Salient features of grassland, forest and desert ecosystem

It is a presentation on grassland, forest and desert ecosystem

1. ON SUBMITTED BY – SURBHI YADAV BSC BIOSCIENCE Terrestrial ecosystem:-salient features of grassland forest & desert ecosystem P R E S E N T A T I O N SUBMITTED TO – DR. RASHMI TRIPATHI MA’aM

2. SYNOPSIS Terrestrial Ecosystem :- GRASSLAND FOREST DESERT

3. in tr od uc ti on A terrestrial ecosystem is a type of ecosystem found only on biomes. Six primary terrestrial ecosystems exist: tundra, taiga, temperate deciduous forest, tropical rainforest, grassland and desert.

4. A community of organisms and their environment that occurs on the land masses of continents and islands. Terrestrial ecosystems are distinguished from aquatic ecosystems by the lower availability of water and the consequent importance of water as a limiting factor. Terrestrial ecosystems are characterized by greater temperature fluctuations on both a diurnal and seasonal basis than occur in aquatic ecosystems in similar climates. The availability of light is greater in terrestrial ecosystems than in aquatic ecosystems because the atmosphere is more transparent in land than in water. Gases are more available in terrestrial ecosystems than in aquatic ecosystems. Those gases include carbon dioxide that serves as a substrate for photosynthesis, oxygen that serves as a substrate in aerobic respiration, and nitrogen that serves as a substrate for nitrogen fixation. Terrestrial environments are segmented into a subterranean portion from which most water and ions are obtained, and an atmospheric portion from which gases are obtained and where the physical energy of light is transformed into the organic energy of carbon-carbon bonds through the process of photosynthesis.

5. Terrestrial ecosystems occupy 55,660,000 mi² (144,150,000 km²), or 28.26% of Earth's surface. Although they are comparatively recent in the history of life (the first terrestrial organisms appeared in the Alchi period, about 425 million years ago) and occupy a much smaller portion of Earth's surface than marine ecosystems, terrestrial ecosystems have been a major site of adaptive radiation of both plants and animals. Major plant taxa in terrestrial ecosystems are members of the division Magnoliophyta (flowering plants), of which there are about 275,000 species, and the division Pinophyta (conifers), of which there are about 500 species. Members of the division Bryophyta (mosses and liverworts), of which there are about 24,000 species, are also important in some terrestrial ecosystems. Major animal taxa in terrestrial ecosystems include the classes Insecta (insects) with about 900,000 species, Aves (birds) with 8,500 species, and Mammalia (mammals) with approximately 4,100 species.

6. Organisms in terrestrial ecosystems have adaptations that allow them to obtain water when the entire body is no longer bathed in that fluid, means of transporting the water from limited sites of acquisition to the rest of the body, and means of preventing the evaporation of water from body surfaces. They also have traits that provide body support in the atmosphere, a much less buoyant medium than water, and other traits that render them capable of withstanding the extremes of temperature, wind, and humidity that characterize terrestrial ecosystems. Finally, the organisms in terrestrial ecosystems have evolved many methods of transporting gametes in environments where fluid flow is much less effective as a transport medium.

7. The organisms in terrestrial ecosystems are integrated into a functional unit by specific, dynamic relationships due to the coupled processes of energy and chemical flow. Those relationships can be summarized by schematic diagrams of trophic webs, which place organisms according to their feeding relationships. The base of the food web is occupied by green plants, which are the only organisms capable of utilizing the energy of the Sun and inorganic nutrients obtained from the soil to produce organic molecules. Terrestrial food webs can be broken into two segments based on the status of the plant material that enters them. Grazing food webs are associated with the consumption of living plant material by herbivores. Detritus food webs are associated with the consumption of dead plant material by detritivores. The relative importance of those two types of food webs varies considerably in different types of terrestrial ecosystems. Grazing food webs are more important in grasslands, where over half of net primary productivity may be consumed by herbivores. Detritus food webs are more important in forests, where less than 5% of net primary productivity may be consumed by herbivores.

8. There is one type of extensive terrestrial ecosystem due solely to human activities and eight types that are natural ecosystems. Those natural ecosystems reflect the variation of precipitation and temperature over Earth's surface. The smallest land areas are occupied by tundra and temperate grassland ecosystems, and the largest land area is occupied by tropical forest. The most productive ecosystems are temperate and tropical forests, and the least productive are deserts and tundras. Cultivated lands, which together with grasslands and savannas utilized for grazing are referred to as agroecosystems, are of intermediate extent and productivity. Because of both their areal extent and their high average productivity, tropical forests are the most productive of all terrestrial ecosystems, contributing 45% of total estimated net primary productivity on land.

