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The enamel covering of our teeth also withstands extreme acid-base fluctuations, some of which come from various populations of bacteria that grow in our mouths. Overall, enamel is by far the toughest material in our bodies, and scientists have been examining its structure and composition for decades.

Tooth enamel is clear and only covers and protects the crown (or top part) of teeth. Your dentin makes up the bulk of teeth and is responsible for their color. The roots of teeth are protected by something called cementum. This connective tissue is similar to bone, but not nearly as dense as tooth enamel. If your tooth enamel is weakened because of over-exposure to plaque and acid, supplemental minerals such as calcium and phosphate can strengthen your teeth. Neutralization of acids can help protect your enamel from damage. If your mouth is dry, you may have an issue producing ample saliva, which raises the mouth’s pH and assists in neutralizing acid. Seek the help of your Pella, IA family dentist if upping your hydration with water doesn’t seem to help this issue.

 

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Unlike your heart or brain, your teeth weren't ready to work from the day you were born. Although babies have the beginnings of their first teeth even before they are born, teeth don't become visible until babies are about 6 to 12 months old.

After that first tooth breaks through, more and more teeth begin to appear. Most kids have their first set of teeth by the time they are 3 years old. These are called the primary teeth, baby teeth, or milk teeth and there are 20 in all. When a child gets to age 5 or 6, these teeth start falling out, one by one.

A primary tooth falls out because it is being pushed out of the way by the permanent tooth that is behind it. Slowly, the permanent teeth grow in and take the place of the primary teeth. By about age 12 or 13, most kids have lost all of their baby teeth and have a full set of permanent teeth.

There are 32 permanent teeth in all — 12 more than the original set of baby teeth. Most people have four teeth (called wisdom teeth) grow in at the back of the mouth when they're between 17 and 25 years old. These complete the adult set of 32 teeth.

 

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Vitamin D is a prohormone that is essential for normal absorption of calcium from the gut, and deficiency of vitamin D is usually more common than either isolated calcium or phosphorus deficiency and is the commonest cause of rickets/osteomalacia.

Vitamin D is essential for skeletal health. It promotes differentiation of enterocytes and the intestinal absorption of calcium and phosphorus. This helps in bone mineralization. In conditions of hypocalcemia or hypophosphatemia, vitamin D stimulates bone resorption, thereby maintaining serum levels of calcium and phosphorus. Vitamin D deficiency or resistance thus causes hypocalcemia and hypophosphatemia. Hypocalcemia stimulates the release of parathyroid hormone (PTH), which, through its actions on bone and kidney, partially corrects the hypocalcemia but enhances urinary phosphate excretion, leading to hypophosphatemia and osteomalacia. 25(OH)D also plays an important role in extraskeletal health. Vitamin D deficiency may be associated with certain immunological conditions such as multiple sclerosis, type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease, mood disorders, and cancers such as breast, prostate, and colon cancer. In adolescents, low serum vitamin D levels are associated with increased risk of hypertension, hyperglycemia, metabolic syndrome, and higher risk of upper respiratory infections. This chapter focuses on the skeletal manifestations of vitamin D deficiency.

 

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The lifecycle of plants differs from species to species. There are those that complete their lifecycle in one year (called annuals) and those that live for more than one year, flowering once or many times in their lifetime (perennials)

Those that flower only once, produce seeds and die. The next generation of the plant is established from these seeds and the cycle gets repeated. Such plants are known as monocarpic. (Whereas polycarpic plants are those that flower many times during their lifetime.) Kurinji is monocarpic. Monocarpic plants flower only on attaining maturity. The time taken to mature varies for different species of kurinji. So, different species of kurinji have different intervals of flowering too.

Neelakurinji matures in 12 years time and flowers every 12 years. That is, it takes another 12 years for the seeds to sprout and grow 30 to 60 centimetres high for another glorious bloom. Each shrub reproduces once in its lifetime and dies after flowering.

India is home to nearly 46 species of kurinji, with most of them showing an unusual flowering behaviour, varying from annual to 16-year blooming cycles.

