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Terrestrial Ecosystem/Aquatic Ecosystem


Terrestrial Ecosystem Aquatic Ecosystem

Terrestrial Ecosystem

terrestrial ecosystem is an ecosystem found only on landforms. Six primary terrestrial ecosystems exist: tundra, taiga, temperate deciduous forest, tropical rain forest, grassland and desert.
• Taiga:
Taigas are cold-climate forests found in the northern latitudes.
Taigas are the world’s largest terrestrial ecosystem and account for about 29% of the Earth’s forests. The largest taiga ecosystems are found in Canada and Russia.
Taigas are known for their sub-arctic climate with extremely cold winters and mild summers.
They primarily consist of coniferous trees, such as pines, although there are some other deciduous trees, such as spruce and elm, that have adapted to live in these areas that receive little direct sunlight for much of the year.
Taigas are home to large herbivores, such as moose, elk, and bison, as well as omnivores, such as bears.

• Tundra:
The tundra ecosystems of the world are found primarily north of the Arctic Circle.
They consist of short vegetation and essentially no trees.
The soil is frozen and covered with permafrost for a large portion of the year.
Caribou, polar bears, and musk ox are some of the notable species who call the tundra home.
• Temperate:
Temperate forests are the regions which have seasonal variation in climate i.e., the climate changes a lot from summer to winter.
The annual rain fall is about 750- 2000 mm and soil is rich. Such types of forests are found in west­ern and central Europe, Eastern Asia and eastern North America.
These forests have deciduous trees (oaks, maples etc.) and conif­erous trees (pines).
These forests contain abundant micro-organ- isms, mammals (hares, deer, fares, coyotesetc). Birds (warblers, wood peckers, owls etc.) snakes, frogs, salamanders etc.
• Tropical Rain forests:
Tropical rain forests are special ecosystems which accommodate thousands of species of animals and plants.
These are usually densely packed tall trees those form a ceiling from the sun above. The filing prevents the growth of smaller plants.
The temperature remains almost same throughout the year.
Such types of forests are found in Brazil of South America (Neotropic) and Central and West Africa. The area is always warm and muggy.
• Grasslands:
Grasslands are areas dominated by grasses. They occupy about 20% of the land on the earth surface.
Grasslands occur in both in tropical and temperate regions where rainfall is not enough to support the growth of trees.
Grasslands are found in areas having well defined hot and dry, warm and rainy seasons.
• Deserts:
Desert are hot and low rain areas suffering from water shortage and high wind velocity.
They show extremes of temperature. Globally deserts occupy about 1/7th of the earth’s surface.
Desert animals include shrew, fox, wood rats, rabbits, camels and goat are common mammals in desert.
Other prominent desert animals are, reptiles, and burrowing rodents insects.
They adapt themselves to the dry weather conditions of desert area as stated in Adaptation topic
MAN MADE CHANGES
All natural environments and ecosystems now have an unprecedented problem to deal with humanity. Humans have brought about profound changes in a few centuries which would otherwise be expected over thousands or millions of years. The full impact of these remains to be accurately estimated. Major human impacts on ecosystems include the following:
1. Habitat Destruction and Fragmentation
The most direct impact of humans on ecosystems is in their destruction or conversion. Clear-cutting (the cutting of all trees within a given forest area) will, obviously, destroy a forest ecosystem. Selective logging may also alter forest ecosystems in important ways. Fragmentation- the division of a once continuous ecosystem into a number of smaller patches- may disrupt ecological processes so that the remaining areas can no longer function as they once did.
2. Climate Change
It is now widely accepted that human activities are contributing to global warming, chiefly through the accumulation of “greenhouse” gases in the atmosphere. The impact of this is likely to increase in the future. As noted above, climate change is a natural feature of the Earth. Previously, however, its effects were mitigated as ecosystems could effectively “migrate” by moving latitude or altitude as the climate changed. Today, so much of the world’s land surface has been appropriated by people that in many cases there is no such place for the remaining natural or semi-natural ecosystems to migrate to.
3. Pollution
Contamination of the natural environment through a range of pollutants- herbicides, pesticides, fertilizers, industrial effluents, and human waste products- is one of the most pernicious forms of impact on the natural environment. Pollutants are often invisible, and the effects of air pollution and water pollution may not be immediately obvious, although they can be devastating in the long run.
4. Introduced Species
Human beings have been responsible either deliberately or accidentally for altering the distribution of a vast range of animal and plant species. This includes not only domesticated animals and cultivated plants but pests such as rats, mice, and many insects and fungi. Species which become naturalized may have a devastating impact, through predation and competition, on natural ecosystems, particularly on islands where native species have evolved in isolation. For instance, foxes, rabbits, cane toads, feral cats, and even buffaloes and camels have wreaked havoc in many ecosystems in Australia. Plants such as the South American shrub Lantana have invaded natural forests in many tropical and subtropical islands, causing major changes to these ecosystems, while the African water hyacinth Eichhornia has similarly disrupted freshwater ecosystems in many of the warmer parts of the world.
5. Over-Harvest
Removal of excessive numbers of animals or plants from a system can cause major ecological changes. The most important example of this at present is the over-fishing of the world’s oceans. Depletion of the great majority of accessible fish stocks is undoubtedly a cause of major change, although its long-term impact is difficult to assess.


