what causes Dandruff?

Dandruff is a harmless, chronic condition that occurs when the scalp becomes dry or greasy and produces white flakes of dead skin that appear in the hair or on the shoulders. People most often think of dandruff as anything that produces a flaky scalp.

Although it is harmless, dandruff can be embarrassing for those who have it. Dandruff usually starts between the ages of 10 and 20 and affects up to 40% of people over the age of 30.

Skin cells are formed continuously on the scalp, so the shedding of dead skin cells is a normal process. With dandruff, however, skin cells are shed at a faster rate than normal. Oil from the scalp causes the skin cells to clump together and appear as white flakes.

Dandruff can be caused by a number of things, including dry skin; sensitivity to hair products; and skin conditions such as psoriasis, seborrheic dermatitis, or eczema.

The overgrowth of yeast can also cause dandruff. This overgrowth can be caused by stress, hormones, too much oil on the scalp, or problems with the immune system.

The symptoms of dandruff include white flakes of dead skin in the hair and on the shoulders, as well as an itchy, red, or scaly scalp. Common dandruff flakes are usually scattered throughout the scalp.

If seborrheic dermatitis is the cause of dandruff, the symptoms usually appear gradually. The scalp becomes dry or greasy and feels itchy. As skin cells die, they turn to yellowish scales. A bad case of seborrheic dermatitis can also cause symptoms in other parts of the body. Yellowish or reddish scaling can appear on the hairline, in and around the ears, or on the nose and chest. Affected newborn babies may get a thick and crusty rash on the scalp, called cradle cap.

The flakes associated with psoriasis look like silver scales, which may also commonly be apparent on the ears, extremities, trunk, palms, and soles.

why does human hair turn gray?

Have you ever watched someone try to cover up gray hair by dyeing it? Or maybe you wonder why your granddad has a full head of silver hair when in old pictures it's dark brown. Getting gray, silver, or white hair is a natural part of growing older, and here's why.

Each hair on our heads is made up of two parts:

1. a shaft — the colored part we see growing out of our heads
2. a root — the bottom part, which keeps the hair anchored under the scalp

The root of every strand of hair is surrounded by a tube of tissue under the skin that is called the hair follicle (say: FAHL-ih-kul). Each hair follicle contains a certain number of pigment cells. These pigment cells constantly make a chemical called melanin (say: MEL-uh-nin) that gives the growing shaft of hair its color of brown, blonde, black, red, and anything in between.

Melanin is the same stuff that makes our skin's color fair or darker. It also helps determine whether a person will burn or tan in the sun. The dark or light color of someone's hair depends on how much melanin each hair has.

As we get older, the pigment cells in our hair follicles gradually die. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color — like gray, silver, or white — as it grows. As people continue to get older, fewer pigment cells will be around to produce melanin. Eventually, the hair will look completely gray.

People can get gray hair at any age. Some people go gray at a young age — as early as when they are in high school or college — whereas others may be in their 30s or 40s before they see that first gray hair. How early we get gray hair is determined by our genes. This means that most of us will start having gray hairs around the same age that our parents or grandparents first did.

Gray hair is more noticeable in people with darker hair because it stands out, but people with naturally lighter hair are just as likely to go gray. From the time a person notices a few gray hairs, it may take more than 10 years for all of that person's hair to turn gray.

Some people think that a big shock or trauma can turn a person's hair white or gray overnight, but scientists don't really believe that this happens. Just in case, try not to freak out your parents too much. You don't want to be blamed for any of their gray hairs!

Is Sperm good for our skin?

Sperm is one of the vital components when planning to start a family. Like a women's egg, a man's sperm must be healthy in order to reach and penetrate the egg.  Though sperm is mainly used for procreation, it can have extraordinary benefits for everyday life.

In sperm, a crystalline polyamine compound called Spermine can be found. This particular compound is also known as an antioxidant. It is believed to diminish wrinkles, smooth skin and help with taming or preventing acne. Bioforskning, a Norwegian company, has synthesized the compounds into a facial cream.  According to Bioforskning, the cream Spermine is 30 times more effective than vitamin E and can delay the aging process by 20 percent. However, nature's most natural facial cream can cost you a whopping $250.  

