Deserts are landforms of sand and sediments. They are the cradles of centrifugal eolian forces. Among all the terrestrial ecosystems, deserts are typical landforms due to their unique ecological conditions.
Desert and near-desert areas cover nearly one-third of the land surface of the globe . Deserts alone covers about one-seventh of the land surface.
Deserts alone cover about seventh of the land surface.
We normally call deserts as “sand seas or oceans of sands”. Most of the major desert areas like as the Sahara, the Arabian, the Kalahari, and the Deserts of Australia all lie between 10 and 30 degrees north or south of the equator. Deserts are dry ecosystems comprising a substantial part of the globe. Deserts are to be fully understood in earth science studies. This report is about the Deserts as unique landforms.
Deserts alone cover about seventh of the land surface.
We normally call deserts as “sand seas or oceans of sands”. Most of the major desert areas like as the Sahara, the Arabian, the Kalahari, and the Deserts of Australia all lie between 10 and 30 degrees north or south of the equator. Deserts are dry ecosystems comprising a substantial part of the globe. Deserts are to be fully understood in earth science studies. This report is about the Deserts as unique landforms.
While studying the physical features and geomorphology of landforms, a very unique nature of landmass comes into our mind. It is very unique in various aspects. That is the dry landmass called as the Desert.
Earth has numerous land areas covered by deserts. Among all the terrestrial ecosystems, deserts are very typical landforms due to their unique ecological conditions.
Temperate forests and tropical rain forestsAlen Shaji
The word forest is derived from Latin ‘Foris’ meaning outside, the reference being to village boundary fence, and must have included all uncultivated and uninhabitated land.
Today a forest is any land managed for the diverse purposes of forestry whether covered with trees, shrubs, climbers, etc.
The forest biomes include a complex assemblage of different kinds of biotic communities.
Optimum conditions of temperature and ground moisture responsible for the growth of trees contribute greatly to the establishment of forest communities.
In addition, 50 mm rainfall is a pre-requisite for the trees.
The nature of soil, wind and air currents determines the distribution (abundance or sparseness) of forest vegetation.
The temperate forest biomes are characterized by a moderate climate and broad-leaved deciduous trees, which shed their
leaves in fall, are bare over winter and grow new foliage in the spring.
Wetlands are... areas where a water table is at, near, or just above the surface
and where soils are water-saturated for a sufficient length of time such that excess
water and resulting low soil oxygen levels are principal determinants of vegetation
and soil development. wetlands will have a relative abundance of obligate
hydrophytes in the vegetation community and soils featuring “hydric” characteristics.
Grass land ecosystems in india.
types of grasslands
uses of grassland
threats to grasslands
flora and fauna of grassland ecosystems
interesting facts
grassland ecosystem conservation
Wetlands exist along the borders of water courses and water bodies, in topographically low lying areas. Wetlands are the interfaces between land and water. This module explains the importance of wetlands as promising ecosystems.
Hydrologic Cycle is also called as Water Cycle. It basically deals with transformation of water in different forms starting from gaseous stage (water vapor) to liquid state (water on earth's surface), and water inside soil as underground water.and again back to gaseous stage. The cycle has no starting or end.
desert ecosystem
Deserts and semi arid lands are extremely specialised and sensitive ecosystems that are easily destroyed by human activities. The plants and animals that inhabit these dry areas can live only in this ecosystem.
Desert ecosystem, is usually believed to be barren, but this fragile ecosystem supports numerous amazing living creatures, known for their adaptability.
Deserts alone covers about seventh of the land surface. We normally call deserts as “sand seas or oceans of sands”. Most of the major desert areas like as the Sahara, the Arabian, the Kalahari, and the Deserts of Australia all lie between 10 and 30 degrees north or south of the equator. Deserts are dry ecosystems comprising a substantial part of the globe
While studying the physical features and geomorphology of landforms, a very unique nature of landmass comes into our mind. It is very unique in various aspects. That is the dry landmass called as the Desert.
Earth has numerous land areas covered by deserts. Among all the terrestrial ecosystems, deserts are very typical landforms due to their unique ecological conditions.
Temperate forests and tropical rain forestsAlen Shaji
The word forest is derived from Latin ‘Foris’ meaning outside, the reference being to village boundary fence, and must have included all uncultivated and uninhabitated land.
Today a forest is any land managed for the diverse purposes of forestry whether covered with trees, shrubs, climbers, etc.
The forest biomes include a complex assemblage of different kinds of biotic communities.
Optimum conditions of temperature and ground moisture responsible for the growth of trees contribute greatly to the establishment of forest communities.
In addition, 50 mm rainfall is a pre-requisite for the trees.
The nature of soil, wind and air currents determines the distribution (abundance or sparseness) of forest vegetation.
The temperate forest biomes are characterized by a moderate climate and broad-leaved deciduous trees, which shed their
leaves in fall, are bare over winter and grow new foliage in the spring.
