Saturday, May 10, 2014

Activity on biodegradable and non-biodegradable substances

Aim:  To study Biodegradable and Non-biodegradable substances

Materials Required: Two pots, soil, plastic, polythene, aluminum foils,  canes, plants & animal waste, waste papers
1.     Take two pots  half filled with soil,
2.     label them – Biodegradable and Non-biodegradable,
3.     Put plastic polythene, aluminum foils in non biodegradable pot.
4.     Put plant and  animal waste in – Biodegradable pot
5.     Record changes occur in these pots at least for 6 days
6.     Take images showing  the top view
                                         Non- Biodegradable substances

                                                           Biodegradable substances                                                                    
1.     No change in the Non- biodegradable pot
2.     Bio degradable substances break down naturally.
1.   Biodegradable waste is waste that can break down by biological processes into natural components and be recycled naturally by the action of bacteria or other saprophytes. Examples are old vegetables / food, paper, cardboard, deceased animals, and phyto plastics (special plastics that break down when exposed to the sun after some time) etc.

2.   Non biodegradable waste is waste that does not break down into natural components and exists in the environment for a long time or may harm the various members of the eco- system.. Examples would be tyres, plastics, electronic components, metals etc.

Hypogeal and Epigeal Germination

Aim: To show Epigeal / Hypogeal Germination

Materials Required: Pot with soil, Bean or Gram seeds, water

Procedure :put 5-6 seeds in the soil sprinkle water. Click photographs from initial absorption of water to the seedling's emergence from the ground. Paste  images showing stops of germination  in the file.

Germination is the process by which a plant grows from a smaller seed (or "germ") into a larger, mature plant.
There are two types of germination depending on whether the cotyledons are lifted above ground or remain below ground: epigeal and hypogeal.

Epigeal Germination (Dicots) 
 In epigeal (epi=above) germination, the hypocotyl (hypocotyl is the stem below the cotyledons) pushes the cotyledons above ground. * The cotyledons function as leaves until the true leaves emerge.
* Example - bean, canola Draw diagram in the file

Hypogeal Germination (Dicot) 

 In hypogeal germination, the cotyledons remain below ground.
The epicotyl (stem above the cotyledons) grows and raises the plumule out of the soil.
Example – pea,gram
 Draw this diagram in the file

Experiments on Seed Germination

Aim: Experimental Set up to show conditions essential for germination.

Materials Required: Beaker/glass, Glass strip/ scale, 3 bean/gram seeds, water

Procedure: Take three dry bean or gram seeds of equal sizes and tie them on a scale of 6’” inches in a line as shown in the figure. Place this strip in a beaker and pour water till the middle bean or gram is half immersed in water. Leave the set up at room temperature. For -4 days and observe.

Observation: You will observe that only the middle seed germinates properly with the shoot and root. The top seed above the water will not germinate at all and the one totally immersed in water will give out only a small radicle.
1.    This is an experimental set up to study conditions essential for germination.
2.     Only the middle seed germinates normally as it gets sufficient water, oxygen and temperature.
3.     The topmost seed does not germinate as it does not get water. It gets only oxygen and temperature.
4.    The lower most seed is immersed in water. It gets enough water and temperature but not enough air. Hence it gives out only a small radicle.

Tuesday, December 8, 2009

Management of Natural Resources..Part 2

Why do we seek to build dams?

1. Large dams can ensure storage of adequate water which can be used for irrigation. Canal systems leading from dams can transfers water to great distances eg. Indira Gandhi Canal has brought greenary to large areas of Rajasthan.

2. Stored water can be used for generating electricity.

3. Dams also control floods.

What are the reasons for opposition to construction oflarge dams like Tehri Dam on river Ganga?

Large dams Construction causes three problems:

Social Problems: Large numberof peasents and tribals are displaced without adequate compensation or rehabilitation.

Economic Problem: Huge amounts of public money is used in constructing dams without yhe generation of proportionate benefits.

Encironmental Problems: Dam construction leads to deforestation and loss of biological diversity.

What is Narmada Bacho Andolon?

It is a protest against raising ythe height of Sardar Sarover dam on river Narmada.

What is water shed management?

  • Watershed management amphasises soil and water conservation to increase biomass production.
  • Watershed management increases income of watershed community
  • It also prevents droughts and floods.
  • It increase the life of the dewnstream dam and reserviors.

What are the ancient or traditional systems of water harvesting?

  • Digging small pits and lakes.
  • put in place simple watershed systems.
  • Building small earthen dams
  • Construting dykes
  • sand and limestone reservoir
  • Setting up rooftop water collecting units

Name some of the ancient or traditional water harvesting structure/systems still in use.

