My Science School

The sweet scent of flowers is designed to attract insects who seek food in the shape of pollen and the fragrant-smelling nectar. This nectar is a solution of sugars produced in little sacs called nectarines at the base of the flower petal.

     The insects have a part in the process of fertilization. Almost all plants perpetuate themselves by means of sexual reproduction, during which a male reproductive cell or sperm fuses with female reproductive cell or egg.

     When bees or other insects visit flowers in search of the sweet-smelling nectar, parts of their hairy bodies become dusted with pollen which contains the male reproductive cells. This rubs off on the flower’s carpels which contain the egg or ovule.

Insects seem to be strongly attracted by sweet scents. In fact, some flowers, such as the meadow sweet, are so highly scented that insects are attracted to them although they have no nectar to offer. Most insect-pollinated flowers have evolved wonderful devices for guiding the movements of that pollen is dusted over the insect’s body

Reindeer moss is a species of lichen so called because it is the staple winter food of reindeer (and caribou) in Arctic and Sub-Arctic regions. The animals reach the plant by scraping away the snow with their feet. But Plant growth in those cold northern lands is so slow that the lichen can take more than 30 years to recover after the reindeer have grazed. These domesticated herds therefore have to travel long distance in search of food, and the Laplanders of northern Scandinavia, who depend on the animals for their livelihood, must travel with them.

      Fortunately, reindeer moss is especially abundant in Lapland, although it also grows extensively in much of northern Europe, the tundra (or treeless plains) of Siberia and the barren expanses of Arctic America.

     During the short summer the reindeer are able to feed on herbage and shoots then accessible in the valleys. These versatile animals provide the Laplanders with meat, milk, cheese and the raw materials for clothing, shoes and tents. They are also a means of transport.

     Reindeer moss is sometimes eaten by human beings, after being powdered and mixed with other food. But it leaves a slightly burning sensation on the human palate. This bluish-grey plant grows erect in tufts, and is remarkable for its many branches, which, strangely, resemble a deer’s antlers.

 

 

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.

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.