The earth has all the essential elements like Carbon Dioxide, Hydrogen, Nitrogen and Oxygen which act as building blocks for the origin of life. The earth is neither too hot nor too cold. It has exactly right temperature range for carrying out the precious life sustaining chemical reactions.
Factors which make the earth suitable for life to evolve and survive
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| Earth |
The earth has a protective shield of "Ozone" layer high up in its atmosphere to save living from extremely harmful ultraviolet (UV) radiations coming from sun.
Superlatives : World
»» Fastest Bird : Swift
»» Tallest Building : Burj Khalifa, Dubai (UAE)
»» Largest Delta : Sundarbans, India (8,000 sq. miles)
»» Largest Mammal : Whale
»» Largest Diamond Mine : Kimberly (South Africa)
»» Longest Life span of an Animal : about 200 years, (Giant Tortoise)
»» Largest Volcano : Mauna Loa (Hawaii)
»» Longest Railway Tunnel : Seikan Rail Tunnel Seikan (Japan), 53.85 km
»» Brightest Star : Sirius (aka Dog Star)
»» Most Intelligent Animal : Chimpanzee
»» Tallest Building : Burj Khalifa, Dubai (UAE)
»» Largest Delta : Sundarbans, India (8,000 sq. miles)
»» Largest Mammal : Whale
»» Largest Diamond Mine : Kimberly (South Africa)
»» Longest Life span of an Animal : about 200 years, (Giant Tortoise)
»» Largest Volcano : Mauna Loa (Hawaii)
»» Longest Railway Tunnel : Seikan Rail Tunnel Seikan (Japan), 53.85 km
»» Brightest Star : Sirius (aka Dog Star)
»» Most Intelligent Animal : Chimpanzee
Organic Evolution
More and more creation of organism by gradual changes from low categories animal to higher animal is called organic evolution. There are several evidence regarding organic evolution.
Homologous organ : Organ which are seen different due to use in various function but its structure and embryonic embryonic development are similar.
Example - Flipper of Whale, featurer of bat, forlimb of horse, Paw of cat and hands of human.
Analogous organ : Organ which looks similar due to be used in similar function but their internal structure and embryonic development are different.
Example - feature of butterfly, bats and birds all looks similar but their internal structure and origin are different.
Vestigial organ : These are organs which appear functinless in an organism but functional in their ancestor.
Example - vermiform appendix of large intestine and nictitating membrane of human. Vermiform appendix is functional in herbivorous mammal even now.
Fossils : Fossils are the remains of ancient plant or animal which provide evidence for evaluation. Example - Archaeoptery.
Archaeopteryx : It is a fossils look like bird but near a number of features found in reptiles. So, it is a connecting link between aves and reptile.
Homologous organ : Organ which are seen different due to use in various function but its structure and embryonic embryonic development are similar.
Example - Flipper of Whale, featurer of bat, forlimb of horse, Paw of cat and hands of human.
Analogous organ : Organ which looks similar due to be used in similar function but their internal structure and embryonic development are different.
Example - feature of butterfly, bats and birds all looks similar but their internal structure and origin are different.
Vestigial organ : These are organs which appear functinless in an organism but functional in their ancestor.
Example - vermiform appendix of large intestine and nictitating membrane of human. Vermiform appendix is functional in herbivorous mammal even now.
Fossils : Fossils are the remains of ancient plant or animal which provide evidence for evaluation. Example - Archaeoptery.
Archaeopteryx : It is a fossils look like bird but near a number of features found in reptiles. So, it is a connecting link between aves and reptile.
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| Organic Evolution |
Carbon and its Compounds
Carbon : Carbon is non-metal having atomic number 6 and mass number 12. It is placed in group (IV) A or group 14 in periodic table.
Allotropy : The substances which have same chemical properties, but different physical properties are called Allotropy.
Example : Allotropis of Carbon - Diamond, Graphite, Charcoal.
Diamond : Diamond is the purest form of carbon. It is the hardest natural known substance. It is transparent, and specific gravity 3.52. It is bad conductor of electricity and heat.
Diamond has very high refractive index 2.415. It is chemically inert and on heating above 1500°C, transferred into graphic. It form tetrahedral crystals and subsidization of C-atom is sp raise to the power 3.
Diamond has high mp and density. Black diamonds called carbonado contains traces of graphite.
Graphite : Graphite is soft, greasy, dark greyish colored crystalline solid. It is good conductor of heat and electricity. Its specific gravity is 2.3. The hybridization of carbon is graphite is sp2 and it has hexagonal layer structure.
Graphite is chemically more reactive than diamond. Its layer structure is held by weak van der waal's force.
Graphite is used in making for lining and making electrodes of electric furnances, in making refractory crucible, in making lead pencils, as a moderator in nuclear reactor as lubricant in machinery, as a reducing agent in steel manufacturing.
Allotropy : The substances which have same chemical properties, but different physical properties are called Allotropy.
Example : Allotropis of Carbon - Diamond, Graphite, Charcoal.
Diamond : Diamond is the purest form of carbon. It is the hardest natural known substance. It is transparent, and specific gravity 3.52. It is bad conductor of electricity and heat.
Diamond has very high refractive index 2.415. It is chemically inert and on heating above 1500°C, transferred into graphic. It form tetrahedral crystals and subsidization of C-atom is sp raise to the power 3.
Diamond has high mp and density. Black diamonds called carbonado contains traces of graphite.
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| Graphite and Diamond |
Graphite : Graphite is soft, greasy, dark greyish colored crystalline solid. It is good conductor of heat and electricity. Its specific gravity is 2.3. The hybridization of carbon is graphite is sp2 and it has hexagonal layer structure.
Graphite is chemically more reactive than diamond. Its layer structure is held by weak van der waal's force.
Graphite is used in making for lining and making electrodes of electric furnances, in making refractory crucible, in making lead pencils, as a moderator in nuclear reactor as lubricant in machinery, as a reducing agent in steel manufacturing.
Orbital speed of a satellite
Orbital speed of a satellite is independent of its mass. Hence satellites of different masses revolving in the orbit of same radius have same orbitational speed. Orbitational speed of a satellite is depends upon the radius of orbit. Greater the radius of orbit, lesser will be the orbital speed.
»» The orbital speed of a satellite revolving near the surface of earth is 7.9 km/sec.
Period of Revolution of a satellite : Time taken by a satellite to complete one revolution in its orbit is called its period of revolution.
i.e. period of revolution of = circumference of orbit / orbital speed
Period of Revolution of a satellite depends upon the height of satellite from the surface of earth. Greater the height, more will be the period of Revolution. Period of Revolution of a satellite is independent of its mass.
»» The period of Revolution of a satellite revolving near the surface of earth is 1 hour 24 minutes.