My Science School

The Mu Koh lanta national park in Southern Thailand had a rather unusual appeal to make to the public. The park authorities requested the public to donate cone-shaped shells they may have to the hermit crabs that have boomed in the last few months in the park. The population of the crustaceans, which protect themselves by wearing and living inside the discarded shells of other animals such as sea snails, has exploded on some islands in the Mu Koh Lanta national park Marine biologists believe the lack of visitors to the park in the backdrop of the COVID-19 pandemic could be a contributing factor. They feel that low number of tourists means fewer activities in the coastal areas, which could have led to the high survival rates of the hermit crabs.

As tens of thousands of hermit crabs thrive on the island, there is a serious shortage for shells. Some hermit crabs, having outgrown their previous homes, have moved into pieces of rubbish such as plastic cans, bottles, or caps. While going without a shell make them extremely vulnerable to their predators, living inside plastic homes is not safe either. The hermit crabs that climb into plastic bottles find the surface too slippery to get traction. Therefore, they cannot climb out of them. A 2020 study found that around 570,000 hermit crabs die annually from getting caught in plastic debris on two tropical islands in the South Pacific.

Plastic debris, in fact, creates a cascade of death for hermit crabs, because when a hermit crab dies, it releases chemical signal to other crabs conveying that its shell is available for occupation. This lures other crabs into the plastic container. One after the other hermit crabs get into the bottle or plastic can thinking they will get their next home, when in reality, it’s their last home.

Have you heard of the vacancy chain?

Hermit crabs begin their lives in larval forms on the seafloor. The larvae eventually metamorphose into small crabs, at which time they must search for their own shells. Hermit crabs are not true crabs - they do not grow their own shells, instead they have hard exoskeleton in the front and soft body in the back, which they protect using the discarded shells of other animals. As the hermit crab grows in size, it must find a larger shell and abandon the previous one.

These social animals display a fascinating behaviour when they are out to look for a new shell. At least 20 individual hermit crabs line up in size order - biggest to smallest - to see if a new shell turns up and who fits into it best. Their curled tail with a hook enables their bodies to fit inside these borrowed shells. Once a member fits into a new shell, it will eject itself from its former calcified castle and the next smallest will take this hand-me-down home, while leaving its older one for another and so on - the aim is that everyone walks away with a new shell that is a better fit than their old one! Scientists call this the vacancy chain.

 

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The literal translation of rhinoceros is ‘nose-horned’. It comes from the Greek word 'rhinokeros' from ‘rhinos’ meaning ‘nose’ and 'keras' meaning 'horn of an animal’. 

Rhinoceros are killed by some poachers for their horns, which are bought and sold on the black market, and used by some cultures for ornaments or traditional medicine. East Asia, specifically Vietnam, is the largest market for rhino horns. By weight, rhino horns cost as much as gold on the black market. Some cultures believe the horns to have therapeutic properties and they are ground up and the dust consumed. The horns are made of keratin, the same type of protein that makes up hair and fingernails. Both African species and the Sumatran rhinoceros have two horns, while the Indian and Javan rhinoceros have a single horn. The IUCN Red List identifies the black, Javan, and Sumatran rhinoceros as critically endangered.

The family Rhinocerotidae consists of only four extant genera: Ceratotherium (white rhinoceros), Diceros (black rhinoceros), Dicerorhinus (Sumatran rhinoceros), and Rhinoceros (Indian and Javan rhinoceros). The living species fall into three categories. The two African species, the white rhinoceros and the black rhinoceros, belong to the tribe Dicerotini, which originated in the middle Miocene, about 14.2 million years ago. The species diverged during the early Pliocene (about 5 million years ago). The main difference between black and white rhinos is the shape of their mouths – white rhinos have broad flat lips for grazing, whereas black rhinos have long pointed lips for eating foliage. There are two living Rhinocerotini species, the Indian rhinoceros and the Javan rhinoceros, which diverged from one another about 10 million years ago. The Sumatran rhinoceros is the only surviving representative of the most primitive group, the Dicerorhinini, which emerged in the Miocene (about 20 million years ago).

 

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Athlete's foot is a rash on the skin of the foot. It is the most common fungal skin infection. There are three main types of athlete's foot. Each type affects different parts of the foot and may look different.

Athlete's foot is caused by a fungus that grows on or in the top layer of skin. Fungi (plural of fungus) grow best in warm, wet places, such as the area between the toes.

Athlete's foot spreads easily. You can get it by touching the toes or feet of a person who has it. But most often, people get it by walking barefoot on contaminated surfaces near swimming pools or in locker rooms. The fungi then grow in your shoes, especially if your shoes are so tight that air cannot move around your feet.

