BIOELEMENTS AND THEIR PERCENTAGES

The elements which are used in formation of various chemical compounds from which living organisms are made are called Bio-elements.

Out of 92 naturally occurring chemical compounds, only 16 are bio-elements and out of these 16 only 6 account for 99% of the total mass in human body.

Percentages of Bio-Elements by Mass in Human Being

Oxygen                                                              65%

Carbon                                                               18%

Hydrogen                                                           10%

Nitrogen                                                               3%

Calcium                                                                2%

Phosphorous                                                        1%

Potassium                                                       0.35%

Sulphur                                                           0.25%

Chlorine                                                          0.15%

Sodium                                                            0.15%

Magnesium                                                     0.05%

Iron                                                                0.004%

Some elements like Copper, Manganese, Zinc and iodine are present in Traces.

PROTECTION AND CONSERVATION OF ENVIRONMENT

Industrialization has helped mankind to raise the standard of living. It has at the same time destroyed our environment. Tons of industrial waste and effluents in solid, liquid or gas form are being injected into the environment by the industries. These effluents frequently contain sizable amount of certain very toxic even carcinogenic materials. Heavy 'metals like lead from automobiles, chromium from tanneries, are playing havoc to human health. Environmental pollution has reached alarming level in some countries.

This problem, therefore, needs to be addressed or else it would soon be out of control in which case the bio-components of the world ecosystem would suffer irreparable loss and this environment would no longer support life on this planet.

Biology has helped mankind in attracting attention to this problem and the biologists are striving to find the solution to set this environment right wherever it has deteriorated. Biologists have already asked for the treatment of industrial effluents to be made obligatory. Several ways of bioremediation (removal or degradation of environmental pollutants or toxic materials by Hiring organisms) are also under investigation. For example algae have been found to reduce pollution of heavy metals by bio-absorption.

Biologists are also working out the list of endangered species of plants and animals which if not protected would soon be extinct. They have, therefore, stressed the needs for their protection.

The environmental pollution is a national problem in Pakistan. Our rivers, canals are highly polluted with the mixing of city sewage and industrial wastes. The life in fresh water of Pakistan is towards decline. Fish populations have been most adversely affected. We need to take protective measures as early as possible. In cities, particularly the exhaust from auto-mobiles is enormously adding lead into the atmosphere. There is then a need for lead free petrol to reduce the pollution. 

BIOLOGY AND THE SERVICE OF MANKIND

The science of biology has been helping mankind in much way in increasing food production; in combating diseases and in protecting and conserving environment. Biological advances in the field of food and health have resulted in high standard of living.

Plant production has been tremendously increased by improving existing varieties and developing new high-yield and disease — resistant varieties of plants and animals used as food. Plant and animal breeders have developed, through selective breeding, using the principles of genetics, new better varieties of wheat, rice, corn, chicken, cow and sheep. Poultry breeders have developed broilers for getting quick and cheap white meat. Genes for disease resistance and other desirable characters are introduced into plant, using the techniques of genetic engineering. Such transgenic plants (plants having foreign DNA incorporated into their cells) can be propagated by cloning (production of genetically identical copies of organisms/cells by asexual reproduction) using Special techniques such as tissue culture techniques etc. Plant pathogenic fungi and insect pests of crops which weaken he-plants and reduce the yield had traditionally been controlled by using chemical fungicides and insecticides (pesticides). Use of these chemicals poses toxicity problems for human beings as well as environmental pollution. Moreover, there are chances of insects becoming resistant to the effect of these chemicals. Biological control (control by some living organisms) eliminates all such hazards. In biological control, pests are destroyed by using some living organisms that compete with or even eat them up. An aphid that attacks walnut tree is being controlled biologically by a wasp that parasitizes this aphid.

Even some bacteria are being used as bio-pesticides. Effective control of a particular disastrous disease or all the common diseases of a plant can be achieved by using all relevant, appropriate methods of disease control. Such an approach of disease control is called "integrated disease management". 

Soil is a complex medium. It is almost impossible to conduct experiments on nutrient requirements of plants by growing them in soil. Hydroponic culture technique is used to test whether a certain nutrient is essential for plant or not. In this technique the plants are grown in aerated water to which nutrient mineral salts have been added. Hydroponic farming, however, is yet not feasible. Astronauts may use it for growing vegetables.

Different techniques of food preservation have been developed for protecting food from spoilage and for its use and transport over long distance without damaging its quality. One of these is pasteurization, developed by Louis Pasteur. It is being widely used for preservation of milk and milk products. Disease Control There has been fantastic progress in the area of health and disease control. Three pronged actions are usually taken against various diseases.

