Cockroach,insect surviving without head

It is unbelievable to say that any living being can live without head. How to believe? as the respiratory organ lie within the head and the brain which control the functions of the body is also within the head. Is there any living being that can survive without head?

Cockroach is the only one living being which has being known as the insect which can live without head for long time It is famous for having the capacity of surviving in any difficult situation. Million years ago, due to falling of meteors all the dinosaurs were disappear but the only one living being that is cockroach was able to survive at that time also. But, how is it possible that it can survive without head?

First of all, let's talk about human that how he/she die after his/her head being cut. When the head is cut off from the body there is more flow of blood. This results the decrease in pressure of blood and brings the deficiency in circulation of oxygen. Not only this ,due to deficiency of blood in the body, man ultimately dies. If blood does not come also, due to presence of respiratory organ that is nose is within head , man dies.

But the network of blood vessels is not so complicated as that of developed living being in the body of cockroach . It has open circulatory system due to which blood pressure is low. When the head of the cockroach is cut off blood coming from it immediately freezes as a result there is no chance for the overflow of blood.

For respiration, it does not have the organ like nose as that of human. It has small holes all over the body for respiration process which is called the spiracle and it is not controlled by the brain too.

The spiracles send oxygen directly to the cells through trachea. So that it is not necessary for blood to send oxygen all over the body parts. Cockroach is cold blooded animal so it is not necessary for them to take food frequently. It can survive for 2-3 weeks without any food.
Cockroach as well as other insects have ganglia in different parts of their body due to which body can perform normal activities in absence of brain too. That's why, until it is not attacked by any predators or by the bacterias or viruses attack them cockroach can survive for few weeks without head.

Why doesn't earth fall towards sun?

According to Newton's law of Gravitation, the force of attraction exists between every two bodies. But for small bodies this force is negligible. But earth and sun are two heavenly bodies having masses 6*10^24 kg and 2*10^30 kg respectively. In such case, force of attraction have a large value.

Such large force is enough to attract the earth by the sun. In such cases, earth would have collapse into the sun. But actually, it does not happen, earth is always at the fixed distance from the sun. Now the question arises, why does not earth fall into the sun although there exists a large force of attraction between them?

We know the force which is required to move a body uniformly in a circular path and acts along the radius and is directed towards the center of the circular path is termed as centripetal force.
Also, we know earth moves round the sun in a circular path. For the bodies to remain in circular path centripetal force is required which is directed towards the center. Since, the attraction force between earth and sun is towards the center of sun. So, the necessary centripetal force is provided by the attraction force between them. On the other hand, the direction of velocity with which the earth is moving is always perpendicular to the centripetal force. So, it does not have any component along the center of the sun.

Hence, the earth does not fall towards the sun due to its attraction.

Know about virus

The Russian Botanist D.I Ivanowsky prepared an infectious extracts from tobacco plants that were suffering from mosaic disease. When the extract was allowed to pass through a filter which is able to prevent the passage of bacteria, the filtered fluid was still infectious. In 1898 , Beijerink coined the name 'virus' (Latin-poison) due to infectious nature. Mayer (1886), Beijirink (1898) established the existence of viruses by discovering many viral diseases in plants and animals. In 1900, Walter Reed discovered the virus of yellow fever , the first known viral disease of man. In 1915, F.W Twort and F.D Herelle independently noticed that bacteria were also infected by virus and those viruses that infect only bacterias were named as bacteriophase. Schelsinger (1933) was first to determine the chemical composition of viruses.Wendell Stanley, in 1935 isolated a virus in a crystalline form and reported that viruses were made exclusively of proteins. Pirie and Bawden (1936 ) give the concept that viruses are made up of nucleic acid and protein. Likewise, Harshey and Chase (1952) showed that only he nucleic acid is responsible for infection but protein is non infectious.

