My Science School

Archaeopteryx lived around 150 million years ago — during the early Tithonian stage in the late Jurassic Period — in what is now Bavaria, southern Germany. At the time, Europe was an archipelago and was much closer to the equator than it is today, with latitude similar to Florida, providing this basal bird, or "stem-bird," with a fairly warm — though likely dry — climate.

Various specimens of Archaeopteryx showed that it had flight and tail feathers, and the well-preserved "Berlin Specimen" showed the animal also had body plumage that included well-developed "trouser" feathers on the legs. Its body plumage was down-like and fluffy like those of the feathered theropod Sinosauropteryx, and may have even been "hair-like proto-feathers" that resemble the fur on mammals, according to a 2004 article in the journal Comptes Rendus Palevol.

Interestingly, the Archaeopteryx specimens found thus far lack any feathering on the upper neck and head, which may be a result of the preservation process.

Based on its wings and feathers, scientists believe Archaeopteryx likely had some aerodynamic abilities.

A 2018 study published in the journal Nature Communications also found evidence that Archaeopteryx could fly, although not like any bird alive today does. The researchers used synchrotron microtomography — a tool that uses radiation to make magnified, 3D digital reconstructions of an object — to study the Jurassic creature's fossils. Even though Archaeopteryx didn't have the same features in its shoulders that help modern birds fly, its wings looked like those of modern birds that fly, they found.

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Velociraptor retained its feathers, and possibly used them to attract mates, regulate body temperature, protect eggs from the environment or generate thrust and speed while running up inclines.

Velociraptor had a relatively large skull , which was about 9.1 inches (23 centimeters) long, concave on the upper surface and convex on the lower surface, according to a 1999 description of a Velociraptor skull, published in the journal Acta Palaeontologica Polonica. Additionally, its snout was long, narrow and shallow, and made up about 60 percent of the dinosaur's entire skull length.

Velociraptor had 13 to 15 teeth in its upper jaw and 14 to 15 teeth in its lower jaw. These teeth were widely spaced and serrated, though more strongly on the back edge than the front.

Velociraptor's tail of hard, fused bones was inflexible, but likely kept it balanced as it ran, hunted and jumped. 

Velociraptor, like other dromaeosaurids, had two large hand-like appendages with three curved claws. They also had a sickle-shaped talon on the second toe of each foot. 

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Bone-headed dinosaurs, or thick-headed lizards, are known scientifically as pachycephalosaurs.

They are a strange group of herbivorous dinosaurs which possessed a thick-boned dome on the top of their skulls.

The unusual and distinctive feature of Pachycephalosaurusis the high, domelike skull formed by a thick mass of solid bone grown over the tiny brain. This bone growth covered the temporal openings that were characteristic of the skulls of related forms. Abundant bony knobs in front and at the sides of the skull further added to the unusual appearance. Pachycephalosaurusand closely related forms are known as the bone-headed, or dome-headed, dinosaurs. These dinosaurs, which are also found in Mongolia, had a variety of skull shapes. In the most basal forms, the dome was not thick but flat. Late forms had thick domes shaped like kneecaps, or a large sagittal crest with spikes and knobs pointing down and back from the sides of the skull. It has been suggested that these animals were head butters like living rams, but the configuration of the domes does not support this hypothesis. Flank-butting remains a possibility in some species, but a more likely function in most was species recognition or display.

Credit : Britannica

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Opossum is a marsupial endemic to the Americas. It loves to visit human homes and raid garbage for food. Its favourites are nuts and fruits, but it also love to hunt mice, birds and insects.

To escape its predators, it plays possum. That is, it pretends to be dead in appearance and in smell. It carries its babies in its pouch or on its back when it goes looking for food.

An opossum, when confronted with a threat, will often hiss or bare its teeth. Or more likely, run. But if it is surprised by a predator, it will enter a catatonic state. It basically faints and is in a state of unconsciousness. The opossum has no control over this; it’s involuntary.

