Brianna+Robinson

Post #1: Genetics =Heterochromia=

Heterochromia- A difference in coloration in two structures or two parts of the same structure that are normally alike in color.

When heterochromia is seen in someone's eyes, it occurs when the pigment that makes your eyes a certain color (melanin) isn’t dispersed and concentrated in equal amounts inside the irises. Most of the time, heterochromia is inherited from parents, but it also can be caused by a disease or a syndrome, or even an injury.

Actress Mila Kunis has heterochromia. One eye is green and one is brown.

An example of this would be David Bowie’s artificial heterochromia. He got into a fight in a bar and damaged his eye. Since then, one pupil became permanently dilated, thus resulting in it looking darker than the other one.



David Bowie appears to have heterochromia, but he was not born with this. His left pupil, permanently dilated, appears darker than the right.

As for genetic disorders it may be caused by, there are several that could cause it, including Waardenburg syndrome, Sturge-Weber syndrome, and Parry-Romberg syndrome. For example, in Waardenburg syndrome, the modified genes will disrupt the movement of melanocyte in many different regions of the body, and can cause patches of skin of different colors, not just different eye colors. Something else that can cause heterochromia is chimerism, a rare disorder that occurs when two fertilized eggs create one embryo. The different set of genes will act by their own instructions, but overall make one person. They will just have two different eye colors. A look at how the amount of melanosomes have on eye color. media type="youtube" key="O65r_86bKrw?feature=player_detailpage" height="360" width="640"

====Although heterochromia is a unique condition, there are many causes of it. It is interesting and rather shocking that our body is capable of doing something like this. So is it received through genetics? Absolutely, but heterochromia has been proven to be much more than just a hereditary condition.====

Further Reading:
 * io9- [] (io9 explores the possibilities that heterochromia is more than a mutation)
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 * Environmental Graffiti: Heterochromia in Animals-[] (Some images of animals with heterochromia)
 * MedlinePlus-[] (The medical side of heterochromia)

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Post #2: Evolution New Human Species Found in Kenya = =

After all of these years of believing //Homo erectus// was the only human species to ever walk Earth, scientists in Kenya claim that they have found a new species. Through fossils thought to be 2 million years old, scientists believe that there were actually two pre-human species, and these led to the human species.

Koobi Fora, where the fossils were found.

There are three fossils that make up this incredible discovery: a skull and two parts of a lower jaw. These were all discovered in the same place: the deserts of Koobi Fora, Northern Kenya. When put together, they create one whole cranium. When all three fossils were put together, scientists were able to create this full cranium, supposedly from a species other than //Homo erectus//.

The first fossils were found in 1972, and it wasn’t until 2012 that a team led by scientist Meave Leakey found the remainder of the complete cranium. She believed that it wasn’t from our ancestor, //Homo erectus//, but a distant cousin that possibly even shared a common ancestor with //Homo erectus//. Meave Leakey digging out the fossil of the unknown species. She led the team that discovered the new //Homo erectus// like species.

However, experts in human evolution do not agree with this claim whatsoever. They accuse Leakey of jumping to conclusions with her lack of hard evidence. It is now a question of whether this cranium was possibly from a mutation of //Homo erectus//, or could it be something completely new?

One thing was for sure: these fossils don’t match //erectus//, but it does have a flat face and big teeth. So it looks very similar, but it’s not the same.

Tim White is an evolutionary biologist at the University of Berkeley California, and he doesn’t believe any of this. White compares Leakey’s conclusions to examining the jaw of a female gymnast and a male shot-putter. Ignore the faces in the crowd, and Leakey would decide the gymnast and shot-putter to be different species. Tim White (left) and Roy Caldwell (right). White is an evolutionary biologist and doesn't buy into Leakey's claim of a new species.

Even others who agree and buy Leakey’s proposal, like Eric Delson, admit that it’s “not definite”. media type="youtube" key="HOuRCUMj8hE?feature=player_detailpage" height="360" width="640"

Further Reading: (These are all articles about what happened in Kenya)
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Sources:
 * [|http://io9.com/5932362/a-new-human-species-has-been-identified-in-Africa]
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Post #3: Dynamic Equilibrium =The Reasons We Blink=

Human blinking is done to protect the eyes by lubricating the cornea. This happens when the tear glands release salty secretions. These can flush away dust particles. On average, we blink every 4-6 seconds. However, this is more than is needed for the suitable ocular lubrication, so scientists have been led to believe that there is another reason that we blink besides protecting the eyes.

Scientists have proven that we are acquiring information, we begin to blink. We blink when we absorb information or process it.  An example of us blinking when acquiring information is reading. We will blink approximately 3-8 times a minute, compared to about 15 times a minute when we aren’t doing something that requires a lot of attention. It’s also been proven that when our eyes switch to the next page or the next line of text, we will likely blink.

Japanese researchers Tamami Nakano, Shigeru Kitazawa, and other colleagues have recently theorized that eye blinks are also commonly caused by resetting and delivering attention.

Shigeru Kitazawa, one of the researchers responsible for theorizing eye blinks are due to changing attention.

Nakano experimented this by showing some volunteers an episode of //Mr. Bean//. All the volunteers were hooked up to an fMRI scanner, and the researchers noticed that during the episodes, the participants were blinking for about 17.4 times per minute (on average). They also noticed that when the blinking was taking place, there was a lot of activity happening in two opposing anatomical brain networks that are responsible for attention. The Mr. Bean episode shown to the volunteers of Nakano's experiment, which proved that during a pause or scene change, the volunteer would likely blink.

Blinking can also be related to psychological reasons, like nervousness, loud noises, stress or tension. And although, depending on what you’re focusing on, concentrating can cause stress, someone who is concentrating to complete a difficult task will most likely blink less than normal. Also, there is an obvious link between the frequency of blinking and someone's emotions. For example, if you're tired, you will blink more and they will last longer than a well rested person.

Blinking when you hear loud noises actually has a name: it's the acoustic startle-reflex eye blink, and like other eye blinks, is the body's way of protecting itself. The startle-reflex eye blink can also happen when you are in fear of potential danger, like being told something is going to happen to you, even though it won't.

When we hear loud noises, our nervous system reacts, and we will tend to blink more frequently. This is called the acoustic reflex eye-blink.

But one thing that always has puzzled us is the reason we don't even seem to notice when we blink. Why don't we just see blackness about 10-15 times a minute?

Davina Bristow of the UCL Institute of Neurology says that "a blink lasts on average 100-150ms... We'd immediately notice if the outside world went dark, especially if it was happening every few seconds. But we are rarely aware of our blinks, even though they cause a similar reduction in the amount of light entering the eye, and this gives us an uninterrupted view of the world."

media type="youtube" key="9h-OWvp4LS0?feature=player_detailpage" height="360" width="640"

media type="youtube" key="M5IB6Ip58Eg?feature=player_detailpage" height="360" width="640"

Further Reading:
 * [] (kids site with trivia about blinking)
 * [] (Davina Bristow's interview)
 * [] (Nakano's experiment)
 * [] (why we blink AND wink)

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