What Smells? How We Perceive Scents.

Take a deep breathe in through your nose. What do you smell? Lunch? Pencil lead? Somebody mowing the lawn? Whatever it is, you just utilized one of the most basic senses we humans possess. It can alert us to the danger of a fire or rotting food, and allow us to appreciate the scent of flowers and perfumes. But how exactly does the sense of smell work? 

When you inhale, chemoreceptors (a form of sensory cells) detect tiny molecules of the substance that are floating in the air. Everything and anything that you smell gives off these molecules. These chemoreceptors are specialized neurons, similar in size to a stamp. This section is referred to as the olfactory epithelium. They are exposed to the air and project cilia outwards to increase surface area. The molecule of smell will attach to the cilia and cause a reaction in the neuron. The chemoreceptor then  sends electrical signals to the brain, which then interprets the signals and converts them to a smell. 

Fascinatingly enough, every chemoreceptor is encoded by a separate gene. If this gene is missing or not intact, one will not be able to smell a specific scent. If these neurons are lost or damaged, they can result in a syndrome called anosmia. Anosmia is the total loss of smell, and can have many causes. These include, but are not limited to:

• head trauma
• old age
• toxins
• intranasal drug use
• smoking

• nasal polyps
• upper respiratory tract infection. 

More interesting than the basic process of smell, however, is its connection with memory. A specific smell can evoke various memories and moods in different people. This is due to the fact that the part of the brain that deals with smell (the olfactory bulb) is positioned inside the limbic system - the section of the brain that deals with memory and feelings. This allows connections to be made between these two systems easily. However, the key aspect of this phenomenon is the idea of "conditioned responses." When one encounters a new scent, one connects it with the place and activities that are ongoing. For instance, the musty smell of old books in a library, or the scent of baking cookies at your grandmother's house. This may be part of the reason why people show different preferences towards various smells. 

Sources:

http://science.howstuffworks.com/environmental/life/human-biology/smell.htm

http://health.howstuffworks.com/human-body/systems/nose-throat/question139.htm

http://en.wikipedia.org/wiki/Anosmia

http://en.wikipedia.org/wiki/Olfaction

Images courtesy of:

http://www.boston.com/lifestyle/health/articles/2011/07/18/how_smell_works/

http://purplepaperplanes.files.wordpress.com/2010/03/smell_flower.jpg

Quarks!

Here is another neat science video created by the vlogbrothers about quarks:

Mendilian Genetics; or, Why Can't I Curl my Tongue?

For the past few days I have been investigating genetic traits. These traits are determined by alleles. You receive one allele from each of your parents. These alleles can carry the genetic code for a dominant or recessive gene. If you receive two dominant alleles or one dominant and one recessive allele, you will express the dominant trait. If you receive two recessive alleles you will express the recessive trait. I tested myself and a variety of my family members for four different traits. These traits were: attached ear lobes, widow's peak, hitchhiker's (bent) thumb, and ability to curl your tongue. My findings are below.

From this chart I was able to create the following three pedigrees:

Pedigree for Attached Earlobes. 

Pedigree for Widow's Peak

Pedigree for Tongue rolling

I was quite surprised that only one member of my family had unattached earlobes, none of my family had widow's peaks, and that neither my cousin, my brother, nor myself was able to roll our tongues while our parents could. I found this odd because unattached earlobes are dominant, widows peaks are dominant, and tongue rollers are dominant. I was unable to create several pedigrees because my grandparents could have been AA and Aa or Aa and Aa. There were several such situations, in which it was impossible to find a result.

Gene Therapy

A diagram explaining Gene Therapy

Imagine the treatment of a cancer patient. It is typically a long string of doctors appointments, surgeries, and medications such as chemotherapy. But what if there was a way to treat cancer with a simple injection? It seems incredible, and yet this is the aim of a new type of medical treatment called gene therapy. Not only would gene therapy treat cancer, but it could also treat cystic fibrosis, familial hypercholesterolemia, HIV/AIDS, gaucher disease, hearing loss, and could allow patients with circulatory problems in the legs to avoid amputation.

So, how would this incredible process work? It would begin on a molecular level. All of the aforementioned diseases and complications are caused by imperfections and mutations of the DNA. These are obviously very hard to treat with medications, and are typically hereditary. They can affect almost any part of the DNA. It is clearly quite hard to change a gene that is written into each and every cell in the human body, and coming up for a cure for these diseases has always been quite daunting. This is where gene therapy comes in. Gene therapy is the use of genes as treatment or prevention for diseases.