1. Preventive measures

2. Vaccination/Immunization

3. Drug treatment/Gene therapy 

Preventive Measures:

The advances in biological sciences have provided us information about the causative agents of the diseases and their mode of transmission. For instance the AIDS (Acquired Immune Deficiency Syndrome) is caused by HIV (human immune deficiency virus) and it spreads through free sexual contact, through blood transfusion, by using contaminated syringes or surgical instruments etc. Therefore, doctors advise us to take precautions on these fronts so that we do not contract the disease, which is at present incurable. Similarly hepatitis is caused by H.virus which is spread through blood transfusion by using contaminated syringes and surgical instruments etc. In this case also doctors advise us to be careful and avoid the point of contact.

Vaccination/Immunization:

Many diseases such as polio, whooping cough, measles, mumps etc can easily be controlled by vaccination or "shots".

Edward Jenner first developed the technique of vaccination in 1796, Cowpox pus is known as vacca (from Latin word vacca means cow). From this word evolved the present term vaccination and vaccine. Since then, inoculation or vaccination is carried out to make the people immune from viral or bacterial epidemics or, for some diseases the individuals are vaccinated in their early life to make them immune to those diseases. It is claimed that small pox has been totally eliminated from the world by using this method.

Scientists are making continuous efforts to develop vaccine against other diseases. Even vaccine against AIDS is being administered in humans on experimental basis.

Drug Treatment/Gene Therapy:

If a person becomes sick with disease, he is subjected to the action of antibiotics which can kill bacteria. The antibiotics are, however, useful in bacterial disease and that only when bacteria have not, developed resistance to antibiotics. In cancer, radiotherapy and chemotherapy is used.

 In radiotherapy, the cancerous part is exposed to short wave radiations from the radioactive material repeatedly at regular intervals. Chemotherapy consists of administrating certain anticancer chemicals to the patients at regular intervals. These chemicals may kill both cancerous and normal cells.

Recently a new technique has been developed to repair defective genes. This consists of isolating the normal gene and inserting it into the host through bone marrow cells. This is called gene therapy. Combating disease utilizing all methods as and when required and ensuring a participation of community in this programme is known as integrated disease management. This requires awareness of the community about the severity of the problem, its causes and its remedies. This is a very effective programme for elimination and control of dangerous diseases from the human society.

Besides its contribution to food production and health of man, biology has discovered a number of means and developed technologies for the welfare of mankind as for example cloning; protection and conservation of environment etc.

Cloning:

Cloning is a technology for achieving eugenic aims. A clone is defined as a cell or individual and its entire asexually produced offspring. All members of a clone are genetically identical except when a mutation occurs. Generally no normal animal reproduces naturally by cloning. Several insects many plants do, in some circumstances whereas few do so regularly.

In 1997 scientists in Scotland succeeded in cloning a sheep. Other mammalian species (mice and cows) have since been cloned. In this procedure the nucleus from a fertilized egg is removed and a nucleus from a cell of a fully developed individual is inserted in its place. The altered zygote is then implanted in a suitable womb where it completes its development. The new individual formed in this way is a genetically identical clone of the individual whose nucleus was used. Thus cloning could make multiple copies of a desired genotype.

Another type of cloning is the division of a single egg or early embryo into one or more separate embryos. This is the same process that normally creates identical twins. Offspring from this type of cloning are genetically identical but carry chromosomes from each of the two parents. This type of cloning has already been used to produce genetically identical cattle and other farm animals.

Man is likely to adopt cloning techniques for commercial production of valuable animals of known pedigree such as horses etc.

 At some places scientists are making attempts to clone human embryo which they believe can serve as transplant donor. There is a lot of controversy on this issue as to whether human cloning should be attempted or not.

BIOLOGICAL METHOD

Science is a systematized knowledge. Like other sciences, biological sciences also have a set methodology. It is based on experimental inquiry. It always begins with chance observation. Observations are made with five senses viz, vision, hearing, smell, taste and touch, depending upon their functional ability. Observations can both be qualitative and quantitative. Quantitative observations have accuracy over qualitative as in the former variables are measurable and are recorded in terms of numbers. An observer organizes observations into data form and gives a statement as per experience and background knowledge of the event. This statement is the hypothesis, which is tentative explanation of observations. At this stage you should look at the ways of devising hypothesis. There are two ways of formulating hypothesis. A hypothesis can be the result of deductive reasoning or it can be the consequence of inductive reasoning.

