Tuesday, August 28, 2012

Hadrosaurs - Tough Teeth for Top Chewing

Research into Hadrosaur Dentition Provides Clue to the Group's Success

One of the most successful group of large, land animals known to science are the Hadrosauridae, a group of Ornithischian (bird-hipped), plant-eating dinosaurs that evolved from the Iguanodontids during the Cretaceous geological period. These animals evolved into many families and genera, some species grew up to twelve metres in length or more and they dominated terrestrial ecosystems across the northern hemisphere up until the demise of the Dinosauria 65 million years ago.

This type of dinosaur, commonly called "duck-billed" dinosaurs as they all had horny beaks is classified into two major taxons - the Lambeosaurinae and the Hadrosaurinae. Lambeosaurs, dinosaurs such as Parasaurolophus, Corythosaurus and Olorotitan had hollow, ornate head crests. The Hadrosaurinae, animals such as Gryposaurus, Maiasaura and Edmontosaurus lacked the often flamboyant crest. Instead, these dinosaurs had flat, crestless heads or their snouts were ornamented with bony lumps or solid crests.

Rise of the Duck-Bills

There are other differences between these two clades of dinosaurs. For example, the Hadrosaurinae generally had broader jaws and wider beaks than their Lambeosaurinae cousins. This suggests different feeding habits with the narrow-beaked Lambeosaurs being more selective feeders. Both types of Hadrosaur had many hundreds of closely packed, diamond-shaped teeth in their jaws, some specimens had over 1,400 individual teeth in their mouths. These teeth formed a "dental battery", interlocked to form a very efficient grinding surface to help these animals tackle tough plant material. The upper and lower tooth batteries were angled so that when the mouth was closed the teeth formed a natural grinding surface. For many years palaeontologists had known that these animals were very efficient processors of plant food, perhaps a clue to this groups's success but new research proposes that the structure of the teeth themselves made these dinosaurs much more effective consumers of plants than most of today's grazers.

Study into Tooth Structure of Hadrosaurs

A team of American scientists led by biologist Gregory Erickson of Florida State University (Tallahassee) have been testing the grinding capabilities of eighty-five million year-old duck-billed dinosaur teeth and examining their internal structure. Their research shows that the Hadrosaurs evolved extremely sophisticated teeth, more sophisticated than modern mammalian herbivores such as bison, horses and elephants.

Using teeth supplied by the American Museum of Natural History (New York), the research team created models of the jaws of these types of dinosaurs and subjected the teeth to diamond abrasion to simulate wear on the tooth surface as a result of grinding up plant material. The teeth were then examined under light and electron microscopes and the degree of wear calculated.

Better Than Mammalian Molars

The study demonstrates that unlike most mammalian molars and pre-molars which are composed of four major tissues that wear at different rates, creating coarse, roughened surfaces to help break down tough plants, the duck-bills evolved a six tissue dental composition which improved the teeth's ability to grind up food.

Tough, strong teeth designed to tackle plants has evolved repeatedly in the ungulates and other mammal groups. However, a similar innovation in dental complexity occurred much earlier in the history of life on Earth, with the Hadrosaurs. Most reptilian teeth are not as complex, it seems that as the Iguanodontids gave rise to the Hadrosaurs so the teeth of these animals evolved into extremely efficient grinders. The external layer of enamel being supported by layers of other tissue such as dentine. Importantly, the researchers also discovered that the way tissues were distributed varied substantially within each individual tooth. Each tooth in the dental battery would assume a different function as the morphology and the grinding surface of the tooth changed as it became worn. Different surfaces would be exposed as the teeth migrated across the grinding and chewing surface of the jaw, before eventually falling out to be replaced with new teeth that emerged from the jawline.

Efficient Jaws and Efficient Teeth

The morphology and structure of the teeth would have enabled these herbivores to grind up tough plants such as horsetails, ferns, conifer needles and the newly evolved flowering plants. Most reptiles have much more simple teeth structures and the scientists are not sure how such dentition evolved. The lack of transitional fossils between Iguanodontids and Hadrosaurs is hindering the team's progress as they search for answers in the fossil record.

