Survival Tips: Shark Encounters

Beautiful demonstration of taming shark

Whilst my eyes slowly wandered in my Biology lesson, I came a cross a 'Did you know' statement that my teacher made; it read - "If you turn a shark upside down, it will go into a trance-like state called tonic immobility for 15 minutes."

Well, the first thing that sprung to mind was, if I ever were to go snorkelling or diving and I happen to encounter a shark, I would know the exact solution for the situation. The most sensible thing to do is to flip it on its head and swim away safely... within 15 minutes.

After that thought, I decided to research into it a little; A brief definition of tonic immobility I found stated:

"Tonic immobility (TI) is an unlearned reflex, characterised by a state of immobility and torpor. This behaviour has been reported to occur in a variety of animals – including insects, amphibians, reptiles, birds, mammals and fish."

It occurs to me that scientists have not truly discovered why this condition happens but the unnatural posture is believed to change the animal's 'semi-motor interchange with the environment'. It is always thought to be a way for protection but evidences suggest that some predators are using this to an advantage whilst preying on others.

Take a Deep Breath!

Humans and marine mammals both belong to the class Mammalia, but how can marine mammals such as the seal, hold their breath under water for up to at least 30 minutes where Humans struggles even for 5 minutes.

Dr Michael Berenbrink and his team recently published an explanation on how marine mammals can store large amounts of oxygen.

The protein - myoglobin is used to store oxygen in mammals' muscle; this is what give muscles the red colour. In marine mammals, there are high concentrations of this protein in their muscles, causing them to appear black. In order for more oxygen to be stored in the muscles, much of myoglobin is needed. However, proteins tend to stick to each other at high concentrations - this causes clogging in the muscles and the loss of function of the proteins.

From tracing the changes of myoglobin through the evolutionary history of marine mammals, it was discovered that the protein evolved to have non-stick properties. Their myoglobin is positively charged and so will repel each other at high concentrations due to like charges. In this way, the animals can "pack" large amounts of oxygen in their muscles without clogging them up. 

This "physiological change" allows scientists to understand the transition of mammals from land to water and also estimate the dive time of e.g. whales from fossils. 

We are the Kings of Humanity!

Recently, an article has been published about a theory on the extinction of the Neanderthal. Neanderthals are an extincted species of the genus Homo (Homo neanderthals) which is very closely related to us; it is sometimes considered as a subspecies of Homo sapiens.

Neanderthals have a larger cranial capacity than modern humans indicating that their brains are larger as well. They are also stronger than humans, particularly their arms and hands. So, why did a species that is stronger and possibly be more intelligent than us become extinct when we are still in existence now?

Over the years, scientists have been suggesting hypotheses about the extinction of neanderthals. According to fossil records, neanderthals and modern humans coexisted several thousand years ago in Europe leading many scientist to believe that we were the reason why.

• Violence was one of the hypotheses - Jared Diamond suggested that the neanderthals suffered a series of conflict similar to the genocides. 

Genoides:- "the deliberate and systematic destruction in whole or part of an ethnic, racial, religious or national group."

• Parasites or pathogens - Due to the different lifestyles of modern human and neanderthals, the latter are more susceptible to pathogens.
• Competition - division of labour; both female and male neanderthals both took the occupation of hunting and did not have division of labour between the two sexes and so "resulted in the poor extraction of resources from the environment". Due to anatomical differences, the neanderthals require 30% more energy for running or walking than modern humans and so could not run as fast and so were not able to survive. The fact that humans have a relationship with dogs gave them an advantage in hunting whereas neanderthals did not have that relationship. 

• Interbreeding - As modern humans shares a lot of nuclear DNA with neanderthals, it is suggested that neanderthals interbred with the ancestors of modern humans and there was a variation in the genes leading to us today.
• Climate change

The recent theory that was published states that the neanderthals skull has larger eye sockets therefore they had bigger eyes and so their brain used more of its processing powers for visual images. Whilst humans used the processing power to to develop and work out the world we were living in, the neanderthals focused on processing image. This is believed to be because of the area in which they lived in - shorter days and longer nights resulting in lower light intensity. 

The reason that the neanderthals became extinct is still an unsolved puzzle and is still being investigated today.

Talk to me about bananas!

A famous rumour about questions that are asked in the Cambridge interview is : talk to me about bananas.

Um... it's yellow.

When I was discussing this matter with my small brown headed friend and this blonde lanky weirdo, we started to come up with some ideas.

1. It contains potassium, and if you eat more than 9 a day, you will DIE.
2. 50% of the DNA of a banana is the same as the DNA of humans.
3. You should really eat a banana upside down as spiders lay eggs on the top (bananas grow upwards)
4. Banana does not actually help with constipation, it actually makes constipation worse.

That's about it.

The quesiton tell me about a banana is not the exact question that Cambridge will ask but it is to illustrate what sort of questions they might ask according to the subjects you're applying to. For example, if you are studying Chemistry, they might ask you how many atoms you think there is in a banana.

So, I concluded, better off knowing more general knowledge; starting off with a banana.