Using genes as a treatment? As fantastical as it sounds, this is the reality of gene therapy.  A "normal" gene is put into the genome in place of an "abnormal" gene which causes a disease or disfunction. This is done with several different treatments which fall under two headings: Germ-line gene therapy and somatic gene therapy. Germ-line gene therapy is when genes are introduced into reproductive cells or into embryos, so that the child will not have genetic abnormalities. On the other hand, somatic gene therapy is when therapeutic genes are inserted into cells to replace the current DNA or to make a protein/substance that is not present or not working in the patient. Most current research is developing somatic gene therapy.

Somatic gene therapy usually works via a "vector". The vector delivers the new gene to the patients cells. These vectors are almost always a virus which has had the infectious DNA replaced with the proper gene. These are either a retrovirus (such as HIV, which works well in dividing cells), an Adenovirus (such as the common cold, which works well in non-dividing cells), an Adeno-associated virus (which inserts DNA at a specific singular site on chormosome 19) or Herpes simplex virus (typically causes cold sores). There are new ways of developing gene therapy, including introducing the DNA directly to the cells, creating an artificial lipid with a water-based core which can travel directly through a cell membrane to deliver the gene, chemically linking the DNA to a molecule that attaches to the cell receptors, or even adding a 47th chromosome, which would not affect the cell in any way other than changing the defective gene.

Like any advancement in science, there are some questions and possible complications that come up when discussing gene therapy. If we put aside the omnipresent issue of "playing god", there are still a few problems. The primary problem is the use of viruses. Many scientists and researchers fear that one of the viruses injected into the DNA will go awry. Instead of being completely removed, the original virus would still retain its own DNA and begin infecting people. Although this is a justified concern, I believe that the benefits far outweigh the risks. If the makers of the injections are thorough in their testing, the company can have a product that is both safe and infinitely helpful to the modern world.

Check out this game about gene therapy!

http://ghr.nlm.nih.gov/handbook/therapy/genetherapy

http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml

http://www.encyclopedia.com/topic/gene_therapy.aspx

http://autocww.colorado.edu/~toldy2/E64ContentFiles/VirusesMoneransAndProtists/RetrovirusB1.html

A Gene that can Cure Cancer and Diabetes?

When you think of a cure for cancer and diabetes, what comes to mind? Probably scientists, hard at work in a lab. But surely not a group of Ecuadorians who are all under three and a half feet tall. According to this article, scientists have discovered a that these people are immune not only to cancer, but also to diabetes. This is because they have a disease known as Laron syndrome, and it may be the key to finding a cure for two very deadly diseases.


The cause of this syndrome is directly tied to the cell cycle. It turns out that Laron syndrome is caused by a specific mutation of a gene which is a receptor for Human Growth Hormone. This gene is known as IGF-1, and if a person has Laron syndrome they have very little IGF-1. Therefore, the Human Growth Hormone is not accepted by the cells, and the person does not grow. This ties into the ideas of proto-oncogenes and tumor suppressors. Certain parts of the cell, called proto-oncogenes, tell the cell when to go through the cell cycle and split apart. If there are no proto-oncogenes, as with Laron syndrome, the cell will not split.


This is a remarkable progression in the war against cancer and other deadly diseases. If scientists can find a way to change the ways our genes deal with the Human Growth Hormone to cure cancer without harming us in any other way, it would be truly remarkable. However, I highly doubt this could happen. It is always dangerous to mutate a person's genes, and without proper checks this could create even larger problems than cancer itself. Nevertheless, it seems that the secret to curing cancer could really have been hiding in a small village of Ecuador.




Sources:
http://www.nytimes.com/2011/02/17/science/17longevity.html?_r=1

Cellular Respiration

A video I made last year for my bio class explaining cellular respiration:

Lymphoma: HL and NHL (no, not that NHL)

For a human being to function well, it is imperative that they remain healthy. This is the role of the immune system: to keep a body functioning smoothly.  One key component of the immune system is the lymphatic system. The lymphatic system is made up of vessels that carry a substance called lymph. They lymph is cycled around the body, and remove bacteria, viruses, and rouge cells. It travels trough various areas that contain lymphatic tissue such as: the tonsils, the thymis gland, the spleen, and the bone marrow. It also travels through many small pockets of lymph tissue around the body called "lymph nodes". The purpose of the lymph nodes is to filter the lymph, which has picked up large amounts of foreign substances in the body. This is all very well and good, as long as the system works. It can be interrupted by several factors, some as  simple as infections, which make the lymph nodes swell up. One of the most serious disturbances to the lymphatic system is a type of cancer called lymphoma.  It is the seventh most common cancer in adults and the third most common cancer in children.