Referring to Hadrosaurs as "walking pulp mills", Gregory Erickson and his research colleagues have declared the duck-billed teeth lined jaws as one of the most sophisticated grazing and grinding mechanisms ever to evolve in terrestrial mega herbivores. Their teeth are more complex and better adapted to grinding than most of the large plant-eating mammals found today.

Wednesday, August 22, 2012

How to Use Technology in Science Class

Spider Attack Preserved in Amber

Researchers from Oregon State University (college of science) have discovered a remarkable fossil showing the moment when an orb spider approached its victim ensnared in its web. The fossil consists of the remains of the spider and a parasitic wasp, preserved in amber just as the spider was about to pounce upon the insect, as it was held fast by the silken threads of the spider's web. Amber is the hardened remains of sticky, often scented resin that is produced by certain types of trees as protection against damage to bark and in order to help protect against disease and fungal attacks. Insects and other organisms can become trapped in the sticky resin as it flows down the trunk or branches and when fossilised and preserved as amber, these organic remains can be studied by scientists. Trees first evolved the ability to produce resin of this nature in the Jurassic, but this piece of amber, discovered in the Hukawng Valley (also known as the Hukaung Valley), in northern Burma dates from the later Cretaceous geological period.

Famous Amber Fossil Site in Asia

The Hukaung Valley has been mined for amber and gold for many years, it has already produced a number of amber fossils containing insect remains. About ten years ago, the fossilised remains of the world's oldest bee was discovered in an amber nodule from a mine in the Hukaung Valley. However, this is the first discovery of a predator/prey interaction concerning a spider and an insect trapped in a web. The amber nodule containing the fossilised remains has been dated to approximately 97-100 million years ago (Albian faunal stage of the Cretaceous) - a time when the dinosaurs ruled the Earth.

Social Behaviour in Arachnids

In addition to the first spider, the silk and the remains of the spider's attempted meal, the wasp, the amber nodule also contained the remains of a second male spider. Scientists at the Oregon State University have interpreted this as evidence of social behaviour amongst arachnids. Most extant species of spider are solitary hunters, often they are cannibalistic towards their own kind, mature males and females will attack immature members of their own species. A number of species today show signs of social behaviour, living in colonies or aggregations. The Oregon based team postulate that this fossil is evidence of such social, colonial activity in spiders back in the Cretaceous, the first evidence found of tolerance of other members of their own species by a spider.

Professor Emeritus of Zoology at Oregon State University, George Poiner Junior, a recognised authority on invertebrate fossils stated that the juvenile spider was attempting to pounce on the trapped, tiny parasitic wasp, but it never quite reached it. Both animals were covered in the tree resin before the spider could reach its victim.

Amazing Amber Fossils Found

Over recent years, palaeontologists have discovered some amazing fossil specimens preserved in amber, from ancient Arthropods, to numerous types of insect, pollen, plant debris, even a frog, hairs from mammal and feathers from either an ancient bird or a dinosaur. Such fossils provide an insight into deep time, a micro world which helps scientists to understand more about ecosystems and habitats.

Wasp Being Attacked by Ancient Spider

The wasp has been identified as an ancestor of today's parasitic wasps that attack and disable spiders and insects and lay their own eggs into the paralysed body of their victim or instead, parasitise the eggs of such creatures. The kind of spider preserved in the amber, a relative of today's tropical orb spiders, but a member of an extinct genus would probably have been the sort of creature the wasp would have liked to attack. As the research team members have stated in their press conferences, this fossil preserves the moment when a spider was able to turn the tables on a parasitic wasp. There were at least fifteen silken threads preserved in the amber nodule, evidence of the spider's web. Some of these threads had trapped the wasp.

Article Source: http://EzineArticles.com/7324056


Technology has made its way into mainstream life and it is important to incorporate it into the classroom. Science in the classroom is introduced in elementary school and often technology is a tool that can be used to encourage the interest of the student in the subject matter. If the student can grasp the basics and develop an interest in science at an early age, studies show that the student will continue that interest throughout his school years. Adding technology to the classroom initially costs a great deal. However, the expense is worth it when compared to the positive outcome achieved.