Magadha Empire/Society


Magadha Social and Economic Conditions in the 6th Century BC and Onwards (Pre-Mauryan Period)

Magadha Empire

• Of all the kingdoms of north India, Magadha emerged powerful and prosperous.
• It became the nerve centre of political activity in north India.
• Magadha was endowed by nature with certain geographical and strategic advantages. These. Its geographical and strategic position between the upper and lower part of the Gangetic valley was a great advantage due to which it rose to imperial greatness.
• The iron ores in the hills near Rajgir and copper and iron deposits near Gaya added to its natural assets. Its location at the centre of the highways of trade of those days contributed to its wealth.
• Rajagriha was the capital of Magadha.
• During the reign of Bimbisara and Ajatasatru, the prosperity of Magadha reached its zenith.
Factors for the Rise of Magadha
1. The close vicinity and control over richest deposits of copper and iron ore rendered better weapons and instruments.
2. Favourable geographical location enabled it to control the whole lower Gangetic plain.
3. Its rich alluvial soil provided a strong agricultural base. The fertility enabled the peasants to produce considerable surplus which could be mopped by the rulers in the form of taxes.
4. The thick forests beyond Gaya in South Bihar supplied timber for building and elephants for the army. It was Magadha which first used elephants on large scale in wars.
5. The two capitals of Magadha, Rajgriha and Pataliputra were situated at very strategic points. Rajgriha was surrounded by a group of five hills and it was rendered impregnable. Pataliputra was situated at the confluence of the Ganges, the Gandak and the Son, and therefore formed a water-fort or jaldurga.
• Some historians maintain that it was the introduction of iron implements which enabled the people to clear the jungle and reclaim the fertile land of the eastern Gangetic plains and led finally to the rise of the powerful Maha Janapadas.
• But hitherto there is no archeological evidence to clearly support this thesis of economic change as the main reason for the rise of Magadha.
• Iron, however, did play an important role during this period, as it was used mostly for making weapons and Magadha may have had strategic advantage due to its access to the iron ore deposits in Chota Nagpur and its better armament.
• Magadha’s first great campaign was directed against Anga, its neighbour, which was equally close to those iron ore deposits and perhaps controlled the trade routes through which iron would reach northern India. In this way, Magadha eliminated a dangerous competitor at the very beginning of its imperial career.
• All these factors account for the expansion and stability of Magadha, which gradually swallowed all other contemporary states.
• Initially, Magadha appeared to be rather badly placed on the trade-route but after Bimbisara, it got some foothold in Kasi by contracting a marriage alliance with the kingdom of Kosala and annexed Arya, the position was radically changed. Thus, the internal trade of Magadha was linked with the foreign trade which became even more lucrative. This factor gave a boost to trade and thus, helped in its rise.
Bimbisara (546 – 494 B.C.)
• Bimbisara belonged to the Haryanka dynasty.
• He consolidated his position by matrimonial alliances.
• His first matrimonial alliance was with the ruling family of Kosala. He married Kosaladevi, sister of Prasenajit. He was given the Kasi region as dowry which yielded large revenue.
• Bimbisara married Chellana, a princess of the Licchavi family of Vaisali. This matrimonial alliance secured for him the safety of the northern frontier. Moreover, it facilitated the expansion of Magadha northwards to the borders of Nepal.
