Life Science(Biology)

Soil is the upper weathered layer of the earth's crust.The vertical section through the upper crust of the earth is called soil profile . Study of soils is called pedology and the process of soil formation is called pedogenesis .1 cm soil formation takes about 200-400 years.    The removal of the fertile top layer of the earth or any slight disturbance in its structure is called soil erosion.   .    Photograph: Landslides at Kailashahar to     Dharmanagar road , 23 rd June,2024   Types of soil erosion:-  It is of two types: (A) Normal or Geological erosion: It is a very slow process  due to normal physical and biological equilibrium without any interference of human beings . (B) Accelerated Erosion: It occurs rapidly due to physical and biological activities.Rainfall, landslide, earthquake,overgrazing and human activities are the main factors in such case. Agents of soil erosion:  Water and wind are the main two ag...

  Courtesy:PV education   The process through which heat is trapped near Earth's surface by greenhouse gases is called greenhouse effect . These gases are - carbon dioxide, methane, nitrogen oxides and CFCs.These gases allowed the sunlight to shine onto Earth's surface but trap 90% of  the heat that reflects back to the atmosphere. Thus , these gases act as insulating glass walls of a greenhouse and keep the climate favorable for living beings by about 33° C.       Climate Scientists now agree that increase of greenhouse gases are directly linked to the increase of global temperature and affecting global climate.This is called climate change.       Greenhouse gas emissions increased 70% between 1970-2004 due to anthropogenic activities. Burning of fossil fuels to run power plants, vehicles,etc is responsible for the 80% increase of carbon dioxide in this timespan. Cutting of trees has accelerated the addition of this gas a...

       India is situatedat the tri- junction of three realms: Afrotropical, Indo-Malayan and Paleo - Arctic realms which makes it rich in biological diversity.It represents 10 Biogeography zones, 26 Biogeography provinces with  ecosystems like forest, wetland, desert,  costal and marine. Though India shares 2.4% of world's land area, but represents 11% flora and 6.5% fauna of the world.Out of 17 megabiodiverse nations India ranks 9th in terms of richness of  higher plant species.      Approximately 65% of Indian  geographical area has been survayed and over 46,000 plant  species and 81,000 animal species has been recorded .To preserve this rich biodiversity it has been divided into10 biogeographic zones:  (1) Trans Himalayas with 3 provinces : (A) Ladakh Mountains (B) Tibetan Plateau  (C) Sikkim Himalayas  (2) The Himalayas with 4 provinces: (A) North West Himalayas  (B) West Himalayas (C) Cent...

                           Index 1. SRI Method of Rice Cultivation  2.Tea Plantation Process 3. CTC Tea Processing  4. Benefits of CTC tes 5.Orthodox Tea Processing 6. Benefits of Orthodox Tea  7. Difference between CTC Tea and orthodox tea  8. Green Tea System of Rice Intensification(SRI) Cultivation  1 Season • Suitable for both Kharif and Rabi seasons with assured water supply and proper drainage. 2 Varities •High- yielding varities (HYVs) ,hybrids, and long- duration varities showing good tillering ability are preferred. 3 Nursery Management •3.1 Seed Rate • Single seedling/hill: 7-8 kg/ ha • Two seedlings/ hill : 12-15 kg/ ha • 3.2 Preparation of Nursery Area • Prepare a 100 mt2 raised bed for 1 Ha of main field near a reliable water source. • Lay plastic sheet or polythene gunny bags underneath to prevent roots from penetrating deep into the soil. • 3.3 Preparation of Soil Mi...

       A rain with pH of about 5.2 or below due to the presence of sulphur dioxide and nitrogen oxides as a result of combustion of fossil fuels.     The term acid rain  was coined by Scottish chemist Robert Angus ( father of acid rain) in 1852. His findings were published in : Air and rain: The beginnings of a Chemical Climatology ,  1872. According to EPA ( Environmental Protection Agency) sulphur dioxide and nitrogen oxides released from thermal power plants , vehicles and oil refineries, volcanic activities, forest fire and bacterial decomposition of the organic matters are the main cause of acid rain. In the above reactions formation of these acids  in the atmosphere are described. Acid rain contains sulfuric acids or nitric acid and these may in any form of precipitation or dust, gases, snow,fog ,hail,etc.So, it may be of wet deposition or dry deposition. Normal pH of rain or ordinary water is around 5.6 because of the prese...