Category Biology

Why yews are often found in churchyards?

     Yews have long been associated with religious worship. So it is likely that churches were originally built near the sacred trees rather than the other way round.

     These trees live longer than any other species in Europe and can grow to an enormous size. Many are thought to be well over 1,000years old. Yews were revered by the druids of ancient Britain, France and Irelands and no doubt early Christian missionaries preached in the shelter of the trees before their first churches were built. Hywel Dda Howell the Good a Welsh king, who reigned in the 10th century, set a special value on “consecrated yews”.

   Some yews are even older than the ancient churches beside them, suggesting that the church was built on a spot already devoted to worship. The association continued, and it became traditional for yews to be planted in church yards.

    Also the great age to which yews live caused them to be regarded as a symbol of immortality and, therefore, associated with death, as man only becomes immortal after he dies.

What is a salamander?

A salamander is amphibian-an animal that lives both on land and in the water. It is a lizard like member of a group of back-boned creatures between fish and reptiles. This class includes frogs and toads. Like fish and reptiles, the salamander is cold-blooded.

      It was anciently believed that the first salamander was born out of the court of a fire and that the so called fire salamanders were unaffected by heart. In fact, the salamander is active usually only in the cool of the night, when it hunts worms, slugs and insects.

     The salamander, which grows up to about 11 inches long, is attacked by few enemies, as its skin glands are poisonous. But the European water snake is not affected by the venom and frequently asked the salamander its prey.

Where do flies go in the winter?

   

 

    During winter flies will hibernate sometimes in large groups, in any available dry and warm space such as an attic.

     The reason there are so few houseflies in winter is that their eggs will hatch only at temperatures between 240 centigrade and 350 centigrade (750 Fahrenheit and 950 Fahrenheit). Meanwhile their numbers steadily diminish owing to insecticides and natural causes. This is a good thing since flies often carry diseases.

When does a hermit crab change its shell?

      A hermit crab changes its shell when it has grown large enough to need a bigger home. This type of crab has a soft abdomen or “tail”, which is folded up under the body, but it is not protected by a shell of its own as are most other crabs. Instead, the hermit uses empty snail shells as portable shelters, often having to fight with another crab for possession of an attractive home. Sometimes the home seeker pulls out of the original occupier, eats it and then takes over the shell.

    One of the claws of the hermit is larger than the other. The crab uses this to stop up the entrance after withdrawing into the shell. The last two legs on its abdomen have roughened pads which grip the inside of the shell and hold the body in position. The crab has a spiral-shaped abdomen and moves in and out of its shell with a spiral movement.

    One kind of hermit occupies a sponge which conveniently grows at the same pace as the crab. Sometimes sea-anemones enter into partnership with hermit crabs and take up residence on top of the shells. The crab provides the sea-anemone with transport and in return, receives an extra shield against attack.

Why so we have a dawn chorus?

          The song of the birds at dawn has given pleasure to millions of people and has been celebrated in poetry and prose for many years. The most usual explanation given in the Middle Ages was that the birds sang each day in praise of God and the beauty with which he had clothed the world. More recently, there was the feeling that the birds sang joyously to welcome the rising of the sun, which meant food, warmth and activity.

          However, scientists now think that the dawn chorus is made up of the warning signals of each bird as he re-establishes his territory for courtship, nesting and food getting is the first step in the breeding cycle and the area is defended against competing birds of the same species by a warning song, although seldom by actual fighting. A robin, incidentally, has a particularly strong sense of territory.

Why do some elephants have very large ears?

          African elephants have larger ears than Indian, or Asiatic, elephants because they live in hotter conditions and are bigger and more aggressive and active. The huge ears of the African elephant, sometimes three and a half feet wide, enable it to hear more acutely. When the animal charges it fans out it ears, augmenting its terrible appearance and striking fear into the heart of ay enemy.

        The ears also present a large surface for losing body-heat. Africa can elephants, which are at a disadvantage in the heat because of their large size, wave their ears to keep cool and to chase away flies. The African elephant is the biggest and noblest of land animals, reaching a height of 11 feet and a weight of nearly six tons.

        The Asiatic elephant is smaller. It inhabits the forests of South-east Asia from India to Ceylon and Borneo. It does not like heat and seeks the deep shade of the forest.