BIOFERTILIZERS

·         Generally, the term "Fertilizer" is used for "Fertilizing material or Carrier", meaning any substance which contains one or more of the essential elements (nitrogen, phosphorus, potassium, sulphur, calcium, magnesium, iron, manganese, molybdenum, copper, boron, zinc, chlorine, sodium, cobalt, vanadium and silicon). Thus, fertilizers are used to improve the fertility of the land.

·         Biofertilizers may be defined as “Substances which contains living strains of microorganisms (Bacteria, Fungi and Algae) that colonize the Rhizosphere or the interior of the plants and promote growth by increasing the supply or availability of primary nutrients to the target crops, when applied to soils, seeds or plant surfaces”.

·         Biofertilizers infuse nutrients by natural processes such as synthesis of Growth promoting substances, Fixing nitrogen and Solubilizing phosphorous in the Rhizosphere.

NEED OF BIOFERTILIZERS

·         The heavy use of synthetic fertilizers for past many decades has led to depletion of essential nutrients from soil, contamination of the soil with harmful and non-degradable substances, pollution of water resources and destruction of friendly insects and essential microorganisms from the soil.

·         The global demand for fertilizers is much higher than the availability. The costs of chemical fertilizers are also increasing every other day, making them unaffordable by marginal and small farmers.

TYPES OF BIOFERTILIZERS

1)     Nitrogen fixers

a)     Free living or Asymbiotic or Non – symbiotic Nitrogen fixers

·         Aerobic Heterotrophs– Azotobacter sp., Achromobacter sp.  and Beijerinckia sp.

·         Aerobic Autotrophs– Nostoc sp., Anabaena sp., Colothrix sp. and Blue Green Algae (BGA)

·         Anaerobic Heterotrophs – Clostridium sp., Klebsiella sp. and Desulfovibrio sp.

·         Anaerobic Autotrophs – Chlorobium sp., Chromnaticum sp., Rhodospirillum sp. and Methanobacterium sp.

b)     Symbiotic Nitrogen fixers – Rhizobium sp., Bradyrhizobium sp., Azhorhizobium sp., Frankia sp., Blue Green Algae and Anabaena azollae

c)      Associative symbiotic Nitrogen fixers – Azospirillum sp. and Herbaspirillum sp.

d)     Endophytic Nitrogen fixers – Gluconacetobacter sp. and Burkholderia sp.

 

2)     Phosphorous solubilizers

a)     Bacteria – Bacillus megaterium var phosphaticum, Bacillus subtilis, Bacillus circulans, Bacillus polymyxa and Pseudomonas striata.

b)     Fungi – Aspergillus awamori and Penicillium sp.

3)     Phosphate mobilizers

a)     Arbuscular mycorrhiza (AM) – Glomus sp., Gigaspora sp., Acaulospora sp., Scutellospora sp. and Sclerocystis sp.

b)     Ectomycorrhiza – Laccaria sp., Pisolithus sp., Boletus sp. and Amanita sp.

c)      Ericoid mycorrhiza – Pezizella ericae

d)     Orchid mycorrhiza – Rhizoctonia solani

4)     Potassium mobilizers – Frateuria aurentia

5)     Silicate and Zinc solubilizers – Bacillus sp.

6)     Manganese solubilizers – Penicillium citrinum

7)     Silicate solubilizers – Bacillus mucilaginous

8)     Plant Growth Promoting Rhizobacteria (PGPR) – Pseudomonas fluorescence

ADVANTAGES OF BIOFERTILIZERS OVER CHEMICAL FERTILIZERS

1)     Biofertilizers have replaced the chemical fertilizers as chemical fertilizers are not beneficial for the plants. Chemical fertilizers decrease the growth of the plants and make the environment polluted by releasing harmful chemicals.

2)     Plant growth can be increased if biofertilizers are used, because they contain natural components which do not harm the plants.

3)     If the soil will be free of chemicals, it will retain its fertility which will be beneficial for the plants as well as the environment, because plants will be protected from getting any diseases and environment will be free of pollutants.

4)     Biofertilizers destroys harmful components from the soil which cause diseases in the plants.

5)      Biofertilizers are not costly and even poor farmers can make use of them.

6)      Biofertilizers are environment friendly and protect the environment against pollutants.

7)     Biofertilizers provides plant nutrients at very low cost.