Lymphoma affects the lymphocytes found in the lymph. These lymphocytes identify any foreign cells, bacteria, viruses, and mutated cells. There are two different types of lymphocytes: B cells and T cells. B lymphocytes create antibodies which alert other cells, such as white blood cells, to the presence of pathogens so that the pathogens can be destroyed. T cells can kill pathogens without any outside help, and also assist in regulating the immune system. Once they have encountered a pathogen initially they will recognize it upon any further encounters. This is a key component in the way vaccines work. When a vaccine is injected into a person, the lymphocytes recognize the strain of the bacteria or virus and will attack it in the future.

A lymphoma occurs when either the B or T cells grow and multiply rapidly. The cells will continue to multiply, forming a large mass called a tumor. This tumor prevents the areas around it from having enough resources to function normally. Lymphomas are also able to metastasize and spread across the body very rapidly via the channels that make up the lymphatic system. Lymphomas are separated into two different categories: Hodgkin's Lymphoma (referred to as HL) and non-Hodgkin's Lymphoma (referred to as NHL). As of 2010, 628,415 people had lymphoma or were in remission. 153535 of these cases were HL and 474880 were NHL. 


The first known example of Hodgkins.  lymphoma was found in 1666, by Malpighi. In his paper De viscerum structuru exercitatio anatomica, he describes the disease that would later be referred to as "Hodgkin's lymphoma" or "Hodgkin's disease". Almost 200 years later, in 1832, Hodgkin publishes his own paper on the lymphoma, and thus the affliction was named after him. Research into "Hodgkin's disease" continued for many years afterwards, and in 1898 Cal Sternberg, a German researcher, discovers the Reed-Sternberg cells present in Hodgkin's lymphoma. Four years later, in 1902, Dorothy Reed, working at the Johns Hopkins Hopital in the United States, discovered the Reed-Sternberg cell on his own. From that point on scientists devoted time and energy into finding a cure of this disease

An image of a lymphoma

Hodgkin's lymphoma is given a separate classification because it occurs from one specific abnormality in the B cells alone. The tumors also contain Reed-Sternberg cells, named for the scientists who initially discovered the cell. Hodgkin's lymphoma will typically start in the area around the neck. It will then spread downward through the nodes to the rest of the body. If the cancer manages to spread below a person's diaphragm it will infect the spleen and therefore infect both the liver and the bone marrow. The cancer will also begin in the chest occasionally. From there it will spread to the areas around the heart and the lungs. There are five different types of Hodgkin's Lymphoma: Nodular Sclerosing Hodgkin Lymphoma (NSHL), Mixed Cellularity Hodgkin Lymphoma (MCHL), Lympocyte Depleted Hodgkin Lymphoma (LDHL), Lymphocyte-rich Classic Hodgkin Lymphoma (LRCHL), and Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL). There are four different stages of HL. Stage I is the infection of one singular lymph node region. Stage II affects two lymph node areas on the same side of the diaphragm (either waist up or waist down). Stage III has lymph nodes affected on both sides of the diaphragm (both waist up and waist down). Stage IV indicates that the cancer has spread outside of the lymph nodes. The cause of Hodgkin's lymphoma is currently unknown, but there are many risk factors that can lead the the development of a tumor. Primarily, it is believed that immune suppressive diseases increase a person's risk of developing the disease. These include: having had mononucleosis as a young adult, having suffered fromhuman T-cell lymphoctyotropic virus (a virus that affects the lymphatic system, also called HTLV), having contracted HIV, being infected with Hepatitis B or C, having herediaty diseases that affect the immune system (severe combined immunodefience, ataxia telangiectasia), having received immune suppressive therapy, exposure to toxic chemicals, or having a family history of lymphoma. 