 

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In the avian world colour is one of the aspects that differentiates one species from another. But did you know that in many species, there are colour differences between male and female birds? Invariably, the males are brighter and more colourful than the females. Why is this so? Come, let's find out Naturalist Charles Darwin attributed this difference to the theory of sexual selection. After extensive research he arrived at the conclusion that female birds of certain species usually chose to mate with males that were brighter in colour, which led to males gradually evolving to be more and more colourful For long scientists have gone with this explanation. However. more recent studies point to a few other reasons for the muted colours of the females. According to a study published a few years ago, in many species of birds both males and females started out looking similar - bright and colourful. However, female started losing colour faster than the males gained it The study says this evolution is because of natural selection. The drab colour of the females is said to have emerged to help them escape predation by blending in with their surroundings. This comes in handy also during nesting, which helps keep their lineage alive.

 

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We tend to think of plants and trees as solitary beings. This may be due to the fact that they are in mobile and silent. We do not perceive them to be communicating with each other, the same way animals, birds and humans do (They do not moo, neigh or sing sweet songs to interact with their fellow beings. nor do they seem to share food like social animals and birds). But the reality is far from it. There is a busy networking going on right under your feet. Yes, underneath the forest floor, intertwined with the roots is a secret network of fungi through which plants and trees communicate and share nutrition with each other.

A majority of land plants live in symbiotic relationship with soil fungi. The fungi cannot photosynthesise, as they have no access to light or chlorophyll whereas the trees photosynthesise. Trees use the sun's energy to refashion carbon dioxide and water into sugar. Fungi get sugar and carbon from trees, and in return release nutrients such as phosphorous and nitrogen. as well as water collected from their environment) to the trees.

How do they do this? The fungi is made up of a mass of thin threads, known as mycelium through which they absorb nutrients from their environment. The roots of trees and mycelium join together to form the mycorrhizal networks. As fungi colonise many plants at the same time, the mycorrhizal networks connect individual plants and trees, forming a larger network. This network ferries nutrients and chemical signals (communication) between trees. They even connect trees that are miles away Ester Peter Wohlleben dubbed this Gennan forester network the woodwide web. "

Through this network trees also send distress chemical signals about drought disease or an insect attack. Other trees pick up these signals and increase their own resistance to the threat. A parent tree uses the fungal network to feed the seedlings that have sprouted under its shade. Researchers have found how old trees are able to survive with resources from younger ones.

A fungal network also boost the host plants immune system because when a fungus colonises the roots of a plant it triggers the production of defence-related chemicals in plants. Simply plugging in to mycelial networks makes plants more resistant to disease.

 

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Minks are small mammals, native to the Northern Hemisphere. They belong to the weasel family. Both the European minks and the American minks are valued for their luxurious fur.

Why is coronavirus in minks a concern?

Scientists say minks may be more susceptible to the coronavirus than other animals due to a combination of genetic and environmental factors. In mink farms, where thousands of animals are kept in close proximity, COVID-19 can spread rapidly from animal to animal.

Unlike dogs, cats and some other animals, which show only mild symptoms, minks can get very sick and even die from the infection. So far, minks are the only animals known to both catch the virus from people and transmit it to them.

Which are the other places where minks have contracted COVID-19?

Coronavirus cases have also been detected in farmed minks in four other European countries: the Netherlands, Spain, Sweden and Italy. Millions of animals have been culled in these places too. In the U.S., more than 15,000 minks have died of the coronavirus since August, and authorities are keeping about a dozen farms under quarantine while they investigate the cases.

 

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Denmark's decision to cull millions of minks over coronavirus fear has shocked animal lovers around the world. While the scientific community is divided over the validity of the concern, we will take a look at what is culling and why it is carried out in the first place.

Denmark began culling millions of minks over coronavirus fear last month. A mutated form of coronavirus that can spread to humans was found among minks in hundreds of fur farms in the country. More than a dozen people were found to have caught the infection from the animals. However, there is no evidence that the mutations that originated in minks pose an increased threat to humans.