If you touch something that has fungi on it, you can spread athlete's foot to other people—even if you don't get the infection yourself. Some people are more likely than others to get athlete's foot. Experts don't know why this is. After you have had athlete's foot, you are more likely to get it again.

Most of the time, a doctor can tell that you have athlete's foot by looking at your feet. He or she will also ask about your symptoms and any past fungal infections you may have had. If your athlete's foot looks unusual, or if treatment did not help you before, your doctor may take a skin or nail sample to test for fungi.

Not all skin problems on the foot are athlete's foot. If you think you have athlete's foot but have never had it before, it's a good idea to have your doctor look at it.

 

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Human rhinoviruses group of viruses — of which there are more than 100 types — is by far the most common identified cause of colds. The viruses grow best at the temperature inside the human nose.

Human rhinoviruses (HRVs) are highly contagious. However, they rarely lead to serious health consequences.

Recent research has found that HRVs manipulate genes and it is this manipulation that brings about an overblown immune response. The response causes some of the most troublesome cold symptoms. This information could lead scientists to important breakthroughs in the treatment of the common cold.

Potential complications of infection include otitis media, sinusitis, chronic bronchitis, and exacerbations of reactive airway disease (eg, asthma). Although rhinovirus infections occur year-round, the incidence is highest in the fall and the spring.

 

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Hepatitis A is caused by a virus that infects liver cells and causes inflammation. The inflammation can affect how your liver works and cause other signs and symptoms of hepatitis A.

The virus most commonly spreads when you eat or drink something contaminated with fecal matter, even just tiny amounts. It does not spread through sneezing or coughing.

Unlike other types of viral hepatitis, hepatitis A does not cause long-term liver damage, and it doesn't become chronic.

In rare cases, hepatitis A can cause a sudden loss of liver function, especially in older adults or people with chronic liver diseases. Acute liver failure requires a stay in the hospital for monitoring and treatment. Some people with acute liver failure may need a liver transplant.

No medication can get rid of the hepatitis A virus once you have it. Your doctor will treat your symptoms -- they may call this supportive care -- until it goes away. They’ll also do tests that check how well your liver is working to be sure your body is healing like it should.

 

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Culex pipiens is commonly referred to as the House Mosquito. It is the main vector, or carrier, of St. Louis Encephalitis, West Nile Virus, Western Equine Encephalitis, Heartworm in dogs, and bird Malaria.

The House mosquito species is also a conveyor of Rift Valley Fever, Sindbis virus, and filariasis in other regions of the world. Although its main target has been birds, the House mosquito is now targeting humans and mammals on a regular basis. The mosquito bites an infected bird and then goes to another blood meal host, whether a human or another bird, and bites that new victim, injecting it with the virus from the original bird. This process has helped to spread diseases from bird to bird, and more recently, from bird to humans and other mammals. Culex pipiens can therefore be considered a “bridge” vector as it transmits viruses between birds and mammals.

Considered to be a medium-sized mosquito, the adult Culex pipiens may reach up ¼”. The House mosquito species' body is usually brownish or grayish brown. The proboscis and wings are usually brown.

Eggs are laid in rafts of 150-350 eggs in polluted or foul water in a variety of water-filled containers or areas. The eggs usually hatch within 2 days.

Larvae are known as wigglers since they seem to move in that manner. They feed on fungi, bacteria and other tiny organisms through straw-like filters. These larvae will undergo growth throughout the four instars of this stage.

Pupae are known as tumblers because of the way they seem to “tumble” through the water. Their rounded, comma-like shape makes this mode of movement easy. These pupae do not eat during the 1-2 days in which they will become an adult mosquito. If you suspect you have a house mosquito infestation, then an effective mosquito control system can offer protection against these pests and their mosquito-borne diseases.

 

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Typhoid, caused by S. Typhi bacteria, is a water-borne disease that spreads because of poor sanitation. Eating uncovered or spoilt food and drinking contaminated water are the two major causes of typhoid. Symptoms include fever, headache, joint pain, and sore throat.

Signs of high fever, lethargy, body pain, vomiting, poor appetite, dry cough, weight loss, and diarrhoea appear in a Typhoid infected person. Typhoid easily spreads through contaminated water/food or getting in close contact with the infected person. It lasts for 7-10 days and can be treated through antibiotic therapy.

Avoid drinking contaminated water or eating food without washing hands. Personal hygiene is a must and is always recommended. Carry a sanitizer where water is not available.

Monsoon in India comes with varieties of airborne and water-borne disease and hence, it is important to enjoy monsoons with the best health insurance policy and Arogya Sanjeevani Policy. A mediclaim insurance comes with benefits of medication, hospitalization and other covers. When sick, opt for cashless hospitals as it settles the amount directly with the insurance company or the provider.

