Category Zoology

When do bees swarm?

             Bees swarm in late spring in search of new home. During the winter the queen bee begins to lay her eggs and the colony sets about rearing its young. As the weather becomes warmer and the early flowers appear, the raising of young bees increases rapidly.

              By the end of spring the colony has become so overcrowded that a large number of the bees, including the old queen, leave the hive and establish a new queen emerges who will experience the same swarming instincts the following year. And so the cycle of activity goes on.

How do frogs breathe under water?

               Under water, frogs breathe through their skins. A frog is an amphibian. That is o say it lives both on land and in water. It has lungs, but it has no ribs and therefore cannot expand its chest and suck air into its lungs as do reptiles, birds and mammals. On land air is drawn in and out of the frog’s nostrils, which have valves in them, by pulsations of the floor of the mouth. The air is forced in and out of the lungs by contraction of the throat and body muscles. A frog’s mouth is always kept tightly closed and the   pulsations of throat vary from 120-140 a minute.

               Even on land the skin plays a greater part in breathing than the lungs. However, air can be absorbed only through a moist skin. If the skin becomes too dry, the frog will die. Therefore the skin contains glands which secrete a clear mucus or smile whose function is to keep the skin moist and supple. The skin absorbs water as well air, for frogs do not drink.

                Frogs are cold-blooded. That means they are as warm or as cold as the air or water surrounding them. In winter they hibernate under water, where their body temperature fails, their bodily functions are kept at a minimum and breathing is carried on entirely through the skin.

When is a butterfly formed?

            A caterpillar starts to become a butterfly as soon as it enters the chrysalis stage, by wrapping itself in cocoon. During this phase, known as pupation, the insect gradually develop all the butterfly characteristics, including wings. For some butterflies the transformation may be completed in one or two weeks. But others need many months before they are ready to leave the cocoon and     fly away.

            From the time it is hatched to the time it starts the pupation stage, a caterpillar or larva does little more than eat, grow larger and moult several times. This larval stage varies according to the species. Small caterpillars will complete their development in a week but some large varieties will take us two years or more.

            When this period is over the caterpillars spins a cocoon under a leaf or even underground, and enters it to begin the transformation. Many cocoons are of silk.

Where was the first Zoo?

 

 

The first zoo was formed in China in the 12th century B.C. But it was not called a zoo. When, the ancient Chinese king who started it, wanted to collect different types of animals from all over his empire. He kept them in what he called a “garden of intelligence”, near his palace.

      Some of the largest zoos are in North America. There are big ones in the Bronx, New York City, and in Washington and San Diego.

When do birds migrate?

Million of birds of many different varieties migrate at the end of summer. With unfailing regularity they leave the regions where they were born to fly to warmer climates for the winter. The following springs they return to their breeding grounds.

       Each year these migratory birds travel as much as 20,000 miles, finding their day back on time with extraordinary precision. Some travel as individuals.

     Migration is triggered off by the length of daylight, which apparently affects the birds’ nervous systems. When the days get shorter the birds receive the signal to leave for their warmer winter grounds, and, when the daylight increases to a certain level, they receive another signal to return home.

Fossils

 

What are fossils?

Fossils are the traces of ancient animals and plants found buried in rock. Sometimes a fossil retains the shape and structure of the hard parts of an animal, such as fossilized dinosaur bones. These are not the original bones, because minerals have replaced them over millions of years, but they have the same shape. Other fossils are just the impression of an animal or plant, created when the plant or animal was buried in mud that has gradually solidified into rock. Even footprints of animals such as dinosaurs have been preserved. 

Picture credit: google

 
 

 

 

How old are fossils?

Ancient history has been divided up into eras, which are periods of time identified by the fossilized forms of life from that period. The oldest era, called the Palaeozoic, contains fossils ranging from many primitive life forms up to some of the earliest land-dwelling animals. During this era, fishes, amphibians and early reptiles appeared. The Mesozoic era was the age of giant reptiles, when dinosaurs stalked the world. The Cenozoic era in which we still live is the age of mammals and birds. All fossils can be placed in these eras, which are subdivided further into smaller periods.

Picture credit: google