Not only can sperm provide healthy skin, but also it can be used as an anti-depressant. In a recent study, researchers demonstrated that women who were directly exposed to semen were less likely to be depressed. The study stated mood-altering hormones that are present in semen can be absorbed through the vagina. Some of these mood-altering chemicals include, but are not limited to prolactin, a natural anti-depressant; oxytocin, which assist in enhancing one's mood and serotonin, a widely known antidepressant neurotransmitter.

Sperm is also directly linked to the frequency and intensity of a woman's morning sickness. According to SUNY-Albany psychologist Gordon Gallup, the frequency of morning sickness is directly related to the frequency of insemination during pregnancy.  Gallup and graduate student Jeremy Atkinson revealed women who undergo artificial insemination may experience worst cases of vomiting, and nausea.

When it comes to cooking, although semen may be the farthest thing from your mind, according to "Natural Harvest-A Collection of Semen-Based Recipes," semen is very nutritious. The cook book advertises semen as an "inexpensive" ingredient that can give any food an "interesting twist."

Lastly, if by any chance you are in dire need of invisible ink, semen may suffice. During World War I, the British Intelligence Service discovered semen can act as invisible ink. Unlike other chemicals used, semen did not react to means of detection such as iodine vapor.

Unless you are a part of an intelligence serve of some kind, invisible ink may not be essential, however if you ever need a facial Spermine may be a great option. 

Do Werewolves exist?

Throughout history, werewolves have played an integral part in the cult literature as creatures that were not of men or wolf – but both. Most common legends attest to how these creatures can shape-shift from a man to a wolf or wolf-like creature by the light of the full moon. Silver is the only weapon that can stop them, and the disease of lycanthropy can be spread by a mere scratch or bite.

Although Hollywood has romanticized the thought of werewolves and how not all of them are vicious killing machines, is there anything to worry about for the common man walking home one night during the light of the full moon? It is doubtful since no real evidence has ever been brought to public knowledge aside from folktales and lore. Why should the belief of werewolves be met with suspicion and skepticism?   Can we answer the question… do werewolves exist?

Translations from ancient times often lead to the creation of rumors and myths.

For example, Procopius of Caesarea recorded a battle between the Roman Empire and the Isaurians. These South Asian people were merely farmers when they were called to battle in the fifth century. In the recording, Procopius recalled how the Isuarians were slain due to their inability to wage war against Rome. He referred to most of these people as Lycaones. Many believe this to be related to the latin word, Lycaon – an animal of the wolf kind. In reality, Lycaones refers to the Lycaonians – a people of Asia Minor positioned relatively close to the Isuarian lands that were incapable of battle due to inexperience.

This isn’t the only incident in where misunderstanding of texts has created myths and legends

In the late 16th century, rumors of the werewolf stretched far and wide across Europe. When Peter Stubbe committed heinous crimes against the people of Bedburg, his ferocious nature was akin to that of a wolf. In much the same way that Vlad Tepes was depicted as a vampire, Stubbe’s actions earned him a reputation as he killed in much the same fashion a wolf would while taking down prey.

The story of the Werewolf of Bedburg was literature developed in order to help a people understand the cruel and inhumane nature that psychopaths can embrace. Peter Stubbe could no more change shape into a wolf as Vlad the Impaler could turn into a bat.

Humans often attempt to build myths and legends around certain aspects of existence in order to understand current situations. Five hundred years ago, most of the people on the planet knew the Earth was flat. Two hundred years ago, certain people on the planet believed the shining objects in the sky were gods looking down upon them.

Throughout history, those suffering from hypertrichosis were viewed as werewolves merely because the condition forces the growth of thick hair on the face and body. Could you imagine being hunted merely because you grew hair covering your face?