In 1981, Matthews defined virus as the set of one or more nucleic acid molecules enclosed in a protective coat of protein and able to organize its own replication within a suitable host cell.
Viruses are the causative agents of many infectious diseases like mumps, common cold, flu, small pox etc. It is an obligatory parasitic pathogen with at least one dimension of less than 200 millimicrons; on average they are about 50 times smaller than bacteria. They do not have a cellular structure or any metabolic activity as they do not have enzyme systems and protein synthesis machinery and cannot reproduce outside living cells . They can be recognised only by their biological behaviour such as, by the disease they cause. Their exact nature was a mystery for long. Most of the virus have only one nucleic acid DNA or RNA. Rous sacroma virus, producing certain cancer is only virus having both DNA and RNA . Some small viruses have been crystallised and behave as chemical like TMV and poliomyelitis.

Viruses are found in
1. Helical shape eg. TMV, influenza virus.
2. Polyhedral shape eg. polio virus
3. Tadpole shape eg. bacteriophases

Viruses are broadly classified into following types.
1. Plant virus: Virus which infects only plant is known as plant virus. Their genetic material is RNA. The first plant virus to discover was Tobacco Mosaic Virus . eg of plant virus are bean mosaic virus, potato virus.
2. Animal virus: Virus which infects only animal is known as animal virus. Their genetic material is DNA. eg. rabies virus
3. Bacteriophase: Virus infecting bacterial cell is known as bacteriophase. They contain DNA as genetic material.

They are also classified based on the type of their nucleic acid which are as follows:
1. DNA virus (Deoxyvira): Virus containing DNA is known as DNA virus.
2. RNA virus (Ribovira): Virus containing RNA is known as RNA virus.

How clouds remain in the sky?

There exists an attraction between any two bodies in this universe which is known as force of gravitation. When a body is allowed to fall freely, the body will be attracted towards the earth due to the force of gravity. But we see clouds floating in the sky. Doesn't the earth's force of gravity affect the cloud?

Actually, it is not true to say that clouds always remain in the sky. Some type of clouds remain on the surface of earth such as fog. There are traces of water vapour in air. When air is cooled these traces of water vapour changes into small droplets of water. Cloud is the group of these droplets of water. Flowing air helps cloud to remain in the sky.

But due to air, cloud when goes higher than the surface of the earth it becomes more cold. Now the cloud which is becoming colder and colder the small water droplets come in contact and becomes a huge one. The flowing air can't withstand the cloud which is formed due to big droplets of water and due to force of gravity it falls on earth in the form of rain.

Relation of biology with other sciences

All the disciplines of science are related to each other. Biology is such a subject which can't be studied in isolation. So, the term biology is broadly named as 'life science' so as to cover its wide scope which involves the knowledge from other sciences such as physics, chemistry, geography etc. as a result other new branches of biology have been introduced
Biophysics,Biochemistry,Biogeography. These involves the knowledge of application of physics, chemistry, and geography respectively. in order to describe all the phenomenon of biology.
Some of the examples of interrelation of biology with other branches of science are:
1. With physics
a. Study on the structure functioning of human eye requires knowledge of optics.
b. Sunlight is necessary for photosynthesis.
c. Result of photosynthesis and respiration is the production of oxygen and carbondioxide .
d. Heat energy is required for maintenance of life.
e. Conduction of water in plants from root to the leaf is provided by the properties of adhesion and cohesion of water molecules and capillary system.
f. Study of photoperiods on flowering of plants involves stimulus of light.
g. Chemical energy is transferred to heat energy as a result of consumption of ATP.
h. Many biological instruments such as microscope, chromatography, x-ray diffraction, fractionation, autoradiography etc. follow the physical applications.
2. With chemistry
a. All living organisms are composed of organic and inorganic compounds.
b. Molecules are broken down or synthesized in metabolic processes.
c. Molecules move in and out of the cells by diffusion and osmosis.
d. Transportation of oxygen needs haemoglobin to form oxyhaemoglobin.
e. For proper functioning acid base equilibrium in a cell maintains the PH of the protoplasm.
3. With geography
a. Study of distribution of communities always involves the knowledge of geography.
b. Distribution , adaptation, and evolution are related with the climate of area.
4. With mathematics and statistics
a. Census of wild animals is based on application of mathematics and statistical applications.
5. With sociology
a. study of human behaviour, social relationship and antisocial relationship for example criminals terrorists etc. requires the study on human nervous system and study of glands, hormones etc. It also requires the knowledge of principles of inheritance, pedigree analysis etc.