Wetlands are... areas where a water table is at, near, or just above the surface
and where soils are water-saturated for a sufficient length of time such that excess
water and resulting low soil oxygen levels are principal determinants of vegetation
and soil development. wetlands will have a relative abundance of obligate
hydrophytes in the vegetation community and soils featuring “hydric” characteristics.
Grass land ecosystems in india.
types of grasslands
uses of grassland
threats to grasslands
flora and fauna of grassland ecosystems
interesting facts
grassland ecosystem conservation
Wetlands exist along the borders of water courses and water bodies, in topographically low lying areas. Wetlands are the interfaces between land and water. This module explains the importance of wetlands as promising ecosystems.
Hydrologic Cycle is also called as Water Cycle. It basically deals with transformation of water in different forms starting from gaseous stage (water vapor) to liquid state (water on earth's surface), and water inside soil as underground water.and again back to gaseous stage. The cycle has no starting or end.
desert ecosystem
Deserts and semi arid lands are extremely specialised and sensitive ecosystems that are easily destroyed by human activities. The plants and animals that inhabit these dry areas can live only in this ecosystem.
Desert ecosystem, is usually believed to be barren, but this fragile ecosystem supports numerous amazing living creatures, known for their adaptability.
Deserts alone covers about seventh of the land surface. We normally call deserts as “sand seas or oceans of sands”. Most of the major desert areas like as the Sahara, the Arabian, the Kalahari, and the Deserts of Australia all lie between 10 and 30 degrees north or south of the equator. Deserts are dry ecosystems comprising a substantial part of the globe
What is a desert? What is its importance and how it is formed? What are the animals and plants that can live in a desert easily? That's all is present in this PowerPoint Presentation
Drought & Desertification measures of mitigation ,Types of drought SANDEEP PATRE
Drought & Desertification measures of mitigation ,Types of drought ,Drought Causes, Effects of Drought .
Types of deserts and the global distribution of deserts, Factors for desert formation, Mitigation:
E-content is a Comprehensive package of teaching material put into hypermedia format. Hypermedia is multimedia with internet deplorability. E-content can not be created by a teaching faculty alone . It needs the role of teacher, Video editor, production assistants, web developers (HTML 5 or Adobe captivate, etc). Analyze the learner needs and goals of the instructional material development, development of a delivery system and content, pilot study of the material developed, implementation, evaluating, refining the materials etc. In designing and development of E-content we have to adopt one of the instructional design models based on our requirements.
Pedagogy is the most commonly understood approach to teaching. It refers to the theory and practice of learning. Pedagogy is often described as the act of teaching. Pedagogy has little variations between traditional teaching and online teaching. Online teaching pedagogy is a method of effective teaching practice specifically developed for teaching via the internet. It has a set of prescribed methods, strategies, and practices for teaching academic subjects in an online (or blended) environment, where students are in a physical location separate from the faculty member.
Technology has changed the possibilities within teaching and learning. Classes, which prior to the digital era were restricted to lectures, talks, and physical objects, no longer have to be designed in that manner. Training in a synchronous virtual classroom can only be successful with the active participation and engagement of the learners. Explore the Virtual Classroom’s features and see how they can support and enhance your tutoring style.
• The monitoring and evaluation of the institutional processes require a carefully structured system of internal and external review. The NAAC expects the Institutions to undertake continuous Academic and Administrative Audits (AAA). This presentation is intended to serve as advisory to all accredited HEIs who volunteer to undertake AAA. The pros and cons of this process are also highlighted. Academic and Administrative Audit is the process of evaluating the efficiency and effectiveness of the administrative procedure. It includes assessment of policies, strategies & functions of the various administrative departments, control of the overall administrative system, etc. This checklist gives an overview what the audit committee members may look into while visiting an institution for this purpose. It invariably follows the Quality Indicators Framework prescribed by Accreditation Council in India.
• The monitoring and evaluation of the institutional processes require a carefully structured system of internal and external review. The NAAC expects the Institutions to undertake continuous Academic and Administrative Audits (AAA). This presentation is intended to serve as advisory to all accredited HEIs who volunteer to undertake AAA.
Chemical analysis data of water samples can not be used directly for understanding. They are to be used for various calculations in order to determine the quality parameters that have a lot of significances. A. Balasubramanian and D. Nagaraju, of the Department of Studies in Earth Science, Centre for Advanced Studies, University of Mysore, Mysore-570006, Karnataka, India have recently brought out a software and its application manual as a good book for reference and execution. The Name of the software is WATCHIT meaning Water Chemistry Interpretation Techniques. This software computes more than 100 parameters pertaining to water quality interpretations. The software follows its own method of approach to determine the required results. Systems International Units are used. Limited input parameters are required. This is suitable for all scientific research, government water quality data interpretations and for understanding the quality of water before using it.
