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Slash and burn consists of cutting and burning of forests or woodlands to create fields for agriculture or pasture for livestock, or for a variety of other purposes. It is sometimes part of shifting cultivation agriculture, and of transhumance livestock herding. Historically, the practice of slash and burn has been widely practiced throughout most of the world, in grasslands as well as woodlands, and known by many names. In temperate regions, such as Europe and North America, the practice has been mostly abandoned over the past few centuries. Today the term is mainly associated with tropical rain forests. Slash and burn techniques are used by between 200 and 500 million people worldwide.[1] Older English terms for slash and burn include assarting, swidden, and fire-fallow cultivation. Slash and burn is a specific functional element of certain farming practices, often shifting cultivation systems. In some cases such as parts of Madagascar, slash and burn may have no cyclical aspects (e.g., some slash and burn activities can render soils incapable of further yields for generations), or may be practiced on its own as a single cycle farming activity with no follow on cropping cycle. Shifting cultivation normally implies the existence of a cropping cycle component, whereas slash-and-burn actions may or may not be followed by cropping.

Biomes are the major regional groupings of plants and animals discernible at a global scale. Their distribution patterns are strongly correlated with regional climate patterns and identified according to the climax vegetation type. However, a biome is composed not only of the climax vegetation, but also of associated successional communities, persistent subclimax communities, fauna, and soils.

The global distribution pattern: Where each biome is found and how each varies geographically. A given biome may be composed of different taxa on different continents. Continent-specific associations of species within a given biome are known as formations and often are known by different local names. For example,the temperate grassland biome is variously called prairie, steppe, pampa, or veld, depending on where it occurs (North America, Eurasia, South America, and southern Africa, respectively). The general characteristics of the regional climate and the limitations or requirements imposed upon life by specific temperature and/or precipitation patterns. Aspects of the physical environment that may exert a stronger influence than climate in determining common plant growthforms and/or subclimax vegetation. Usually these factors are conditions of the substrate (e.g., waterlogged; excessively droughty, nutrient-poor) or of disturbance (e.g., periodic flooding or burning). The soil order(s) that characterize the biome and those processes involved in soil development. The dominant, characteristic, and unique growthforms; vertical stratification; leaf shape, size, and habit; and special adaptations of the vegetation. Examples of the last are peculiar life histories or reproductive strategies, dispersal mechanisms, root structure, and so forth. The types of animals (especially vertebrates) characteristic of the biome and their typical morphological, physiological, and/or behavioral adaptations to the environment.

The global distribution pattern: Where each biome is found and how each varies geographically. A given biome may be composed of different taxa on different continents. Continent-specific associations of species within a given biome are known as formations and often are known by different local names. For example,the temperate grassland biome is variously called prairie, steppe, pampa, or veld, depending on where it occurs (North America, Eurasia, South America, and southern Africa, respectively). The general characteristics of the regional climate and the limitations or requirements imposed upon life by specific temperature and/or precipitation patterns. Aspects of the physical environment that may exert a stronger influence than climate in determining common plant growthforms and/or subclimax vegetation. Usually these factors are conditions of the substrate (e.g., waterlogged; excessively droughty, nutrient-poor) or of disturbance (e.g., periodic flooding or burning). The soil order(s) that characterize the biome and those processes involved in soil development. The dominant, characteristic, and unique growthforms; vertical stratification; leaf shape, size, and habit; and special adaptations of the vegetation. Examples of the last are peculiar life histories or reproductive strategies, dispersal mechanisms, root structure, and so forth. The types of animals (especially vertebrates) characteristic of the biome and their typical morphological, physiological, and/or behavioral adaptations to the environment.

The four major types of biomes are aquatic, grasslands, forests, and desert. Aquatic biomes are probably the most important of all the biomes. Their medium, water, is a major natural resource. Aquatic biomes can be subdivided into freshwater, seawater and atmospheric biomes. Grasslands can be subdivided into savanna, temperate grasslands (prairie) and tundra. This classification corresponds to decreasing average temperatures. Forests receive more precipitation than other biomes and vary from boreal, to temperate, to rainforest. This classification corresponds to increasing temperatures. Deserts have the fewest species and the most extreme climate

These ecosystems are either barren or with scanty vegetation consisting of mainly thorny bushes. Deserts are classified as warm (hot) and cold (temperate) deserts. The hot deserts are the Sahara in Northern Africa, Kalahari in Southern Africa, Thar in India, Atacama in South America, deserts of Mexico and Australia.The deserts of Iran and Turkey, Gobi desert of Mongolia, some deserts of Argentina are recognised as temperate or cold deserts. Characteristics of Desertsi) Most deserts receive some rain every year but not uniform. ii) Light green covering of annuals is seen just after rains.iii) Have scanty vegetation, clear skies, hot days and extremely cold nights. iv) Soil is rocky and encrusted with sand or salt.v) Long periods without precipitation and extreme temperature (50 - 60oC) conditions (arid lands) impose considerable restraints on the flora and fauna which inhabit there. vi) Sandy storms are very frequent.vii) Occur generally in rain shadow areas. Flora1) Includes succulents such as Cacti and Euphorbias, which can store water in their tissues. 2) Trees with long spreading roots such as Acacia, Prosopis, Phoenix (dates) are found.3) Ephemerals (short lived) such as Boerhaavia repens are seen only during rainy season. FaunaMost desert animals are nocturnal and avoid the heat of the day by burrowing into the cooler soil. Animals include ants, locusts, lizards, Gila monster, coral snake, rattle snake, burrowing owls, Gambel's quail, kangaroo rats, rabbits, camel, skunk, badger foxes, jackals and desert cats. In general, the organisms having specialised structural and physiological and behavioural adaptations to withstand the extreme temperatures only can survive in a desert.

tropical rainforests are considered a type of tropical wet forest (or tropical moist broadleaf forest) and may also be referred to as lowland equatorial evergreen rainforest

and may also be referred to as lowland equatorial evergreen rainforest

Rainforests are home to half of all the living animal and plant species on the planet.[2] Tropical rain forests are called the "world's largest pharmacy" because over one-quarter of modern medicines originate from its plants.

A biome is an area on the earth's surface that has a certain set of characteristics. There are seven kinds of biomes in the world: tundra, taiga, temperate forest, tropical rainforest, desert, grassland, and ocean. The map above shows where each of these biomes can be found around the world. Although it does not appear in the key, the ocean is represented by the blue area on the map.

Shrub and scrubland biomes are found in dry, temperate area. They have mild winters and very hot summers. Dry weather and lightening storms sometimes cause flash floods during the summer. Flash fires start and spread quickly. They make room for new plants to grow by burning the large, older plants. The heat of the fire causes seed shells to crack. After the fire, the seeds sprout and grow into new plants. The main plants are low-growing woody plants with evergreen leaves. These plants have a tough skin that holds in moisture and thorns that protect the plants from grazing animals. Many plants have long roots that enable them to find water underground. Some suck water from the stems of other plants.