Ask The Science Experts

Mimosa pudica (also known as the “sensitive plant” or “Tickle Me plant”) is well known for its rapid leaf movement. In the evening the leaflets will fold together and the whole leaf droops downward. It then re-opens at sunrise. This type of movement is called nyctinastic movement. The leaves also close up under various other stimuli, such as touching, warming, or shaking (hence the name, Tickle Me plant).

The stimulus can also be transmitted to neighboring leaves. The scientific term for these are seismonastic movements. The movement is caused by “a rapid loss of pressure in strategically situated cells that cause the leaves to droop right before one’s eyes”. [Wikipedia] This characteristic is quite common within the Mimosaceae family. Gradual loss of pressure can also cause the plant to close its fronds as is sometimes the case when it is exposed to a strong wind, rain or sunlight.

Why the plant’s leaves close up when exposed to these external stimuli is most likely an evolutionary response. As the leaves fold down, sharp thorns are exposed and would make the plant less tasty for herbivore animals that might want to eat them.

Posted by the science guy for the best selling science toys of 2008.

This is a bit of a humorous post as this question has made the rounds on the Internet for the last several years. The short answer is: goldfish are egg-layers and as such, they’re never considered pregnant. A female goldfish carrying eggs is said to be “ripe” but no ichthyologist would say she’s pregnant. You may have stumbled upon posts or trivia lists saying that a pregnant goldfish is called a twit, twat, twerp or whatever. They’re not.

Posted by the Triop Guy for Triassic Triops make great fishy gifts!

What causes the Bubonic Plague and how deadly is it?

The Bubonic plague is a disease of the lymphatic system caused from the bite of an infected flea. The fleas are often found on rodents and seek live hosts (such as humans) when their rodent hosts die. Once established, bacteria rapidly spread to the lymph nodes and multiply. Yersinia pestis can resist phagocytosis and even reproduce inside phagocytes and kill them. As the disease progresses, the lymph nodes can hemorrhage and become necrotic. Bubonic plague can progress to lethal septicemic plague in some cases. Bubonic Plague kills about 50% of infected patients within one week.

What most people reading this were probably searching for is actually the Black Death, a specific incident of a Bubonic Plague epidemic that happened in Europe in the 1340s. At the time of the breakout, the world’s population is estimated to have been about 450 million. The Black Death killed about 75 million, or roughly one sixth of the population on Earth. Compare those figures to today’s population and that would be the equivalent of over 1 Billion people dying from the breakout.

The name “Black Death” comes from the fact that the disease causes symptoms like spots on the skin that are red at first and then turn black. Other symptoms include heavy breathing, continuous blood vomiting, aching limbs and terrible pain. The pain is usually caused by the actual decaying, or decomposing of the skin while the infected person is still alive.

Posted by admin for the best selling toys of 2008 at Atomic Elephant Science & Toy Co. For another interesting read, check out their list of the 10 deadliest insects of all time.

At birth, the genes that make the pigment protein are not being read by the cell (they are turned off). Almost all babies have blue eyes because the iris has not yet made brown pigment (called melanin) that colors the iris.

As the child’s eyes are exposed to light (as they weren’t in the womb), the light then triggers the cell to start reading the gene. But it can take a while for the cell to ramp up to the final levels of pigment. That is why so many babies have blue eyes for their first months of life. Usually by their first birthday a baby’s eye color has settled in, but sometimes the iris doesn’t make enough melanin until about 3 years of age.

A nice description from About.com follows: “An infant’s eye color is determined by a substance called melanin. Melanin is a dark pigment contained in the iris, the structure that controls how much light is allowed into the eye. The color of the iris is determined by the amount of melanin in the iris. Light eyes have very little pigment, whereas darker eyes have a lot. In newborns, the pigmentation process of the iris is not yet complete. Babies with darker skin are usually born with dark eyes that stay relatively dark. Iris color in lighter-skinned babies is usually a blue or bluish-gray color at birth, then change as they grow. Melanin production changes during the first year of life, usually resulting in a darker, deeper eye color.”

Sources: Understanding Genetics at TheTech.org. Posted by admin for the science and educational best selling toys.