8)     Biofertilizers helps for the survival of beneficial microorganisms in soil.

9)     Biofertilizers helps to get high yield of crops by making the soil rich with nutrients and useful microorganisms necessary for the growth of the plants.

10)Biofertilizers are also known to provide better nourishment to plants than chemical fertilizers.

 

Industrial production of Acetic acid

Acetic acid is a crucial platform substance. Only 10% of the world's production, which is used to make vinegar, is made by bacterial fermentation. It is primarily created synthetically. Acetic acid can be produced by a variety of microorganisms, some of which also incorporate CO into the process. 

Definition:

   Although it may have been preceded by certain fermented foods derived from milk, acetic acid (also known as ethanoic acid or methyl carboxylic acid) has been generated since the invention of winemaking, which goes back to at least 10,000 BC. Given that the Latin term acetum denotes sour or sharp wine, it is generally accepted that the first vinegar, which is an aqueous solution of acetic acid, was produced as a byproduct of the damaged wine. It served as a drug at first and was perhaps the very first antibiotic ever discovered. For the majority of human history, all acetic acid was produced using the same traditional method, which involved fermenting sugar to ethyl alcohol and then oxidizing it by microbes to generate vinegar. 

Acetic acid, which has the molecular formula CH3COOH, is also referred to as ethanoic acid, ethylic acid, vinegar acid, and methane carboxylic acid. Vinegar gets its distinctive smell from acetic acid, a byproduct of fermentation. In water, vinegar contains 4-6 percent acetic acid.

Two stages of fermentation were used to create this product. The process begins with anaerobic fermentation, which is the alcoholic conversion of carbohydrates into ethanol by yeasts and continues with aerobic fermentation (oxidation of ethanol into acetic acid by AAB). Before alcoholic fermentation can begin, the basic materials - starch or complex carbohydrates - need to be saccharified in order to release fermentable sugars. Due to the growing demand for vinegar, technical advancements were required to produce the product. Currently, three main techniques are used to produce vinegar: the submerged process, the generator process, and the slow surface culture fermentation, which is known as the "Orleans" or "traditional process."

Acetic Acid Production:

i. Chemical-based method:

Acetic acid as an industrial chemical is produced from fossil fuels and chemicals by three processes: acetaldehyde oxidation, hydrocarbon oxidation, and methanol carbonylation.

ii. Biology-based method

    i. Aerobic process production:

Food-grade acetic acid is produced by the two-step vinegar process. The first step is the production of ethanol from a carbohydrate source such as glucose. This is carried out at 30°C using the anaerobic yeast Saccharomyces cerevisiae. The second step is the oxidation of ethanol to acetic acid. Although a variety of bacteria can produce acetic acid, only members of Acetobacter are used commercially, typically the aerobic bacterium Acetobacter aceti at 27-37°C. This fermentation is incomplete oxidation because the reducing equivalents generated are transferred to oxygen and not to carbon dioxide:

C6H12O6 + 2CO2 + 2CH3CH2OH.

The overall theoretical yield is 0.67 g acetic acid per gram of Glucose. At the more realistic yield of 76% (of 0.67, i.e., 0.51 g per gram glucose), this process requires 2.0 pounds of sugar or 0.9 pounds of ethyl alcohol per pound of acetic acid produced. Complete aeration and strict control of the oxygen concentration during fermentation are important to maximize yields and keep the bacteria viable. Submerged fermentation has almost completely replaced surface fermentation methods. The draw-and-fill mode of operation can produce acetic acid at concentrations up to 10% wt/wt in continuous culture at pH 4.5 in about 35 hours.

2CH3CH2OH + 02 -+ 2CH3COOH + 2H20.  

    ii. Anaerobic process production:

    In 1980 another process for the production of acetic acid emerged based on anaerobic fermentation using Clostridia. These organisms can convert glucose, xylose, and some other hexoses and pentoses almost quantitatively to acetate according to the following reactions:

C6H12O6 + 3CH3COOH, 2C5H10O5 + 5CH3COOH.

Typical acidogenic bacteria are Clostridium aceticum, Clostridium thermoaceticum, Clostridium formicoaceticum and Acetobacterium woodii. Many can also reduce carbon dioxide and other one-carbon compounds to acetate.

