Desert, WHAT IS ARID LAND OR DESERT HABITATS? Arid land or desert refers to the area of very low rainfall and high evaporation rate. Arid lands are the driest habitats, receiving less than 25cm of annual rainfall.
TYPES OF ARID LAND OR DESERT
There are two major types of arid lands or desert. These are hot deserts and cold deserts.
characteristics of Hot deserts:
hot deserts of the world are located on the western coasts of the continents within latitude 15o-30o North and South of the equator. Examples of hot deserts are Sahara desert (North Africa), Arabian desert and Kalahari deserts (South Africa), Great Australia desert (Australia) and Atacama deserts of South America.
characteristics of Cold deserts:
cold deserts are located or found in the interiors of the continents around 45o-60o North and South of the equator. The deserts is found in interior of Eurasia, North America and in Patagonia (South America)
Characteristics of Arid Lands (hot deserts)
The major characteristics of arid lands (hot deserts) include the following:
Scarcity of water: rainfall in arid land is very low and it may occur in few occasions during a whole year and it is always below 25cm per anum.
Hot temperatures of desert:
the deserts temperature are usually very high especially during the day but very low at night.
Presence of sandy soils:
High sunshine: the sunshine in arid land is very high since there is little vegetation to shield it rays.
Predominance of strong winds:
strong winds are often associated with deserts since there is no vegetation cover to reduce the speed of winds.
the hot deserts have scanty vegetation. It has short and scanty grasses with little and scattered trees and shrubs.
Low relative humidity
the relative humidity of hot deserts is usually very low since the area is characterized by low rainfall, high temperature and scanty vegetation.
Presence of drought resistant plants:
the hot desert is characterized by the presence of drought resistant (xerophytic) plant species such as thorny bushes, bulbous cacti, dwarf acacias, and oleander.
Distribution of organisms (plant species) in arid lands or hot deserts
Plant species commonly found in hot deserts include: drought resistant plants like thorny bushes, bulbous cacti, scattered dwarf acacia, wiring grasses, date palm, baobab trees and euphorbia spp. Adaptive features of plants in arid lands Adaptive features of Cactus: cactus is a leafless plant with prickles or thorns to reduce transpiration. It also has thick succulent stem and side branches to store water for long drought. 2.Adaptive features of Acacia: this is a drought resistant plant, it has deep roots which absorb underground water deep down in the soil.
3. Adaptive features of Baobab tree: the leaves are waxy, hairy or needle-shaped to help reduce the rate of transpiration.
Adaptive features of Wiring grasses in the desert
it has narrow and slender leaves which helps to reduce the rate of transpiration in the plant. Adaptive features of Oleander: this plant has extremely deep roots which is able to absorb underground water deep down in the soil. distribution of organisms (animal species) in arid lands
Animals commonly found in arid lands
include: camel, rodents (e.g. rats), lizards, snakes, toads, zebras, desert tortoise, pocket mice, locusts, grasshoppers, ants, butterflies, moths and beetles.
Adaptive features of animals in arid lands
- Adaptive features of Camel in desert habitat: a camel can drink a lot of water to sustain itself for several days and hence can withstand a wide range of body temperature up to 40oC during the day. It can also walk for several days without drinking water. 2. Adaptive features of Kangaroo rat: this animal remains in burrow during the day to avoid excessive heat thereby cutting evaporation from its body.
3.Adaptive features of Lizards and snakes these animals have scales which limit the rate of water loss from their body.
4. Adaptive features of Locust: it has water-proof bodies and impervious cuticles. It also produces dry waste products, e.g. uric acid and guanine to enable it conserve water.
Adaptive features of Food chain in arid or desert land habitat
The food chain in arid land can be demonstrated by the following examples:
1. Plants==Desert rats==snakes
Factors affecting arid lands
The major abiotic factors affecting arid land are almost the same with that of grassland. These factors are temperature, rainfall, sunlight, wind, and low relative humidity.
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- how population market concept
Meaning: Capital formation or capital accumulation refers to increasing a country’s stock of real capital. That is, it refers to increasing the net investment in form of fixed assets.
For a country to be able to accumulate more capital, there must be increase in savings and a reduction in consumption of consumer goods. The rate of economic development of any country is directly related to the rate of capital formation. In most advanced countries like Britain, Japan and the United States of America, stocks of capital are high as a result of high rate of capital formation whereas in many developing countries of the world, there is a low rate of capital accumulation as a result of low per capita income and low savings, which results in what is termed vicious circle of poverty.
Causes of low capital formation in West African countries
The causes of low capital formation in West African countries include:
- Existence of a vicious circle of poverty: The existence of low income results in low savings and in turn results in a shortage of capital for investment, which results in low investment. Low investment leads to low, output, and eventually to low income. The low income result again to low savings and the vicious circle continues.
- Wasteful expenditure: Many governments in West African countries are involved in wasteful expenditure as they embark on prestigious but productive ventures thereby resulting low capital formation
- Inequitable distribution of income:In many West African countries, only individuals are rich while the poor. Even the few rich ones spend their money on prestigious projects which are on-productive and these generally give rise to low capital formation.