 

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Birds evolved from a group of meat-eating dinosaurs called theropods. That's the same group that Tyrannosaurus rex belonged to, although birds evolved from small theropods, not huge ones like T. rex.

The oldest bird fossils are about 150 million years old. These ancient birds looked quite a lot like small, feathered dinosaurs and they had much in common. Their mouths still contained sharp teeth. But over time, birds lost their teeth and evolved beaks.

"Birds are living dinosaurs, just as we are mammals," said Julia Clarke, a paleontologist studying the evolution of flight and a professor with the Department of Geological Sciences at the University of Texas at Austin. 

In spite of the physical differences that distinguish all mammals from other species, every animal in that group — living and extinct — can trace certain anatomical characteristics to a common ancestor. And the same is true for birds, Clarke told Live Science.

"They're firmly nested in that one part of the dinosaur tree," she said. "All of the species of birds we have today are descendants of one lineage of dinosaur: the theropod dinosaurs."

 

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Living organisms thrive in different kinds of habitats, including acquatic environments. An important factor that helps some creatures adapt to changes in the external environment is the regulation of their internal environment - physiological processes. And body temperature plays a crucial role in this adaptation. As you may be aware, warm-blooded animals - such as birds and mammals - are those that maintain a high body temperature, and this temperature does not change with any change in the environment. On the other hand, cold blooded animals - such as fish, amphibians, and reptiles - tend to have temperatures that change depending on their surroundings. While warm blooded animals are generally called homeotherms, cold-blooded animals are called poikilotherms. And then there are heterotherms. These are creatures - such as some species of birds and mammals - that generate their own body heat but whose temperatures are also regulated by their environment. They have variations in temperature within different regions of their body, and during different times of the year too. In such cases, the body temperature is usually warmest at the core and much lower in the extremities. For example, the feet of penguins are cold to match their surroundings so that their feet are not stuck to the ice they are on. But their core body temperature is conserved by warning the blood returning from the extremities. Also, during winters, penguins are said to have body temperatures lower than normal, and this helps them conserve energy. Though heterotherms are usually small creatures, a study has shown that the king penguin - a large bird weighing about 10 kg - too exhibits heterothermy.

 

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It is estimated that only 2% of the world’s population have green eyes, making it the rarest eye colour in the world.  People with green and other light-colored eyes tend to have a higher eye cancer risk, specifically intraocular melanoma. When people have green eyes, they are usually not apparent until the person is at least 6 months old. Green-eyed people are typically born with blue or gray eyes that eventually transition to green.

Green eyes are sometimes confused with hazel eyes, which have both brown and green in them. To tell the difference, go into natural lighting (outside during the day), and look at your eyes compared with someone you know to have green, hazel, or brown eyes. The difference should be clear between them.

 

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Thug life

Bdelloid rotifers are literally like superheroes and not surprisingly, they are found everywhere, even in Antarctica. They are masters of survival. If there's a lot of water, they're happy. If it's completely dry, they're still happy because they can simply dry up and stay in that state for years; when there's water again, they continue as if nothing happened. The secret to their success? Stealing DNA from organisms like plants, fungi or other microbes to repair damages to their own DNA. If that's not the coolest superpower, what is?

Big brother

Capable of growing to a size of 1.5 inches, Gromia sphaerica is a type of amoeba that is not only big (by microbe standards), but most importantly, it's a single cell that grows to that size! Just let that sink in for a moment. First discovered in the Arabian Sea, this is not its sole special feature. This single-celled microbe somehow manages to roll along on the sea floor all by its own and leaves a distinct trail on the seafloor. Strange or amazing?

Simple hermits

For a long time, a certain species of Trichoplax was thought to be only its larval form it was that simple. With only four types of cells making them up (for comparison, a human being is made up of at least 200 different types of cells), they seem to be the champions of minimalism. No organs. No front or back. Just an upper and bottom side – latch on, eat, excrete. Simple.

Travel and hunt in packs

Much like wolf packs, Myxococcus xanthus species travel in a swarm and how they travel together is simply fascinating. They have a hair-like organelle called pili that helps each bacterium latch on to its neighbour or onto the surface if they're crawling on it. They feed on everything on their path as they travel. And what when they find no food? They form a tower, instead, and produce a fruiting body that turns the bacteria into spores equipped with better survival abilities.

Bring on the radiation

Radiation -- the biggest danger to all living organisms is not a concern for Deinococcus radiodurans. These microbes can bravely withstand gamma radiation 3,000 times the amount that a human can cope with. They do this by having multiple copies of their genome in separate compartments and the ability to repair damages quickly. This also means they can travel to outer space without space suits!