Water conservation refers to reducing the usage of water and recycling of waste water for different purposes like domestic usage, industries, agriculture etc. This technical article highlights most of the popular methods of water conservation. A special note on rainwater harvesting is also provided.
This module gives an overview of general applications of current hydrogeological aspects. It is for the basic understanding of students and research scholars.
Climate Extreme (extreme weather or climate event) refers to the occurrence of a value of a weather or climate variable above (or below) a threshold value near the upper (or lower) ends of the range of observed values of the variable. Extreme weather and climate events, interacting with exposed and vulnerable human and natural systems, can lead to disasters.
WATER RESOURCES PLANNING AND MANAGEMENT POSSIBILITIES IN CHAMARAJANAGAR TALUK...Prof. A.Balasubramanian
Any unplanned development and utilization of water resources with result in water scarcity. In many parts of the developing world. Such a situation exists. In order to do proper planning and
management of water resources, it is necessary to conduct detailed analyses of the factors, which influence the water availability and its uses. In the present study, a comprehensive analysis have been undertaken for proper utilization of water resources in Chamarajanagar Taluk, which has been identified as one of the drought hit districts of Karnataka, in India. The factors analysed in this work are, surface and groundwater availability, land use, cropping pattern, recharge potential of soils and the rainfall pattern in typical areas of Taluk. It is observed that the problem of water scarcity is mainly due to the lack of irrigation planning and management. Hence, a
modified cropping pattern is suggested by taking into consideration of all available water resources and other conditions.
In broad terms, cultural geography examines the cultural values, practices, discursive and material expressions and artefacts of people, the cultural diversity and plurality of society.
It also emphasizes on how cultures are distributed over space, how places and identities are produced, how people make sense of places and build senses of place, and how people produce and communicate knowledge and meaning.
Minerals are formed by changes in chemical energy in systems which contain one fluid or vapor phase. In nature, minerals are formed by crystallisation or precipitation from concentrated solutions. These solutions are called as ore-bearing fluids. Ore-bearing fluids are characterised by high concentration of certain metallic or other elements.
Fluids are the most effective agents for the transport of material in the mantle and the Earth's crust.
Soils are complex mixers forming the skin of the earth's surface. Soil is a dynamic layer in which many complex chemical, physical and biological activities are going on constantly. Soils become adjusted to conditions of climate, landform and vegetation, and will change internally when those controlling conditions change. Soils are products of weathering. Soils play a dominant role in earth's geomorphic processes in a cyclic manner. The characteristics of soils are very essential for several reasons. This module highlights these characteristics.
GIS TECHNIQUES IN WATER RESOURCES PLANNING AND MANAGEMENT IN CHAMARAJANAGAR ...Prof. A.Balasubramanian
The over-exploitation and contamination of groundwater continue to threaten the long-term sustainability of our precious water resources, in spite of the best efforts made by various agencies.
This has many serious implications to the economic development of a country like India. Lack of
judicious planning and integration of environmental consideration to ground water development
projects are primarily responsible for such a state of affair in the ground water sector. Geographical Information Systems could be of immense help in planning sustainable ground water management strategies, especially in hard rock areas with limited ground water potential. Data collected from
Satellite Imagery and through field investigations have been integrated, on a GIS platform, for demarcation and prioritization of areas suitable for ground water development and ground water augmentation. An attempt has also been made to assess the vulnerability of the area to ground water
contamination. This paper demonstrates the utility of GIS in planning judicious management of ground water resources in a typical hard rock area of Chamarajanagar Taluk, Karnataka, state India.
Nanobiomaterials are very effective components for several biomedical and pharmaceutical studies. Among the metallic, organic, ceramic and polymeric nanomaterials, metallic nanomaterials have shown certain prominent biomedical applications. Enormous works have been done to synthesize, analyse and administer the metallic nanoparticles for various kinds of medical and therapeutic applications, during the last forty years. In these analyses, the prominent biomedical applications of ten metallic nanobiomaterials have been reviewed from various sources and works. It has been found that almost nine of them are used in a very wide spectrum of medical and theranostic applications.
A variety of Nano-biomaterials are synthesised, characterised and tested to find out their potentialities by global scientific communities, during the last three decades. Among those, nanostructured ceramics, cements and coatings are being considered for major use in orthopaedic, dental and other medical applications. The development of novel biocompatible ceramic materials with improved biomedical functions is at the forefront of health-related applications, all over the world. Understanding of the potential biomedical applications of ceramic nanomaterials will provide a major insight into the future developments. This study reviews and enlists the prominent potential biomedical applications of ceramic nanomaterials, like Calcium Phosphate (CaP), Tri-Calcium Phosphate (TCP), Hydroxy-Apatite(HAP), TCP+HAP, Si substituted HAP, Calcium Sulphate and Carbonate, Bioactive Glasses, Bioactive Glass Ceramics, Titania-Based Ceramics, Zirconia Ceramics, Alumina Ceramcis and Ceramic Polymer Composites.