9. G rassland

10. MAJOR AREAS UNDER GRASSLANDS

11. Grasslands are areas where the vegetation is dominated by grasses (Poaceae), however sedge (Cyperaceae) and rush (Juncaceae) families can also be found. Grasslands occur naturally on all continents except Antarctica. Grasslands are found in most ecoregions of the Earth. For example, there are five terrestrial ecoregion classifications (subdivisions) of the temperate grasslands, savannas, and shrublands biome (ecosystem), which is one of eight terrestrial ecozones of the Earth's surface

12. Contents 1 Vegetation 2 Evolution 3 Climates 4 Biodiversity and conservation 5 Human impact and economic importance 6 Types of grasslands 6.4.1 Tropical and subtropical 6.4.2 Temperate 6.4.3 Flooded 6.4.4 Montane 6.4.5 Tundra 6.4.6 Desert and xeric Animals

13. The Konza tallgrass prairie in the Flint Hills of northeastern Kansas V egetation Grassland vegetation can vary in height from very short, as in chalk grassland, to quite tall, as in the case of North American tallgrass prairie , South American grasslands and African Savanna.

14. Graminoids are among the most versatile life forms. They became widespread toward the end of the Cretaceous period, and fossilized dinosaur feces (coprolites ) have been found containing phytoliths of a variety of grasses that include grasses that are related to modern rice and bamboo. The appearance of mountains in the western United States during the Miocene and Pliocene epochs, a period of some 25 million years, created a continental climate favorable to the evolution of grasslands. Existing forest biomes declined, and grasslands became much more widespread. Following the Pleistocene ice ages , grasslands expanded in range in the hotter, drier climates, and began to become the dominant land feature worldwide. EVOLUTION

15. Grasslands often occur in areas with annual precipitation between 600 mm (24 in) and 1,500 mm (59 in) and average mean annual temperatures ranges from −5 and 20 °C (Woodward et al. 2004). However, some grasslands occur in colder (−20 °C) and hotter (30 °C) climatic conditions .Grassland can exist in habitats that are frequently disturbed by grazing or fire, as such disturbance prevents the encroachment of woody species. Species richness is particularly high in grasslands of low soil fertility such as serpentine barrens and calcareous grasslands, where woody encroachment is prevented as low nutrient levels in the soil may inhibit the growth of forest and shrub species. CLIMATE

16. Grasslands dominated by unsown wild-plant communities ("unimproved grasslands") can be called either natural or "semi- natural" habitats. The majority of grasslands in temperate climates are "semi-natural". Although their plant communities are natural, their maintenance depends upon anthropogenic activities such as low- intensity farming, which maintains these grasslands through grazing and cutting regimes. These grasslands contain many species of wild plants, including grasses, sedges, rushes and herbs; 25 or more species per square meter is not unusual. Chalk downlands in England can support over 40 species per square meter. In many parts of the world, few examples have escaped agricultural improvement (fertilising, weed killing, ploughing or re-seeding). BIODIVERSITY & CONSERVATION

17. Human impact and economic importaNCE A restored grassland ecosystem at Morton Arboretum in Illinois .

18. Grassland vegetation often remains dominant in a particular area usually due to grazing, cutting, or natural or manmade fires, all discouraging colonisation by and survival of tree and shrub seedlings. Some of the world's largest expanses of grassland are found in African savanna, and these are maintained by wild herbivores as well as by nomadic pastoralists and their cattle, sheep or goats . Grasslands may occur naturally or as the result of human activity. Grasslands created and maintained by human activity are called anthropogenic grasslands . Hunting peoples around the world often set regular fires to maintain and extend grasslands, and prevent fire-intolerant trees and shrubs from taking hold. The tallgrass prairies in the U.S. Midwest may have been extended eastward into Illinois, Indiana, and Ohio by human agency. Much grassland in northwest Europe developed after the Neolithic Period, when people gradually cleared the forest to create areas for raising their livestock . The professional study of grasslands falls under the category of rangeland management, which focuses on ecosystem services associated with the grass-dominated arid and semi-arid rangelands of the world. Rangelands account for an estimated 70% of the earth's landmass; thus, many cultures including those of the United States are indebted to the economics that the world's grasslands have to offer, from producing grazing animals, tourism, ecosystems services such as clean water and air, and energy extraction

19. These grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome Notable tropical and subtropical grasslands include the Llanos grasslands of South America . Tropical and subtropical

20. TEMPERATE Negri Nepote Temperate Grasslands in New Jersey

21. Mid-latitude grasslands, including the prairie and Pacific grasslands of North America, the Pampas of Argentina, Brazil and Uruguay, calcareous downland, and the steppes of Europe. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinoceroses, and wild horses. Carnivores like lions, wolves and cheetahs and leopards are also found in temperate grasslands. Other animals of this region include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds (both Old and New World varieties), grasshoppers, meadowlarks, sparrows, quails, hawks and hyenas.

