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.