One way to add technology in a science classroom is to use a liquid-crystal display (LCD) projector. This is a video projector that can display computer data on a screen or other flat surface. This technology takes the place of the overhead projector. Light from a lamp of metal-Halide is sent through Diachronic filters or prisms that separate the light. Three panels of red, green, and blue make up the video signal. The polarized light passes through these panels and each pixel can be opened or closed. The opening and closing of the pixels is what yields the range of colors found in the image that is projected. Some of the other technology available is digital light processing (DLP) or liquid crystal on silicon (LCOS) and are decreasing in cost so that they are becoming more affordable for classroom use.

The technology involved in the LCD allows the unit to be smaller and portable. In order to get the best resolution it is recommended that the projection surface be gray, white, or black. The color produced is a direct correlation to the quality surface and projector used. White is usually the choice for classroom user. The projector must be located at the correct distance from the projection surface and the ratio is usually found in the material that comes with the LCD. This technology was first invented by Gene Dolgoff in 1968, but it wasn't until 1984 that he put together the first projector. The technology later evolved into the high-definition television (HDTV).

The LCD projector can be used in the science classroom to project images onto the screen. This enables all the students to view the data of one computer. With a limited budget, the school is able to still integrate information from the computer for all the students, without having to supply each student with a computer. It is recommended that the teacher start with an informative, perhaps animated, video that will introduce the content to the student. This will capture the attention of the student and the student will retain more of the content when his interest is captured. The teacher can search the web for sites that offer free streaming or look to the curriculum for these tools.

Try to select a model for projection that will allow you to point and click and manipulate the projection. For example, if the module is on the content of the atom, then manipulating the screen can teach the student how atoms combine to form different substances. Dragging two hydrogen atoms to one oxygen atom would show the student the content of water. If a smart board is also connected to the LCD then the student can use a special pen to manipulate and the smart boards can give life to abstract concepts that enable a student to grasp the content. Experiments can also be done by manipulating the LCD images and this will help students participate in experiments that may not be available due to the high cost of separate lab stations and materials.

Tuesday, August 14, 2012

Bizarre Dinosaurs - Amargasaurus - Dragon-Like Dinosaur

Amargasaurus - A Bizarre Relative of Diplodocus

As an increasing number of bizarre forms of Sauropod are unearthed, the family tree of these huge long-necked dinosaurs is becoming more complicated. Although, thanks to recent discoveries of more basal Sauropods and Prosauropods the evolution of these Saurischians has become a little clearer, there is still a lot of confusion over the taxonomic relationships between the various families of these long-necked dinosaurs.

Monster from Argentina

The Argentine Amargasaurus for instance, is an example of a strange-looking, long-necked dinosaur and the strata from which the single fossil skeleton so far known was discovered adds to the mystery of the Sauropods. The global fossil record indicates that the Diplodocid type of Sauropod was beginning to become rare during the early Cretaceous. Their heyday appears to have been the late Jurassic when behemoths such as Diplodocus, Barosaurus and Apatosaurus roamed. However, the fossils of Amargasaurus date from the early Cretaceous (Hauterivian faunal stage - approximately 135-130 million years ago). This indicates that this particular group of long-necked dinosaurs were still present, at least in the southern hemisphere during the early Cretaceous.

Bizarre Looking Prehistoric Animal

Amargasaurus also had a very strange appearance, being relatively small compared to the Diplodocids known from the upper Jurassic deposits of the Morrison Formation of the western United States. For a start, it was only about 12 metres in length, considerably smaller than Diplodocus and Apatosaurus and it had a much shorter neck, compared to other Diplodocids.

The most distinguishing feature though was that along the neck and back of the animal was an array of long, spines extending up from the back bone. These spines consisted of two rows of long spines over the neck and shoulders, gradually reducing to a set of single spines running along the back to the hind quarters.

The exact purpose of these spines is hotly debated by scientists. Some believe that they supported a brightly coloured sail that could have been used as signalling device amongst members of the herd, whilst others suggest that the spines were for defence against attack from large meat-eaters that shared the same environment. This frill makes this animal look similar to dragons from mythology. Those spines on the neck which are paired, may not have supported a sail, but been covered in horn helping to protect a vulnerable part of this animal's body. Certainly, with the likes of members of the Allosaur family wandering around it would pay to have some form of protection, but the precise purpose of these spines remains unclear.