Deductive Reasoning:

Deductive reasoning moves from the general to the specific. It involves drawing specific conclusion from some general principle/assumptions. Deductive logic of "if   then" is frequently used to frame testable hypothesis. For example, if we accept that all birds have wings (premise # 1), and that sparrows are birds (premise # 2), then we conclude that sparrows have wings. If all green plants require sunlight for photosynthesis, then any green plant when placed in dark would not synthesize glucose, the end product of photosynthesis. The other way of reasoning used in the formulation of hypothesis is inductive reasoning which is reasoning from the specific to the general. It begins with specific observations, and leads to the formation of general principle. For instance, if we know that sparrows have wings and are birds, and we know that eagle, parrot, hawk, crow are birds, then we induce (draw conclusion) that all birds have wings. The science also, therefore, uses inductive methods to generalize from specific events. In fact sometimes scientists also use other ways to form a hypothesis which may include:

• (1) Intuition or imagination.
• (2) Esthetic preference.
• (3) Religious or philosophical ideas.
• (4) Comparison and analogy with other processes.
• (5) Discovery of one thing while looking for some other thing. 

These ways can also sometimes form basis for scientific hypothesis. Hypotheses as you already know are subjected to rigorous testing.

Repeated exposure of a hypothesis to possible falsification increases scientist's confidence in the hypothesis when it is not falsified. Any hypothesis that is tested again and again without ever being falsified is considered well supported and is generally accepted. This may be used as the basis for formulating further hypothesis. So there is soon a series of hypotheses supported by the results of many tests which is then called a theory. A good theory is predictive and has explanatory power. One of the most important features of a good theory is that it may suggest new and different hypotheses. A theory of this kind is called Productive.

However, even in the case of productive theory the testing goes on. In fact many scientists take it as a challenge and exert even greater efforts to disprove the theory. If a theory survives this skeptical approach and continues to be supported by experimental, it becomes a scientific law. A scientific law is a uniform or constant fact of nature.

Examples of biological laws are Hardy-Weinberg law and Mendle’s law of inheritance.

BRIEF REVIEW OF LIVING WORLD IN SPACE, TIME AND PHYLETIC LINEAGE

Living World In Space:

Living world of today is enormous in size. It has been reproducing and evolving since the time of its origin on this planet. Today almost all parts of the world abound in living organisms. The distribution of organisms in space can be studied through biomes. A biome is a large regional community primarily determined by climate. It has been found that the major type of plant determines the other kind of plants and animals. These biomes have, therefore, been named after the type of major plants or major feature of the ecosystem. The major biomes of the world you will study in the chapter of ecology.

Living World in Time:

Since the time of origin of life on this planet, various organisms were evolved and dominated this planet during various periods of geological time chart. This has been found by the study fossils which allow biologists to place organisms in time sequence. A geological time passes and new layers of sediments are laid down; the older organisms are in deeper layer, provided sequence of layers has not been disturbed. Therefore, the fossils found in the same layer must have been younger layers. In addition it is possible to date or age the rocks by comparing the amounts of certain radioactive isotopes they contain. The older sediment layers have less of these specific radioactive isotopes than the younger layers. A comparison of layers gives an indication of the relative age of the fossils found in rocks. Therefore, fossils found in same layer must be alive during the same geological period.

Phyletic Lineage:

When we look at the biodiversity (the number and variety of species in a place), we find that there are nearly 2,500,000 species of organisms, currently known to science. More than half of these are insects (53.1%) and another 17.6 % are vascular plants. Animals other than insects are 19.9 % (species) and 9.4 % are fungi, algae, protozoa, and various prokaryotes. This list is far from being complete. Various careful estimates put the total number of species between 5 and 30 millions. Out of these only 2.5 million species have been identified so far.

The life today has come into existence through Phyletic lineages or evolving populations of the organisms living in the remote past. Evolutionary change often produces new species and then increases biodiversity. A phyletic lineage is an unbroken series of species, arranged in ancestor to descendant sequence with each later species having evolved from one that immediately preceded it. If we had a complete record of the history of life on this planet, every lineage would extend back in time to the common origin of all early life. We lack that record because many soft bodied organisms of the past had not left their preserved record as fossils.

LEVELS OF BIOLOGICAL ORGANIZATION

Biological Organization:

Biological association, or the chain of life, is the pecking order of complex biological structures and frameworks that characterize life by means of a reductionist method. The traditional order, as point by point underneath, stretches out from atoms or molecules (or lower) to biospheres.