It does indeed appear if the opossum is dead. Its teeth are visible, as if in a death grimace. It emits a foul substance from its anus, the smell described as corpse-like.

A predator is confronted with what appears to be dead, unhealthy prey, and may leave the opossum alone.

This death-feigning strategy, as some sources note, is not without its risks. The opossum is unconscious. So if the predator decides to gnaw on the opossum anyway, there’s no escape. It is also commonly cited as a reason why you see so many road-killed opossums, but I found a lack of research support for this.

The opossum will remain in this unconscious state for minutes to hours.

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You can identify it by the colours on its body. Its crown, wings, tail and belly sport different shades of blue, while its neck its neck and throat are purplish and the chest is brown.

It lives in open areas and agricultural landscapes. It is generally quiet, but turns vociferous during the breeding season. It makes a harsh chack… chack… sound.

It is known for my acrobatic courtship displays. The male Indian Roller is known for its unique and startling sexual display which it performs during the breeding season. During the course of the display the Indian Roller bird flies high up in the sky and descends downwards in a circular motion, flapping its winds rapidly.

Many states in India have made the Indian Roller their state bird. The Indian roller is considered to be a sacred bird in Hindu mythology and is associated with the deity Lord Shiva. The species of the Indian Roller bird does not face the threat of extinction. It is not an endangered species.

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Tardigrade is a phylum, a high-level scientific category of animal. (Humans belong in the Chordate phylum — animals with spinal cords.) There are over 1,000 known species within Tardigrade, according to Integrated Taxonomic Information System (ITIS).

In many conditions, they survive by going into an almost death-like state called cryptobiosis. They curl into a dehydrated ball, called a tun, by retracting their head and legs. If reintroduced to water, the tardigrade can come back to life in just a few hours.  

While in cryptobiosis, tardigrades' metabolic activity gets as low as 0.01 percent of normal levels, and their organs are protected by a sugary gel called trehalose. They also seem to make a large amount of antioxidants, which may be another way to protect vital organs. Water bears also produce a protein that protects their DNA from radiation damage, according to research by the University of Tokyo.

In cold temperatures, they form into a special tun that prevents the growth of ice crystals. 

Tardigrades reproduce through sexual and asexual reproduction, depending on the species. They lay one to 30 eggs at a time. During sexual reproduction, the female will lay the eggs and the males will fertilize them. In asexual reproduction, the female will lay the eggs and then they will develop without fertilization. 

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Tardigrades, also known as water bears, are microscopic, usually about 0.5 mm long. These water-dwelling, eight-legged micro-animals can survive extreme heat and cold, besides even radiation in space. They are often found on mosses and lichen. Did you know when short on water they can dry out for years and revive without any damage when reintroduced to water?

Tardigrades are semi-aquatic. They can survive in watery as well as terrestrial environments — from oceans and lakes to mountains, forests and sand dunes. They're found all over the world, from frigid Antarctic glaciers to active lava fields. They’re most commonly found living in moss.

Most tardigrades eat algae and flowering plants, piercing plant cells and sucking out their contents though their tube-shaped mouths. Some, however, are carnivorous and may eat other tardigrades.

Tardigrades are nature’s pioneers, colonizing new, potentially harsh environments, providing food for larger creatures that follow. Scientists say, for instance, that tardigrades may have been among the first animals to leave the ocean and settle on dry land.

Tardigrades pose no threat to humans. Scientists have yet to identify a species of tardigrade that spreads disease.

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The Sphynx cat, or simply Sphynx is a breed of cat known for its lack of fur. Hairlessness in cats is a naturally occurring genetic mutation, and the Sphynx was developed through selective breeding of these animals, starting in the 1960s.

According to breed standards, the skin should have the texture of chamois leather, as it has fine hairs, or the cat may be completely hairless. Whiskers may be present, either whole or broken, or may be totally absent. The cats have a narrow, long head and webbed feet. Their skin is the color that their fur would be, and all the usual cat markings (solid, point, van, tabby, tortie, etc.) may be found on the Sphynx cat's skin. Because they have no fur they lose more body heat than coated cats which makes them warm to the touch and prone to finding warm places.