Denmark is the world's biggest producer of mink fur and its main export markets are China and Hong Kong. Mink farms have been found to be reservoirs of the coronavirus with over 200 of the 1,200 farms affected. Danish scientists are worried that genetic changes in mink-related form of the virus have the potential to render future vaccines less effective. Global health officials are now considering minks a potential risk, particularly in the midst of a resurgence of the virus in the human population. Denmark decided to cull all the minks in the country (instead of just the ones in the affected farms) as a precautionary step to protect people from contracting the virus. But later rolled back the order as it did not have the legal basis to kill all the animals.

While some scientists feel the concerns over mutated strain are exaggerated, others think the virus could jump from minks to other animals. Let's take a look at what culling is and why is it being done...

What is culling?

Culling is the organised and systematic elimination of sick or surplus farm or wild animals and birds, Culling or the selective slaughtering is carried out by authorised wildlife officials with proper permits and approvals.

Why are they culled?

• Mass killing of birds and animals are carried out when they are infected with a contagious disease. It is done to avoid the spread of the disease to other animals and humans. For instance, in the United Kingdom badger culling has been carried out for years to control the spread of bovine tuberculosis (bTB). Badger is a carrier of bTB.

• Aggressive invaders, such as invasive birds that take over nesting sites or attack native birds, are culled to save the local ecological balance.

• Culling is carried out to keep certain animal and bird populations in check. Unusual population growth may cause an imbalance in local ecology, disrupting food sources and other essential resources. In certain parts of Australia, kangaroos are considered vermins (pests), because they damage crops and compete with livestock for scarce resources. Kangaroos are involved in more than 80% of vehicle animal collisions there. In some places of the country, kangaroos are said to outnumber humans.

How is culling perceived by experts?

Culling has always been controversial. On one side, conservationists support it for the common good of all the species in an ecosystem. They perceive culling as a necessary means to protect native biodiversity. But on the other side, animal activists protest over the effectiveness and humaneness of different methods of culling. They oppose when governments resort to culling as a short-term measure Opposition also comes from the perception that every animal should have the right to live.

 

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Originally Answered: From an evolutionary standpoint, why is human childbirth so painful?

If you look at the human pelvis compared to that of other mammals, ours is more bowl- or basin-like; in fact the word pelvis means “basin.”

But then, the next question is, why is the human pelvis shaped like that? Why isn’t the outlet wider, to allow for easier and more comfortable childbirth? The answer to this has to do with our upright locomotion, and has two facets: visceral support and locomotion.

First of all, in animals such as the chimpanzee or gorilla, which walk on all fours, the weight of the abdominal organs is supported by the strong, three-layered muscular wall of the abdomen. But stand a primate upright, and that weight now bears down on the pelvic floor. Something new is needed to support all that; otherwise we’d have a much more major problem than we do now with intestinal loops herniating through the pelvic floor. Guts need support.

So concurrently with the evolution of an upright posture, the floor of the pelvis—the bottom of the basin—turned inward to better support and strengthen the muscles of the pelvic floor that hold up one’s guts, especially those bulky, heavy intestines. Now, viewed from the inside, our pelvic floor looks like this. Notice that even the coccyx, our vestigial “tailbone,” turns inward to help support these muscles. (This is one example of why the concept of “vestigial” doesn’t mean “useless.”)

The second reason for this pelvic remodeling is locomotion: it enabled the femurs to angle inward so the knees fall below the body’s center of gravity, as this comparison of chimpanzee (left) and hominid (right) illustrates. This allows for sustained comfortable standing, comfortable bipedal walking (compare all the movies one may have seen of orangutans and chimpanzees walking on their hind legs), and perhaps most importantly, efficient long-distance running.

All of this pelvic remodeling, however, created the problem in childbirth that started this discussion thread. For the infant’s head to squeeze through this narrower pelvic outlet, especially as hominids evolved larger brains and craniums, meant that there was increasing selection pressure for infants to be born before the bones of the cranium fused and made the skull rigid. The skull must be able to deform a little bit to squeeze through the birth canal (a term meaning the combination of pelvic outlet, pelvic muscles, and vagina).