  • Khadins and Nadis in Rajasthan
  • tals in Maharashtra
  • Bundhis in M.P.and U.P.
  • ahars in Bihar
  • Kulhs in H.P.
  • Eris in T.N.
  • Surangams in Kerala
  • Kattas in Karnataka

Describe the structure of water harvesting structure in largely terrain?

  • In a largely level terrain water harvestinh structures are mainly crescent shaped earthen embankments or low, straight concrete and rubble checked dams built across seasonal flooded gullies.
  • Monsoon rains fill ponds behind the structures.
  • Only large structures holds water throughout the year while most dry up after monsoon
  • The main purpose of water harvesting structures is not to hold the surface water but to recharge the ground water.

Write significance of water stored in ground.

  • It does not evaporate, but recharges wells and provides moisture for vegetation over a wide area.
  • It does not provide breeding grounds for mosquitoes like stagnant water bodies.
  • Ground water is not contaminated by human and animal waste.

Why do we need to use coal and petroleum (Fossil Fuels) judiciously?

  • Coal and petroleum are non- renewable resources. These were formed from degradation of biomass millions of years ago and will be exhausted in future.
  • When coal and petroleum are burnt, they release SO2, CO2 oxides of N2. When combustion takes place in insufficient oxygen, CO is formed along with N2O and SO2 which are all poisonous high concentration and pollute our environment.
  • CO2 formed by complete combustion of fossil fuel is a green house gas and causes global warming

What are two advantages of giving people control over resources?

1. Controls mismanagement of resources

2. Reduces over- exploitation of these resources.

How is Ganga river getting polluted? Which project has bean laiddown by Government to clean Ganga?

Causes of Pollution

  1. Largely untreated garbage and sewage is dumped into Ganga every day from state like U.P. Bihar andWest Bengal.
  2. Huamn activities like bathing, washing ofclothes, immersion of ashes or unburnt corpses pollute water.
  3. Chemical effluents from industries also pollute Ganga and these toxic chemicals kill fish and other aquatic organisms in the river

A multicroreproject-- Ganga action plan was imlemented in 1985 to clean Ganga water

What changes can you make in your habits to become more environment friendly?


  1. Save water by repairing the leaked taps.
  2. Switch off unnecessary lights and fans
  3. Don't waste food
2.Say no to plastic bags, disposable plastic cups

3.Reuse the thing again and again eg. using jam bottles to store some other material

4. Growing plants at your home and in surroundings

5.Stop using products like fur. Ivory from wild life.

Draw diagram of traditional water harvesting system --Khadin System

Refer to Fig16.3 Page No. 276 of NCERT Book

Monday, November 30, 2009

Management of Natural Resources

What is Ganga Action Plan and when was it implemented?

It is a massive multi-crore project implemented in 1985.It is to clean the excess pollution from the river Ganga.

Write the causes of pollution in the river Ganga.

  1. Untreated sewagesuch as garbage and excreta are dumped into the Ganga.
  2. Pollution is also caused by other human activities like bathing, washing and immersion of ashes or unburnt pieces of dead bodies.
  3. Industries also contribute in Gang's pollution by adding chemical effluents and make thewater toxic, killing aquatic organisms.

How can you detect the presence of pollutants in river?

  1. Presence of Coliform bacteria. It indicates contamination by disease causing microorganisms.
  2. Ph of water can be detected by using universal indicator or litmus paper.

What is the essential mantra for reduction in pollution in the environment?

Three R's--reduce,recycle and reuse. Discuss

What is sustainable development?

It is not only meets the immediate needs of human society but also leaves sufficient resources for future generations.

Why should we conserve forest?

1. Forest bring rainfall and screen us from wind and sun.

2.Forest preserve wild life and provide suitable habitat for multiplication of wild animals and plants.

3. Forest by affecting the rainfall, wind velocity, temperature and CO2 concentration influences ecoclimate of atmosphere.

4. Forest prevent soil erosion which otherwise will result in the swelling of rivers and flooding of low lying areas.

5. Forest purify our air through photosynthesis.

6. Forest serve as beautiful place for recreation and tourism.

7. Forest provides us many valuable products like wood, fuel, pulp, paper, gum, resin, oil, honey, medicines, drugs, spices, etc.

What is wild life? Why should we conserve it?

1.The term wild life covers any or all non cultivated plants and non domesticated animals in natural surroundings.

2.Wild life has links in the food chain and if any of links is disturbed the balance in nature is disturbed.

3.Wild life also helps in biological control eg. Birds like hawks and snakes eat rats which otherwise will damage our crops.

4.Wild life helps in maintaining that keeps the soil fertile.

