biological – Awesci – Science Everyday

Crocodiles Do Not Die

By Anupum Pant

Technically some animals like Alligators, Flounders and Crocodiles do not die. Instead of aging biologically, they just keep on growing physically. But why do Crocodiles all over the world keep on dying?

Senescence

In reality, we do see them dying. So, it would be right to say that they have the potential to live forever. To understand this we’ll have to first look at the term – Senescence.

Senescence is a term used to indicate gradual deterioration of the body with age. In simpler words, you could call it ‘aging’. Specifically, weakening of muscles, lowering mobility, poor sensory acuity and age-related diseases are signs of an animal showing senescence. Most animals exhibit Senescence. So, as we get older our deteriorated life parameters increase our risk of dying – Humans exhibit Senescence; Crocodiles do not.

Negligible Senescence

But, here on Earth, living with us, are a few species that exhibit Negligible Senescence. That means, they show almost no signs of aging, or they are ‘biologically immortal’. Animals like these only die due to diseases, accidents or predators.

In animals, sea urchins, lobsters, clams and hydras are some examples. Vertebrates like a few Tortoises, Turtles, Crocodiles, Alligators, Rougheye rock fish and Flounders have been not observed to have aged biologically. That is the reason we had a 255 year old tortoise in the Kolkata zoo till the year 2006.

Among trees, probably the best example for an individual would be one Methuselah tree, which has been living for 4800 years. Its exact whereabouts are kept a secret to save it from us. On the other hand, a colony of a single tree has been estimated to be around 80,000 years old. It is also the heaviest known organism.

Side note: Tardigrades survive extreme conditions using a technique called cryptobiosis. They can die and literally come back to life.

Back to Crocs

Crocodiles have no such thing as old age. A 7-year-old crocodile is as good as a 70-year-old one in terms of agility and other life parameters. Aging has no effect on them. Although they can’t die of natural aging, they also can’t live forever. Nature has a way of killing them. The way they die is out of starvation or if they contract a disease.

They keep growing throughout their lifespan and they require more and more food. So, as they keep getting older they need a lot more food. When that amount of food is unavailable, they die from starvation. That is the reason we don’t see 1000 year old crocodiles that are 50 feet long. Still, see what this hunter shot in Australia in the year 1957 – It was an 8.1 m (28 feet) long crocodile!

Even if making human beings biologically immortal is an extremely controversial area, it doesn’t stop scientists. Scientists love to study organisms that exhibit negligible senescence because they’d love to find out a way to halt the aging process in humans by mimicking their gene structures. Probably, in the near future, we’ll find a way to demonstrate limitless Telomere regenerative capacity like Planarian Flatworms in humans.

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The Red Rain of Kerala

By Anupum Pant

In the year 2001, between 25^th July and 25^th September, people from the Indian state of Kerela (Kottayam and Idukki districts) experienced a bizarre oddity – The Red Rain of Kerala. Sporadic heavy downpours of mysteriously colored water left the people of Kerala dazed. More recently, red rains were also seen in parts of Sri Lanka between 15^th November and 27^th December, 2012.

Yellow, Black and Green rains have also been reported several times since 1896.

Red Rain of Kerala – Studies

A study conducted in India showed that the rain was colored because these raindrops contained millions of spherical and oval red particles which had an internal structure. These things looked like biological cells. Initially, when scientists weren’t able to confirm the existence of DNA (a fact which has baffled scientists) in them, in spite of an internal structure present in the cells, some started claiming that the origin of these red particles was extraterrestrial, possibly, coming from an exploded meteor.

Later the mystery was solved, the presence of DNA was confirmed and a study, destroying popular media claims, concluded that the red rain of Kerala had been colored due to airborne spores originating from a type of algae. There was nothing alien about it.

The unusual color of the rain was due to the presence of a unicellular micro-organism belonging to Kingdom Protista, of the Phylum Euglenozoa, known as Trachelomonas. Trachelomonas was the main cause of reddish downpours in other regions of the world as well.

[Source: The Red Rain of Kerala]

Harnessing The Power of Nature – Biological Data Storage

by Anupum Pant

The present storage technology

Storage technology has come long way from the year 1956 when IBM, the massive corporation started pushing this technology. Its journey started with data storage densities of orders as low as 40 bits per square inch in 1956 (RAMAC 350). This effort from their side indeed brought in great results and IBM could set a record of density record of 14.3 billion bits per inch, by the year 2000.

Today, in the year 2013, most HDDs (Hard Disks Drives) are able to store with densities of around 500 Billion bits per square inch; technology at this level has brought Terabyte sized HDDs to our computers. The research being done on increasing density of data is still a bustling area. As a result, we often see news breaking in with breath-taking new storage technologies almost every month.

Latest Stories

Just a few months back, using a technique called nanopatterning a team from Singapore was able to show 3300 billion bits per square inch. That is almost 6 times the density of a normal HDD. It means that a 1TB HDD of present size could hold 6TB if this could come to manufacturing units.

Seagate, in another story, promised data densities of the order 1TB per square inch (8000 billion bits per square inch) within the next decade. Which would enable hard drives of up to 60 TB in capacity.

A similar thing has happened to compact disks. From CDs to DVDs to Dual Layer DVDs to BluRays and several other storages that didn’t last – from zip drives to holographic storage. The data storage densities have improved dramatically.

Is it enough?

Although, our present ability to store a lot of data in small physical spaces is enough for now, to meet the future demands we will need to keep progressing with an unbelievable rate. The fact – physical storage is reaching its limit gradually, could bottleneck our progress in the future.

Biological Storage Devices

The exact storage concept used in amazing natural systems like the human brain and DNA has remained elusive for decades now. To keep up with the rapid pace of development it is important that we step up our work in this area. I think, the answer to our demands lies with the nature.

A brain, for instance, is estimated to be able to store something closer to 2.5 petabytes (or a million gigabytes). The sad part, we don’t exactly know how it stores. Moreover, we don’t even know how we could precisely calculate their storage limits. These estimates are just a theoretical calculation. We still have a long way to go.

The greatest storage device

Recent successful experiments with storage and retrieval of data in the human DNA has come with a new hope for the future. Teams at the EU Bioinformatics Institute and Harvard University have successfully stored famous speeches, photos, and entire books, and then retrieved them with 99.99% accuracy.

Being able to store data in the DNA will confer upon us three advantages. Firstly, it will be fast (very), yes, faster than the flash drive. Secondly, it won’t age with repeated storage cycles (around 10,000 years), at least not like HDDs which have moving parts. Finally, DNA will enable us to reach data densities of unimaginable levels. Imagine being able to store of half a million DVD disks in a single gram of DNA! Technically that would amount to 700 terabits per gram (measuring in area is difficult for an entity like this). Others have reached to densities as much as 2.2 petabytes per gram.

Bring DNA drives to our PCs I say!