The human body is not developed well enough to force inter-species transformations. Bones would have to break, muscles and tendons would snap, and the shock to our systems would be catastrophic. The DNA of a human would unravel like a rug with a loose string and a child yanking on the end.  It’s physically impossible to quickly morph into a much larger species.

why do humans have different eye colors?

Eye color is the result of variations in the amount of melanin, a pigment found in the front part of the iris of the eye.  The lack of this pigment results in blue eyes, some pigment gives green and lots of pigment gives brown eyes.

 

So light brown eyes just have a bit less melanin than darker brown eyes.  All of the different shades of eye color happen the same way.  Blue-green eyes have an amount of melanin between green and blue, hazel eyes have an amount of pigment between green and brown, etc.  

 

Some people have eyes that have different colored patches.  For example, blue eyes with a green or brown circle around the pupil are pretty common.  In these eyes, different parts of the iris make different amounts of melanin.  

 

What we don't have yet is a good handle on how this all happens genetically. Scientists have a pretty good model based on two genes that can help explain blue, green, and brown eyes.  This is the model we based our eye color calculator on.

 

Scientists have even found the key gene, OCA2, which can explain why some people have brown eyes and some people don't.  Despite some work, scientists haven't been able to find the key gene involved in green eyes.  This is most likely because there is more than one gene.

 

A new study has identified three new genes that affect eye color. Scientists don't know what each of these genes exactly do and they don't know how to use them in eye color calculators just yet.  But given what we know about eye color, we can make some pretty good guesses about what these genes probably do...

 

Most likely these genes are either responsible for making melanin themselves or they control how much melanin other genes make.  Either way you end up with different shades of eye color based on the combination of genes that you have.

 

What I thought I'd do for the rest of the answer is first go through some background about genes. Then I'll talk about the new genes scientists found and finally I'll give a few examples of how these new genes can be involved in producing different shades of eye color.

 

Genes are Instructions

 

Your genes have the instructions for making and running you.  Each gene is made of DNA and has the instructions for some small part of you.

 

So there is a gene that decides whether or not you have red hair.  And one that decides whether or not you can taste a bitter chemical called PTC.  And so on.

 

Some traits are too complicated to be the result of a single gene.  These traits come about when lots of genes work together.

For example, it takes a set of genes to instruct a cell to be a nerve cell.  It also takes a set of genes to tell a cell in the iris of the eye to make specific amounts of melanin.

 

Now it isn't actually the genes that do any of this. Genes have the instructions for proteins, which do the actual work.

  

For example, OCA2 (the eye color gene we talked about earlier) has the instructions for making something called the P-protein.  And the P-protein is a key player in making melanin in a cell.

 

It is important to mention that people with different colored eyes don't have different eye color genes.  They have different versions of the same genes, which make slightly different versions of the same proteins.

 

For example, everyone has an OCA2 gene.  What gives different people different colored eyes is the version of the OCA2 gene they have.

 

Some people have a version of OCA2 that makes a lot of P-protein in the iris.  These folks have brown eyes. Other people have versions of OCA2 that either make less and/or a weak form of the P-protein.  These folks make very little melanin in the iris and so most end up with eyes that aren't brown.  All of these folks, no matter the eye color, have an OCA2 gene.

 

Think of genes as playing cards. A deck of cards has 4 versions of an ace (diamonds, clubs, hearts, and spades).  But no matter the suit, an ace is an ace in most card games.  The same thing can be said about genes.  No matter the version of OCA2, we all still have an OCA2 gene.

What is new?

In the recent eye color study scientists looked at the DNA of people with a variety of eye colors ranging from the lightest blue to the darkest brown. The researchers found three new regions in their DNA that can be associated with eye color.

 

One of these regions is a gene called LYST. This gene was previously linked to coat color in cattle and eye color in mice. 

 

The other two genes have never been linked to eye color before. Scientists believe that these genes are also responsible for the different shades of color observed in the human eye.

 

Now it isn't surprising that scientists found more than one other gene. We always knew there were more than two genes involved in eye color because there are more than three eye colors out there.

 

Unfortunately we don't yet know the specifics of what these genes do. But based on what we know about eye color, we can imagine some possible functions for these new eye color genes.  