The present forest and tree cover of the country is 78.37 million ha in 2007 which is 23.84% of the geographical areas and it includes 2.82% tree cover. This becomes 25.25%, if the areas above tree line i.e., 4000m are excluded from the total geographical area. The forest cover is classified into 3 canopy density classes.
1. Very Dense Forest (VDF) with canopy density more than 70%
2. Moderately Dense Forest (MDF) with Canopy density between 40-70% and
3. Open Forest (OF) with Canopy density between 10-40%
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
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Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
Diabetes is a rapidly and serious health problem in Pakistan. This chronic condition is associated with serious long-term complications, including higher risk of heart disease and stroke. Aggressive treatment of hypertension and hyperlipideamia can result in a substantial reduction in cardiovascular events in patients with diabetes 1. Consequently pharmacist-led diabetes cardiovascular risk (DCVR) clinics have been established in both primary and secondary care sites in NHS Lothian during the past five years. An audit of the pharmaceutical care delivery at the clinics was conducted in order to evaluate practice and to standardize the pharmacists’ documentation of outcomes. Pharmaceutical care issues (PCI) and patient details were collected both prospectively and retrospectively from three DCVR clinics. The PCI`s were categorized according to a triangularised system consisting of multiple categories. These were ‘checks’, ‘changes’ (‘change in drug therapy process’ and ‘change in drug therapy’), ‘drug therapy problems’ and ‘quality assurance descriptors’ (‘timer perspective’ and ‘degree of change’). A verified medication assessment tool (MAT) for patients with chronic cardiovascular disease was applied to the patients from one of the clinics. The tool was used to quantify PCI`s and pharmacist actions that were centered on implementing or enforcing clinical guideline standards. A database was developed to be used as an assessment tool and to standardize the documentation of achievement of outcomes. Feedback on the audit of the pharmaceutical care delivery and the database was received from the DCVR clinic pharmacist at a focus group meeting.
Micro RNA genes and their likely influence in rice (Oryza sativa L.) dynamic ...Open Access Research Paper
Micro RNAs (miRNAs) are small non-coding RNAs molecules having approximately 18-25 nucleotides, they are present in both plants and animals genomes. MiRNAs have diverse spatial expression patterns and regulate various developmental metabolisms, stress responses and other physiological processes. The dynamic gene expression playing major roles in phenotypic differences in organisms are believed to be controlled by miRNAs. Mutations in regions of regulatory factors, such as miRNA genes or transcription factors (TF) necessitated by dynamic environmental factors or pathogen infections, have tremendous effects on structure and expression of genes. The resultant novel gene products presents potential explanations for constant evolving desirable traits that have long been bred using conventional means, biotechnology or genetic engineering. Rice grain quality, yield, disease tolerance, climate-resilience and palatability properties are not exceptional to miRN Asmutations effects. There are new insights courtesy of high-throughput sequencing and improved proteomic techniques that organisms’ complexity and adaptations are highly contributed by miRNAs containing regulatory networks. This article aims to expound on how rice miRNAs could be driving evolution of traits and highlight the latest miRNA research progress. Moreover, the review accentuates miRNAs grey areas to be addressed and gives recommendations for further studies.
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
2. 2
Introduction:
Deserts are landforms of sand and sediments.
They are the cradles of centrifugal eolian forces.
Among all the terrestrial ecosystems, deserts are
typical landforms due to their unique ecological
conditions.
Desert and near-desert areas cover nearly one-
third of the land surface of the globe .
Deserts alone covers about one-seventh of the
land surface.
3. 3
We normally call deserts as “sand seas or
oceans of sands”.
Most of the major desert areas like as
the Sahara, the Arabian, the Kalahari, and
the Deserts of Australia all lie between 10 and 30
degrees north or south of the equator.
Deserts are dry ecosystems comprising a
substantial part of the globe.
4. 4
The following are the modules covered in this
unit:
1. Geomorphology of Deserts
2. Types of Deserts
3. Flora of deserts
4. Fauna of deserts
5. Natural Resources of deserts.
5. 5
1. Geomorphology of Deserts
Deserts are created by changes in climate and
accumulation of sands and other rocky wastes. A
high proportion of the desert floor is an erosion
surface of a bedrock.
Sand covers about 10 to 20 per cent of the
deserts. The rest of the land consists mostly of
gravels, boulders, mountains, and various types of
soils.
6. 6
A desert landscape includes various landforms
created by wind erosion. In the heart of the desert
the wind has a free play. Wind erosion creates
mounds of sand dunes and flat-topped hills known
as mesas and buttes.