5. Trees and vegetation purify air by giving out O2.

6. Trees and vegetation prevent soil erosion by wind and water.

7.Wild species of plants and animals are destroyed by man to satisfy his demands of food , Fashion and sports eg leopard is killed for skin which is warm and decorative, antelops for their horns and many economically useful plants yielding medicines etc. As a result many species have become extinct while others are at the verge of extinction. Thus man needs to preserve this treasure of nature.

Q Steps for conservation of forests

  1. A master plan is to be prepared for massive a forestation project which should include growing appropriate kinds of trees in plains as well hills.
  2. Forests should be prevented from forests fires.
  3. Cutting and uprooting of ligneous species should be punishable by law. Grazing of animals should be allowed in a controlled manner.
  4. As there is great pressure on forests for fuel, firewood farming should be done on degraded land with proper planting techniques.
  5. Public should be made aware on subjects like tree felling, tree planting, land reclamation, forest planning, proper use of forest products etc through programmes on radio, television.

Steps for Conservation of wild life

  1. Hunting and trading of wild life should be punishable by law particularly endangered species.
  2. National parks and sanctuaries should be set up to provide natural habitat for wild life.
  3. Forest should be conserved.
  4. More attention should be given to conserve endangered species of plants or animals to prevent their extinction.
  5. The Government Department should conduct periodic surveys of National Parks/ Bioreserves/Sanctuaries to have knowledge of all population species of wild animals and birds.
  6. Some of the international organizations which help in conservation of wild life are IUCN, WWF, and FAO etc.

Why forests are called biodiversity hot spots?

Forests are rich in biodiversity. There are many endemic species of plants and animals found in forest. Since forests are undergoing rapid habitat loss, there is danger of many species becoming extinct. Thus forests are priority areas for conservation so these are called hot spots.

What are the causes of damage to forests?

  1. Local people damage forests to fulfill their daily needs.
  2. Deforestation caused by industrial needs.
  3. Deforestation caused by development projects like building roads dams.
  4. By tourists or in making arrangements for tourists.
  5. Forest Fire is also one of the causes of damage to forests.

Why biodiversity is important?

1.It is important for stability of an ecosystem.

2. It is important for the well being and healthy functioning of an ecosystem.

Enlist the stakeholders who should be considered, while we think of conservation of forest

The stakeholders are

  1. The people who live in and around forests and depends on forest products.
  2. The forest department of Goverment responsible for managing the forest and control the resources and revenues form forest.
  3. The industrialist, who use forest produce as raw materials.
  4. The wild life and nature enthusiasts who are involved in wild life and nature conservation.

What do the local people need from the forest?

  1. Use bamboo to make huts.
  2. Use basket for collecting and storing food materials.
  3. Gather fruits, nuts, and medicines from forest.
  4. Use wood to make implements for agriculture, fishing and hunting.
  5. Large quantities of firewood
  6. Do hunting and fishing.

Discuss how the forests have been damaged/ affected after they had been taken over by the Forest Department of our Goverment.

  1. Local needs and knowledge were ignored in the management practices.
  2. Large areas were cleared and converted to monoculture of pine, teak or eukalyptus.
  3. This leads to destruction of biodiversity in the area.
  4. Local people were not able to fulfilltheir needs.
  5. But these plantations are the important source of revenue for the Forest Department

Does prejudice against traditionl use of Forest areas have any basis? Justify your answer.

  1. The Great Himalayan National Park has alpine meadows. The nomadic shepherds used to take their flock of sheep in this area from the village every summer.
  2. When the National park was established and the area was taken over by the Government. The practice of grazing by sheep was probhited.
  3. Now it is seen that without grazing the grasses first grow very tall and fall over the others and prevent the fresh growth of grasses. Grazing allows the fresh growth of grasses.

Quote three instances where human intervention saved the forests from destruction

  1. Bishnoi Community in Rajasthan take forest and wild life conservation as a religious tenet.King of Rajasthan ordered to get wood for their palace.Workers went to Khejrali village near Jodhpur in Rajasthan to get the wood of Khejri trees. It was opposed by Bishnoi community. Amrita Devi Bishnoi sacrificed her life along with 363 others in 1731 for protection of Khejri trees. Government is giving Amrita Devi Bishnoi National award for wild Life Conservation.
  2. 'The Chipko Andolan'(Hug the trees Movement) In 1970's a contractor was given permission by the Forest Department to cut trees in a given area of the forest near to Reni Village Garwal. When the contractor reached the area, menfolks of the local community were not present. Without any fear the women of the village went to the forest and hugged the tree trunks which prevented the contractors men from felling the trees.
  3. 1.Sal Forest in South- West districts of wesr Bengal were degraded. It was recognised by West Bengal Forest Department. They tried to revive the forest but failed. As they used traditional methods and policies and not involving local people.The Forest Department Started to involve the villagers in managment practices.