22. Similar to montane grasslands, polar Arctic tundra can have grasses, but high soil moisture means that few tundras are grass dominated today. However, during the Pleistocene ice ages, a polar grassland known as steppe-tundra occupied large areas of the Northern Hemisphere. These are in the tundra biome. Desert and xeric Also called desert grasslands, this is composed of sparse grassland ecoregions located in the deserts and xeric shrublands biome. TUNDRA

23. Animals Mites, insect larvae, nematodes and earthworms inhabit deep soil, which can reach 6 metres (20 ft) underground in undisturbed grasslands on the richest soils of the world. These invertebrates, along with symbiotic fungi, extend the root systems, break apart hard soil, enrich it with urea and other natural fertilizers, trap minerals and water and promote growth. Some types of fungi make the plants more resistant to insect and microbial attacks . Grassland in all its form supports a vast variety of mammals, reptiles, birds, and insects. Typical large mammals include the blue wildebeest, American bison, giant anteater and Przewalski's horse . While grasslands in general support diverse wildlife, given the lack of hiding places for predators, the African savanna regions support a much greater diversity in wildlife than do temperate grasslands . There is evidence for grassland being much the product of animal behaviour and movement ; some examples include migratory herds of antelope trampling vegetation and African bush elephants eating acacia saplings before the plant has a chance to grow into a mature tree.

24. importance Grasslands provide home to many different animals that were hunted & domesticated. They are used as grazing area for cattle of Rugler community. They maintain biodiversity. Protect restored habitat for many plants and animals including pheasants, ducks, songbirds & endangered species.

25. F orest Ec osystem

26. A forest is a large area dominated by trees.Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function.According to the widely used . Food and Agriculture Organization definition, forests covered four billion hectares (15 million square miles) or approximately 30 percent of the world's land area in 2006 . Forests are the dominant terrestrial ecosystem of Earth, and are distributed across the globe.Forests account for 75% of the gross primary productivity of the Earth's biosphere, and contain 80% of the Earth's plant biomass . Forests at different latitudes and elevations form distinctly different ecozones: boreal forests near the poles, tropical forests near the equator and temperate forests at mid-latitudes . Higher elevation areas tend to support forests similar to those at higher latitudes, and amount of precipitation also affects forest composition . Human society and forests influence each other in both positive and negative ways. Forests provide ecosystem services to humans and serve as tourist attractions. Forests can also affect people's health. Human activities, including harvesting forest resources, can negatively affect forest ecosystems

27. Etymology Since the 13th century, the Niepołomice Forest in Poland has had special use and protection. In this view from space, different coloration can indicate different functions . The word forest comes from Middle English, from Old French forest (also forès ) "forest, vast expanse covered by trees"; first introduced in English as the word for wild land set aside for hunting without the necessity in definition for the existence of trees. Possibly a borrowing (probably via Frankish or Old High German) of the Medieval Latin word foresta "open wood", foresta was first used by Carolingian scribes in the Capitularies of Charlemagne to refer specifically to the king's royal hunting grounds. The term was not endemic to Romance languages (e.g. native words for "forest" in the Romance languages evolved out of the Latin word silva "forest, wood" (English sylvan ); cf. Italian, Spanish, Portuguese selva ; Romanian silvă ; Old French selve ) ; and cognates in Romance languages, such as Italian foresta , Spanish and Portuguese floresta , etc. are all ultimately borrowings of the French word.

28. Evolution The first known forests on Earth arose in the Late Devonian (approximately 380 million years ago), with the evolution of Archaeopteris . Archaeopteris was a plant that was both tree-like and fern-like, growing to 10 metres (33 ft) in height. Archaeopteris quickly spread throughout the world, from the equator to subpolar latitudes . Archaeopteris formed the first forest by being the first known species to cast shade due to its fronds and forming soil from its roots. Archaeopteris was deciduous, dropping its fronds onto the forest floor. The shade, soil, and forest duff from the dropped fronds created the first forest . The shed organic matter altered the freshwater environment, slowing it down and providing food. This promoted freshwater fish.

29. Temperate rainforest in Tasmania's Hellyer Gorge Forests account for 75% of the gross primary productivity of the Earth's biosphere, and contain 80% of the Earth's plant biomass. Forest ecosystems can be found in all regions capable of sustaining tree growth, at altitudes up to the tree line, except where natural fire frequency or other disturbance is too high, or where the environment has been altered by human activity. ecology

30. The latitudes 10° north and south of the equator are mostly covered in tropical rainforest, and the latitudes between 53°N and 67°N have boreal forest. As a general rule, forests dominated by angiosperms ( broadleaf forests ) are more species-rich than those dominated by gymnosperms ( conifer , montane , or needleleaf forests ), although exceptions exist . Forests sometimes contain many tree species within a small area (as in tropical rain and temperate deciduous forests), or relatively few species over large areas (e.g., taiga and arid montane coniferous forests). Forests are often home to many animal and plant species, and biomass per unit area is high compared to other vegetation communities. Much of this biomass occurs below ground in the root systems and as partially decomposed plant detritus. The woody component of a forest contains lignin, which is relatively slow to decompose compared with other organic materials such as cellulose or carbohydrate.

