple cell models that can almost be called life. The protocells are built from fatty molecules that can trap bits of nucleic acids that contain the source code for replication. Combined with a process that harnesses external energy from the sun or chemical reactions, they could form a self-replicating, evolving system that satisfies the conditions of life, but isn't anything like life on earth now, but might represent life as it began or could exist elsewhere in the universe. The replication isn't wholly autonomous, so it's not quite artificial life yet, but it is as close as anyone has ever come to turning chemicals into biological organisms.

The below video shows a protocell forming from fatty acids:



Original article here.

Red-wing Blackbirds Riding on Red-tailed Hawk?

The pictures below were taken by a photographer in Minnesota. They show Red-Winged Blackbirds hitching a ride on the back of a Red-Tailed Hawk. He claims this is not terribly uncommon, as red-winged blackbirds are extremely protective of their nests. They will dive-bomb humans, and he claims it is reasonable that they were harass a hawk. The birds apparently only stay for a matter of seconds.

So are the pictures real or Photoshopped? You decide:

Water Bears can Survive in Space

Space is extremely cold (near absolute zero) and it is a vacuum with no oxygen, plus the additional threat of lethal radiation from stars. It is considered the most hostile of environments, where unprotected humans would last for a fraction of a second.

But new research shows that some animals - "water bears", properly known as tardigrades - can survive exposure to the open-space vacuum, cold, and radiation just fine.

This is the first time that any animal has been tested for survival under open-space conditions. Tardigrades are tiny invertebrate animals from 0.1 to 1.5mm in size that can be easily found on wet lichens and mosses. Because their homes often fall dry, tardigrades are very resistant to drying out and can resurrect after years of dryness. Along with this amazing survival trick comes extreme resistance to heat, cold and radiation —so tardigrades seemed like an ideal animal to test in space.

The dried-up tardigrades were aboard a spacecraft launched by the European Space Agency in September 2007 and were exposed to open space conditions in a low Earth orbit of around 168 miles altitude. After their safe return to Earth, it turned out that while most of them survived exposure to vacuum and cosmic rays alone, some had even survived the exposure to the deadly levels of solar UV radiation, which are more than 1000 times higher than on the surface of the Earth. Even more so, the survivors could reproduce fine after their space trip.

Below are a pair of videos with water bears in action:





Original article here.