• Bananas contain three natural sugars - sucrose, fructose and glucose with fibre.
• Bananas gives an instant and sustained boost of energy and provide as much energy for a 90-minute workout.
• Eating a banana also helps with depression - banana contains tryptophan, the body turns this protein into serotonin which relaxes you and improves your mood.
• Banana is also high in iron - iron is part of the Haemoglobin molecule in red blood cells. This helps your blood readily carry oxygen and so prevents diseases like anemia.
• Banana is extremely high in potassium yet low in salt - perfect fo high blood pressure; reducing the risk of blood pressure and stroke.
• Brain Power!! Research has shown that the potassium in the banana helps students become more alert and so assits learning.

Just found out a load of random facts about a banana... Well, at least now you know to eat a banana before an exam. :D

Why so blue?

Why is the sky blue?

This might be the question that has appeared in many little heads. It might be a very common question, but do you actually know why?

I have came across this question for many times, and for the first time now, I am going to get to the end of it!

The light from the Sun is white, but it is made up of all the colours of the rainbow - a spectrum. The experiment that probably all of us did some at some parts of our life - the prism experiment proves exactly this. The white light entering the prism is diffracted and as all the colours in the white light has different wavelenghts, they diffract at different angles; the white light is separated into red, orange, yellow, green, blue, indigo and violet.

When sunlight enters the Earth's atmosphere, it collides with all the gas and dust particles in the atmosphere causing it to scatter or deflect in all directions. Blue light has a shorter wavelength than red and so is scattered the most. The scattered blue light is refected into our eyes and that is why we see a blue sky most of the time.

The light that are scattered somethings collide back together to make white light again. So we actually see a lot of white light as well as blue. This is why the sky isn't a matt blue colour, but a sky blue.

At sunsets, the sun is further away from the earth and so, the light from the Sun has to pass through even more gas and dust particles in the atmosphere; so the blue light scatter even more allowing the red and yellow lights to past through straight to your eyes.

At polluted areas on Earth, the whole sky might seem red because there will be more and larger dust and water particles present in the atmosphere.

Now wait a minute.

Back to blue. If the colour with the shortest wavelength scatter the most in the Earth's atmosphere, then why isn't the sky violet?

This is explained by how the eye perceives colour. The human eye is sensitive to light between 380 and 740 nm. In the retina of the eye, there are cones for detecting colour. Each cone contains pigments that restrict the range of wavelength that it responds to - long, medium and short wavelengths. The peak of each responses are at 570 nm (yellow), long, 543 nm (green), medium and 442nm (between blue and violet) for long. However, the three cones are sensitive over broad, overlapping wavelength ranges - meaning that two different spectra can cause the same response in a set of cones. 

Now think about different colours of light. Red light and green light makes yellow light; and this is due to the overlapping of wavelengths. This is exactly what is happening in the sky. The blue and violet wavelengths elicits the same cone response as blue light and white light. So in other animals, the sky colour is undoubtedly different.

Ah-Choo!

At this time of the year, Christmas is gone, New Year is gone. What's left to be gone is only the cold, wet and frosty weather. In this season, the sniffles and sore throats just would not go away! I'm not an exception. For those of you who understands my situation, I'm sure you want to do anything possible to get rid of it. So what exactly is causing all these sneezing?

So what is a cold? According to Wikipedia,: "The common cold (also known as nasopharyngitis, rhinopharyngitis, acute coryza, or a cold) is a viral infectious disease of the upper respiratory tract which affects primarily the nose. 

Whoa whoa whoa... A-what? Naso-pha? 

It is basically a disease that infects the soft lining on the nose causing the sneezing and sniffling. The most common symptoms is a runny nose. However, sometimes, the same symptoms can become more serious. 

There are a lot of misconceptions and false beliefs about the common cold; this includes the one about the weather. You don't actually catch a cold from the cold - so tell your Moms to relax when you're going out without a coat. Colds are caused by viruses, but they are more common in autumn and winter because people tends to gravitate inside to avoid the cold and wet weather outside. This makes it easier for viruses to jump from one person to another. Cold viruses are spread by airborne droplets and by hand.

There is no effective way to treat a cold and make it go away quicker and as colds are caused by viruses, there is no reason to see a doctor as antibiotics are not needed. So how do you avoid getting a cold in the first place?

1. Stay away from people with colds! 

2. Avoid crowded areas where they is a greater risk of infection.

3. Avoid touching your eyes and nose.

4. Wash your hands thoroughly.

5. Ventilate your room. 

But if you're unfortunate enough to already be infected, here some ways to treat it:

1. Drink plenty of fluid, ideally water. Warm drinks can also sooth most symptoms.

2. Sleep with a high pillow.

3. Do not smoke! This will irritate the infected soft lining of the nose even more.

4. Use over-counter medicines to relieve symptoms such as sore throats and coughs, but avoid using more than one cough and cold medicine at the same time.

5. Wash your hands often and throw tissues away after use to prevent your cold from spreading. 

Lastly, I hope we get well soon...