31. Even, dense old-growth stand of beech trees ( Fagus sylvatica ) prepared to be regenerated by their saplings in the understory, in the Brussels part of the Sonian Forest. A forest consists of many components that can be broadly divided into two categories that are biotic (living) and abiotic (non-living) components. The living parts include trees, shrubs, vines, grasses and other herbaceous (non-woody) plants, mosses, algae, fungi, insects, mammals, birds, reptiles, amphibians, and microorganisms living on the plants and animals and in the soil Components

32. Biogradska forest in Montenegro Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation

33. A forest is made up of many layers. Starting from the ground level and moving up, the main layers of all forest types are the forest floor, the understory and the canopy. The emergent layer exists in tropical rainforests. Each layer has a different set of plants and animals depending upon the availability of sunlight, moisture and food. Forest floor contains decomposing leaves, animal droppings, and dead trees. Decay on the forest floor forms new soil and provides nutrients to the plants. The forest floor supports ferns, grasses, mushroom and tree seedlings. Understory is made up of bushes, shrubs, and young trees that are adapted to living in the shades of the canopy. Canopy is formed by the mass of intertwined branches, twigs and leaves of the mature trees. The crowns of the dominant trees receive most of the sunlight. This is the most productive part of the trees where maximum food is produced. The canopy forms a shady, protective "umbrella" over the rest of the forest. Emergent layer exists in the tropical rain forest and is composed of a few scattered trees that tower over the canopy. Layers:-

34. A dry sclerophyll forest in Sydney, which is dominated by eucalyptus trees. types

35. Forests can be classified in different ways and to different degrees of specificity. One such way is in terms of the biome in which they exist, combined with leaf longevity of the dominant species (whether they are evergreen or deciduous). Another distinction is whether the forests are composed predominantly of broadleaf trees, coniferous ( . needle-leaved) trees, or mixed. Boreal forests occupy the subarctic zone and are generally evergreen and coniferous. Temperate zones support both broadleaf deciduous forests ( e.g. , temperate deciduous forest) and evergreen coniferous forests ( e.g. , temperate coniferous forests and temperate rainforests). Warm temperate zones support broadleaf evergreen forests, including laurel forests. Tropical and subtropical forests include tropical and subtropical moist forests, tropical and subtropical dry forests, and tropical and subtropical coniferous forests. Physiognomy classifies forests based on their overall physical structure or developmental stage (e.g. old growth vs. second growth). Forests can also be classified more specifically based on the climate and the dominant tree species present, resulting in numerous different forest types (e.g., Ponderosa pine/Douglas-fir forest).

36. TREND ANALYSIS OF FOREST GROWTH IN INDIA (ALL FIGURES IN Sq. km)

37. (a) Temperate Forest Ecosystem:- The temperate forest ecosystem is very important on Earth. Temperate forests are in regions where the climate changes a lot from summer to winter. Tropical rain forests are in regions where the climate stays constant all year long. Temperate forests are almost always made of two types of trees, deciduous and evergreen. Deciduous trees are trees that lose their leaves in the winter.

38. Ever­greens are trees that keep them all year long, like pine trees. Forests can either be one or the other, or a combination of both. A fourth kind of forest is a temper­ate rain forest. These are found in California, Oregon and Washington in the United States. These forests are made of redwoods and sequoias, the tallest trees in the world. The amount of rainfall in an area determines if a forest is present. If there is enough rain to support trees, then a forest will usually develop. Otherwise, the region will become grasslands.

39. BIOME TYPE % OF LAND FOREST 32 RANGELAND& PASTURE 26 DESERT 20 CROPLAND 11 TUNDRA & WETLANDS 09 URBAN AREAS 02 TOTAL 100 WORLD LAND USE PATTERN (FAO IN MILLER,2004)

40. (b) The Tropical Rain Forest Ecosystem: Tropical rain forests are one of the most important areas on Earth. These spe­cial ecosystems are homes to thousands of species animals and plants. Contrary to popular belief, rain forests are not only densely packed plants, but are also full of tall trees that form a ceiling from the Sun above. This ceiling keeps smaller plants from growing. Areas where sunlight can reach the surface are full of interesting plants. Do you know where rain forests get their name? They are so named because they receive a lot of rain – an average of 80 inches a year. The temperature doesn’t change very much during the year. It is always warm and muggy. The famous Amazon jungle is located in Brazil, in South America. This particular forest is called the Neotropics. Other large blocks are located in Central and West Africa.