Atomic or Subatomic Level:

Each and every living and nonliving matter is structured by simple units called atoms and sub atomic particles such as electrons, protons & neutrons. 

Molecular level:

Life forms i.e. organisms; generally don't occur in isolated structures. The atoms consolidate with one another by means of ionic or covalent bonding to deliver compounds. Hydrogen, oxygen, carbon, nitrogen, phosphorous and sulfur are the most general atoms found in biological or organic molecules. The distinctive sorts of bonding license organic atoms to be structured in incredible variety and intricacy. These may be micro particles with low atomic weight like CO₂, H₂O and so forth or macromolecules with high sub-atomic weights e.g. starch, proteins and so forth.

Biological world has two sorts of particles: Organic and inorganic.

Organic molecules are those molecules which contain both carbon and hydrogen while inorganic molecules exclude carbon and hydrogen together in a particle. An organism is generally structured by huge number of micro and macro particles of many distinctive sorts. Some most paramount and bounteous natural atoms in living beings are glucose, amino acids, unsaturated fats, glycerol, nucleotides, etc.

Organelles and Cells:

Diverse and colossal number of macromolecules orchestrates themselves in a specific manner to structure cells and their organelles. In case of microorganisms, and most protists, the whole life form comprises of a solitary cell. In most parasites, plants and creatures, the organism may comprise of up to trillions of cells. Various sub-cell structures like mitochondria, endoplasmic reticulum, Golgi-body, ribosomes and so on have been observed and studied on for their structure and functionality. It has ended up clear that functionality of these cells is accomplished by these particular structures practically comparable to the organs of the body. These structures are called organelles. The division of work inside the cell is carried out by these organelles. The prokaryotes have just a set number and kind of organelles in their cytoplasm. Eukaryotes are rich in number and sorts of membranous organelles. A cell membrane is, however, present in all cells whether prokaryotic or eukaryotic.

Tissue level:

In multicellular organisms, clusters of similar cells are composed into loose sheets or groups performing comparable functions; these groups are called tissues. Each one tissue has a specific function in the life of the living being e.g. glandular tissue, muscle tissue, xylem tissue, phloem tissue, etc. They are specific for secretion, contraction, conducting water and for translocation of proteins, sugars respectively.

Organ and System:

Different tissues having related functionalities gather together in a structure to perform its function with incredible effectiveness. Such structures are called organs and they are particular to perform specific functions. For instance, stomach which is an organ has a function of food processing (digestion), has a secretory epithelium which secretes the gastric juice and a muscular tissue (smooth) for contracting the walls of the stomach and blending the food with the enzymes altogether and moving the sustenance to the posterior end. The development of organs additionally has a specific quality in light of the fact that this prompts an effective achievement of their functions both qualitatively and quantitatively. In animals, organ development is much more complex and characterized. The organ level of organization is considerably less definite in plants than it is in animals. At the most we might recognize roots, stems; leaves and regenerative structures. Obvious functions, the recognizing functions, can be appointed to each of these structures. Roots anchor the plant into soil firmly, stockpiling of sustenance and acquiring water and minerals. The shoot upholds the whole plant while the leaves are essential organs for food making. Flowers or other reproductive structures are engaged in delivering the cutting edge (reproduction). 

Individual:

Different organs in plants and animals are assembled together to structure a distinctive individual which has characters not quite the same from other members of the same specie.

Population:

A populace is a grouping of living organisms of the same species living in the same area in the same time. Samples are the figure of rats in a field of rice, the number of pupils in your science class, or human populace in a city.

Populace is a more elevated level of natural association than organisms in light of the fact that here a group of living beings of the same species is included. This level of association has its own features which came into being by living of a group of organisms of the same species. Some of these characteristics are gene frequency, gene flow, age, populace density, etc. 

Community:  

Populaces of different species (plants and animals) living in the same territory shape a group or community. Communities are dynamic accumulations of living beings; in which one populace may increment and others may shrink because of variance in abiotic elements. A few communities are complex while different communities may be simple and straightforward. In a straightforward community any change can have extreme and ongoing impacts. The record makes it clear that an organism can be observed and studied at different levels of association. It can be learned at subatomic, nuclear, atomic, macromolecular, organelle, cell, tissue, organ level. We can likewise take a look at community as a single person, as a piece of a group that incorporates different populaces and a piece of community of an ecosystem which incorporates abiotic variables. The organisms can communicate by predation, parasitism, mutualism, and commensalism.