General characteristics & faunal adaptations in: Terrestrial (grassland and desert ecosystem).

 

General characteristics & faunal adaptations in:

Terrestrial (grassland and desert ecosystem).

Desert Ecosystem

Types and Characteristic Features:

·              One can find at least one desert on every continent except Europe and Antarc­tica. Each desert is different in some way, but they all have one thing in com­mon. In order for an area of land to be considered a desert, it must receive less than 10 inches of water a year.

·              How come deserts get such little water? Clouds are scarce in these regions, and we all know that without clouds, there can’t be rain, snow or any other precipi­tation. But clouds also serve another purpose – they block out some of the Sun. The desert gets mighty hot during the day because the Sun beats down on the sand. At night, the desert gets very cold, because there aren’t clouds around to keep the heat from escaping to the atmosphere.

·              There are plenty of differences between the deserts of the world. Some deserts are made of very fine, red sand, others consist of sand mixed with pebbles and rocks. The desert sand started out as rock, but years of weathering by wind and water has created dunes in the deserts. These sands are mostly minerals, and sometimes oil can be found hidden deep within the rocks.

Structure and Function:

The different components of a desert ecosystem are:

(A) Abiotic Component:

The abiotic component includes the nutrients present in the soil and the aerial environment. The characteristic feature of the abiotic component is lack of organic matter in the soil and scarcity of water.

(B) Biotic Component:

The various biotic components representing three functional groups are:

(a) Producer organisms:

The producers are mainly shrubs or bushes, some grasses and a few trees. Surprisingly, there are many species of plants that survive in the desert. Most of them are succulents, which mean they store water. Others have seeds that lay dormant until a rain awakens them. Regardless, these plants find a way to get water and protect themselves from the heat.

The most famous desert plant is the cactus. There are many species of cacti. The saguaro cactus is the tall, pole shaped cactus. The saguaro can grow up to 40 feet tall. It can hold several tons of water inside its soft tissue. Like all cacti, the saguaro has a thick, waxy layer that protects it from the Sun.

Other succulents include the desert rose and the living rock. This strange plant looks like a spiny rock. It’s disguise protects it from predators.

The welwitschia is a weird looking plant. It has two long leaves and a big root. This plant is actually a type of tree and it can live for thousands of years.

There are many other kinds of desert plants. Some of them have thorns others have beautiful flowers and deadly poisons. Even in the worst conditions, these plants continue to thrive.

(b) Consumers:

These include animals such as insects and reptiles. Besides them, some rodents, birds and some mammalian vertebrates are also found.

Desert Insects and Arachnids:

There are plenty of insects in the desert. One of the most common and destructive pests is the locust. A locust is a special type of grasshopper. They travel from place to place, eating all the vegetation they find. Locusts can destroy many crops in a single day.

Not all desert insects are bad, though. The yucca moth is very important to the yucca plant, because it carries pollen from the flower to the stigma. The darkling beetle has a hard, white, wing case that reflects the Sun’s energy. This allows the bug to look for food during the day.

There are also several species of ants in the desert. The harvester ants gather seeds and store them for use during the dry season. And the honey pot ants have a very weird habit. Some members of the colony eat large amounts of sugar, so much that their abdomens get too large for them to move. The rest of the colony feeds off this sugar.

There are also arachnids in the desert. Spiders are the most notable arachnids, but scorpions also belong in this group. Some species of scorpions have poison in their sharp tails. They sting their predators and their prey with the piercing tip.

Desert Reptiles:

Reptiles are some of the most interesting creatures of the desert. Reptiles can withstand the extreme temperatures because they can control their body tem­peratures very easily. You can put most of the desert reptiles into one of two categories: snakes and lizards.

Many species of rattlesnakes can be found in the desert. Rattlesnakes have a noisy rattle they use to warn enemies to stay away. If the predator isn’t careful, the rattlesnake will strike, injecting venom with its sharp fangs. Other desert snakes include the cobra, king snake and the hognose.

Lizards make up the second category of desert reptiles. They are probably the most bizarre looking animals in the desert. While some change colors and have sharp scales for defense, others change their appearance to look more threaten­ing.

One such creature is the frilled hazard. When enemies are near, the lizard opens its mouth, unveiling a wide frill. This makes the hazard look bigger and scarier. The shingle back has a tail with the same shape as its head. When a predator bites at the tail, the shingle back turns around and bites back. There are only two venomous lizards in the world, and one of them is the gila monster. It has a very painful bite.

 

Desert Birds:

Like the other inhabitants of the desert, birds come up with interesting ways to survive in the harsh climate. The sand grouse has special feathers that soak up water. It can then carry the water to its young trapped in the nest.

Other birds, like the gila woodpecker, depend on the giant saguaro as its home. This woodpecker hollows out a hole in the cactus for a nest. The cool, damp inside is safe for the babies.

The roadrunner is probably the most well known desert bird. Roadrunners are so named because they prefer to run rather than fly. Ostriches also prefer to use their feet. Even the young depend on walking to find food and water. The galah is one of the prettiest desert birds. It is one of the few species that return to the same nest year after year.

Desert Mammals:

There are several species of mammals in the desert. They range in size from a few inches to several feet in length. Like other desert wildlife, mammals have to find ways to stay cool and drink plenty of water. Many desert mammals are burrowers.

They dig holes in the ground and stay there during the hot days. They return to the surface at night to feed. Ham­sters, rats and their relatives are all burrowers. Not only do the burrows keep the animals cool, they are also a great place to store food.

Of course, not all animals have in holes in the ground. The kangaroo and spiny anteater both live in the Australian desert region. Spiny anteaters are unusual mammals because they lay eggs.

The desert is also full of wild horses, foxes and jackals, which are part of the canine family. And we can’t forget the cats. Lions are found all over the deserts of southern Africa. They get their water from the blood of their prey.

Camels – The Cars of the Desert:

Camels could be included in the mammal section. Camels are the cars of the desert. Without them, people would have great difficulty crossing the hot ter­rain.

There are two types of camels: Bactrian and dromedary. The main differ­ence between the two is the number of humps.

Dromedaries have one hump, and Bactrian have two.

Both kinds are used by people, but only Bactrian’s are found in the wild.