Sand drifts, Crescentic Dunes or Barchans, Loess
and Longitudinal dunes and sand sheets are the
notable wind-borne geomorphic features.
7. 7
One of the most remarkable features of desert
dunes is their power of collecting all the sand
from their neighborhood.
Dunes are large piles of wind-borne sands
reaching a maximum height of 250 metres above
the surface.
Dunes show many shapes and patterns that change
continually due to the highly active winds.
Deserts are considered to be highly dynamic
geomorphic features.
8. 8
The sand bodies of deserts are always on rolling
motion due to the prevailing action of wind.
Dunes are characterized by two-sided slopes one
along the windward direction and the other along
the leeward side.
Deserts are characterised by the following
ecological factors:
a. Sandy soils and a rocky substratum
b. Scanty rainfall and high evaporation
9. 9
c. Hot and Cold weather
d. Prevailing Wind action
e. Poor Soil Moisture and water resources
Soils in desert regions are generally fertile but
lacks soil moisture to encourage plant growth.
Rainfall is a determining factor of deserts.
Rainfall is very scanty in all desert regions. It
spite of these deserts are not barren wastelands.
10. 10
Most of the deserts receive less than 200 mm
rainfall per year.
However, the amount of rainfall may vary greatly
from year to year.
A desert may not receive any rain for several
years and in some cases about 250mm of rain
might fall within a few hours.
Desert plants cannot use so much water at once,
and the desert soil cannot absorb all of it. Most of
the water runs off, carrying away the soil
particles.
11. 11
Climatologically, deserts are the hottest places in
the world because they absorb more heat from the
Sun than any other land in humid climates.
Deserts are mostly under arid to semi-arid
climates. The temperature varies during day and
nights.
In summer, desert temperatures often reach upto
38 °C during the day. They drop upto 25 degrees
C or more at nights.
12. 12
During the winter, temperatures in the desert
range from 10 to 21 °C. Clouds would reflect
much of the sun's intense radiation during the day,
slowing the rate of heating of the air near the
surface.
At night, clouds and water vapour would absorb
much of the earth's radiation--most of which
consists of infrared rays--slowing the rate of
cooling. Winters are much colder in middle
latitude semiarid areas and deserts.
13. 13
Winds that descend the leeward slopes of these
ranges are warm and dry.
Another controlling factor of desert is the
presence of water. Due to very scanty rainfall and
sandy soil, deserts have no or very little
possibility of holding water. Only in some
depressions very little water may exists. Soil
moisture is a rare feature in deserts. Even if little
soil moisture is present, due to hot climate and
prevailing winds, it will be evaporated quickly.
14. 14
The drainage system is made up of dried streams
called arroyos. After a rainfall, water fills the
arroyos.
They run down the mountains and cut away the
land, carrying deposits of gravel, rock, and sand to
the bottom.
Oasis is a wet and fertile zone in a desert with
vegetation.
Underground water comes nearer to the ground
surface.
15. 15
Open wells and springs do exist in such spots.
Water that occurs within an oasis has been drawn
through groundwater base flow from distant
catchments like mountains or hills.
Because oases have some water, farming and
settlement are expected to be more.
Some oases may be small and can support only a
few people, but others are large enough to support
millions of people.
16. 16
The typical desert topography includes playas,
alluvial plains, Pediments, inselbergs, mesas,
buttes and badlands.
Playa are dry lake beds formed by evaporation
from temporary (few hours to several months),
shallow accumulations of excess water (playa
lake) following infrequent and intense
rainstorms.
17. 17
Playas are characterized by mudcracks and
precipitated salt crystals, forming salt pans.
Alluvial fans are sediments deposited downslope
of the land, typically as aprons at the mouth of
canyons or as a piedmont plain.
Alluvial fans coalesce to form a bajada, a broad
alluvial apron with an undulating surface.
Pediments are the sloping low-relief surfaces
adjacent to mountains resulting from erosion and
retreat of the mountain front.
18. 18
Most covered by thin veneer of debris, alluvial
fans, or bajadas.
Inselbergs are isolated, steep-sided erosional
remnants of bedrock (characterized by greater
resistance to weathering than surrounding
mountains) that rise above flat desert plains.
Inselberg is a German word meaning "island
mountain".
Mesas are broad, flat-topped erosional remnants
bounded on all sides by steep slopes.
19. 19
Mesas consist of relatively easily weathered
sedimentary rocks capped by nearly horizontal
and more resistant rock layer.
Buttes are isolated pillar-like structures resulting
from continued eathering and erosion of mesas
Badlands are areas of closely spaced ravines with
little or no vegetation.
20. 20
Types of Deserts
The distribution of arid regions or deserts is
determined by the climate and topography, such
that arid terrains may be subdivided into
a) tropical deserts and
b) topographic deserts.
Characteristics common to all deserts include
irregular rainfall of less than 250 mm per year,
very high evaporation rates often 20 times the
annual precipitation, and low relative humidity
and cloud cover.