 

By now you know that OCA2 is a very important eye color gene. So there could be other genes that influence how OCA2 works. In fact we already know of a gene called HERC2, which does just that.

 

HERC2 is needed for eye cells to read OCA2.  Some people have a version of HERC2 that can't do its job very well.  These folks' eye cells can't read the OCA2 gene very well either.

 

If OCA2 isn't read, no P-protein gets made.  And no P-protein means very little melanin in the iris, which means an eye color other than brown.

 

You probably noticed that I didn't say these genes lead to blue eyes.  Instead I kept saying they lead to the lack of brown eyes.

 

HERC2 and OCA2 can explain why many people's eyes aren't brown.  We need other genes to explain why eyes are green, blue, light brown, hazel and so on. This is where the new genes for the new study could play a role.

Making Green Eyes

Let's look at a couple of ways that these new genes might cause green eyes.  They might do this by turning the OCA2 gene up or down.

 

Imagine someone has a working HERC2 and OCA2 gene.  Without other genes around, this person would have brown eyes.  Now imagine that this person has a version of one of the new genes that turns the OCA2 gene down.  This person will now have green eyes instead of brown.

 

Now imagine someone with a weak HERC2 gene.  This person's OCA2 is turned way down so that he or she would have blue eyes if there were no other genes around.

 

But imagine that this person has a version of one of the new genes that turns the OCA2 gene up.  Now more P-protein gets made and so this person has green eyes.

 

As you can see, a single eye color can be obtained in multiple ways!  And our final eye color is determined by how all of these different genes and their different versions work together.

 

Think of the cells in the iris of your eye as melanin producing factories. The workers of these factories are proteins that serve like workers in an assembly line and carry out the different steps for making melanin.

 

So you can imagine that any of the new genes could have the instructions to proteins involved in the different steps of producing melanin. The shared efforts of these new genes could for example boost melanin levels to produce hazel eyes, or reduce total melanin resulting in blue eyes.

Why are the world's deserts located at 30 degrees latitude?

Deserts on Earth exist at 30 degrees latitude because of warm air, calm winds and virtually constant areas of high pressure forming in the atmosphere above. These deserts experience dry and hot conditions year-round and see plenty of sunlight, little wind and very little precipitation. This area of desert lands forms in the areas of latitude 30 degrees north to 30 degrees south of the Equator.

The region containing most deserts on Earth takes several names, including the Tropic of Cancer, Tropic of Capricorn and the horse latitudes. In these regions, the sun follows a high orbital path. It appears directly overhead at 12 p.m. at least once a year, a phenomenon occurring no other place on the planet. Although they exist at the same degrees of latitude, deserts bear different physical and biological features. They attain shapes and climates from surrounding landscapes.

Deserts situated near mountains generally experience less rainfall than deserts exposed in flat, open lands, as mountains absorb precipitation before it reaches deserts. The winds generated in the horse latitudes blow from a westerly direction and lack tremendous force. These winds lack the power for moving clouds across continents, which reduces precipitation in deserts. Although beneficial for desert climates, atmospheric conditions in the horse latitudes pose problems for sailors, whose boats slow to a standstill in the absence of winds.

How do ocean form?

Nearly 3.8 billion years ago, temperatures on Earth cooled below 100 degrees Celsius for the first time, allowing water, which existed on the planet in gaseous form, to condense into rain and collect on the planet's surface, according to the American Museum of Natural History. This water collected in low-lying areas, eventually becoming a primitive ocean.

This early ocean was likely very shallow and covered the majority of the Earth's surface, as continents did not exist yet and would not for some time, according to the American Museum of Natural History.

A report by the BBC indicates that the most recent of all supercontinents to form on the planet, Pangea, formed about 270 million years ago and split into sections about 200 million years ago. Pangea was a landmass covering almost one-third of the planet's surface. Scientists refer to the surrounding ocean as Panthalassa.