Hence, human infants are born in a less mature state than the infants of the great apes and many other mammals from cats to cattle. This immaturity is seen especially in the state of the nervous system at birth. Our infants, unlike so many others, can’t sit up, stand up, walk, grab ahold of their mothers for a ride (like a baby monkey or chimp), or even hold things in their hands. This is a price we pay for our bipedal locomotion; birth is painful and our infants require much more extensive parental care than those of other primates.

The last fact is a further selection pressure that favored evolution of longer-lasting pair bonds between human mates. Biparental care was necessary for optimal survival of our offspring. Thus, for reasons traceable back to or pelvic anatomy, humans evolved multiyear pair-bonding and a greater (though far from perfect) degree of monogamy compared to other primates.

In short, the advantages of bipedalism have so outweighed the disadvantages of birth pain and infant helplessness that, in the grand scheme of things, it has all been worthwhile. Birth pain is one of the prices we pay for human nature and civilization.

 

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This question was already answered more than two centuries ago in the late 1700s by an eccentric Italian scientist, Lazzaro Spallanzani. At the time, the leading theories were that food either fermented, rotted or was crushed to little pieces within the stomach. Spallanzani was the first to conduct extensive observations on digestion within the living body of animals, himself among them.

He fed birds with food in perforated containers which had a long piece of string attached. He would then pull out the containers from the poor birds after a varying number of hours. From his results, he concluded that a major part of digestion is the solvent action of fluids in the stomach. He named these fluids gastric juice.

To demonstrate the direct effect, he extracted a large quantity of gastric juice from the stomachs of birds and placed chewed food in the juice and kept it at body temperature for three days. By repeated additions of gastric fluid, the food eventually became completely dissolved.

Not satisfied with the bird results, he experimented on himself! He would place small pieces of food inside tiny linen bags, sewing them up, swallowing them and inspecting what emerged at the other end the next day. He sometimes swallowed the semi-digested meat the second or third time (yikes…).

The linen bag passed through him without causing any trouble and the content disappeared the next day. In another experiment, he waited three hours after swallowing a tube containing beef and vomited it back up, to prove that digestion occurs in the stomach, not the intestines. Finding the beef had already turned soft, he confirmed his prediction. Apparently, even he was grossed out by this experiment and couldn’t do it again.

The speed of the process suggested that the meat had neither fermented nor rotted but had been dissolved by gastric juices through the cloth. We now know Spallanzani was correct: the hydrochloric acid in the gastric juice breaks down the meat and the digestive enzymes split up the proteins. The acidic gastric juice also kills bacteria, the agent behind ‘rotting’. The proteins and fats are broken down further into amino acids and fatty acids in the small intestine and get absorbed through the digestive wall into the bloodstream. There’s nothing left to rot.

 

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Potassium plays a role in every heartbeat. A hundred thousand times a day, it helps trigger your heart to squeeze blood through your body.

It also helps your muscles to move, your nerves to work, and your kidneys to filter blood

The U.S. Department of Agriculture recommends 4,700 milligrams per day for healthy people. The easiest way to get this amount is by adding high-potassium fruits and vegetables to your diet.

It's possible to get too much of a good thing, though. Ask your doctor before starting a potassium supplement.

If you have kidney failure or other kidney problems, talk with your doctor about how much potassium you should get.

 

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Mineralized tissues, such as bone, teeth, antler and horn, are important elemental storage sites in animals. These tissues contain necessary elements, both major, such as calcium (Ca), phosphorus (P), magnesium (Mg) and sulphur (S), and trace elements, such as iron (Fe), zinc (Zn), manganese (Mn) and cadmium (Cd).

Bones are living tissue. They’re made up of the protein collagen and the mineral calcium phosphate. This enables bones to be strong but flexible.

Collagen is like scaffolding that provides the bone’s framework. The calcium fills in the rest. The inside of the bone has a honeycomb-like structure. It’s called trabecular bone. Trabecular bone is covered by cortical bone.