Non-Hodkgin lymphoma was first differentated from Hodgkin's lymphoma by Henry Rappaport in the years 1956 tp 1966, which led to the Rappaport classification, the first classification of Non-Hodgkin lymphoma. The classification "Non-Hodgkin's lymphoma" refers to any type of lymphoma without the Reed-Sternberg cells, which can affect both the B cells and the T cells and has a variety of genetic markers. There is a one in fifty chance that a person will develop non-Hodgkin's lymphoma at some point in their life, although the affliction is more common in men. There are thirty different types of non-Hodgkin's lymphoma, which fall into three different classifications. These are classifications are Indolent (slow-growing, low grade), Moderately aggressive (intermediate grade), and aggressive (high grade). These are differentiated by how quickly the cancers are spreading, with low grade as the slowest spreading and high grade as the fastest spreading. As with HL, the cause of NHL is unknown. However, scientists and researchers have linked the disease to "immune suppression". Immune suppression is when a person has had a disease which has impacted their immune system to a point at which it does not function properly. Some examples of these diseases would be HIV, HTLV, Hepatitis B or C, hereditary diseases that affect the immune system (severe combined immunodeficience, and ataxia telaniectasia) and mononucleoisis. Additionally, having contact the bacterium Heliobacter pylori can also increase the likelihood of developing a lymphoma (and has also been linked to stomach cancer). An interesting factor that can increase the chance of a person having a lymphoma is living in a faming community. Doctors believe that the use of pesticides and herbicides may be the reason, because they contain certain chemicals. These chemicals may also be found in black hair dye, the use of which has been linked to NHL. As with HL, a family history of lymphoma is also a factor. 


Both HL and NHL have very similar symptoms. The most common of these are: swelling of the lymph nodes, fever, unexplained weight loss, sweating, chills, lack of energy, itching, rashes, lower back pain, and sore lymph nodes after drinking alcohol. Unfortunately, the symptoms vary greatly between cases, and are often misdiagnosed as the common cold or the flu.


There are three different treatments used on both HL and NHL. These are radiation therapy, chemo therapy, and biological therapy (or immunotherapy). Radiation therapy employs high-energy rays (radiation) to kill the cancerous cells. This is used on specific areas of the body, rather than the entire body. Chemotherapy uses powerful drugs to kill cancer cells. These are administered intravenously, then circulate trough the bloodstream impacting the entire body. Biological therapy is a relatively new type of therapy, which essentially trains the body to remove the cancerous cells on its own. There are three different types of biological therapy used to treat cancers. The first us Monoclonal anitbodies. A monoclonal antibody is an anibody that is made in a lab instead of in the body. They are designed to attack a certain pathogen. They are used by the immune system to kill tumor cells and or can bring raditation or chemotherapy directly to an “antigen”. The second is Cytokines. They are naturally in the human body, but can also be created in a lab. They are then brought into the body to assist in the finding of cancers. The third is a cancer vaccine. These vaccines do not prevent a cancer from developing, instead they allow the immune system to recognize cancerous cells and destroy them. After Hodgkin's Lympoma has been treated, patients typically make a strong recovery. Similarly, 30-60% of patients with aggressive non-Hodgkin's Lymphoma can be cured. However, there is currently no cure for indolent NHL, although patients typically live up to twenty years after the cancer has been diagnosed. Even after being treated, people who have had HL can have complications such as infertility, liver failure, lung problems, and the development of other cancers. People who have had NHL and are in remission can become Autoimmune hemolytic anemic and develop other infections. 


In conclusion, there are a wide variety of lymphomas. They can be fatal if ignored, and are often mistaken for the common cold. However, when they are found they are usually treatable,  and if we continue to focus our efforts on innovative treatments, such as immunotherapy, this cancer could be cured. 


Sources:
http://www.emedicinehealth.com/lymphoma/article_em.htm 

http://www.lymphoma.org/site/pp.asp?c=bkLTKaOQLmK8E&b=6299689

http://www.cancer.gov/cancertopics/treatment/biologicaltherapy

http://www.lls.org/all_page?item_id=7030

http://www.lymphomainfo.net/lymphoma/symptoms.html

http://health.nytimes.com/health/guides/disease/hodgkins-lymphoma/overview.html?scp=1&sq=lymphoma&st=cse

http://health.nytimes.com/health/guides/disease/hodgkins-lymphoma/in-depth-report.html

http://health.nytimes.com/health/guides/disease/non-hodgkins-lymphoma/overview.html