2. A.K.Banerjee. A forest officer involved the villagers in reviving the Sal forests in Arabari Forest range of Midnapur district. He involved local villagers to protect 1,272 hectares of badly degraded Sal Forests. Employment was given in both Silviculture and Harvesting operations. They were allowed to take 25% of the final harvest, fuel wood and fodder collection on payment of a nomianl fee. Sal Forests recovered remarkably by 1983 and the Forest were valued at Rs 12.5 Crores.

Sunday, July 20, 2008

Life processes

Students First Terminal Exams is approaching. Let us revise the text book questions of chapter Life processes.
Q1. Why is diffusion insufficient to meet the oxygen requirements of multicultural organisms like humans?
Ans . In unicellular organisms the entire surface of the organism is in contact with the environment. But in multicultural organisms all the cell may not be in direct contact with the surrounding environment. So diffusion is insufficient to meet the oxygen requirements of all the cells.
Q2. What criteria do we use to decide whether something is alive?
Ans. Living organisms must do breathing, movements, growth and development. Living creatures must keep repairing and maintaining their structures. They also produce their young ones.
Q3. What are outside raw materials used for by organisms?
Ans. Carbon based molecules like carbohydrates, proteins. and fats. Other molecules such as lipids, Vitamins and minerals are also essential.
Q4. What processes would you consider essential for maintaining life?
Ans. Digestion, Respiration Transportation and Excretion are essential for maintaining life.

Q1. What are the differences between autotrophic and heterotrophic nutrition?
Ans. Refer modes of nutrition given in the blog
Q2. Where do plants get each of the raw materials required for photosynthesis?
1. CO2 –from atmosphere through stomata
2. H2O – From soil through roots.
3. Other raw materials like nitrogen, phosphorus, iron and magnesium are taken up from the soil. Nitrogen is the most important material which is absorbed in the form of NO3-, NO2-.or is taken in the form of organic compounds which are prepared by bacteria from atmospheric nitrogen is used to form protein.

Sunday, May 18, 2008

Nutrition in Plants

Autotrophic Nutrition: In this type of nutrition organisms makes its food itself by the process of photosynthesis. The organism takes CO2 and H2O from the environment and in the presence of chlorophyll and sunlight makes its food in the form of carbohydrates (Glucose). It is the source of energy to the plants. Excess glucose is stored in the form of starch.
CO2 + H2O Chlorophyll C6H12O6 + 6H2O+ 6O2
Steps of photosynthesis:
1. Chlorophyll absorbs light energy and converts it into chemical energy.
2. Splitting of water molecule and O2 is released.
3. Carbon dioxide is reduced to form carbohydrates.
Site of photosynthesis:
Transverse Section of leaf: In leaf two surfaces are present, upper epidermis and lower epidermis. In between the two epidermises mesophyll cells are present which are rich in chloroplast. Chlorophyll pigments are present in the chloroplast. Photosynthesis occurs in the chlorolopast of mesophyll cell of leaf.
Raw materials required for photosynthesis
Carbon dioxide: The epidermis of leaf has minute pores called stomata through which exchange of gases takes place between leaf and environment. CO2 from environment enters into the leaf cells through stomata.
Water: Water is absorbed by roots of the plant from the soil. Water is conducted through xylem up to the leaves.
Q How do desert plants, in which the stomata are closed at day time, carry out photosynthesis?
Ans: In desert plants the stomata are closed during day time. At night stomata opens CO2 diffuses into the leaf cells and is converted into an intermediate compound called malic acid. In the day time CO2 is released from malic acid and used to form food in the presence light.
Q. Explain the structure of stomata with the help of diagram.
Stomata are minute pores present in the leaf epidermis. The opening and closing of stomata is regulated by two guard cells. Nucleus and cloroplasts are also present in the guard cells.They are protected by surrounding epidermal cells.
Q Write the mechanism of opening and closing of stomata?
Ans. When the guard cells gain water they become turgid or swollen and stomata opens. When the guard cells lose water they shrink and stomata closes.
Q When plants do close their stomata?
Ans. When plants do not need CO2 for plants their stomata are closed. This also prevents the loss of water from the plant by transpiration.
Q,. How do plants get other materials for its growth and developments?
Plants need other minerals like N, S, Mg, Zn, Ca, P etc .Plants take these materials from the soil with the help of roots. The most important mineral is N. It is absorbed in the form of nitrate or nitrite and are used to form proteins.