Life in Desert: Climate and Geology,Ecosystem And Cultures
Desert regions, which represent one-fifth of the land area of the world, may seem to the casual observer to be barren, lifeless places; however, many deserts thrive with an abundance of fascinating plant-life, animals both large and small and even human cultures. Covering the diverse range of life and conditions of desert climates can be difficult in a single lesson, making a smaller themed series of lessons helpful.
Climate and Geology of the Desert :
The defining aspect of a desert climate is low annual rainfall, to the point where vegetation is sparse or nonexistent. Deserts are also typified by extreme variation in temperature, ranging from the sweltering heat in the daytime to near freezing temperatures at night in some regions. One of the best examples of such a widely varying temperature desert is the Gobi Desert of Mongolia, which, while hot during the summer, experiences the same bitter winters as the surrounding regions of Asia. One of the main geological conditions that create deserts is the rain shadow effect created in the lee of large mountain ranges, where the downwind area receives very little precipitation.
Wind erosion is usually rampant in desert areas due to the lack of plant life, leading to a depletion of arable soil and the buildup of massive sand dunes, which are basically just heaps of eroded rock particles. Deserts often have unusual hydrological features that cause what rainfall there is to drain into concentrated landlocked basins, which may become an oasis if the amount of water is large enough to remain year-round. The highly active erosion processes of the desert also give rise to geological features such as hoodoos and canyons, created by the erosion of softer rock from around a more robust stone, leading to a protrusion. Due to the fact that the soil conditions of most desert climates prevent absorption, flash flooding is not unheard of during the few periods of rain that the desert actually experiences.
Desert Ecosystem :
The Ecosystem of the desert typically has a lower biomass per square acre than other regions; however, despite the barren appearance of the desert, there are actually a number of unique plants and animals that thrive under difficult conditions of desert life. Perhaps the most archetypal image of a desert plant is the hearty cactus, which through its unique evolutionary adaptations retains enough moisture to survive long stints without any rain, flowering briefly once a year or sometimes at even longer intervals. The animals of the desert are also worth exploration, including species such as scorpions, snakes, vultures and a host of small to medium desert mammals that manage to survive the adverse conditions. For example, some species of desert cats can survive nearly exclusively on the liquid ingested when devouring their prey, which themselves go for long periods of time without drinking from a source of water directly.
Cultures of the Desert Lesson Ideas:
The human cultures of the deep desert, such as the Bedouin Arabs, make for an interesting lecture topic. The Bedouins are a migratory desert people that move from one oasis to another, living off the land in a simple but sustainable tribal lifestyle. Some of their Arab cousins also set up permanent settlements around these oases. The most notable cultures of the deep desert is that of the ancient Egyptian civilization.
The ancient Egyptians took advantage of the inundation cycle of the River Nile, allowing them to form an unusual agrarian society while in the midst of an otherwise barren desert. Unfortunately, in the modern era, the River Nile has been dammed, making the famous inundation cycle a thing of the past. Among the great accomplishments of the ancient Egyptian civilization is the advancement of modern medicine, the invention of electroplating – for coating other metals in a thin layer of gold – and amazing feats of engineering.