http://lymphoma.about.com/od/hodgkinlymphoma/p/hodgkintypes.htm

http://www.oncologychannel.com/nonhodgkins/types.shtml

http://www.lymphomainfo.net/hodgkins/timeline.html

http://www.news-medical.net/health/Non-Hodgkin-Lymphoma-History.aspx

Photosynthesis

It's a well known fact that plants need water and sunlight to make food, but how is that possible? Essentially, plants create their own food through a process called photosynthesis. Photosynthesis is made up of two different processes called the light dependent reaction (also called the light reaction) and the light independent reaction (also called the dark reaction or the Calvin cycle). Both of these reactions take place in the chloroplast (shown at the left). The light reactions specifically take place in the thylakoid. Inside each thylakoid there is a system very similar to the electron transport system. This reaction is shown in the image below labeled "Light dependent reaction". This reaction begins with energy from the sun. The plant can use this energy because they have several pigments, one of which is chlorophyll. These pigments allow the plant to absorb the sun's energy. One photon of energy enters into photosystem two (PSII) and bounces off of the walls of photosystem two. The photon then reaches the reaction center at the base of the photosystem. There, a water molecule (H2O) has broken apart into H+ and O2. When the water is broken apart, an electron is released. The photon excites the electron, giving is energy. This electron travels up to the top of photosystem two. It then descends across the system and entersphotosystem one (PSI). As is descends it pumps one H+ ion from the stroma into the thylakoid lumen (the area inside the thylakoid). Once the electron is inside photosystem one, it travels upward until is reaches the electron carrier. There, it reduces NADP+ to NADPH. As this process repeats, a high concentration of H+ ions is build up in the lumen. These ions then travel through the ATP synthase one by one. As they move through, they physically rotate the synthase. This creates energy, and the energy converts ADP and P to ATP. 

As a review, the inputs of the light dependent reaction are as follows:

1 H2O

Light

and the outputs are:

1 O2 (final product)

2 ATP (used in the Calvin Cycle)

1 NADPH (used in the Calvin Cycle)

Light dependent reaction

The next component of photosynthesis is the Calvin Cycle. The calvin cycle creates G3P, or PGAL, which the plant uses to make glucose. It takes three molecules of CO2 to create one molecule of PGAL, therefore this explanation will be describing the cycle in terms of three molecules of CO2. The Calvin Cycle begins with CO2, in this instance three molecules. These molecules of CO2 combine with three molecules of RuBP to form a six carbon molecule. The enzyme rubisco assists in this joining. This is a brief transition phase, and soon these molecules split into three carbon molecules, for a total of six three carbon molecules. These molecules must be rearranged and gain phosphates. Therefore, six ATP oxidize to form ADP and six NADPH oxidize to form six NADP+ and phosphate. Next, the three carbon molecules each lose a carbon. These carbons form a PGAL, and the unused substances are rearranged. The rearranging takes energy, and three ATP oxidize to become 3 ADP. The result is three Rubisco and the cycle continues. When two PGALs are created, they combine to form glucose.

As an overview, the inputs of the Calvin cycle (when one pyruvate is created) are:
3 CO2
9 ATP
6 NADPH

And the outputs are:

9 ADP
6 NADP+
6 P
1 Pyruvate

The equation for photosynthesis is: 6CO2 + 6H2O -> C6H12O6 + 6CO2


This autotrophic system of plants is amazing. Plants take in CO2 and water, two substances that are abundant on our planet, and they convert them to food and oxygen. This phenomenon is present every plant, and even some species of bacteria. It is an essential factor to maintaining the delicate balance of life on Earth. Although we have not yet studied this in class, I believe that the amount of light will assist in photosynthesis and the amount of water. Light would increase the amount of photosynthesis because light is used to excite the electron in the light reaction and water would assist because if there is a lack of water a light reaction cannot occur and therefore there will be no energy to use in the dark reaction.


Sources:

http://en.wikipedia.org/wiki/Photosynthesis

Images:

http://dft.ba/-anQ

http://micro.magnet.fsu.edu/primer/java/photosynthesis/

http://www.daviddarling.info/images/Calvin_cycle.jpg

Allergic to your Cell Phone?

When you think about cell phones, what comes to mind? Texting, perhaps, the iphone, or even radiation. But an allergic reaction? In the past few years, scientists have been finding rashes on the faces of teenagers and adults, along the jawline. The cause of these rashes was a mystery, until recently. The New York Times released an article this Tuesday, which linked the rash toNickel found in cell phone casing.

