Longitudes extent from the north pole to south pole. These are the north-south lines. All meridians are halves of great circles.Latitudes are the east-west lines. Only one latitude, the equator, is a great circle.Relative location : It tells a particular place with respect to another place.Absolute location : It indicates position based on the coordinates […]
About 71% of earth is covered with water and 29% is the land mass.There are 7 continents—1. Asia (largest), 2. Africa, 3. North America, 4. South America, 5. Antarctica,6. Europe, 7. Australia (Smallest) OceansThere are four oceans. In order of decreasing size, they are:1. Pacific Ocean, 2. Atlantic Ocean, 3. Indian Ocean, 4. Arctic Ocean.The
The age of the earth has been estimated as 4.6 billion years. Many methods like radioactive dating, fossil records etc. have been used to determine the age of the earth. Scientists have also discovered that life on earth started some 570 million years ago. The first 345 millions years saw the development of marine life.
Space means outer space or the region beyond earth. It is that portion of the universe which is beyond the immediate influence of earth. The study of region beyond earth and the objects present in it is called space science.Space science is used for continuous weather monitoring and weather forecasting on the earth. This is
Solar System Solar System : The sun, nine planets, moons of the planets, meteors, meteorites, comets, etc. are all the members of solar system. All the members of the solar system revolve round the sun.Some Facts about Solar System(a) The sun is the centre of the solar system. It is a star and nearest to
Many scientists have made many researches in the field of botany. A brief description of these is given below. Some Important Things to know
Autotroph : It is defined as an organism that can make organic molecules from inorganic nutrients.Continent Drift : The drift of continents with respect to one another over the plates in the earth’s interior.Extinction : Disappearence of species from the earth is called extinction, e.g. Dodo became extinct from Mauritius.Fossil : The remains of ancient
The world in which we live constitute our environment. High population and industrialisation has polluted the environment and has caused many problems. This chapter describes environment and its pollution.Environment : The physical and biological world where we live is called our environment. It has three components : (i) Physical surroundings (ii) Living organisms (iii) Meteorological
Forest : A forest is a biotic community having trees, shrubs and any other woody vegetations usually with a closed canopy.Economic importance of Forests1. Forests conserve fertility of the soil, 2. Cause rains, 3. Give wood, paper, medicines, rubber, resins, gums, shellac, natural dyes, lac, honey, wax, cork, 4. Provide fuel wood, 5. Provide shelter
Biotechnology : It is an important branch of biology which makes use of the knowledge of biochemistry, molecular biology, microbiology, and genetic engineering for the benefit of the mankind.The word, Biotechnology, was used for the first time in the Leeds Council in United Nations in 1920.The results of biotechnology were used for the first time
What makes the movement of plants is discussed in this chapter.Conditions necessary for Plant Movements1. Water : Proper water supply is essential for certain kind of movements.2. Temperature : Movement of plants can take place within a certain range of temperature only.3. Oxygen : The energy produced during respiration due to oxygen, makes the plants
Growth : Growth may be defined as a vital irreversible process which brings about a permanent change in any plant in respect of its size, form, weight and volume.Cellular growth has three main aspects as phases of growth. These are—(i) Cell division : It is the first step of growth of a plant and carries
Significance of Photosynthesis : It is a physico-bio chemical process of the world which is responsible for existence of life on the earth.Photosynthesis : Plants with chlorophyll convert the solar energy into chemical energy. Plants synthesise carbohydrates using raw materials got from the surroundings. They store that chemical in the form of potential energy in
Catalysis : Some chemicals alter the rate of chemical reaction without undergoing any change, usually hasten the rate of reaction, such substances are known as catalysts and the phenomenon is known as catalysis.Enzymes : We may call enzymes as organic catalysts. Enzymes increase the rate and efficiency of biochemical reactions in cells.Simple Enzyme : Enzymes
Fertilizers are those chemicals which improve the fertility of the soil and increase crop productivity. Chemical fertilizers played an important role in ‘Green Revolution’ in multiplying crop productivity to several times. Large scale use of chemical fertilizers has resulted into several evil effects such as the loss of soil fertility, environmental pollution, and persistence of