21. 21
Tropical Deserts:
The Tropical deserts have a big diurnal
temperature range and very high daytime
temperatures, whereas mid-latitude deserts have a
wide annual range and much lower winter
temperatures (in the Mongolian desert the mean
temperature is below freezing point for half the
year).
22. 22
Heat enhances evaporation over deserts.
Deserts and adjacent semi-arid regions
(steppes), which may have rainfall between 10
and 20 inches per year, are characterized by a
non-continuous vegetation cover. The tropical
desert lie within latitudes from 5º to 30º and are
mainly caused by the descent of air. This is
responsible for the warmness of land and loss of
moisture.
23. 23
Topographic Deserts:
Topographic controls on desert formation also
reflect a deficiency in rainfall. Topographic
deserts are located near the center of continents,
where climates are hot in summer and cold and
dry in winter. These regions are typically far
from ocean moisture sources, and most often are
cut off from rain-bearing winds by high
mountains.
24. 24
Based on their surface forms and soil
composition, deserts are classified into the
following four types:
a) Rocky Deserts
b) Stony Deserts
c) Sandy Deserts
d) Clayey Deserts.
Rocky deserts have uneven topography between
mountain ridges and groups of small hills.
Mountain ridges have rugged summits and crests,
steep slopes with outcrops of rocks.
25. 25
Talus and scree debris are numerous on hill sides.
They are not completely devoid of vegetation.
Isolated small and large shrubs can be located on
the lower parts of the slopes., in valleys and
depressions. Some water springs appear on valley
floors.
Stony deserts are completely flat or gently
undulated areas with stones of rocky wastes
comprising sharp edged rock fragments or
pebbles.
26. 26
There may not be any vegetation and water.
Sahara and Arabian Deserts are stony deserts.
Sandy deserts are areas of loose sand which forms
hillocks in the shape of barchans and dunes. These
are characterised by uneven surfaces of
undulating chains of dunes with isolated short
valleys or hollows with little vegetation. They
resemble like sea-waves. Barchans reach a height
of 200m. It is difficult to walk straight across on
these zones.
27. 27
One has to clim the crets and descend into the
hollows. It is easier to walk aided by wind. Sand
storms are common creating an atmospheric haze.
Clayey Deserts are not extensive. The clayey
floors are crackd into polygonal sections. Soil is
of fine silt in composition with sparse vegetation.
Soils of Clayey deserts are mostly saturated with
salts.
28. 28
The geographical classification of deserts also
include:
a) Continental deserts- eg. Gobi desert
b) Rain-shadow deserts- due to tall mountain
ranges- eg. Judean desert in Israel
c) Coastal deserts- Eg. Atacama Desert in S.
America, Namib Desert of Africa.
d) Trade wind deserts- Eg. Sahara desert-
temperature goes upto 57deg.C
e) Monsoon deserts- eg. Thar Desert in India,
Cholistan Desert of Pakistan
29. 29
f) Polar deserts- Eg. The Dry Valleys of
Antarctica – are ice free for thousands of years.
g) Extra-terrestrial deserts- deserts of other
planets, Eg. Mars have shown eolian features.
h) Montane deserts.
2. Flora of deserts
Most deserts plants are drought or salt tolerant,
such as Xerophytes. Some store water in their
leaves, roots and stems.
30. 30
Other desert plants have long tap roots that
penetrate the water table, anchor the soil, and
control erosion. The stemps and leaves of some
plants can lower the velocity of sand-carrying
winds and protect the ground from erosion.
The following three life forms of plants that are
adapted to deserts:
a) The annuals, which avoid drought by growing
only when there is adequate moisture
31. 31
b) The succulents- such as the cacti, which store
water and survive
c) The desert shrubs- which have numerous
branches with small but thick leaves to store
water.
Adaptation to desert environment and arid climate
involves the ability to avoid wilting and remain
dormant for long periods rather than an increase
in transpiration efficiency. Desert soils are
infertile, lacking in humus and generally grey or
red in colour.
32. 32
Deserts cannot support the abundant plant and
animal life as found in humid climates. But many
kinds of plants and animals thrive in deserts. The
few plants capable of surviving such conditions
are widely spaced, scrubby and often thorny.
Long-rooted plants (phreatophytes) such as the
date palm and musquite commonly grow along
dry stream channels.
33. 33
Salt-loving plants ( halophytes) such as saltbushes
grow in areas of highly saline soils and near the
edges of playas (dry saline lakes).
Xerophytes are drought-resistant and survive by
remaining leafless during the dry season or by
reducing water losses with small waxy leaves.
They frequently have shallow and widely
branching root systems and store water during the
wet season (for example, succulents and cacti
with pulpy stems).
34. 34
Desert plants survive compete with small amount
of water available.