Parameter for AAB::

pH

pH The optimum pH for the growth of AAB is 5.5 to 6.3. However, these bacteria can survive at low pH values of between 3.0 and 4.0, and some strains have been isolated from an aerated media containing acetate that could grow at pH values as low as 2.0 to 2.2. It was postulated that there are three groups of strains that might exist in vinegar production, namely, acidophilic strains that grow only at a pH value of about 3.5, acetophobic strains that only grow at pH levels higher than 6.5, and acetotolerant strains that can grow at both these values. There may be a gradual development from acetophobic to acetotolerant strains and, with prolonged exposure to low pH and high acetic acid concentrations, to acetophilic strains. This suggests the development of a gradual acid resistance in these bacteria.

Temperature

The optimum growth temperature for most AAB is 25◦C to 30◦C. The maximum temperature for the growth of A. aceti wasfound to be about 35◦C. Thermotolerant AAB that are able to grow at 37◦C to 40◦C have also been isolated. These bacteria were able to oxidize ethanol at 38◦C to 40◦C at the same rate that mesophilic strains do at 30◦C, as well as being able to oxidize ethanol more rapidly than the mesophilic strains at the higher temperatures. AAB can also be active at lower temperatures, and weak growth was observed even at 10◦C.

Production of Acetic acid

Batch fermentations in 16-L vessels with automatic pH control were conducted as a basis for predicting continuous fermentor performance at different dilution rates. Continuous fermentations in 0.3-L chemostats were performed to determine for C. thermoaceticum. Batch fermentations were conducted in pH-, temperature-, and gas-controlled New Brunswick 16-L Microferm fermentors. These units had provisions for homogeneous mixing, constant headspace flushing with CO2, gas, sterile sampling, automatic pH control, and in-place sterilization. Chemostats with a working volume of 333 mL were set up for continuous work. The units contained provisions for flushing the headspace with gas and sparging with C02 or N,, plus pH control with 10% NaOH. The headspace of the feed medium reservoir was also flushed with N, to maintain its anaerobic state.

German Method 

In 1832, German chemist Schutzenbach established the German process which is one of the quick processes (trickling method). It is also one of the oldest methods of acetic acid production. Acetic acid bacteria are Gram-negative and aerobic bacteria. The acetic acid bacteria were grown and fermented thick slim coating beech wood shavings occurs in 5000-6000 liters of wood /steel tank while the alcoholic liquid distributes of spray mechanism covered with AAB. During, the pH was maintained in the range between 2.5-3.2 and they produced at 27-30◦C of 88-90% of acetic acid from ethanol and the remaining substrate is used in biomass production. Depending on the size of the acetifier, production capacity was 70000- 100000 at 10% acidity. The acetic acid yield is approximately 1-2 kg/m^3.h. A high yield of acetic acid was produced in surface culture of 57 611 mg/L with inoculum techniques. 

Parameters: 

    (i) mash circulation, 

    (ii) cooling water through heat exchanger, 

    (iii) amount of air passed through the system.

 The advantages is it requires low space requirements, Low costs, and high acetic acid concentration. Drawbacks, high risk of clogging because of cellulose and high loss of ethanol by evaporation, and difficulty to producing AA production.

Application:

1. Antibacterial property for injuries like burns. -  Therapeutic effects
2. Used to prevent growth, spoilage and preserve. - Beverages industry
3. Food condiment and preserving meats and vegetables. - Food industry
4. Defensive effect and decrease fatality - Cardiovascular diseases
5. Used for diabetic treatment and decrease blood sugar levels. - Antidiabetic effect
6. Used in paper coatings, emulsion, resins for paints. - Petrochemical industry
7. Laboratory washing. - Machineries
8. Used in laundry detergents - Homecare
9. Managing soft tissues injury - Orthopaedic surgery

Reference:

1. Cheryan, M., Parekh, S., Shah, M., & Witjitra, K. (1997). Production of Acetic Acid by Clostridium thermoaceticum. Advances in Applied Microbiology, 1–33. doi:10.1016/s0065-2164(08)70221-1 

2. Li, P., Li, S., Cheng, L., & Luo, L. (2014). Analyzing the relation between the microbial diversity of DaQu and the turbidity spoilage of traditional Chinese vinegar. Applied microbiology and biotechnology, 98(13), 6073-6084.

3. Bayan, L., Koulivand, P. H., & Gorji, A. (2014). Garlic: a review of potential therapeutic effects. Avicenna journal of phytomedicine, 4(1), 1.