According to Web MD, "A nickel allergy is a skin reaction that develops after exposure to nickel or items containing the metal." This essentially means that a nickel allergy is caused by touching or wearing nickel for a long period of time. In America, 3% of men have this allergy and 20% of women. This is because many items of jewelry contain nickel. Therefore, the jewelry wearers are more exposed to the nickel. This is the same process that occurs with cell phone users. However, with a cell phone user it is called, "Contact dermatitis with a Nickel allergy". If a person is constantly talking on their cell phone, the face can become hypersensitive to nickel. This hypersensitivity becomes an allergy.

A nickel allergy has several, rather similar, symptoms. The most common are:

• A rash where the nickel has touched the skin
• Itching
• Red areas of skin
• Dry areas of skin (these can look like burns)
• Blisters

This allergy can come from other objects as well. Some examples are watchbands, zippers, belt buckles, hairpin, dental fillings, prosthetics, and even the frames of glasses. People with severe nickel allergies must limit their contact with some of these objects, and avoid eating oatmeal, chocolate, nuts, beans and dried fruit; which contain small amount of nickel. 

However, it is possible to treat this allergy. Doctors recommend using steroid creams, such as cortisone, and preventing any further contact by using a headset.

Link to a brief Masher video summarizing the cell phone issue:
http://www.masher.com/player.jsp?key=0dbe76c7-a2bc-cb73-63d8-0000effb001b&adscheme=0

Sources:
http://www.nytimes.com/2010/11/23/health/23really.html?_r=1&ref=health
http://www.webmd.com/allergies/nickel-jewelry-allergy
http://www.businessweek.com/lifestyle/content/healthday/645796.html
http://www.mayoclinic.com/health/nickel-allergy/DS00826/DSECTION=symptoms
http://www.cmaj.ca/cgi/content/full/178/1/23
http://allergies.about.com/b/2008/10/16/mobile-phone-allergy.htm
http://preparednesspro.files.wordpress.com/2009/06/person-on-cell-phone.jpg

Intro to Chemistry

A neat intro to Chemistry video:

Melanosomes: Dinosaurs in White, Orange, and Grey

Anchiornis huxleyi

What color was a Tyrannosaurus Rex? What about a triceratops, or a pterodactyl? Pink and yellow, or more earthy shades, like brown and grey? Since the discovery of the dinosaur, their hues, vibrant or otherwise, were a mystery. This was until the discovery of melanosomes.

Melanosomes are "pigment filled sacs" that determine the colors of the feathers of birds. In essence, the cells carry the color of the species within them, in the form of melanin. In 2009, a researcher at Yale, by the name of Dr. Prum, discovered that these melanosomes could be kept in a fossil for millions of years.

These melanosomes were so well preserved because instead of being on the outside of the feathers, they were contained within. This meant that they were protected from damage as long as the feathers remained intact.

The Yale scientists conducted studies on several ancient dinosaur feather fossils, and discovered that it was possible to determine the color of the fossil from the melanosomes. Therefore, they teamed up with paleontologists from the Beijing museum of Natural History and Peking University. These scientists were led by Fucheng Zhang. Together, they took the fossil of a Anchiornis huxleyi, which lived 150 million years ago during the "Middle Jurassic" into the "Late Jurassic". This tiny dinosaur had very long legs, which were covered with feathers (as were its arms). They took out twenty nine "chips" of the fossil to examine under a microscope, and found that these pieces contained melanosomes.

After finding the melanosomes in the dinosaurs, the scientists had to compare these melanosomes to the melanosomes found in modern birds. They already knew that this dinosaur had two different types of melanosomes, called eumelanosomes and phaeomelanosomes. Eumelanosomes are found in dark colors, such as black, grey, and brown. The phaeomelanosomes can be found in feathers that range in shade from yellow to red. However, the scientists didn't want a general guess of the colors, they wanted to find the real answers. Thus, they contacted Matthew Shawkey, a scientists who had already done in depth studies of melanosomes in living birds. They matched the melanosomes in the Anchiornis with those of other birds, and discovered that the feathers on the birds arms and legs were black and white, while its head was covered with a magnificent orange plume.

After this discovery, they tried to replicate this process with other fossils that had the "dinosaur fuzz" feathers. They were able to find the color of the Sinosauropteryx's tail (reddish with white rings). They could also make educated guesses about the pigments of the sinonithosaurus, and the confuciusornis, because their feathers were not preserved as well.