Sphynx are known for their extroverted behavior. They display a high level of energy, intelligence, curiosity and affection for their owners. They are one of the more dog-like breeds of cats, frequently greeting their owners at the door and friendly when meeting strangers.

The Sphynx breed also tends to accumulate oils and debris under the nails as well as the skin fold above the nail due to the lack of fur, so, like the ears, the nails and surrounding skin folds need to be cleaned properly as well. Due to these factors the breed may require more grooming than a typical domestic cat with fur. Specialty products for this cat have been developed, though they still require more grooming than most breeds.

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Those who cannot own a dog because of scarcity of space or some other reason could consider having a dog-like cat as a pet. Dog-like cat? Yes, some breeds of domestic cats exhibit unusual dog-like behaviour such as being loyal, friendly, playful, interactive and adventurous. What's more? They can be trained too. Manx, Ragdoll and Abyssinian are some of the cat breeds known to display canine behaviour.       

The cultural assumption that cats are distant from people and lack affection compared to dogs has complications.[3] Animals have individual characteristics based on their environment, particularly their past interactions with people. The nature of selective breeding for both canines and felines varies dramatically across different human cultures as well, with highly distinctive traits (fertility, lifespan, speed, etc) receiving emphasis depending on the historical context.

The feline temperament is particularly malleable to a wide set of environmental factors, especially sudden stresses. For example, after dangerous floods in Canvey Island, cats showed behaviors of psychological shock akin to human struggles. Well-raised kittens frequently demonstrate affection towards humans and a pleasant, docile nature regardless of pedigree. These broad traits are not specific to any particular breed, as the upbringing of the animal is an important factor. Positive interaction with humans in the first few months of life is particularly vital.

Most feline pets in the United States are considered to be domestic short-haired cats, a catch-all term for those with mixed or otherwise unclear ancestries but having related appearances. Several of those cats, or those of the standardized American Shorthair breed, will respond differently to others despite looking very similar, displaying dog-like or otherwise unexpected tendencies. Besides breed-based generalizations, a particular cat's behavior can be assessed by its restraint in using claws during play, its tendency to follow people, and its appreciation of close, frequent human contact.

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If you see green or yellow phlegm, it’s usually a sign that your body is fighting an infection. The color comes from white blood cells. At first, you may notice yellow phlegm that then progresses into green phlegm. The change occurs with the severity and length of the potential sickness.

If you've ever stopped to look at the contents of the tissue after you've blown your nose, you may have noticed that your mucus isn't always perfectly clear. It may be yellow, green, or have a reddish or brownish tinge to it. What do those colors mean?

You might have heard that yellow or green mucus is a clear sign that you have an infection, but despite that common misperception, the yellow or green hue isn't due to bacteria.

When you have a cold, your immune system sends white blood cells called neutrophils rushing to the area. These cells contain a greenish-colored enzyme, and in large numbers they can turn the mucus the same color.

Mucus can also contain tinges of reddish or brownish blood, especially if your nose gets dried out or irritated from too much rubbing, blowing, or picking. Most of the blood comes from the area right inside the nostril, which is where most of the blood vessels in the nose are located. A small amount of blood in your mucus isn't anything to worry about, but if you're seeing large volumes of it, call your doctor.

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Bronchitis is when the tubes that carry air to your lungs, called the bronchial tubes, get inflamed and swollen. You end up with a nagging cough and mucus.

Most often, the same viruses that give you a cold or the flu cause acute bronchitis. But sometimes, bacteria bring it on.

In both cases, as your body fights the germs, your bronchial tubes swell and make more mucus. That means you have smaller openings for air to flow through, which can make it harder to breathe.

Your doctor usually can tell whether you have bronchitis based on a physical exam and your symptoms. They’ll ask about your cough, such as how long you’ve had it and what kind of mucus comes up with it. They’ll also listen to your lungs to see whether anything sounds wrong, like wheezing.