41. (i) Insects of the Tropical Rain Forest: The most feared and well known spider in the world resides in the jungle. Ta­rantulas are one of the creepiest animals you will ever see. Most species of tarantula have poisonous fangs for killing prey and for protection. Although some are life-threatening to humans, others are harmless. Army ants are just one species of ant in the rain forest. They are called army ants because they march in a long, thick line through the jungle. They only stop when the young larvae reach pupil stage. Once the queen lays its eggs, the ants start marching again. Beautiful butterflies fill the forest, but at one time these insects weren’t so pretty. Butterflies start out as caterpillars, which tend to be a tad on the ugly side. They go through metamorphosis, which is the process of changing into a butterfly. Centipedes aren’t so lucky. They don’t turn into butterflies, but in­stead roam the forest looking for food. Some centipedes use poison to kill their prey .

42. (ii) Tropical Rain Forest Birds: The birds of the rain forest are the most beautiful in the world. A wide range of colors can be seen darting through the trees as the forest tops come to life. Many species of tropical birds are kept as pets because of their looks . Hundreds of species of parrot live in the rain forest. The scarlet macaw is just one of these. It is also one of the longest, stretching to a length of 3 feet from its head to the tip of its tail. When these macaws eat a poisonous fruit, they eat a special type of clay that neutralizes the poison. Toucans are also very interesting birds. They have large beaks that they use to reach fruit they can’t get to. Scientists estimate there are 33 species of toucan in the rain forest. Not every tropical bird was blessed with looks. The hoatzin looks more like a peacock without the pretty tail. Hoatzins are terrible flyers – crash landings are common practice. The brown kiwi is a flightless bird that looks more like a rodent with a long beak and feathers. Kiwis live on the ground instead of the trees. They have special claws used for running, digging and defence.

43. (iii) Tropical Rain Forest Mammals: Birds aren’t the only creatures that fly through the rain forests. Several species of flying mammals live in the jungle. From the harmless fruit bat to the unique flying squirrel, the tropical rain forests are full of surprises. The Indian flying fox is one of the largest bats in the world. Its wings can spread out to 5 feet in width. Unlike bats in other parts of the world, these bats do not live in caves. They prefer to .hang in trees during the day. Hundreds or even thousands of bats can be spotted in a single tree. Vampire bats live in the Amazon jungle in South America. The famous stories of blood-sucking bats probably originated here. These bats do in fact drink the blood of their victims. They usually attack farm animals, but have also enjoyed the blood of humans. But vampire bats only drink a very small amount of fluid

44. (iv) Tropical Rain Forest Reptiles: The tropical rain forests of the world are full of reptiles. Reptiles are cold blooded, which means their body temperature depends on their environment. So, it is important for them to stay in warm climates. Snakes are reptiles, and the rain forests are home to many. The mamba family is the most poisonous of all. They kill their prey by injecting poison with their sharp fangs . Anacondas make up another snake family. They are some of the longest crea­tures in the world, as they can reach 30 feet in length. Anacondas prefer to wrap themselves around their prey and squeeze, rather than inject poison. Anacon­das swallow their prey whole and sleep while the food is digesting. Chameleons are interesting lizards that can change color. This enables them to blend in with their surroundings . Not only is this a great disguise from predators, it is also an easy way to sneak up on their prey. Chameleons only eat insects. Geckos are very neat creatures. The flying gecko can glide from tree to tree to escape from predators. Their grip is so strong, that if you tried to pull one off a window, the glass would break before the gecko would let go.

45. (v) Tropical Rain Forest Primates: Monkeys and their cousins are all primates. Humans are also primates. There are many species of monkeys in the tropical rain forests of the world. Monkeys can be divided into two groups: new world monkeys and old world monkeys. New world monkeys live only in South and Central America. Spider monkeys live in the rain forests in the Andes Mountains. They look very strange with their long noses. Spider monkeys eat mostly fruit and nuts, so they are called frugivores. They are joined by the howler monkeys. These primates are so named because they have a special sac that makes their sounds louder. Old world monkeys live only in Africa and Asia. The colobus monkey is one such kind. These monkeys are called foliovores because they eat leaves. They live in small groups of 15, but other primates live in larger groups of up to 200. There are too many species. Chimpanzees, orangutans and gorillas are all called pongids. These primates are more famous than the others. Gorillas are too big to climb trees, so they are found on the forest floor.

46. (c) Boreal or Taiga Forests: The boreal forest ecosystem is the contiguous green belt of conifer and decidu­ous trees that encircles a large portion of the Northern Hemisphere. In North America, the boreal forest stretches across most of northern Canada and into Alaska. It has long been identified as one of the world’s great forest ecosystems.This forest ecosystem covers roughly 35% of Canada’s land mass and is the single largest land based ecosystem in North America. It also contains a signifi­cant proportion of Canada’s biodiversity and has long been recognized as an important global carbon sink.Although the boreal is relatively unknown, it is important as the “great lung” of North America, “breathing in” carbon dioxide and “exhaling” oxygen into the atmosphere. In short, the boreal forest manages to do what the rain forest of the Amazon does but with only the fraction of the flora and fauna.