The shortest known gestation period is 12 to 13 days. This record is shared by three marsupials, which is kind of an unfair comparison to all other mammals as in marsupials, the young are born immature and have to continue developing in a pouch on the mother. The three mammals with this very quick gestation period are:  the American or Virginian opossum (Didelphis marsupialis); the rare water opossum, or yapok (Chironectes minimus), of central and northern South America; and the eastern native cat (Dasyurus viverrinus) of Australia.

More about the Virginia Opossum [source: Wikipedia]

It is the largest member of its genus, family and order and is the largest of the opossums. They are typically 15–20 inches (38–51 cm) long and weigh between 9 and 13 pounds (4–6 kg). Their coats are a dull grayish brown, other than on their faces, which are white. Opossums have long, hairless, prehensile tails, which can be used to grab branches and carry small objects. They also have hairless ears and a long, flat nose. Opossums have 50 teeth and opposable, clawless thumbs on their rear limbs.

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The mitochondrian was first identified at the end of the 19th century by a German pathologist and histologist (tissue researcher) named Richard Altmann. It was given the name “mitochondria” by Karl Benda, a German physician. (1857-1933). [source: wikipedia] Altmann is known for his work involving cell theory and structure. In his study of animal cells, he investigated small granules in the protoplasm of the cell. He called these particles- bioblasts, which he postulated were elementary organisms that had metabolic and genetic autonomy. Today Altmann’s bioblasts are known as mitochondria.

So what are mitochondria?

Mitochondria are the powerhouses of the modern cell, providing some 90% of the energy needed for survival. In 1963, scientists discovered mitochondria had their own DNA, arranged in circles, containing the blueprints for 37 of the molecules mitochondria need to create to generate energy.

The single-cell embryo that results from the merger of the egg and sperm has a solitary nucleus with a matching set of chromosomes with about 100,000 genes from the sperm and 100,000 from the egg. These are coded in about three billion base pairs along the strands of DNA.

The fertilized egg, and all of its descendant cells, divide their chromosomes into two mirror images and then split into new cells with each cell obtaining a full set of genes.

By comparison, the DNA of mitochondria has only 16,569 base pairs and these are all inherited from the cytoplasm of the egg. The male makes no contribution to this complement.

Making Fuel for the whole body

Each mitochondrion has a convoluted inner membrane, like a giant nucleus, within its smooth outer membrane. It generates energy by relaying electrons along a series of proteins embedded in the inner membrane. This series is called the respiratory chain. The electrons interact with oxygen and protons to form water and energy.

Mitochondria direct the energy released from the oxidation of hydrogen to pump protons across the inner membrane. This creates a charge and chemical differential that facilitates the synthesis of ATP Synthase which in turn facilitates the creation of ATP (adenosine triphosphate). ATP is liberated into the cell cytoplasm and distributed throughout the body as fuel for all cellular activities.

The process depends upon a steady supply of oxygen and hydrogen (H+) as well as electrons supplied from food. Should any of these be in short supply, the cells rapidly run out of fuel and die. Should mutations inhibit the process of ATP production, the cells begin to weaken.

Source: Wikipedia and This Magic Sea. Posted by the science toy guy for the best selling Christmas toys of 2008.

The quick answer is that a mature electric eel can produce a shock up to 500 volts at 1 amp of current (500 watts).  The eel’s organs are capable of producing two types of electric discharge– low voltage and high voltage. Both could be harmful to an adult human.

The longer answer, or exactly how the electric eel produces electricity is a bit more complex. Basically, the electric eel has three abdominal pairs of organs that produce electricity. They’re called the Sachs organ, the hunter’s organ and the main organ. The eel’s vital organs are contained in the first one fifth  of its body whereas these electricity producing organs are in the remainder four fifths.

These organs are made of electrocytes lined up in series so the current flows through them and produces an electrical charge. When the eel locates its prey, the brain sends a signal through the nervous system to the electric cells. This opens the ion channel, allowing positively-charged sodium to flow through, reversing the charges momentarily. By causing a sudden difference in voltage, it generates a current. The electric eel generates its characteristic electrical pulse in a manner similar to a battery, in which stacked plates produce an electrical charge. [wikipedia]

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