Which animal is more savage as living life?

        An Animal having the most beautiful things and most defensive things those are making a som
e are good sometimes cause a savage. The Homo sapiens came from the class of animal domain. H. sapiens don't have such savage defensive armed thing. Besides, using the external thing they were used those things are more than equal to Animal defensive things. They were harmed in both unicellular and multicellular living cells as being savage from the H. sapiens. Every day three billion zoonotic living Organimisms killed by H. sapiens for Food purposes & Some other process. 13.7 million birds killed every day and 5 billion birds killed every year. The aquatic animal killed for the day. 2.7 billion Aquatic animals killed for food purposes only, can't include the research and natural phenomenon. The Living Planet Report from the World Wildlife Fund (WWF), which found that in half a century, human activity has washout global wildlife populations by an average of 68 percent. In H. sapiens 1,30,000 Yrs. wandered this plant, 2.5 billion Yrs evolutionary sp. as be the development by 300 million different species to be savaged by Humans, that as we are? Yes! For Land surface, Food things, medical things,  cosmetic things, and  Electric things destroying Animals, Birds, and Aquatic living, ground level living things (Asian Arowana), Research, and more. 

        An ~77 billion land animals killed or slaughtered for food in those things not coming under the unhealth animal. So animals slaughtered by diseases, infections, and wounds. 

Cancer (Types, Preventive measures, Spotting Cancer early)

Cancer

Cancer is the cause of about 30% of all premature deaths from Non-Communicable diseases among adults aged 30-69. Cancer is a collective type of disease where body cells divide uncontrollably and spread into surrounding tissues. Cancer is caused by changes in DNA. Most cancer-causing DNA changes occur in sections of DNA called genes.

IARC (International Agency for Research on Cancer) estimates on the global cancer burden, indicating that it has risen to 19.3 million cases and 10 million cancer deaths in 2020.

There are two forms of cancer:

•           Benign cancer like a Brain tumor

•           Malignant cancer-like Blood cancer

Cancer in Women

1. Breast cancer:

The most common type of cancer among women. According to WHO, breast cancer represents about 25% of all cancers.  American Institute for cancer research, estimates that it is one of the leading cancers types other than lung cancer worldwide for the last decade.

2. Ovarian cancer

Although this type of cancer occurs at any age, older women are at greater risk. In 2018, approximately 22,000 new cases of ovarian cancer were diagnosed.

3. Endometrial cancer

            It is a cancer of the inner lining of the Uterus. Risk of this cancer type increases in older women. Women undergoing hormonal therapies for breast cancer are likely to develop this type of cancer. It accounts for 4.8% of all cancers.

Cancer in men

1.Prostate Cancer

Men are at higher risk of prostate cancer, approximately 1,65,000 men were diagnosed with this type of cancer in 2018, It stands at second place in terms of causing death in men.

2.Bladder Cancer

            Bladder cancer is the abnormal growth of bladder cells and is common among men than women. Bladder cancer is the fourth most common cancer in men, striking 36 in every 100,000 and killing eight among them.

3.Colorectal cancer (also known as Bowel Cancer)

             Colorectal cancer is the third most common cancer that affects both men and women. There were over 1.8 million new cases diagnosed in 2018 according to the American Institute for cancer research.

4. Lung cancer

Lung cancer has the highest incidence and mortality rate globally. In 2020, there was an estimation that 19.3 million new cancer cases and nearly 10 million cancer deaths worldwide according to the Global Cancer Statistics 2020 report from the American Cancer Society (ACS) and the International Agency for Research on Cancer.

Other cancers that are most common in both men and women are Liver cancer, Leukemia cancer, Neuroblastoma cancer and etc.

CHILDHOOD CANCER

•         Different from the older group of cancer caused in children, approximately 300,000 children aged 0 to 19 years old are diagnosed each year.

•         The most common categories of childhood cancers include Leukemia, Brain cancers, Lymphomas, and Solid tumors, such as Neuroblastoma and Wilms tumor.

•         In high-income countries, more than 80% of children with cancer are cured, but in many Low- and Middle-Income Countries (LMICs) only about 20% are cured.

Preventive measures

Prevention is better than cure.

About 25% of cancer in women and 33% of men could be preventable according to the JAMA Oncology study journal.