Role of chemistry in world problems

Nowadays, several problems are created day per day due to increasing population, pollution which has created environmental imbalance in the today's world. Some of the major problems that are facing by the human race in which chemist are doing their best for the contribution towards their solution are listed as under:

1. The Food and Population problem
It is the major problem existing nowadays in the present world. In parts of the world, where population is increasing in a very fast rate, exists the famine problems. The Green Revolution has partly relieved us of this problem. Chemists are developing synthetic plant hormones and growth regulators to increase plant yield. They are developing the acceptable controls of human fertility, pest controls and fertilizers.

2. Environmental pollution and protection
Due to rapidly increasing population human are facing the pollution problems. The use of fossil fuels has contributed to greenhouse effect and polluted the air. The exhaust gases from automobiles like carbon monoxide, oxides of sulphur and nitrogen, unburnt hydrocarbon are more dangerous pollutant of air. Los Angels smog is caused by excessive emission of exhaust gases from automobiles. Chemists must find new fuels, new catalysts to reduce air pollution. Reuse and recycling of materials must be done. Many countries have developed garbage disposal procedures.

3. Excessive use of raw materials of ocean
Ocean is the source and storehouse of raw materials. We obtain food and minerals like magnesium, bromine, iodine e.t.c from oceans. But nowadays, human have started to exploit the vast resource in careless way. Chemists are involved in successful recovery of usable water and minerals from the oceans.

4. New sources of energy
Coal, petroleum, natural gas, nuclear energy are in limited amount. In the last few decades, more attention is focussed on wind energy, solar energy, tidal energy e.t.c. These newer sources of energy require materials and procedures for transferring energy from its source to the users. Chemists can help a lot in developing suitable materials needed in such sources of energy. Recently , a German Research group has developed a catalyst to split water into hydrogen and oxygen with the help of sunlight. Fuel cell technology is just ready to come out for common man's use.

5. New materials

Due to increasing population demand for new products is also increased. New materials such as super conductors, high field magnetic materials, high temperature plastics and structural polymers have been developed and put in to use with advance in technology. Conducting polymers , smart materials, materials based on nano-structures are at various stages of development which can be only prepared by the knowledge and experience in chemistry.

From all these described above, it is clear that chemistry as a science is very much with us today.

About chemistry

The knowledge about nature has grown up into a variety of science whose concepts, techniques , and applications are interdependent. Nowadays, millions of people earn their living by working with the science called chemistry. It is the knowledge about the study of matter, the changes that take place in it and the laws which govern these changes. It is younger than astronomy and older than psychology.

Experiments and explanation are the heart of chemical research. The first step is to define the problems. The next step is to perform experiments, make careful observations and collect data like a rise in temperature, a change in color, the evolution of gas and so on.After a series of experiments, recording and describing the experiment in scientific language using symbols and equation is done. Then the chemist attempts to explain the phenomenon. If a hypothesis is successful it becomes as a theory.
Chemistry is an interesting subject. Many products that we used in our daily life like the households items-plastics, synthetic fibers,synthetic rubber,soaps, body and hair sprays are the products of chemistry. Much of our food, medicine,and drugs are also prepared in chemical laboratories. Every day, more and more new drugs are discovered for the benefit of mankind.
It gives answers to the questions of the different substances having different properties.Why do they have different properties? For example, Why does petrol burn but water does not? What is the difference in composition of petrol and water?
Matter undergoes varieties of changes.For example, Why does iron rust? Why does milk turn sour?
All substances do not occur in nature. For example, plastics does not occur in nature but is prepared by chemical process.Iron does not occur in free state but is extracted from the iron compounds that occur in mines. Washing soda is manufactured by chemical process.
So, if we want to learn all about them, then we should study chemistry.