 The desert ecosystem, first the contents, definition of desert ecosystem, climatic conditions in desert ecosystem, the soil conditions in desert ecosystems, and the plant life in the desert ecosystem. First the desert ecosystem. If we talk about desert ecosystem, basically it is a region which receives the annual precipitation less than 25 cm. If we define the desert ecosystem, we have an ecosystem in which the annual precipitation is less than 25 cm. Second important thing, the desert ecosystem has very extreme environmental conditions. The environmental conditions are extreme, the scarcity of water and the scarcity of vegetation. If the water is less, then ultimately vegetation is less. When vegetation is less, then ultimately the other forms of animal life will also be less. So, we get the most fluctuation in the temperature desert. So, if we talk about climatic conditions, then as we have dry rainfall, rainfall means that the environment is having total dry climatic conditions. As much as we have land biomes, if we start the earth cable from north, then we have the tundra ecosystem, then the coniferous forests, then the deciduous forests, then the grasslands, and then deserts. So, there is less rainfall in deserts. So, they are having the lowest rainfall. So, because of the lowest rainfall, ultimately the life there is also present in the scarcity. So, 25 cm per year is an average rainfall. But there are a lot of desert biomes in which for many years there is no rain, like Sahara Desert. In Sahara Desert, there is no rainfall for many years. Temperature fluctuation is very high in deserts. Like, at a day time, the temperature may cross 40 degree centigrade. The temperature usually crosses 40 degree centigrade. But at night, there is a cold. So, the temperature at night, if the day is 38 or 40 degree centigrade, then at night it will be about 4 degree centigrade. So, temperature fluctuation will be high. We do not get this much temperature fluctuation in any other biome. So, soil conditions. Desert ecosystem, if we look at soil, then normally the soil is very dry. If there is no water in it, then ultimately there is no moisture in the desert ecosystem. Desert soil, if there is no moisture in it, then ultimately it will be the dry land or dry soil. So, there will be low organic contents. Now, because the soil is dry, there is no vegetation on it. When there is no vegetation, then the same vegetation decomposes and increases the organic matter in the soil. So, the deserts are low in the organic content. Now, low organic content means that they are having low fertility. Their fertility is low. They do not need to support the plants. Desert soil is also having low water holding capacity. Usually, the soil that has more organic content has more water holding capacity. Now, because deserts have less organic content in the desert. If organic content is less, then water holding capacity is less. So, the more water is there, then it will go down from the soil. So, plant life. Now, because deserts have a high viscosity of water, so only those plants can grow in the deserts, which have adaptation to survive in low amount of water. Only those plants can survive in which water is less. So, normally, those plants that exist in deserts, they have certain adaptations. Their adaptations include, if you look at the adaptations, number one, they have reduced leaves. Their leaves are reduced. Either they are short, or they are reduced in size. Second one, they are having succulent stem. The water storage capacity in them is very high. If there is a rain in the year, that rain water will be stored in the stem. So, the stem is succulent, and the water storage capacity is very high. Stomata are very deep. Now, because plants, when they are transpired, the water will be lost. So, we have desert plants, they are having the deep stomata. Stomata are very deep, because of which the water loss is minimum. Similarly, they are having vexicutical. So, the cuticles on their leaves or stem are vexic. So, because of the vexicutical portion, when the water evaporates, the water will evaporate very little. So, due to these adaptations, the desert plants, they are able to survive in the extreme environment.