So, what we really care about is how to reduce the risk of cancer by changing our activities like.

A healthy lifestyle like exercising at least twice a week, practicing yoga, a diet that includes a lot of Fruits, Green vegetables like Tomatoes, Carrots, Spinach, Whole grains, Limited meat, Green tea.

Moderate alcohol consumption.

Avoid smoking, tobacco helps in a lot better way to prevent many cancers like lung cancer, prostate cancer, etc.

Avoid contraceptive pills specifically after the age of 35 since it leads to cancer that is caused in women.

In few cancers in women, breastfeeding for a longer time reduces the risk of cancer, like ovarian cancer.

Avoiding hormonal therapy that includes estrogens also contributes to preventing cancer.

Maintaining a healthy weight and being physically active.

The HPV vaccine helps in preventing HPV [Human Papilloma Virus] related cancer like cervical cancer. So, all boys and girls between 11 and 12 years old should get vaccinated.

The best way to protect from skin cancer is, limiting exposure to the sun UV rays and usage of sunscreen lotion with at least SPF 30 or higher.

Avoid plastic containers to consume food.

Knowing the family history of cancer helps in taking precautions to prevent cancer in early-stage if any.

                        Spotting cancer early

Screening cancer at an early stage. Most cancer can be detected in its early stage and it becomes much easier to treat based on gender, age, and few symptoms. For example

Breast cancer: change in the shape, discharge from the nipple, thickening or lump on the breast or all the way under the armpit, pointed pain or discomfort, particularly in either of the breast, should never go neglected.

Colon cancer: usually asymptomatic, but if developed the common symptoms like change in bowel habit towards diarrhea, blood in the urine leading to anemia, weight loss, the lump in the abdomen is common.

Lung cancer: persistent cough [2-3 weeks], chest infections, coughing up blood, weight loss, chest and shoulder pain, breathlessness conditions.

While the exact cause of or any cancer, for that matter – is unknown, there are several risk factors that have been identified, such as radiation exposure, previous cancer treatment, age, so screening cancer in early stage helps in easy treating of that cancer.

Though cancer has destructed millions of lives, worldwide, there is always a hope that stands first not the fear. 

| UGC-NET Paper 1 | Unit - I | Teaching Aptitude |

Teaching Concept, Objectives, Characteristics, 

Teaching Concept

    Teaching Concept : Teaching is a complex process that brings a socially desirable behavioral change in a person. In traditional concepts, teaching is the act of imparting instructions to the learners in the classroom situation. 

    But in modern concept, teaching is to cause the pupil to learn and acquire the desired knowledge, skills, and also desirable ways of living in society. 

    It is a process in which learner, teacher, curriculum, and other variables are organized in a systematic and psychological way to attain some pre-determined goals. 

Teaching Concept

    Teaching is a part of the teaching-learning process. It is required to bring specific changes in a person according to the need of his society and environment in which he is living. ‘Teaching is not an act as it is dynamic in nature, so it is termed as a process.” It is also not a fundamental concept as it is greatly influenced by social and human factors. 

Some Expert Views about Teaching Concept:

    Ryburn’s view: “Teaching is a relationship which keeps the child to develop all his powers.” 

    Burton’s view: “Teaching is the stimulation guidance, direction, and encouragement of learning.” 

   Smith’s view: In the words of B.O. Smith, “Teaching is a system of actions intended to produce learning.” 

Objectives of Teaching Concept

Major objectives of the teaching concept are as follows:

• To bring desired changes in pupils.
• To shape behavior and conduct.
• Acquisition of knowledge
• To improve the learning skills of students.
• Formation of belief.
• To provide a social and efficient member of society.

Nature and Characteristics of Teaching

Nature of Teaching:

Dynamic, Social, and Humane: Teaching is not a fundamental concept because it is greatly influenced by social and human factors that are dynamic in themselves. 

Both Art and Science: Teaching is both art and science. It calls for the exercise of talent and creativity making it an art and involving repertoire of techniques, procedures, and skills that can be studied systematically, described and improved making it science. 

Diverse in Application: In application, teaching is of diverse nature. It may have various forms as formal, informal, directional, instructional, formational, training, conditioning, in­doctrination, talking, showing, doing, remedial, etc. 

Characteristics of Teaching

System of actions: Teaching is a system of actions varied in form and related to content and pupil behaviour under the prevailing physical and social conditions. 