Pangea began splitting down the middle, allowing the Atlantic Ocean to form between South America and Africa and between North America and Europe, according to an article from the Rutgers University Department of Geologic Sciences. Signs of that split are visible on the floor of the Atlantic Ocean. Additional fractures allowed smaller oceans, such as the Indian Ocean, to form. The Pacific Ocean represents much of what was originally known as Panthalassa.

Deserts

Why deserts important?

Deserts are important because they provide corridors for migration for a number of species and yield a number of water-soluble nutrients not available in comparable quantities anywhere else on the planet. The spread of these nutrients benefits species all over the planet.

 

Many birds not indigenous to deserts use the arid lands as migratory paths, stopping for sustenance at oases along the way. Threats that come from the spread of grassland and human use of resources from the oases place these species at risk.

Deserts are the primary source of table salt, borates, potassium and sodium nitrates and gypsum. Soda, nitrates and boron are the most common evaporite minerals that appear only in deserts. Approximately half of the world's stores of fossil fuels come from desert lands, including oil and natural gas, and about half of the world's diamonds, copper, gold, bauxite, iron ore and uranium ore come from the desert as well. The fact that Saharan dust has been found in the Amazon basin shows the worldwide spread of the materials in the desert.

Advancements in industry and technology have permitted the growth of cities in the desert. This increased activity places a strain on the surrounding environment: in the Chihuahuan Desert, for example, about half of the butterfly, mammal and bird species are projected to be gone by 2055, replaced by different species.

Agartha (the hollow earth)

Agartha (sometimes Agartta, Agharti, Agarta or Agarttha) is a legendary city that is said to be located in the Earth's core.It is related to the belief in a hollow Earth and is a popular subject in esotericism.


History

Nineteenth-century French occultist Alexandre Saint-Yves d'Alveydre published the first "reliable" account of Agartha in Europe. According to him, the secret world of "Agartha" and all of its wisdom and wealth "will be accessible for all mankind, when Christianity lives up to the commandments which were once drafted by Moses and God", meaning "When the Anarchy which exists in our world is replaced by the Synarchy." Saint-Yves gives a lively description of "Agartha" in this book as if it were a place which really exists, situated in the Himalayas in Tibet. Saint-Yves' version of the history of "Agartha" is based upon "revealed" information, meaning received by Saint-Yves himself through "attunement".^{[citation needed]}

The explorer Ferdynand Ossendowski wrote a book in 1922 titled Beasts, Men and Gods. In the book, Ossendowski tells of a story which was imparted to him concerning a subterranean kingdom which exists inside the Earth. This kingdom was known to the Buddhists as Agharti.

Connections to mythology

Agartha is frequently associated or confused with Shambhala, which figures prominently in Vajrayana Buddhism and Tibetan Kalachakra teachings and revived in the West by Madame Blavatsky and the Theosophical Society. Theosophists in particular regard Agarthi as a vast complex of caves underneath Tibet inhabited by evil demons, called asuras. Helena and Nicholas Roerich, whose teachings closely parallel theosophy, see Shambhala's existence as both spiritual and physical.

Cats (nine lives?)

The idiomatic expression that cats have nine lives comes not from a literal reality in which cats have an arbitrarily limited immunity but rather from a myth that is likely related to the domestic cat's impressive agility. However, as a figurative way of describing feline dexterity, the nine lives myth conjures up vivid imagery, which may be why William Shakespeare referenced it in his famous tale of star-crossed lovers, "Romeo and Juliet." Overall, it is difficult to pin down an exact origin for this myth, including an explanation for the specific number nine, though it may have origins in Egyptian or Chinese belief systems that ascribe special significance to the number nine.

 The root of the ancient Egyptian emphasis on the number nine is related to the sun god Atum-Ra. This god was supposed to be able to take on a cat's form, and, because he was said to have given birth to eight other gods, Atum-Ra represented the concept of nine lives in a single being. In China, the number nine is considered lucky because of how well divided it is, representing three groups of three. There are other cultures that believe that cats have multiple lives, but the number value does not always equal nine, indicating that the myth is probably simply related to a cat's superior ability to survive falls.

