Revision Assignment for class vii

Q1)Mention the various ways by which qualitative loss in the nutritive value of a food item may occur.
Q2)Name the three food groups and the nutrients present in them.
Q3)Identify the following :
a)Sense organ having receptors for touch,pain and pressure
b)Part of brain which controls thinking
c)Hormone which controls blood sugar level
d)Phytohormone responsible for flowering
Q4)What is food fad?
Q5)Give the function of following
a)Iron
b)Vitamin B
c)Iodine
d)Vitamin K
e)Roughage
f)Vitamin A
Q6)Draw a well labelled diagram of neuron.
Q7)You have accidently put your foot on a sharp object.What happens.Explain your answer with the help of reflex arc.
Q8)Give reasons for the following :
a)Pituitary is called the master gland
B)Adrenaline is called the hormone of fight, fright and flight
Q8)Explain the different type of responses by taking suitable examples.

GLOBAL WARMING

An increase in the Earth's temperature caused by human activities, such as burning coal, oil and natural gas. This releases carbon dioxide, methane, and other greenhouse gases into the atmosphere. Greenhouse gases form a blanket around the Earth, trapping heat and raising temperatures on the ground. This is steadily changing our climate.
Greenhouse Gases
A greenhouse gas is a gas, either naturally occurring or man-made, that absorbs heat in the atmosphere. Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occuring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases: - Carbon dioxide is released to the atmosphere when solid waste, fossil fuels (oil, natural gas, and coal), and wood and wood products are burned. - Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. - Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels.

ASSIGNMENT - NUTRITION IN PLANTS AND ANIMALS

Q1)Pitcher plant synthesize its food by photosynthesis but it also feed on insects. Why?
Q2)what is the function of xylem and phloem in plants?
Q3)Differentiate between intracellular and extracellular digestion.
Q4)Explain the various steps of nutrition in human beings.
Q5)Name the two disorders of digestion and explain them
Q6)What are digestive enzymes?
Q7)How cuscuta obtain its nutrition?

ASSIGNMENT- ORGANISATION IN THE LIVING WORLD

Q1) Name the two conducting tissue present in plants? Give their functions?
Q2) What is population? Give examples?
Q3) Name the various molecules which combine together to form a living cell?
Q4) Give an example of
a) Artificial aquatic ecosystem.
b) Natural aquatic ecosystem.
c) Artificial terrestrial ecosystem.
d) Natural terrestrial ecosystem
Q5) Taking forest as an example, name the population, biotic community and ecosystem you will find in a forest.
Q6) Taking pond as an example, name the population, biotic community and ecosystem you will find in a pond
Q7) Write the basic property of species?
Q8) Name the higher levels of organization and define any one of them
Q9) Name the lower levels of organization and define any one of them.
Q10)Name any two animal tissue.

What Makes Us Grow Taller

The stature to which each of us grows is predetermined in our genes. Tall parents tend to produce tall offspring. And growth also depends on endocrine and nutritional factors.

Also Growth hormone promotes growth during childhood and adolescence, but slackens off when maturity is attained. Too much growth hormone, as is secreted by pituitary tumors, induces gigantism, while too little causes dwarfism. The adolescent growth spurt is correlated with the surge of sex hormones(testosterone and estrogen) secreted at the time of puberty.

Human beings take longer to grow up than any other animal. This is correlated with our considerable longevity but has probably evolved as an adaptation to our higher intelligence.

Most teens can expect to grow a total of about 7 to 10 inches during puberty before they reach their full adult height. Each person is a little different, so everyone starts and goes through puberty on his or her body's own schedule. Those who start a little later than their friends will usually continue to grow a little later, too.

Hopefully students you have got answers to your queries. Good bye for now.

Our senses

What's that smell? Do you hear that noise? Taste this! Look at me! Feel this, isn't it soft? When you hear, or even use these phrases, you probably don't stop to think about why we use them. Well, it's because of our senses. Without us even knowing, our sense organs (nose, eyes, ears, tongue, and skin) are taking in information and sending it to the brain for processing. If we didn't have them, we would not be able to smell, see, hear, taste, or touch anything! Talk about a boring life. Our senses are the physical means by which all living things see, hear, smell, taste, and touch. Each sense collects informaton about the world and detects changes within the body. Both people and animals get all of their knowledge from their senses, and that is why our senses are so important. All senses depend on the working nervous system. Our sense organs start to work when something stimulates special nerve cells called receptors in a sense organ. We have five main sense organs. They are the eyes, nose, ears, tongue, and skin. Once stimulated, the receptors send nerve impulses along sensory nerves to the brain. Your brain then tells you what the stimulus is. For example, your sound receptors would be bombarded by billions of sound waves. When these signals reach the part of the brain called the cerebral cortex, we become conscious of the sounds.

