Thursday, 31 October 2013

Pseudo Prefix

Prefixes are important in biology. Now, it is not a distortion of perception but it is a reality. If you believe that words are pseudo realities, you are wrong. Now the word pseudo. Pseudo word is very important in science. Such is the power of prefix pseudo that if it gets associated to the word science it becomes a pseudo science. And, the meaning is reversed.

Pseudo-stratified epithelium is an epithelium that appears to be layered but it is not actually. Every cell in the layer manages to touch the basement membrane on which they are resting. 

Pseudo-genes are dysfunctional relatives of certain functional genes that fail to express themselves as they do not code for proteins. Multiple mutations in the genes makes them dysfunctional or pseudo-genes

Friday, 3 May 2013

Singing Insects

You must have heard the shrilling sound of certain insects at night in the rainy season that passed by. Ever wondered where they have gone these days? Have they died or gone somewhere?

Many insects like crickets and grasshoppers are heard during the rainy days, i.e., late summer and early autumn. They make sounds and it is hard to locate the source of sound. It can irritate a person and they leave you with no other option than to tolerate their song.

During winter the grasshoppers and crickets slow down their activities and hide themselves in a suitable place such as cracks and crevices in the rocks etc.

Insects do not have the ability to regulate their temperature by generating body heat so they are ectothermic. They take on the temperature of their surroundings. You avoid going out of your home to play when it is very cold outside. Similarly these singing insects too find a quite place for themselves and stop activities to conserve heat.

In many cold countries, where winters are longer and freezing, adults and nymphs die. But how do they appear all of a sudden when the temperature rises? Yes, because when the winter ends, their eggs hatch into new crickets and grasshoppers. And they survive the winter season as eggs.

How will you know that the song whose source you are unable to identify is of a grasshopper hopping around outside or of a cricket’s? Well, crickets sing during the night and the grasshopper during the day. In movies to portray a scene of night, a background shrilling sound of cricket, called jhingur in Hindi is played.

Every cricket and grasshopper is not a singing insect. Only males sing to call females for mating or warding off other males. So when they sense the correct time for mating they start singing.

Now the big question is how do the singing insects sing? Do they have vocal cords in their necks as we do? It is strange but the sound which they produce is not generated by some vocal cords. They sing by rubbing together their two parts of the body.

Crickets rub together roughened parts of their wings. Grasshoppers rub their legs against their forewings. The legs of a grasshopper have a row of ‘tiny-pegs’ on them which they rub against the hard vein on their forewings.

What is even more strange is that these singing insects have ears on their first pairs of legs or on either side of their abdomen!

Singing of crickets is considered a sign of good luck in China. They are popular pets there and kept in cages. In some European countries particularly in Iberian Peninsula, Mexico, South East Asia people use ‘cricket fighting’ as a gambling sport.

What do the singing insects eat, do you know? Like different people eat different things, some prefer to eat non-vegetarian food and some eat vegetarian food. Similarly different singing insects eat different things. Grasshoppers are vegetarian but crickets eat small insects, plants and moulds. 

Turtles and Tortoises

Humanoid Turtles are seen in action cartoons telecast on a TV Channel and are shown to display behaviour opposite to the turtles found in nature. Contrary to the wise, careful and slow- turtles and tortoises, found in nature that survive harsh conditions by acclimatizing; Ninja turtles are aggressive, trained with ninja skills and act as saviors.

Turtles and tortoises are recognized by the hard, rounded shell that they carry on their backs. They have four legs and a tail. They have scales on their bodies, females are egg laying and they do not have capability to generate body heat. They retract their limbs inside their shells to survive in the chilling weather and move out in the sun to get heat. They are cold blooded and are reptiles.

Ever wondered despite having similar traits, why turtles and tortoises have different names? Well, it is a matter of fact. Similar looking turtles and tortoises are different on account of their body size, structure and habitat, they dwell in. Turtles are aquatic while tortoises are land dwelling. The turtles that live in fresh water bodies- rivers and streams and seas and oceans, have streamlined shells, webbed feet and long claws. 

But, the tortoises have relatively rounded shell and bent legs with short and sturdy feet, as they live on land. The small sized turtles feed on frogs, shrimps, snails and aquatic plants but tortoises that are large sized are vegetarians.

The shy turtles and tortoises are animals in armour. They never strike like a warrior does, but they withdraw their heads and limbs when threatened. The upper part of their shell is called ‘carapace’ which means shield and the lower part is called ‘plastron’ which means breast-plate. Both the parts are connected by bridges. Despite having these basic differences, they are similar in that they have common ancestors and are endangered.

The loss of their habitats and nesting sites, pollution and poaching has led to the decline in their numbers. Human encroachment for activities like fishing etc, have led to decline in their numbers due to destruction of their eggs in their nesting sites on the beaches. Orissa is famous for the nesting site of Olive Ridley Turtles along the Rushikulya beach. Female turtles congregate on the beach for mass nesting in the month of February, annually in large numbers. The turtles that come out of eggs leave for the seas.

We come to hear of news reporting their plight and environmental campaigns that are organized to protect them, frequently. Like, in the last December, railway police seized a consignment of 115 turtles being poached from Varanasi to Kolkata. This was a serious offence as such activities can lead to extinction of many species.

Turtles and Tortoises are an integral part of our environment. We need to protect them. India Turtle Conservation Program (ITCP) is a program, jointly hosted by Turtle Survival Alliance (TSA) and Madras Crocodile Bank Trust (MCBT). It is being implemented in partnership of World Wild Fund (WWF) and other organizations repute so as to ascertain the global mission of TSA to reduce the turtle and tortoise extinction to zero. International Union of Conservation of Nature (IUCN) has recognized them as vulnerable and put them into red data list. 

Turtles and Tortoises are considered endangered and are put under the Indian Wildlife Protection Act, 1972. That means, it illegal to keep an Indian species of turtle or tortoise as pet or indulge in turtle and tortoise trade. You can’t make them pets and keep them in your homes to call upon them when you are back, but you can do one thing for sure and that is you can adopt them as celebrities do. Just pay the agencies for sustaining an animal and they will take care of your subject.