Ginkgo biloba is the last surviving species of Ginkgophyta. These long-lived plants evolved during the Permian period 250 million years ago. Ginkgo trees are called living fossils, because they strong resemble ancient remains preserved in the geologic record.
The popularity of ornamental ginkgo trees in Asia has led to their widespread cultivation.
Ginkgos can live for hundreds of years. Their height may be up to 30 meters and a trunk diameter up to 2 meters.
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Every living thing is made up of cells. The cell is the smallest unit with the basic properties of life. Bacteria and yeast consist of only one cell. Plants and animals have many billions of cells. Human beings are made up of more than 75 trillion cells. Only viruses – pathogens of some infectious diseases (for example, influenza, measles, smallpox) – are not cells and do not consist of cells. But they can multiply only in a living cell.
The cell was first discovered by the English physicist Robert Hooke in 1665. He designed microscopes, which gave 140 times increase. Once, examining the thin sections of the cork, he saw that the whole cork consisted of pores. These were the cells.
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The Andes are the tallest mountains in the Western Hemisphere. Mount Aconcagua in Argentina is the highest peak – 22,831 feet high. The mountains run 8,900 kilometers and are the longest mountain chain in the world. They separate a narrow strip of land along the west coast of South America from the rest of the continent. The Cordillera Oriental is the eastern mountain range, and the Cordillera Occidental is the western range.
The best-known people ever to live in the Andes were the Inca. Machu Picchu, remains of the magnificent Inca city, can still be seen in the mountains of Peru. The Europeans arrived in the mountains in the 1500s.
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The wolverine is a mammal of the weasel family. It can give off an unpleasant smell like its relative the skunk. The scientific name of the animal is Gulo gulo. The wolverines live mostly in the northern parts of North America, Europe, and Asia. It is very strong animal with big appetite.
The wolverine looks like a small bear. It ranges from about 66 to 91 centimeters in length and has a long, bushy tail. Its weight is from 9 to 30 kilograms. It has a thick neck and big claws. This nocturnal animal lives alone. It can travel up to 60 kilometers a day looking for food.
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Oaks are trees and shrubs of the beech family. There are about 450 species of oak. They are common in places with mild weather. Oak trees can grow to 45 meters high. Their leaves can have rounded, rough, or smooth edges. The fruit of an oak tree is the acorn – a round nut in a woody cup. The buds are usually in clusters, often with several about the same size, resulting in the numbers of large irregular branches that give most oaks their characteristic rugged crowns. The male flowers develop in the form of drooping catkins, with fewer females, on short stalks, erect above the males.
The roots are quite extensive, reaching out at least three times the height of the tree and down as deep as 4.6-12.2 m.
There are both evergreen (they have no synchronous leaf loss) and deciduous species.
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The term elk refers to different animals in different parts of the world. In Europe it is used for the mammal known in North America as the moose. The American elk is more properly named the wapiti. They live in Canada, Alaska, the Rocky Mountain region of the United States, and in the northern forests of Europe and Asia. They like to be near rivers, ponds, and lakes.
Moose are the largest animals in the deer family, weighing as much as 800 kg and standing as tall as about 2 m. They have a long and large head, long legs, a short neck and tail. They are good swimmers.
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Poplars are fast-growing trees. Aspens and cottonwoods are types of poplar. Poplars are closely related to willows and grow in many parts of North America, Europe, Asia, and North Africa. The center of origin of poplars is in China, in a subtropical climate.
Flowers develop pods filled with tiny seeds. These pods will open and the fluffy seeds will float to the ground. Leaves are oval, heart-shaped, or round.
Wood is used to make furniture, particle board, paper, match straw, dugout boats, artificial silk, packing material, container cardboard, building materials for building houses, essential oils, and tannins. People make violet paint from poplar buds and yellow from its leaves.
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