Professional activity: It is a professional activity involving a teacher and student with a view to the development of students’ personality. Professionalism helps students in being regular and making harmony with their objects towards those they are concentrated. 

Subjected to analysis and assessment: Teaching can be analysed and assessed and analysis and assessment provide feedback for further improvement. 

Interactive process: Teaching is highly dominated by communication skills. Teaching is an interactive process carried with purpose and objectives. 

Specialized Task: It is a specialized task and may be taken as a set of skills for the realization of certain objectives. 

Collection of various modes: Teaching is a collection of various modes of itself. It is a broader term. Terms like conditioning, training, instruction, indoctrination denote a kind of teaching. They are a part of teaching but not a synonym with teaching. These are various modes of teaching contributing to teaching. 

Goals of Teaching

The aims of teaching concept with respect to its various modes are as follows- 

Teaching – To bring changes in the behaviour of students. 

Conditioning – To improve the learning skills of students. 

Training – Shaping behaviour and conduct. 

Instruction – Acquisition of knowledge. 

Indoctrination – Formation of belief. 

Levels of Teaching

    We all know that teaching is a purposeful activity. Through teaching, a teacher brings a desirable change in the learners. Both the concepts of teaching and learning are interrelated to each other. The development of the all-round personality of the learner is the final goal of teaching and learning. During teaching, an interaction takes place between an experienced person (teacher) and an inexperienced one (student). Here the main aim is to bring change in the behaviour of the student. 

    Teachers teach students at three levels. They have to keep in mind about the developmental stage of the learners so that desired educational objectives can be achieved. These three levels are 

Memory level: Thoughtless teaching 

Understanding level: Thoughtful teaching 

Reflective level: Upper thoughtful level 

Hierarchy of Levechingls of Teaching

Memory Level of Teaching (MLT)

    The objective of the Memory Level of teaching is just to impart information or knowledge to the learner. This knowledge or information is factual in nature, which is acquired through a mechanical process (i.e. memorization or rote learning). 

    Memory Level of teaching covers only the knowledge-based objective of Bloom’s taxonomy where the students learn to identify, recall, or remember the objects, events, ideas, and concepts and retain them in memory. 

    Memory level teaching lacks insight. Psychologically, it is cognitive level teaching. 

Important Points of Memory Level of Teaching (MLT): 

• It is supported by Herbart Theory of Appreciation, which states that this level of teaching seeks the learner to acquaint himself with the relationship between the facts and principles. 
• It is the first stage of teaching to get factual information. 
• Useful for children in the lower classes because of their intellect is under development, and they have a rote memory. 
• MLT aims to get factual information, to train memory, to retrain the learning material in-memory storage, to reproduce and recognize the learned information when required 
• Teacher dominated methods are used- like drill, review, and revision and asking questions. 
• The evaluation system mainly includes oral, written, and essay-type examinations. 
• Good memory includes rapidity in learning, the stability of retention, rapidity in recalling, and ability to bring only desirable contents to the conscious level. 
• Memory level teaching acts as the first step for understanding and reflective levels of teaching. It is a pre-requisite for understanding level teaching. 

Merits/ Advantages Memory Level of Teaching: 

• Useful for young children 
• Useful for the acquisition of facts, information of models and structure 
• Help children learn a new concept 
• Useful for slow learners 
• The basis for understanding and reflective level of teaching. 

Demerits / Disadvantages of Memory Level of Teaching: 

• Not suitable for higher classes 
• Use of rote memory 
• Dominance of teacher 
• Little interaction in the classroom 
• No room for initiation and self-learning for the students 
• Not intrinsic motivation 
• Problem of classroom management 
• Loss of retention and recall 

Understanding Level of Teaching (ULT) 

It comes in between the memory level and reflective level. This stage of teaching involves a moderate level of thoughtful behaviour. It is a pre-requisite for the reflective level teaching-learning, which requires the use of higher mental processes. The term “understanding” literally means to comprehend, to grasp, and to have knowledge of, to learn, to interpret and to infer, etc. 

Morris, L.Bigge, in his book, ‘Learning theory for Teachers’, defines that understanding level teaching, “seeks to acquaint students with the relationships between generalizations and particulars, between principles and solitary facts, and which show- the use to which the principles may be applied.” 