47. This forest ecosystem houses the largest and smallest mammal species (wood bison & pygmy shrews) of the North American continent. The Boreal forest has many things: great lakes and northern rivers; vast bogs, fens and other organic wetlands. The rich wildlife diversity of the Boreal is a joy to behold: woodland caribou and lynx; whooping cranes and wood bison; northern owls; woodpeckers with three rather than four toes; colorful wood warblers . The Boreal has more than 5,000 species of conspicuous and colorful fungi, celebrated far more in Scandinavia and Siberia than in North America. Then there are the precious old-growth forests, the richest and most biologically diverse of the Boreal forest communities that are essential for so many Boreal species .

48. Tropic rainforest Temperate rainforests

49. Structure of Forest Ecosystems: Different organisms exist within the forest layers. These organisms interact with each other and their surroundings. Each organism has a role or niche in sustaining the ecosystem. Some provide food for other organisms; others pro­vide shelter or control populations through predation:

50. Producers : All living organisms’ intake energy in order to survive. In a forest ecosystem, trees and other plants get their energy from sunlight. Plants produce their own food, in the form of carbohydrates. Plants are, therefore, called the primary producers, since they produce the basic foodstuffs for other organisms within food chains and food webs. Photosynthesis is the chemical reaction that allows plants to produce their own food.

51. Consumers: Animals cannot produce their own food. They must consume food sources for die energy they need to survive. All animals, including mammals, insects, and birds, are called consumers. Consumers rely on plants and other animals as a food source. Details of these animals in a forest ecosystem have been given earlier.Primary consumers only eat plants and are referred to as herbivores. Second­ary consumers are referred to as carnivores and feed on herbivores. Tertiary consumers are carnivores that feed on other carnivores. Omnivores eat both plant and animal matter .

52. Decomposers: Leaves, needles, and old branches fall to the forest floor as trees grow. Eventu­ally all plants and animals die. So what happens to all of this plant and animal material? Does it sit on the forest floor forever? Thankfully no. These materials are decomposed by worms, microbes, fungi, ants, and other bugs. Decomposers break these items down into their smallest primary elements to be used again. Decomposers are important in that they sustain the nutrient cycle of ecosystems .

53. Clearing and burning of the forests for agriculture,cattle rearing and timber extraction. Clear cutting and conversion of forest land in hilly areas for agriculture,plantation and housing. Forests affected by acid deposition originating from industries. Pesticides spraying to control insects in forest plantation leads to poisoning all the way up the food chain and unintended loss of species . Impact of human activities and natural forces on the forest of India

54. Conservation of Forest Ecosystem Use resources carefully Alternate source of energy for fuel wood Afforestation NP & Wildlife Sanctuaries Control Population

55. Humans are part of Forest Ecosystem : Humans are consumers. We get food and materials from forests. Because of this, we are a part of the forest ecosystem. Human consumption alters forest ecosystems. Human intervention may be necessary to sustain forest communi­ties under the increased pressure of humans.

56. Desert Ecosystem: Types, Characteristic, Structure and Function of Desert Ecosystem

57. Valle de la Luna ("Valley of the Moon") in the Atacama Desert of Chile, the world's driest hot desert Sand dunes in the Rub' al Khali("Empty quarter") of Saudi Arabia The Agasthiyamalai hills cut off Tirunelveli in India from the monsoons, creating a rainshadow region .

58. Deserts usually have a large diurnal and seasonal temperature range, with high daytime temperatures falling sharply at night. The diurnal range may be as much as 20 to 30 °C (36 to 54 °F) and the rock surface experiences even greater temperature differentials.During the day the sky is usually clear and most of the sun's radiation reaches the ground, but as soon as the sun sets, the desert cools quickly by radiating heat into space. In hot deserts, the temperature during daytime can exceed 45 °C (113 °F) in summer and plunge below freezing point at night during winter. Such large temperature variations have a destructive effect on the exposed rocky surfaces. The repeated fluctuations put a strain on exposed rock and the flanks of mountains crack and shatter. Fragmented strata slide down into the valleys where they continue to break into pieces due to the relentless sun by day and chill by night. Successive strata are exposed to further weathering. The relief of the internal pressure that has built up in rocks that have been underground for aeons can cause them to shatter . Weathering:-

59. One square centimeter (0.16 sq in) of windblown sand from the Gobi Desert Exfoliation also occurs when the outer surfaces of rocks split off in flat flakes. This is believed to be caused by the stresses put on the rock by repeated expansions and contractions which induces fracturing parallel to the original surface. Chemical weathering processes probably play a more important role in deserts than was previously thought. The necessary moisture may be present in the form of dew or mist. Ground water may be drawn to the surface by evaporation and the formation of salt crystals may dislodge rock particles as sand or disintegrate rocks by exfoliation. Shallow caves are sometimes formed at the base of cliffs by this means. As the desert mountains decay, large areas of shattered rock and rubble occur.