Feasting on metals

"My home is a deep, dark cave (one dripping with acid). An old mine? Much better, thank you. Not even chemicals like arsenic and mercury scare me. Who am I?" Acidithiobacillus, of course! They typically enjoy meals of minerals like iron and sulphur. Once digested, they release sulphuric acid powerful enough to dissolve limestone rocks. They live in the form of snottites (you heard that right!) -- they look like gooey snot hanging from cave roofs.

Squid buddies

Squids are big and mean predators and you have to be incredible to become their friends. Aliivibrio have the distinction of being the microbes squids come in search of. Soon after hatching, a bobtail squid will collect as many Aliivibrio from their surroundings and transfer them to the light organs in the belly. Why? The bacteria give the squid an awesome blue-green glow instead of a boring old shadow making it virtually impossible to detect - perfect for hunting shrimps!

 

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Butterflies don’t eat; that only drink. Though caterpillars constantly eat, once they turn into butterflies, they only drink liquids, primarily nectar from flowers and juices from fruits. Butterflies drink using a proboscis – a tube that works like a straw – because of which they stick to an all-liquid diet.

They do need other nutrients like nitrogen, salts and amino acids. These can be found in tree sap, wet soil and flower pollen. Somewhat less appealing, they can also get these nutrients from rotten fruit or vegetables, faeces, urine, sweat, tears and (the least attractive of all) rotting carcasses!

These nutritional needs stem from the caterpillar’s food. Plants have almost none of the salts that all animals need. Even plant eating mammals like horses and cows need salts – this is also why plants need fertilizers.

 

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Gingivitis is a form of gum disease that happens when plaque, a naturally-occurring sticky film containing bacteria, builds up on teeth and causes the inflammation of the surrounding gum tissue. Plaque produces toxins that irritate the gums. This can cause the gums to become inflamed, making them red or puffy, or causing them to bleed. This harmful plaque bacteria can even lead to issues beyond gingivitis like weakened tooth enamel. Even with regular brushing, it's important to make sure you’re taking care of your gum line, because a healthy mouth starts there.

There are two main categories of gingival diseases:

Dental plaque-induced gingival disease: This can be caused by plaque, systemic factors, medications, or malnutrition.

Non-plaque induced gingival lesions: This can be caused by a specific bacterium, virus, or fungus. It might also be caused by genetic factors, systemic conditions (including allergic reactions and certain illnesses), wounds, or reactions to foreign bodies, such as dentures. Sometimes, there is no specific cause.

The most common cause of gingivitis is the accumulation of bacterial plaque between and around the teeth. The plaque triggers an immune response, which, in turn, can eventually lead to the destruction of gingival, or gum, tissue. It may also, eventually, lead to further complications, including the loss of teeth.

Dental plaque is a biofilm that accumulates naturally on the teeth. It is usually formed by colonizing bacteria that are trying to stick to the smooth surface of a tooth.

 

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A cavity, also called tooth decay, is a hole that forms in your tooth. Cavities start small and gradually become bigger when they’re left untreated. Because many cavities don’t cause pain in the beginning, it can be hard to realize that a problem exists. Regular dental appointments can detect tooth decay early.

Cavities and tooth decay are among the world's most common health problems. They're especially common in children, teenagers and older adults. But anyone who has teeth can get cavities, including infants.

If cavities aren't treated, they get larger and affect deeper layers of your teeth. They can lead to a severe toothache, infection and tooth loss. Regular dental visits and good brushing and flossing habits are your best protection against cavities and tooth decay.

The signs and symptoms of cavities vary, depending on their extent and location. When a cavity is just beginning, you may not have any symptoms at all. As the decay gets larger, it may cause signs and symptoms such as:

• Toothache, spontaneous pain or pain that occurs without any apparent cause


• Tooth sensitivity


• Mild to sharp pain when eating or drinking something sweet, hot or cold


• Visible holes or pits in your teeth


• Brown, black or white staining on any surface of a tooth


• Pain when you bite down

 

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Wisdom teeth are the third set of molars located in the very back of the mouth. They are the last teeth to grow in, usually between the ages of 17 and 21.

In many people, wisdom teeth are unable to grow in normally. The teeth either become stuck under the gum or are only able to partially break through the gum.

Dentists call these teeth impacted. Wisdom teeth usually become impacted because the jaw doesn't have enough space for all the teeth that are growing in, or because the tooth comes in at the wrong angle and bumps into the tooth in front of it.

Impacted wisdom teeth are fairly common. Although some people never have any trouble with them, impacted wisdom teeth can cause problems. An impacted wisdom tooth can sometimes trap food, plaque, and other debris in the soft tissue around it, leading to swelling, gum tenderness, cavities, and bad breath.

Because they may damage other teeth — or cause pain or infection — dentists or oral surgeons often remove impacted wisdom teeth.

 

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