• Bimbisara also married Khema of the royal house of Madra in central Punjab.
• Bimbisara defeated Brahmadatta of Anga and annexed the kingdom.
• Bimbisara maintained friendly relations with Avanti.
• Bimbisara had also efficiently reorganized the administration of his kingdom.
• Bimbisara was a contemporary of both Vardhamana Mahavira and Gautama Buddha. However, both religions claim him as their supporter and devotee.
• Bimbisara made numerous gifts to the Buddhist Sangha.
Ajatasatru (494 – 462 B.C.)
• The reign of Ajatasatru was remarkable for his military conquests.
• He fought against Kosala and Vaisali.
• He won a great success against a formidable confederacy led by the Lichchavis of Vaisali. This war lasted for about sixteen years. It was at this time that Ajatasatru realised the strategic importance of the small village, Pataligrama (future Pataliputra).
• He fortified it to serve as a convenient base of operations against Vaisali.
• Buddhists and Jains both claim that Ajatasatru was a follower of their religion.
• But it is generally believed that in the beginning he was a follower of Jainism and subsequently embraced Buddhism.
• He is said to have met Gautama Buddha. This scene is also depicted in the sculptures of Barhut.
• According to the Mahavamsa, he constructed several chaityas and viharas. He was also instrumental in convening the First Buddhist Council at Rajagriha soon after the death of the Buddha.
• The immediate successor of Ajatasatru was Udayin.
• He laid the foundation of the new capital at Pataliputra situated at the confluence of the two rivers, the Ganges and the Son.
• Later it became famous as the imperial capital of the Mauryas.
• Udayin’s successors were weak rulers and hence Magadha was captured by Saisunaga. Thus the Haryanka dynasty came to an end and the Saisunaga dynasty came to power.
Sisunaga Dynasty
• The genealogy and chronology of the Saisunagas are not clear. Saisunaga defeated the king of Avanti which was made part of the Magadhan Empire.
• After Saisunaga, the mighty empire began to collapse.
• His successor was Kakavarman or Kalasoka. During his reign the second Buddhist Council was held at Vaisali. Kalasoka was killed by the founder of the Nanda dynasty.
Nandas
• The fame of Magadha scaled new heights under the Nanda dynasty.
• Their conquests went beyond the boundaries of the Gangetic basin and in North India they carved a well-knit and vast empire.
• Mahapadma Nanda uprooted the kshatriya dynasties in north India and assumed the title Ekarat.
• The Puranas speak of the extensive conquests made by Mahapadma.
• The Hathigumpha inscription of Kharavela of Kalinga refers to the conquest of Kalinga by the Nandas.
• Many historians believe that a considerable portion of the Deccan was also under the control of the Nandas. Therefore, Mahapadma Nanda may be regarded as a great empire builder.
• According to the Buddhist tradition, Mahapadma Nanda ruled about ten years. He was succeeded by his eight sons, who ruled successively.
• The last Nanda ruler was Dhana Nanda.
• He kept the Magadhan empire intact and possessed a powerful army and enormous wealth.
• The enormous wealth of the Nandas is also referred to in the Tamil Sangam work Ahananuru by the poet Mamulanar. The flourishing state of agriculture in the Nanda dominions and the general prosperity of the country must have brought to the royal treasury enormous revenue.
• The oppressive way of tax collection by Dhana Nanda was resented by the people. Taking advantage of this, Chandragupta Maurya and Kautilya initiated a popular movement against the Nanda rule.
• It was during this time that Alexander invaded India.