60. The process continues and the end products are either dust or sand. Dust is formed from solidified clay or volcanic deposits whereas sand results from the fragmentation of harder granites, limestone and sandstone.There is a certain critical size (about 0.5 mm) below which further temperature-induced weathering of rocks does not occur and this provides a minimum size for sand grains.As the mountains are eroded, more and more sand is created. At high wind speeds, sand grains are picked up off the surface and blown along, a process known as saltation. The whirling airborne grains act as a sand blasting mechanism which grinds away solid objects in its path as the kinetic energy of the wind is transferred to the ground.The sand eventually ends up deposited in level areas known as sand-fields or sand-seas, or piled up in dune. Exfoliation of weathering rocks in Texas

61. Temperature

62. How the desert is unique and precipitation The desert is unique because most deserts are found next to rainforests and it covers one third of the WORLD.

63. Types and Characteristic Features: One can find at least one desert on every continent except Europe and Antarc­tica. Each desert is different in some way, but they all have one thing in com­mon. In order for an area of land to be considered a desert, it must receive less than 10 inches of water a year. Clouds are scarce in these regions, and we all know that without clouds, there can’t be rain, snow or any other precipi­tation. But clouds also serve another purpose – they block out some of the Sun. The desert gets mighty hot during the day because the Sun beats down on the sand. At night, the desert gets very cold, because there aren’t clouds around to keep the heat from escaping to the atmosphere. There are plenty of differences between the deserts of the world. Some deserts are made of very fine, red sand, others consist of sand mixed with pebbles and rocks. The desert sand started out as rock, but years of weathering by wind and water has created dunes in the deserts. These sands are mostly minerals, and sometimes oil can be found hidden deep within the rocks.

64. Structure and Function: The different components of a desert ecosystem are: (A) Abiotic Component: The abiotic component includes the nutrients present in the soil and the aerial environment. The characteristic feature of the abiotic component is lack of organic matter in the soil and scarcity of water.

65. ( B) Biotic Component: The various biotic components representing three functional groups are:

66. (a) Producer organisms: The producers are mainly shrubs or bushes, some grasses and a few trees. Surprisingly, there are many species of plants that survive in the desert. Most of them are succulents, which mean they store water. Others have seeds that lay dormant until a rain awakens them. Regardless, these plants find a way to get water and protect themselves from the heat. The most famous desert plant is the cactus. There are many species of cacti. The saguaro cactus is the tall, pole shaped cactus. The saguaro can grow up to 40 feet tall. It can hold several tons of water inside its soft tissue. Like all cacti, the saguaro has a thick, waxy layer that protects it from the Sun. Other succulents include the desert rose and the living rock. This strange plant looks like a spiny rock. It’s disguise protects it from predators. The welwitschia is a weird looking plant. It has two long leaves and a big root. This plant is actually a type of tree and it can live for thousands of years. There are many other kinds of desert plants. Some of them have thorns others have beautiful flowers and deadly poisons. Even in the worst conditions, these plants continue to thrive .

67. (b) Consumers: These include animals such as insects and reptiles. Besides them, some rodents, birds and some mammalian vertebrates are also found.

68. Desert Insects and Arach nids: There are plenty of insects in the desert. One of the most common and destruc­tive pests is the locust. A locust is a special type of grasshopper. They travel from place to place, eating all the vegetation they find. Locusts can destroy many crops in a single day.Not all desert insects are bad, though. The yucca moth is very important to the yucca plant, because it carries pollen from the flower to the stigma. The darkling beetle has a hard, white, wing case that reflects the Sun’s energy. This allows the bug to look for food during the day.

69. There are also several species of ants in the desert. The harvester ants gather seeds and store them for use during the dry season. And the honey pot ants have a very weird habit. Some members of the colony eat large amounts of sugar, so much that their abdomens get too large for them to move. The rest of the colony feeds off this sugar.There are also arachnids in the desert. Spiders are the most notable arachnids, but scorpions also belong in this group. Some species of scorpions have poison in their sharp tails. They sting their predators and their prey with the piercing tip.