Some desert plants obtain water from deep
beneath the surface of the earth. For example, the
American mesquite tree has roots that extend as
deep as 12 metres.
Other plants store large amounts of water in their
leaves, roots, or stems.
35. 35
The stem of the barrel cactus bulges with water
after a rainfall and shrinks as the plant uses the
water.
From an ecological point of view, desert can be
classified into a) Hot deserts and b) cold deserts.
All desert vegetation has a highly characteristic
spatial distribution plants.
Individual plants are scattered.
This spacing reduces competition.
36. 36
Some of the typical flora of deserts are:
a) Creosote bush- (Larrea) – North America, hot
deserts
b) Sagebrush –( Artemisia) Great basin- Cool
Deserts
c) Bur sage( Franseria)- high altitude plants
d) Giant cactus- ( Sahuaro)-
In addition to these little grass also grows on
deserts but are grazed by the animals.
Greesewood( sarcobatus) is a typical vegetation in
cool deserts.
37. 37
The extensive bar grounds of deserts is not
necessarily free from plants.
Mosses, algae, and lichens may be present.
Blue green algae are the nitrogen fixers in these
regions also.
After every rainfall, colourful flowers and lush
vegetation cover parts of deserts.
This dramatic change occurs because many desert
plants do not grow during a drought.
38. 38
Due to rain, plants sprout, flower, scatter their
seeds, and die.
The entire process usually takes only a few weeks.
The seeds of annuals can survive even the longest
dry periods.
The seeds lie buried until the rains return. They
then sprout, and the plants complete their life
cycle within a few weeks.
39. 39
In the deserts of Australia, the dominant plants are
tussock grasses, such as porcupine grass or
spinifex, and succulent herbs, such as parakeelya.
After the rains, the deserts come alive with
beautiful flowers, such as the purple mulla-
mullas.
In the deserts of North and Central America,
cactuses are prominent.
40. 40
Cactuses are protected from grazing animals by
their sharp spines.
Many cactuses have beautiful flowers.
In Africa, the most abundant desert plants are the
euphorbias, which have a poisonous milky sap.
The Sonoran Desert of the American Southwest
has the most complex desert vegetation on earth.
The giant “saguato cacti” provide nests for desert
birds and serve as “trees”of the desert.
41. 41
Saguaro grow slowly but may live upto 200 years.
Its branches develop after 75 years. When fully
grown it is 15 m tall and weigh 10 tons.
In addition to these, other types of plants
belonging to pea family and sunflower family are
seen in deserts.
42. 42
3. Fauna of deserts
Animals of the deserts have developed special
body structure and ways of life that enable them
to survive under the extreme heat.
Centipedes, gerbils, kangaroo rats, snakes, and
scorpions spend the day in burrows.
They come out to search for food only when
temperatures drop at night.
43. 43
Many insects, lizards, and tortoises can tolerate
high desert temperatures and are active in the
daytime.
But even they must retreat underground or find
the shade of a tree during the hottest part of the
day.
Some snails, insects, frogs, lizards, mice, and
ground squirrels aestivate in deserts, i.e they sleep
through the summer.
44. 44
Elf owls, roadrunners, snakes, spiders, bees and
butterflies are the other fauna of deserts.
Many desert dwellers have light-coloured skin,
which helps keep them cool by reflecting sunlight.
Desert animals include many kinds of insects,
spiders, reptiles, birds, and mammals.
45. 45
Deer, foxes, wolves, and other animals may visit a
desert after a rainfall.
Most desert animals avoid the extreme midday
heat by feeding at night after the temperature has
dropped.
Many small animals dig burrows underground and
stay there during the day.
Some of these animals are dormant (inactive)
throughout the summer.
46. 46
Desert foxes and hares have long ears.
When overheated, these animals move to a cool
cave or burrow where they can get rid of excess
body heat through their ears.
The Cape ground squirrel makes its own shade by
using its fluffy tail like a parasol.
Fairy shrimp and spadefoot toads may spend
months or years underground waiting for rain to
create ponds.
47. 47
Then they quickly feed and reproduce before the
ponds dry again.
Larger desert animals try to remain in shady areas
during the day.
The evaporation of water from their bodies lowers
their body temperature, but this water must be
replaced.
48. 48
Such animals obtain water from the food they eat
and from the few water holes that exist in a desert.
Desert animals also use water that is produced in
their bodies during digestion.
This source of water is particularly important to
camels, which can go for long periods without
food and water.
Large amounts of fat are stored in the humps of
camels.
49. 49
A camel can live for months on the water
produced when its body breaks down this fat for
use as energy.
Most deserts lie near the edges of the tropics.
Food and water are often scarce in deserts, and
temperatures in the summer can be scorching.
Despite these conditions, many kinds of animals
live there.
50. 50
Whenever deserts are discussed no one can forget
anout the “Ship of the Deserts” ie. The Camels.