Teeth are not living tissue. They’re comprised of four different types of tissue: dentin, enamel, cementum, pulp

While teeth and bones might appear to be the same material at first glance, they’re actually quite different. Bones can repair and heal themselves, while teeth cannot. Teeth are more fragile in that respect, which is why it’s so important to practice good dental hygiene and see a dentist regularly.

 

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Do you really want to know if a mother cat would suffer if she loses one of her kids?

Mama left her kittens inside a box at around 7am but when she returned, just five hours later, she discovered that her two kittens were already dead.

She was found by locals pacing back and forth, meowing incessantly near her lifeless offspring.

Both kittens were stabbed to death by an unknown assailant.

The mother refused to leave, even after locals tried to help her.

So, back to the question…

There are some typical behaviors that a mother cat may exhibit when dealing with the death of a offspring. One of the first things she would to is licking her kitten(s).

You see, licking the kittens is the mother cat’s instinctive behavior after giving birth. It will rigorously lick and groom each kitten. Licking the kittens stimulates breathing, helps to remove any remaining placenta and helps to remove liquid from the kitten’s lungs. The grooming can look quite violent and vigorous but it is normal and necessary.

When a mother cat sees its kitten not moving or breathing, she will lick and cuddle the kitten to try to get it to respond. It may do it for quite some time until she gives up and abandons the kitten to take care of the surviving ones.

Some cats are very trusting to their owners in times of grief or loss. Not all cats do this but some may lay their kitten at your feet for help or empathy. Many cat owners have experienced this and interpret it as their cat’s way of showing that she trusts you to fix her young.

In contrast, some mother cats are overprotective of their young. They will not allow anyone, even their pet parent to come near their kittens, dead or alive.

Sometimes a mother cat will dig the ground where she will bury her dead kitten. She will then cover the body with mud and might lay on the spot for several hours. Some mother cats who have other kittens to attend to, however, will simply remove the dead kitten and abandon it. This is to separate the dead far from the live ones to avoid any health risks.

And sometimes, she would eat her kitten. It may sound gross but some mother cats eat their kittens when they seem to be dead. Eating their dead kittens will provide nutrients that will be dissolved in the mother’s milk and will be beneficial for other kittens. It is very rare but surely it happens and, although this is a distressing sight for humans, this is a normal behavior for animals.

So, answering the question: she surely will suffer. A lot.

 

Credit : Quora

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Kangaroos are famous for their means of locomotion: hopping! They can reach speeds of 60kph, clearing more than 8m with a single hop!

Their muscular tail is used for balance when hopping, and as another limb when moving about. They also use their tail when swimming; that’s right – kangaroos are good swimmers! They swim to avoid predators, and can use their forepaws to drown pursuers.

Kangaroos are famous for their forward-opening pouch, where the joey (baby kangaroo) develops and suckles. A female kangaroo is known as a 'flyer' or a 'doe' and a male kangaroo a 'buck' or a 'boomer' (hence the nickname of the Australian men's basketball team, the Boomers). They live in social groups called mobs.

 

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The tear glands (lacrimal glands), located above each eyeball, continuously supply tear fluid that's wiped across the surface of your eye each time you blink your eyes. Excess fluid drains through the tear ducts into the nose.

The main function of the lacrimal gland is the production of lacrimal fluid, which is involved in the maintenance of a healthy ocular surface. Lacrimal fluid contains proteins, antimicrobial agents, water and electrolytes that ensure adequate lubrication, protection and nutrition of the ocular surface. 

Lacrimal fluid contains a significant amount of water that keeps the surface of the eye moist as well as dissolved elements that are necessary for normal cellular functioning. The fluid also contains antimicrobial agents including phospholipase, lysozyme, peroxidase, lactoferrin and immunoglobulins that provide defence against invading pathogens. In addition, the lacrimal gland produces numerous other substances and proteins including retinol (derived from Vitamin A) and growth factors such as epidermal, fibroblast and keratinocyte growth factors. These are involved in corneal regeneration and maintenance of corneal avascularity and transparency.

 

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