70. Desert Reptiles: Reptiles are some of the most interesting creatures of the desert. Reptiles can withstand the extreme temperatures because they can control their body tem­peratures very easily. You can pu t most of the desert reptiles into one of two categories: snakes and lizards.Many species of rattlesnakes can be found in the desert. Rattlesnakes have a noisy rattle they use to warn enemies to stay away. If the predator isn’t careful, the rattlesnake will strike, injecting venom with its sharp fangs. Other desert snakes include the cobra, king snake and the hognose. Lizards make up the second category of desert reptiles. They are probably the most bizarre looking animals in the desert. While some change colors and have sharp scales for defense, others change their appearance to look more threaten­ing. One such creature is the frilled hazard. When enemies are near, the lizard opens its mouth, unveiling a wide frill. This makes the hazard look bigger and scarier. The shingle back has a tail with the same shape as its head. When a predator bites at the tail, the shingle back turns around and bites back. There are only two venomous lizards in the world, and one of them is the gila monster. It has a very painful bite .

71. Desert Birds: Like the other inhabitants of the desert, birds come up with interesting ways to survive in the harsh climate. The sand grouse has special feathers that soak up water. It can then carry the water to its young trapped in the nest. Other birds, like the gila woodpecker, depend on the giant saguaro as its home. This woodpecker hollows out a hole in the cactus for a nest. The cool, damp inside is safe for the babies.The roadrunner is probably the most well known desert bird. Roadrunners are so named because they prefer to run rather than fly. Ostriches also prefer to use their feet. Even the young depend on walking to find food and water. The galah is one of the prettiest desert birds. It is one of the few species that return to the same nest year after year.Galahs are interesting birds, in that the number of eggs they lay depends on the climate. If the desert is in a drought, they don’t lay any. However, during more tolerable years, the galah may lay as many as five eggs .

72. Desert Mammals: There are several species of mammals in the desert. They range in size from a few inches to several feet in length. Like other desert wildlife, mammals have to find ways to stay cool and drink plenty of water. Many desert mammals are burrowers.They dig holes in the ground and stay there during the hot days. They return to the surface at night to feed. Ham­sters, rats and their relatives are all burrowers. Not only do the burrows keep the animals cool, they are also a great place to store food.Of course, not all animals have in holes in the ground. The kangaroo and spiny anteater both live in the Australian desert region. Spiny anteaters are unusual mammals because they lay eggs.The desert is also full of wild horses, foxes and jackals, which are part of the canine family. And we can’t forget the cats. Lions are found all over the deserts of southern Africa. They get their water from the blood of their prey.

73. Camels – The Cars of the Desert: Camels could be included in the mammal section. Camels are the cars of the desert. Without them, people would have great difficulty crossing the hot ter­rain. There are two types of camels: Bactrian and dromedary. The main differ­ence between the two is the number of humps . Dromedaries have one hump, and Bactrian have two. Both kinds are used by people, but only Bactrian’s are found in the wild. Camels are great for transportation because they use very little water. Camels can withstand very high temperatures without sweating. They also store fat in their humps for food. If a Bactrian camel travels a long distance without eating, its hump will actually get smaller.

74. (c) Decomposers: Due to poor vegetation the amount of dead organic matter is very less. As a result the decomposers are very few. The common decomposers are some bacte­ria and fungi, most of which are thermophile.

75. We think desert as a non arable waste land but it contains lot of minerals which can be harvested by making judicial use of it. The top soil is fertile but very susceptible to erosion. It can be saved by afforestation. Minerals like silica, gypsum, borates are very commonly found. It’s a very big area which should be converted into arable. Importance for man

76. RANK DESERT AREA(in km²) AREA(in mi²) 1 Antarctic Desert (Antarctica) 14,200,000 5,500,000 2 Arctic Desert(Arctic) 13,900,000 5,400,000 3 Sahara Desert (Africa) 9,100,000 3,500,000 4 Arabian Desert (Middle East) 2,600,000 1,000,000 5 Gobi Desert (Asia) 1,300,000 500,000 6 Patagonian Desert(South America) 670,000 260,000 7 Great Victoria Desert (Australia) 647,000 250,000 8 Kalahari Desert (Africa) 570,000 220,000 9 Great Basin Desert (North America) 490,000 190,000 10 Syrian Desert (Middle East) 490,000 190,000 The ten largest deserts

77. References:- https://en.wikipedia.org/wiki/Terrestrial_ecosystem study.com/academy/.../what-is-a-terrestrial-ecosystem https://www.slideshare.net/littlemegan/terrestrial-ecosystems https://www.soinc.org/sites/default/files/uploaded_files https://en.wikipedia.org/wiki/Grassland https://www.slideshare.net/KyrmenMarsh517/kyrmen-marsh https://en.wikipedia.org/wiki/Desert edugreen.teri.res.in Environmental Studies : From crisis to cure en.wikipedia.org/wiki/Grassland biodiv.wri.org environment- guides.com http://www.geocities.com http://www.enchantedlearning.com http://www.blueplanetbiomes.org http://www.mbgnet.net

78. The end…!!