Your doctor may need to do some tests, depending on whether they think you have acute or chronic bronchitis.

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The bronchi are the airways that lead from the trachea into the lungs and then branch off into progressively smaller structures until they reach the alveoli, the tiny sacs that allow for the exchange of oxygen and carbon dioxide in the lungs.

Primary bronchi are located in the upper portion of the lungs, with secondary bronchi near the center of the lungs. Tertiary bronchi are located near the bottom of these organs, just above the bronchioles. No gas exchanges occur in any of the bronchi. When the bronchi become swollen due to irritants or infection, bronchitis results and makes breathing more difficult. Bronchitis sufferers also tend to have much more mucus and phlegm than someone without inflamed bronchi.

The secondary bronchi continue to branch off to form the tertiary bronchi, which are further divided into terminal bronchioles.

There are as many as 30,000 tiny bronchioles in each lung. They lead to the alveoli (tiny air sacs where the exchange of carbon dioxide and oxygen occurs) by way of alveolar ducts.

Together, the trachea and the two primary bronchi are referred to as the bronchial tree. At the end of the bronchial tree lie the alveolar ducts, the alveolar sacs, and finally the alveoli.

The tubes that make up the bronchial tree perform the same function as the trachea. They distribute air to the lungs.

The alveoli are primarily responsible for exchanging carbon dioxide and oxygen, which occurs in the lungs.

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There is no proof to pinpoint what causes hiccups. They are believed to be caused by sudden contractions of the diaphragm. Irritation of the nerves that extend from the neck to the chest can cause hiccups. The diaphragm is a muscle, which is found between the abdominal cavity and the one containing the heart and the lungs, and plays an important role in respiration. The diaphragm pulls the lungs to increase their capacity to draw in more air. A sudden and unequal contraction of the diaphragm is believed to cause hiccups.

Usually, hiccups subside on their own within 10 minutes. Drinking water or being frightened by someone or placing sugar under the tongue does not help stop hiccups. These are myths. In rare cases, hiccups can last for hours, requiring medication. An inflammation in the lower part of the lungs or a swelling of the liver can cause irritation in the diaphragm and may lead to hiccups.

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Biogeography, the study of the geographic distribution of plants, animals, and other forms of life. It is concerned not only with habitation patterns but also with the factors responsible for variations in distribution.

Biogeographic studies divide Earth’s surface—primarily the continents and islands—into regions exhibiting differences in the average composition of flora and fauna. It is thought that the present-day distribution patterns of plant and animal forms, as reflected in such biogeographic regions, are the result of many historical and current causes. These causes include present climatic and geographic conditions, the geologic history of the landmasses and their climates, and the evolution of the taxon (e.g., genus or species) involved.

Biogeography provides evidence of evolution through the comparison of similar species with minor differences that originated due to adaptations to their respective environments. Over time, the Earth’s continents have separated, drifted apart, and collided, resulting in the creation of novel climates and habitats. As species adapted to these conditions, members of the same species that had been separated geographically diverge, resulting in the eventual formation of distinct species. This knowledge is important, as by understanding how adaptations occurred in response to changing environments in the past, we can apply this knowledge to the future.

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Molecular biology, field of science concerned with studying the chemical structures and processes of biological phenomena that involve the basic units of life, molecules. Molecular biology emerged in the 1930s, having developed out of the related fields of biochemistry, genetics, and biophysics; today it remains closely associated with those fields.

Various techniques have been developed for molecular biology, though researchers in the field may also employ methods and techniques native to genetics and other closely associated fields. 

Molecular biology remained a pure science with few practical applications until the 1970s, when certain types of enzymes were discovered that could cut and recombine segments of DNA in the chromosomes of certain bacteria. The resulting recombinant DNA technology became one of the most active branches of molecular biology because it allows the manipulation of the genetic sequences that determine the basic characters of organisms.

Credit : Britannica

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