Related to African Sauropods

Amargasaurus may be a member of the Dicraeosauridae, a group of Sauropods that all possessed long neural spines. Amargasaurus may have been a descendant of the genus Dicraeosaurus, a Diplodocid from the late Jurassic of East Africa. It is just one example of just how bizarre some dinosaurs might have looked. There are a number of dinosaur models available, scale model replicas of Amargasaurus.

Wednesday, August 8, 2012

Pyramid Power - How to Build a Pyramid and Put It to the Test

Do you have a fascination with pyramids? Ever wonder what purpose they served? Well, you're not alone! People have long speculated that these tremendous structures were more than just places to enshrine their nobility after their passing. If the pyramids produce an unseen power, as some people claim, is it possible to harness that power? Read on and find out how you can build a pyramid of any size and test it to see if it will also generate its own pyramid power.

Just how do you test a pyramid? By putting objects inside and observing how these objects are influenced by the pyramid. At least that's what people have done in the past. Razor blades become sharp and hold their edge much longer; fruit dries out but does not rot or mold; plants grow faster and much fuller; milk turns into yogurt if left inside long enough. These are all claims made by pyramid researchers.

What You Will Need

1. 4 pieces of cardboard that are big enough to create the size of pyramid you want.

2. Tape.

3. A directional compass with a base plate.

Laying It Out

The pyramid in Giza was constructed according to amazingly exact dimensions. For your experiments to work, you'll need to duplicate these dimensions as closely as physically possible.

You'll be making 4 triangles out of cardboard and all of them need to be exactly the same size.

Lay one of the pieces of cardboard down and measure the length of the bottom side. Now, multiply that length by 0.951. The result will be the length of the other sides of the triangle.

For instance, if the length of the bottom edge of your cardboard is 10 inches, the length of each of the other sides of the triangle would be 9.51 inches. Set a drawing compass to a width of 9.51 inches and use it to make intersecting arcs above the base. The point where the arcs cross will be the top of the triangle. Draw lines from this point down to each end of the base and one side of your pyramid is complete.

Create 3 more sides just the same way and cut out the triangles from the cardboard.

So that you won't be confused which is the bottom edge, mark the longest (bottom) edge before you cut it out, to show that it belongs at the base.

Putting It Together

Lay one piece down flat with the mark at the bottom. Lay another piece alongside it with its side touching the first, also with the mark at the bottom. Align these pieces carefully so that each edge matches the other and then tape these pieces together.

Align the remaining two pieces in the same way and tape them in place.

Now that you have the 4 sides connected, you can bend the pieces along each of the taped edges and bring your pyramid to life when the final edges are taped.

That's it for the construction, but you have to do one more thing to "activate" your pyramid.

Aligning Your Pyramid

Just like The Great Pyramid in Giza was aligned with uncanny precision to face true north, you need to do the same. It's works like a radio antenna, so the more accurately you orient your pyramid, the greater its energy will be.

To do this, you need a compass with a straight base plate. You also need to know the angle of declination for your particular area.

A compass points to magnetic north. This can vary by many degrees from true north, depending on your location. Your angle of declination helps you convert magnetic north to true north and can easily be found by doing a web search for "find my angle of declination."

If your angle of declination is a negative number, you need to turn your compass in a clockwise direction by that number of degrees to find true north. If the angle is positive, turn the compass counter-clockwise to compensate.

One more thing: When given your angle of declination, you usually are given minutes as well as degrees. To convert these minutes to parts of degrees, divide the minutes by 60. For example: If your declination is 17 degrees, 26 minutes, divide 26 by 60 and you get.43. This would make your total declination 17.43 degrees. You would then adjust the dial on your compass counter-clockwise by 17.43 degrees and this would point you directly to true north.

Lay the adjusted compass on a flat surface, away from any large objects and electrical appliances which could interfere with the magnetic field, and point it to true north. Place the pyramid beside it with one edge aligned parallel with the base plate. This is the direction the pyramid needs to stay in for maximum energy.

Testing Your Pyramid Power

Every pyramid has a "sweet spot" and this is directly in the center at one-third of the distance from the bottom to the top. In the Great Pyramid, this is where the king's chamber was concealed. Keep this in mind when you place something inside. Also, if you're going to sharpen your razors, it helps to orient the edge of the razor in a north/south direction.