Organic Farming


Organic Farming

Organic farming is an agricultural system that works in harmony with nature. It largely excludes the use of synthetic inputs (such as fertilizers, pesticides, hormones, feed additives etc.) and rely upon crop rotation, crop residues, animal manures, off-farm organic waste, mineral grade rock additives and biological system of nutrient mobilization and plant protection.
Organic farming in India has been followed since ancient times. It primarily aims at cultivating the land and raising crops in such a way, as to keep the soil alive and in good health by use of organic wastes (crop, animal and farm wastes, aquatic wastes) and other biological materials along with beneficial microbes (biofertilizers) to release nutrients to crops for increased sustainable production in an eco-friendly and pollution-free environment.
Key characteristics of organic farming:
• It relies on traditional techniques such as crop rotation, green manure, compost and biological. It is accomplished by using farm agronomic, biological and mechanical methods in exclusion of all synthetic off farm inputs.
• It protects the long term fertility of soils by maintaining organic Matter levels and encouraging soil biological activity. It often involves vermiculture and vermicomposting too.
• The biological processes, driven by mycorrhiza, allow the natural production of nutrients in soil throughout growing season.
• Legumes are planted to fix nitrogen into the soil. It allows nitrogen self-sufficiency through biological nitrogen fixation.
• It allows effective recycling of organic materials .
• Natural insect predators are encouraged which can be specific for certain pests or of broad-range.
• Crop Rotation supports a wider range of beneficial insects, soil micro-organisms, and hence, protects species from going extinct.
• A key characteristic of organic farming is the rejection of genetically engineered plants and animals.
• Hardier plants are generated through plant breeding rather than genetic engineering.
Advantages of organic farming over other forms of farming:
• It improves soil health and fertility.
• It requires careful use of water resources hence lead to conservation of water.
• Good animal husbandry
• Using natural pesticides (biological control)
• Recycled crop wastes
• Green manures and legumes
• Increasing genetic diversity
• Use of resistant crops increased employment
• Cost-effective farming
Some Facts:
• Size of the Indian organic food market is Rs. 100 crore.
• Number of organic food farmers in India are 570,000.
• Sikkim has become India’s first fully organic state by converting around 75,000 hectares of agricultural land into sustainable cultivation.
• Uttaranchal is the first state to establish organic commodities board and created organic export zones by establishing organic bio-villages.
• Madhya Pradesh has declared many of its villages as organic.

Seed Village Concept


Seed Village Concept

A village, wherein trained group of farmers are involved in production of seeds of various crops and cater to the needs of themselves, fellow farmers of the village and farmers of neighboring villages in appropriate time and at affordable cost is called “a seed village”
Objectives:
• Increasing the seed production
• Increasing the seed replacement rate
• Organizing seed production in cluster (or) compact area replacing existing local varieties with new high yielding varieties
• Self sufficiency and self reliance of the village
• To meet the local demand, timely supply.
The present programme of seed village scheme is having two phases:
1. Seed production of different crops: The area which is suitable for raising a particular crop will be selected, and raised with single variety of a kind.
2. Establishing seed processing unit: If the seeds are not processed and handled properly, all the past efforts in production may be lost. Thus seed processing and packaging is very important aspect in seed production.
Benefits
• Seed is available at the door steps of farms at an appropriate time.
• Seed availability at affordable cost even lesser than market price.
• Increased confidence among the farmers about the quality because of known source of production.
• Producer and consumer are mutually benefited.
• Facilitates fast spread of new cultivars of different kinds.

Bio-fertilizers


Bio-fertilizers

‘Biofertilizer’ is a substance which contains living microorganism which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant.
Biofertilizers add nutrients through the natural processes of fixing atmospheric nitrogen, solubilizing Phosphorus, and stimulating plant growth through the synthesis of growth promoting substances.
Types of Biofertilizers
The following types of biofertilizers are available to the farmers in India.
• Nitrogen fixing biofertilizers eg.Rhizobium, Bradyrhizobium, Azo-spirillum and Azotobacter.
• Phosphorous solubilising biofertilizers (PSB) eg.Bacillus,Pseudomonas and Aspergillus
• Phosphate mobilizing biofertilizer eg. Mycorrhiza
• Plant growth promoting biofertilizers eg. Pseudomonas sp.
Advantages of biofertilizers:
• They help to get high yield of crops by making the soil rich with nutrients and useful microorganisms necessary for the growth of the plants.
• Biofertilizers have replaced the chemical fertilizers as chemical fertilizers are not beneficial for the plants. They decrease the growth of the plants and make the environment polluted by releasing harmful chemicals.
• Plant growth can be increased if biofertilizers are used, because they contain natural components which do not harm the plants but do the vice versa.
• If the soil will be free of chemicals, it will retain its fertility which will be beneficial for the plants as well as the environment, because plants will be protected from getting any diseases and environment will be free of pollutants.
• Biofertilizers destroy those harmful components from the soil which cause diseases in the plants. Plants can also be protected against drought and other strict conditions using biofertilizers.
• Biofertilizers are not costly and even poor farmers can make use of them.
• They are environment friendly and protect the environment against pollutants.

Sai Praveen

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