What is Ink made of?

Ink is a liquid or paste that contains pigments or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, or quill. Thicker inks, in paste form, are used extensively in letterpress and lithographic printing.

Ink can be a complex medium, composed of solvents, pigments, dyes, resins, lubricants, solubilizers, surfactants, particulate matter, fluorescents, and other materials. The components of inks serve many purposes; the ink’s carrier, colorants, and other additives affect the flow and thickness of the ink and its dry appearance.

History

Many ancient cultures around the world have independently discovered and formulated inks for the purposes of writing and drawing. The knowledge of the inks, their recipes and the techniques for their production comes from archaeological analysis or from written text itself.

The history of Chinese inks can be traced back to the 23rd century BC, with the utilization of natural plant (plant dyes), animal, and mineral inks based on such materials as graphite that were ground with water and applied with ink brushes. Evidence for the earliest Chinese inks, similar to modern inksticks, is around 256 BC in the end of the Warring States period and produced from soot and animal glue.

 The best inks for drawing or painting on paper or silk are produced from the resin of the pine tree. They must be between 50 and 100 years old. The Chinese inkstick is produced with a fish glue, whereas Japanese glue (膠 "nikawa") is from cow or stag.

The process of making India ink was known in China as early as the middle of the 3rd millennium BC, during Neolithic China.^[7] India ink was first invented in China, although the source of materials to make the carbon pigment in India ink was later often traded from India, thus the term India ink was coined. The traditional Chinese method of making the ink was to grind a mixture of hide glue, carbon black, lampblack, and bone black pigment with a pestle and mortar, then pouring it into a ceramic dish where it could dry. To use the dry mixture, a wet brush would be applied until it reliquified. The manufacture of India ink was well-established by the Cao Wei Dynasty (220–265 AD). Indian documents written in Kharosthi with ink have been unearthed in Chinese Turkestan.The practice of writing with ink and a sharp pointed needle was common in early South India. Several Buddhist and Jain sutras in India were compiled in ink.

In ancient Rome, atramentum was used, in an article for the Christian Science Monitor, Sharon J. Huntington describes these other historical inks:

About 1,600 years ago, a popular ink recipe was created. The recipe was used for centuries. Iron salts, such as ferrous sulfate (made by treating iron with sulfuric acid), were mixed with tannin from gallnuts (they grow on trees) and a thickener. When first put to paper, this ink is bluish-black. Over time it fades to a dull brown.

Scribes in medieval Europe (about AD 800 to 1500) wrote principally on parchment or vellum. One 12th century ink recipe called for hawthorn branches to be cut in the spring and left to dry. Then the bark was pounded from the branches and soaked in water for eight days. The water was boiled until it thickened and turned black. Wine was added during boiling. The ink was poured into special bags and hung in the sun. Once dried, the mixture was mixed with wine and iron salt over a fire to make the final ink.

The reservoir pen, which may have been the first fountain pen, dates back to 953, when Ma'ād al-Mu'izz, the caliph of Egypt, demanded a pen that would not stain his hands or clothes, and was provided with a pen that held ink in a reservoir.

In the 15th century, a new type of ink had to be developed in Europe for the printing press by Johannes Gutenberg. According to Martyn Lyons in his book Books: A Living History, Gutenberg’s dye was indelible, oil-based, and made from the soot of lamps (lamp-black) mixed with varnish and egg white. Two types of ink were prevalent at the time: the Greek and Roman writing ink (soot, glue, and water) and the 12th century variety composed of ferrous sulfate, gall, gum, and water.^[Neither of these handwriting inks could adhere to printing surfaces without creating blurs. Eventually an oily, varnish-like ink made of soot, turpentine, and walnut oil was created specifically for the printing press.

In 2011 worldwide consumption of printing inks generated revenues of more than 20 billion US dollars. Demand by traditional print media is shrinking, on the other hand more and more printing inks are consumed for packagings.