These are unique creatures which can not only
survive, but also help the human beings across
hot, dry deserts with little food or water. They
walk easily on soft sand where even trucks would
get stuck, and carry people and heavy loads to
places that have no roads.
Camels also serve the people of the desert in
many other ways.
51. 51
A Camel carries its own built-in food supply on
its back in the form of a hump.
The hump is a large lump of fat that provides
energy if food is hard to find.
There are two chief kinds of camels:
(1) the Arabian camel, also called dromedary,
which has one hump, and
(2) the Bactrian camel, which has two humps.
52. 52
Hybrids (crossbreeds) of the two species were
used widely in Asia.
These hybrid camels had one extra-long hump and
were larger and stronger than either of their
parents.
Camels have been the domestic animals to support
humans for thousands of years. There are several
million Arabian camels, and most of them live
with the desert people of Africa and Asia.
53. 53
This desert ship can go for long distances without
water for days or even months.
The amount of water a camel drinks varies with
the time of year and with the weather. The
camels that graze in the Sahara can go all winter
without water and may refuse to drink if water is
offered to them.
But a large, thirsty camel can drink as much as
200 litres a day. This water is not stored in the
54. 54
camel's body but replaces water previously used
up.
Most animals sweat when hot, and the
evaporation of the water from their skin keeps
them cool.
But camels do not sweat much. Instead, their
body temperature rises by as much as 6 degree
Celsius during the hot summer day and then cools
down during night.
55. 55
On extremely hot days, a camel keeps as cool as
possible by resting rather than feeding.
Adaptation to the topography, landforms and
climate is a unique feature of desert animals. They
live with very scanty food resources.
Human population in deserts are also equally
facing the same issues. Deserts do not support a
large number of people as in humid regions.
56. 56
People living in desert regions must adjust to the
local and prevailing hot or dry climate.
Air-conditioning and irrigation projects have
made life more comfortable for other desert
dwellers.
4. Natural Resources of deserts.
57. 57
Deserts have enormous sands and soil resources.
The soil of deserts are mineral soils often called as
aridisols with low organic content.
Most desert soil is too dry to support widespread
vegetation, but much of it is rich in salt, uranium,
and other minerals. Playas are sources of mineral
deposits formed by evaporation.
Gypsum, sodium nitrate, sodium chloride salts
and Borates are the major precipitates.
58. 58
Minerals formed by evaporation are often referred
to as evaporites.
Many of them are used in the manufacture of
glass, ceramics, enamel, agricultural chemicals,
water softeners and pharmaceuticals.
Sodium nitrites are used for explosives and
fertilizers. Many metallic and non-metallic
mineral resources also are obtained from the
desert zones.
59. 59
Walter in 1954 has measured the net productivity
of a series of deserts and semi-arid communities.
The annual production of dry matter was a linear
function of rainfall upto 600cms.
This has also shown that the overall limiting
factor of deserts in productivity is the moisture.
It has been found that he annual net productivity
of true deserts is less than 2000 kg per hectare.
60. 60
When this is overcome due to rain, then the soil
becomes a limiting factor.
The primary production in deserts depend on the
little amount of available water and also the
consumption strategy adopted by the plants.
It is very low as 30-200 gm/ sq.m in arid zones,
above the ground.
The herbivores have a pronounced impact on
primary producers. The detrital food chain seems
61. 61
to be less important in the desert than any other
ecosystems.
Because of the limited production and
decomposition, nutrients are limited in the deserts.
Date palm tree produces date fruits. They thrive
in hot, dry climates.
They grow along oases throughout northern
Africa and the Middle East.
62. 62
The date palm is one of the oldest crop plants
known to have been used for at least 5,000 years.
Even today, dates form an important part of the
diet in many desert countries. Dates are also
supplied to other places from these lands.
In addition to these, large deposits of oil and
natural gas lie under many desert lands.
Some of the more productive petroleum areas on
Earth are found in arid and semi-arid regions of
63. 63
Africa and the Middle east although oil fields
were originally formed in shallow marine
environments.
Recent climate change, in geological time scale,
has placed these reservoirs in an arid
environment.
The hydrocarbon reservoirs of the North Sea is
associated with extensive evaporite deposits.
64. 64
Many of the major U.S. hydrocarbon resources
may come from aeolian sands.
The location of Oases has been of critical
importance for trade and transportation routes in
desert areas.
Caravans must travel through these places that
supplies water and food. The natural factors
creating deserts have not changed much for
thousands of years.
65. 65
It is observed over the world that various human
activities have caused expansion of desert regions.
This has happened due to continuous loss of
fertile land on the outskirts of such regions.
Planting shelter belts of trees will be one of the
solutions.
The role of human beings in reconstructing the
desert landscapes on their outskirts will certainly
stop their expansion over the other regions.