Herbart mentions three forms of mental reality which play an important role in teaching-learning at the understanding level. They are sense impressions, images, and elective elements of pleasure and pain. In Herbart’s arrangements, the teacher is conceived as an architect as well as the builder of the minds of the students by manipulating ideas to construct a student’s circle of thought. 

He advocated six steps of teaching: 

• Preparation, 
• Presentation, 
• Comparison, 
• Generalization, 
• Application, and 
• Evaluation 

Morrison very clearly stated that understanding is not merely being able to recall something; it is not mere generalization deduced from specific facts; it is an insight into how it may be used in future situations. Morrison asserted that the outcome of all teaching is ‘ Mastery’ and not memorization of facts. He proposed a unit plan, each unit representing an insight which is relatively complete in itself. 

Important points: 

• Morrison is the main proponent of understanding level of teaching. 
• It is ‘memory plus insight’ as it goes beyond just memorizing facts. It focuses on the mastery of the subject. 
• It makes pupils understand generalizations, principles, and facts. 
• It provides more and more opportunities for the students to develop ‘intellectual behaviour’. 
• It provides an active role for both the pupil and the teacher for the assimilation of facts. 6. The evaluation system mainly includes both essay and objective-type questions. 

Merits/ advantages of Understating level of Teaching (ULT): 

• Effective learning 
• Development of different cognition abilities 
• Sets stages for entering into the Reflective Level of Teaching 
• Effective classroom interaction 

Demerits or disadvantages of Understanding Level of Teaching (ULT): 

Ignores higher cognitive abilities 

Less emphasis on intrinsic motivation 

No individualized learning 

Teacher centred 

Reflective Level of Teaching (RLT) 

This Level of teaching is the highest level of teaching-learning activity. It is the stage of learning when students do not merely repeat and revise or answer the questions as asked for; nor do they only understand, learn, interrelate or interpret the concepts but also they ponder upon, contemplate and pay serious thoughtful consideration to the presented contents. 

The main objectives of Reflective Level of Teaching are: 

1. To develop insight into the learner to solve problems. 
2. To develop rational and critical thinking in the students. 
3. To develop the ability of independent thinking and decision making in the students. 

Important Points: 

• Hunt is the main proponent of reflective level of teaching. 
• It is the highest level of teaching and includes both ULT and MLT. 
• It is problem-centric approach of teaching. 
• The students are assumed to adopt some sort of research approach to solve the problem. 
• Classroom environment is to be sufficiently ‘open and independent’. The learners are self-motivated (intrinsic) and active. 
• The aim is to develop the reflective power of learners so that they can solve problems of their lives by reasoning, logic, and imagination, and lead successful and happy lives. 
• The pupil occupies the primary place and teacher assumes the secondary place. 
• The essay-type test is used for evaluation. Attitude, belief, and involvement are also evaluated. 

Merits or Advantages of Reflective Level of Teaching (RLT): 

• It is the most thoughtful mode of operation. 
• Learner-centred approach 
• Development of problem-solving ability 
• Useful for gifted children. 
• Provides maximum flexibility 
• Self-motivation 
• Development of creativity 

Demerits of Reflective Level of Teaching: 

• It is not suitable for lower classes 
• It is a time-consuming process. 
• It is not applicable for dull students. 
• There is an excess burden to the teacher. 

Requirements of Teaching 

The teaching process involves the following variables:

1. Dependent Variable: 

The student is a dependent variable. He is subjected to changes and developments through the efforts of the teacher and teaching process. In the process of teaching, the dependent variable plays the functional or active part. 

2. Independent Variable: 

The teacher is an independent variable. He is responsible for the functioning of students, the dependent variables. He is free to act in the process while students are quite dependent on him. The teacher does plans, organizes, leads and controls the process of teaching. Like dependent variables, independent variables also play the functional or active part. 

3. Intervening Variables 

There is a need for desirable interaction between the dependent and the independent variable to achieve the goals of teaching. This role is played by the intervening variables. The content of teaching, methods and techniques, tactics and strategies management of instructional material and teaching environments, etc., are the Intervening Variables. 

Basic requirements of teaching are:

• All three variables of teaching
• Professionalism
• Suitable environment
• Teacher-student relationship
• Student’s discipline
• Teacher’s devotion to teaching, and also, on the other hand, student’s devotion to learning.