Monotreme

Monotremes are basal mammals that lay eggs (Prototheria) instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). The only surviving examples of monotremes are all indigenous to Australia and New Guinea, although there is evidence that they were once more widespread. The existing monotreme species are the platypus and four species of echidnas. There is currently some debate regarding monotreme taxonomy.

The word monotreme comes from the Greek μονός, monos ("single") and τρῆμα, trema ("hole"), referring to the cloaca

General Characteristics

Like other mammals, monotremes are warm-blooded with a high metabolic rate (though not as high as other mammals; see below); have hair on their bodies; produce milk through mammary glands to feed their young; have a single bone in their lower jaw; and have three middle-ear bones.

In common with reptiles and marsupials, monotremes lack the connective structure (corpus callosum) which in placental mammals is the primary communication route between the right and left brain hemispheres.^[3] The anterior commissure does provide an alternate communication route between the two hemispheres, though, and in monotremes and marsupials it carries all the commissural fibers arising from the neocortex, whereas in placental mammals the anterior commissure carries only some of these fibers.^[4]

Platypus

Long-beaked echidna

Diagram of a Monotreme Egg. 1) Shell; 2) Yolk; 3) Yolk Sac; 4) Allantois; 5) Embryo; 6) Amniotic Fluid; 7) Amniotic Membrane; and 8) Membrane

Extant monotremes lack teeth as adults. Fossil forms and modern platypus young have a "tribosphenic" form of molars (with the occlusal surface formed by three cusps arranged in a triangle), which is one of the hallmarks of extant mammals. Some recent work suggests that monotremes acquired this form of molar independently of placental mammals and marsupials,^[5] although this is not well established.^[6]Toothloss in modern monotremes might be related to their development of electrolocation.^[7]

Monotreme jaws are constructed somewhat differently from those of other mammals, and the jaw opening muscle is different. As in all true mammals, the tiny bones that conduct sound to the inner ear are fully incorporated into the skull, rather than lying in the jaw as in cynodonts and other premammalian synapsids; this feature, too, is now claimed to have evolved independently in monotremes and therians,^[8] although, as with the analogous evolution of the tribosphenic molar, this is disputed.^[9][10] Nonetheless, findings on the extinct species Teinolophos confirm that suspended ear bones evolved independently among monotremes and therians.^[11] The external opening of the ear still lies at the base of the jaw.

The sequencing of the platypus genome has also provided insight into the evolution of a number of monotreme traits, such as venom and electroreception, as well as showing some new unique features, such as the fact that monotremes possess 10 sex chromosomes and that their X chromosome resembles the sex chromosome of birds,^[12] suggesting that the two sex chromosomes of marsupial and placental mammals evolved more recently than the split from the monotreme lineage.^[13] This feature, along with some other genetic similarities with birds, such as shared genes related to egg-laying, is thought to provide some insight into the most recent common ancestor of the synapsid lineage leading to mammals and the sauropsid lineage leading to birds and modern reptiles, which are believed to have split about 315 million years ago during the Carboniferous.^[14][15] The presence of vitellogenin genes (a protein necessary for egg shell formation) is shared with birds, suggesting that when the common ancestor of mammals from ~225 million years ago split into monotremes, marsupials, and placental mammals, egg laying was retained in monotremes and lost in all other mammals. DNA suggests that while this trait is shared and is synapomorphic with birds, platypuses are still mammals and they evolved lactation with other mammals.^[16] L-ascorbic acid is synthesized only in the kidneys.monotremes also have extra bones in the shoulder girdle, including an interclavicle and coracoid, which are not found in other mammals. Monotremes retain a reptile-like gait, with legs on the sides of, rather than underneath, their bodies. The monotreme leg bears a spur in the ankle region; the spur is not functional in echidnas, but contains a powerful venom in the male platypus. This venom is derived from b-defensins, proteins that are present in mammals that create holes in viral and bacterial pathogens. Some reptile venom is also composed of different types of b-defensins, another trait shared with reptiles. It is thought to be an ancient mammalian characteristic, as many non-monotreme archaic mammal groups also possess venomous spurs.