Kathleen+E.

November 30 2013
 * Wiki Post #1 : Genetics**

=__**Evolution of the bird**__= Could dinosaurs still be roaming the earth? Well sadly no but long line of there decants very well could be! Evidence of this was made in the 1970s; paleontologists noticed that Archaeopteryx shared unique features with small carnivorous dinosaurs called theropods. An Archaeopteryx is a genus of early bird that is referred to as a feathered dinosaurs and a modern bird. All the dinosaur groups on the diagram below, except the ornithischian dinosaurs, are theropods. Based on their shared features, scientists reasoned that perhaps the theropods were the ancestors of birds although many were not convinced arguing that birds were simply too small to be dinosaurs. . As birds evolved from these theropod dinosaurs, a lot of their features adapted,take there feathers for example; whether these were for display, camouflage or flight they found several new types of feathers. changing from a branched downy feather to an asymmetrical flight, identical to the feather structure of living birds today.

In 1860, a quarry worker in Germany discover the famous 'London specimen' of Archaeopteryx lithographica. It was a example of a "transitional form" between two vertebrate groups (traditional reptiles and birds); just what Darwin expected would be found sooner or later. Archaeopteryx is an important link between birds and other coelurosaurs (dinosaurs) that has helped to illuminate the evolutionary history (phylogeny) of the group. It is now widely held to be the ancestor of all living birds; this is a common misconception. In fact, recent expeditions in China, Mongolia, Madagascar, Argentina, and elsewhere may uncover dinosaurs that usurp the "urvogel" status of Archaeoptery. Although not everyone agreed that birds are a descended of dinosaurs,most could agree there was a freakish resembelance between there to such as: **1.**Pubis (one of the three bones making up the vertebrate pelvis) shifted from an anterior to a more posterior orientation (see Saurischia), and bearing a small distal "boot". **2**.Elongated arms and forelimbs and clawed manus (hands). **3.**Large orbits (eye openings in the skull). **4**.Flexible wrist with a semi-lunate carpal (wrist bone). **5.**Hollow, thin-walled bones. **6**.3-fingered opposable grasping manus (hand), 4-toed pes (foot); but supported by 3 main toes. **7**.Reduced, posteriorly stiffened tail. **8**.Elongated metatarsals (bones of the feet between the ankle and toes). **9.**S-shaped curved neck. **10**.Erect, digitgrade (ankle held well off the ground) stance with feet postitioned directly below the body. **11**.Similar eggshell microstructure. **12.**Teeth with a constriction between the root and the crown. **13.**Functional basis for wing power stroke present in arms and pectoral girdle (during motion, the arms were swung down and forward, then up and backwards, describing a "figure-eight" when viewed laterally). **14**.Expanded pneumatic sinuses in the skull. **15.**Five or more vertebrae incorporated into the sacrum (hip). **16**.Straplike scapula (shoulder blade). **17**.Clavicles (collarbone) fused to form a furcula (wishbone). **18.**Hingelike ankle joint, with movement mostly restricted to the fore-aft plane. **19**.Secondary bony palate (nostrils open posteriorly in throat). **20**.Possibly feathers... this awaits more study. Small, possibly feathered dinosaurs were recently found in China. It appears that many coelurosaurs were cloaked in an external fibrous covering that could be called "protofeathers."

__Although some scientist still claimed birds were just simply too small to be a descendent of the great dinosaurs. Below is a video showing how dinosaures bodies may have shifted into a bird like form:__ media type="youtube" key="DhUvNpGi7Y0" width="560" height="315"

**For information check out these sites:**
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[] [] [] [] October 11, 2013
 * Wiki Post #1 : Genetics**

=**__ Holoprosencephaly __**=

What is it?
Holoprosencephaly is not something talked about much in today society as it is a rare genetic disease where the brain fails to divide properly into the right and left hemispheres (halves). The severity of Holoprosencephaly varies widely among affected individuals, even within the same family. Holoprosencephaly can be grouped into three types according to the severity of one’s condition .Although it is common within all levels of Holoprosencephaly to have developmental delay and intellectual disabilities. Dysfunction in other parts of the brain can cause seizures, feeding difficulties, and problems regulating body temperature, heart rate, and breathing as well. The sense of smell may be diminished (hyposmia) or completely absent (anosmia) if the part of the brain that processes smells is underdeveloped or missing .The three types are known as alobar, semi-lobar and lobar,

**__Alobar__**
Alobar Holoprosencephaly is the most sever of all three sub types.it is a rare congenital brain malformation in which there is a complete absence of separation of the two hemispheres (which usually occurs around the 4th to 6th weeks) this often leads to a miscarriage or a death quickly after birth. The image below shows the brain scan of a child with Holoprosencephaly,who's brain didn't divide into the right and left hemispheres.



**__Semi-lobar__**
Semi-lobar Holoprosencephaly is when the forebrain doesn’t complete in division, resulting in partial separation of the cerebral hemispheres. In many cases these abnormalities can corrected with surgery after birth. The image below shows the effects this has on a child's physical features a long side of delayed development.



**__Lobar__**
This is the least sever of the three conditions, There is almost a complete ventricular separation; typical facial anomalies are none noticeable with a slight the degree of Holoprosencephaly for example the eyes could be closer together. In some cases the child's brain my be near normal but will still have delayed development. In the pictures below you will see an image of a child with Lobar Holoprosencephaly and what his brain scan would typically look like.

__**For further explanation on how Holoprosencephaly is developed please watch the following video:**__

media type="youtube" key="BOinh2VcapA" width="560" height="315"

For further information check out these sites!
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[] [] [] //brain// scans: [] //semi-lobar// : []
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