The Biosphere

The term "Biosphere" was coined by Russian scientist Vladimir Vernadsky in the 1929. The biosphere is the life zone of the Earth and includes all living organisms, including man, and all organic matter that has not yet decomposed. Life evolved on earth during its early history between 4.5 and 3.8 billion years ago and the biosphere readily distinguishes our planet from all others in the solar system. The chemical reactions of life (e.g., photosynthesis-respiration, carbonate precipitation, etc.) have also imparted a strong signal on the chemical composition of the atmosphere, transforming the atmosphere from reducing conditions to and oxidizing environment with free oxygen. The biosphere is structured into a hierarchy known as the food chain whereby all life is dependent upon the first tier (i.e. mainly the primary producers that are capable of photosynthesis). Energy and mass is transferred from one level of the food chain to the next with an efficiency of about 10%. All organisms are intrinsically linked to their physical environment and the relationship between an organism and its environment is the study of ecology. The biosphere can be divided into distinct ecosystems that represent the interactions between a group of organisms forming a trophic pyramid and the environment or habitat in which they live.

Atmosphere

The atmosphere is the gasesous envelope that surrounds the Earth and constitutes the transition between its surface and the vacuum of space. The atmosphere consists of a mixture of gases composed primarily of nitrogen, oxygen, carbon dioxide, and water vapor. It extends some 500 km above the surface of the Earth and the lower level (troposphere) constitutes the climate system that maintains the conditions suitable for life on the planet's surface. The next atmospheric level, the stratosphere (12 to 48 km), contains the ozone layer that protects life on the planet by filtering harmful ultraviolet radiation from the Sun. Since the Industrial Revolution, man has been altering the composition of the atmosphere by the burning of fossil fuels. Concern has been growing about rising concentrations of carbon dioxide, methane, nitrous oxide, and chloroflurocarbons in the atmosphere because these "greenhouse" gases trap heat energy emitted from the earth surface and increase global temperatures (global warming). In addition, chloroflurocarbons are effective at depleting the Earth's ozone shield that protects the earth surface from the harmful effects of ultraviolet radiation

A Recipe Using All Of The Senses

If you follow this recipe, you will make peanut butter balls and use all of your senses while doing it. Listed below are the ingredients you need. This recipe makes 125 to 140 peanut butter balls.
2 sticks butter
2 cups peanut butter
3 teaspoons vanilla
5 cups powdered sugar
48 ounces semi-sweet chocolate chips
1/4 cups paraffin, melted
Cream butter, peanut butter, and vanilla together; blend in sugar. Form into small round balls. Melt chocolate chip and paraffin in top of a double boiler boiler. Using a toothpick, dip balls into melted chocolate. Place on wax paper and immediately press pecan half on each ball (optional).
You would probably use your senses in this way:
Sight - Using your sight, you are able to read the directions and see the ingredients. You are also able to see the peanut butter balls after they are done.
Smell - When the peanut butter balls are being made, you will smell the peanut butter, the vanilla, and the chocolate chips.
Hearing - You will hear the paraffin and chocolate boiling in the double boiler. You will also hear the wax paper crinkle.
Touch - You will feel the dough as you form it into balls. You will feel the sharpness of the toothpicks and the heat of the chocolate and paraffin. Taste - You will be able to taste the delicious peanut butter balls.

EARTHKEEPER HERO

There are many definitions of a hero. A hero can be described as a person who dedicates his life to the needs of others. Or, a hero can also be described as a person or something that affects or saves others’ lives. A hero can help motivate others. Of course, everyone has his own perception about the characteristics of a hero. And I believe that everyone can be a hero, for himself or for another person. A person must not always be strong or famous or rich to be a hero. All that a person needs to be is just, have honest intentions and great spirit to make something better, not only for many people, but, most importantly, for himself.
A great thing always starts from a little thing. Actually, I have many people that I consider as heroes, for example, my parents, The GOD, teacher, and many more. And there are some organisms who are real heroes for the environment, although they are often forgotten or overlooked. Some of these organisms are bacteria & fungi (decomposers)which are actually environment cleaners. Maybe you will think that it’s ridiculous and maybe you will also wonder why I would choose these organisms as my hero when there are many famous figures in the world. But have you ever thought what your environment would be like if there are no decomposers in your area? We would live in a big trash bin.But maybe you will say, "It’s their job, so of course it’s their responsibility to keep the environment clean." Yes, you may be right again, but at the same time you need to agree that they are very important for our healthy survival.
Good Bye for now dear students. I'll wait for your comments