This is a remarkable study, and who knows, maybe some day we'll learn that the Tyrannosaurus Rex was bright pink!

The height of an Anchiornis compared to the height of a human being.

The sinosauropteryx

Sources:
http://www.nytimes.com/2010/02/05/science/05dino.html?ref=dinosaurs
http://scienceblogs.com/notrocketscience/2010/01/what_colours_were_dinosaur_feathers.php
http://blogs.smithsonianmag.com/dinosaur/2010/02/05/dinosaurs-now-in-living-color/
http://blogs.smithsonianmag.com/dinosaur/2010/01/28/fossil-feathers-may-preserve-dinosaur-colors/
http://en.wikipedia.org/wiki/Anchiornis
http://i.livescience.com/images/ig59_Sinosauropteryx_09.jpg

Sharks!!!

Before dinosaurs roamed the earth, sharks were swimming the seas. For 420 million years, sharks have been evolving and adapting to their environments. One of the most essential aspects of this evolution has been the development of osmoregulation. There are three primary environments in which osmoregulators live: terrestrial, freshwater, and marine. Because sharks primarily live in saltwater, they live in the marine environment. This environment can pose a problem to many animals, as it makes it hard for them to achieve homeostasis, the state at which the ratio of solutes to solvent inside the body equals the ratio of solutes to solvents outside of the body. It is one of the most basic goals of any animal to acheive homeostasis, and thus, over time, each species of animal has developed a unique way of balancing the ratios. A shark is an osmoconformer, as are most animals that live in the marine environment. This means that it adapts its internal environment to have homeostasis with that of the outside. The bodies of sharks are especially high in two substances, urea and trimethylamine N-oxide. Urea is commonly found in urine, and trimethylamine N-oxide is commonly found in decomposing animals. Both of these compounds allow a shark to be isotonic. Any excess salt in the body is removed through the urine. Thus, unlike most animals that live in salt water, sharks do not drink the water that they live in. Instead, they change their concentration gradient by storing large amounts of chemicals inside of their own bodies. This allows can absorb water straight from the ocean and into their own cells. However, this prevents most sharks from living in fresh water, with few exceptions. One of these exceptions would be the bull shark. A bull shark has adapted its kidneys so that when the shark moves into freshwater, the kidneys expel less salt and more urea, allowing the shark to retain more of the salt necessary to reach homeostasis. Overall, the ability of a shark to osmoconform has been vital to their survival for millions of years.

Fun facts:
These facts do not relate to osmoregulation, but they relate to sharks and are quite interesting!
1. The skeleton of a shark is made entirely of cartilage
2. Great White sharks can jump ten feet into the air!
3. Certain species of sharks will stop breathing if they stop moving
4. Great White sharks eat 11 tons of food in one year!
5. A mere 20 of the 350 species of sharks worldwide have attacked humans
6. On average, people kill 73,000,000 sharks each year
7. Magnets can repel sharks
8. Sharks are able to hear the fish that they eat from 800 feet away
9. Sharks can smell one drop of blood in an area of water equivalent to that of an olympic pool (660,000 gallons)
10. The smallest type of shark is eight inches long!

An image of the pygmy shark, the world's smallest shark

Sources:
http://www.thebiohub.blogspot.com
http://en.wikipedia.org/wiki/Shark
http://www.sharks.org.za/osmoregulation.html
http://dsc.discovery.com/sharks/top-shark-facts-10.html
http://dsc.discovery.com/sharks/top-shark-facts-03.html
http://dsc.discovery.com/sharks/top-shark-facts-01.html
http://dsc.discovery.com/sharks/top-shark-facts-04.html
http://dsc.discovery.com/sharks/top-shark-facts-08.html
http://dsc.discovery.com/sharks/top-shark-facts-07.html
http://en.wikipedia.org/wiki/Olympic-size_swimming_pool
http://dsc.discovery.com/sharks/top-shark-facts-09.html
http://static.howstuffworks.com/gif/great-white-shark-1.jpg
http://static.howstuffworks.com/gif/pygmy-shark-2.jpg
http://en.wikipedia.org/wiki/Bull_shark
http://www.sharksavers.org/en/education/shark-biology-behavior/385-how-bull-sharks-can-live-in-fresh-water-through-clever-osmoregulation.html