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DESERT...
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PLANT/WILDLIFE |
"It is concluded, that the few species of plants and animals that survive such a inhospitable weather are the experts in finding/storing food and water"
Deserts may seem empty of life, but amazing numbers of plants and creatures have adapted to live in this mostly waterless habitat. The main aims of both plants and animals are to find and conserve water and to avoid overheating, since many deserts have extremely high temperatures for most of the time.
PLANTS
Plants absorb carbon dioxide through tiny spores for survival. These pores are usually found in the leaves of the plant. These pores cannot be too big, or too much water will evaporate from the plant and cause the plant to wilt
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Thus some plants open their pores only at night when the temperature is low and the rate of evaporation is lower. Some plants save moisture by having few, small leaves. For example, the cactus has no leaves at all. It has a thick outer skin which preents water loss. Its pores are situated in shady spots to take advantage. It can store water under its thick leathery skin to protect the plant from harsh sunlight. However, it has a slow growth rate It takes about forty years to put out a branch and may live up to two hundred years. |
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Desert plants are able to find water. Some bushes have long roots (15m) to search water. Other plants like the creosote bush and some cacti have shallow but horizonally spread roots to absorb dews and brief showers quickly. The creosote bush can even survive a year without rain. Storing water in thick bulbous roots is also another survival technique. But
most desert plants stay dormant until it rains; which then spreads out
covering the desert floor. The plants germinate, grow leaves and flower,
completing their lfie cycle in a few days before scattering their seeds
and die. They then wait for the next time it rains when the cycle would
be repeated again.
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INSECTS, SPIDERS & SCORPIONS
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Most Insects survive by having hard shells or skins for protection against water loss and overheating. They tend to be active during the night and take shelter during the day. Some insects even get their water from the prey. Scorpions cope especially well because they are protected by a hard shell and also kill insects and spiders with a sting from their tails. They have no need to drink because they absorb all the water from their prey. |
REPTILES & AMPHIBIANS
| Most desert snakes are nocturnal. Lizards are most active during the cool times of the day. Their scaly skin has the ability to retain moisture, which is taken from the prey. The sidewinder snakes sithers sideways to travel against extremely hot sand, allowing only part of its body to touch the sand at any one time. Desert geckos posess either fringe-like hairs around their feet or webs between their toes so that they do not sink into the sand. |  |
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There is even an amphibian that survives in the desert. The spadefoot toad buries itself between rains and goes into a kind of hibernation called aestivation. The toad can survive for as long as nine months on it's fat reserves. When it hears the sound of the rain falling, it emerges and lays its eggs in pools of rainwater. |
Birds fly around to search for water. The sandgrouse can travel up to 50 km a day to fetch water for the young in the nest; it brings the water back soaked in its feathers like a sponge. The sandgrouse's nest is on the ground because there are few trees and bushes to use as nesting sites. Hawks, falcons and vultures are also found in deserts, hunting other birds and small mammals that provide them with water as well as food.
Because there is little shade, small mammals such as mice, gerbils, hamsters, desert kangaroo-rats and the North African hedgedog burrow to protect themselves from extreme temperatures. They stay underground during the day and come out to search for food. To reduce water loss they neither pant nor sweat and their urine is highly concentrated. Their fur helps insulate them against the heat. Some larger mammals also burrow.
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Few
huge mammals survive because of the scarcity of food and water, but several
kinds of gazelle and antelope manage to survive off scanty grass. Camels,
wild asses, kangaroos and wallabies are some of the other mammals that
survive in deserts
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