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The Theory of Natural Selection
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In the 1800s, Charles Darwin, a British naturalist, developed the theory of natural selection in his book “On the Origin of Species by Means of Natural Selection”. Darwin had the opportunity to travel around the world as the naturalist on a British survey ship. Wherever Darwin visited, he saw a large number of different kinds of plants and animals and noted how well they were adapted to their particular situations.
He determined that there were several factors that could interact together to allow for natural selection:
1. Individuals within a species showed variation; some of the variations were very useful and others were not. For example, individual animals that are part of the same species show different colour variations. Some colours make the animal more conspicuous while others are less conspicuous.
2. Organisms within a species typically produce many more offspring than can survive. A pair of rabbits may have three to four litters of offspring each summer with several young in each litter.
3. Because of the excess number of individuals, there is a struggle for survival. Individuals within the population must compete with each other for food, space, mates, or other requirements that are in limited supply.
Great horned owls and other large owls typically produce two young at a time, but if food is in short supply, the larger of the two young will get the majority of the food.
4. Because of variation among individuals, some would have a greater chance of surviving and reproducing than others. The competition for resources often results in the less fit individuals dying; therefore, they do not get a chance to reproduce themselves. Even if they do not die, they may mature more slowly and not be able to reproduce as many times as the more fit members of the species.
5. As time passes and each generation is subjected to the same kind of process, there will be an increase in the percentage of individuals showing the favorable variations and a decrease in those having unfavorable variations. The species will become better adapted to its environment.
Задание 1. Найдите в тексте английские эквиваленты:
теория естественного отбора, происхождение, виды, растения, животные, адаптировать, определять, выращивать, кролики, помет, избыток, борьба за выживание (сохранение), популяция, пища, самец, потребности, созревать, окружающая среда.
Задание 2. Выпишите предложения, содержащие описание факторов, которые позволяют осуществлять естественный отбор.
Text 2
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History of Microbiology
Microbiology began with the development of the microscope in the 17th and 18th centuries. By 1680 the Dutch scientist Anthony van Leeuwenhoek had produced a simple hand-held device that allowed scientists to view a variety of microbes – which Leeuwenhoek called “animalcules” – in stagnant water and in scrapings from teeth.
In the late 1700s Edward Jenner conducted the first vaccinations, using cowpox virus to protect people against smallpox. Later an altered form of the rabies virus was used to protect against the dreadful disease rabies. Vaccines remain the major means of protection against most viral infections.
Modern microbiology had its origin in the work of the French scientist Louis Pasteur – considered the father of microbiology – who developed methods of culturing and identifying microbes. During the second half of the 19th century, he and his contemporary Robert Koch provided final proof of the germ theory of disease. Pasteur was the first to propose that microbes cause chemical changes as they grow. Koch derived a central principle of modern microbiology, known as Koch’s Postulate that determines whether a particular germ causes a given disease.
Pasteur and his contemporaries developed pure culture methods for the growth of microbes. Another great advance in pure culture methods came in the late 19th century, when microbiologists discovered that each kind of microbe preferred a certain medium for optimal growth. In 1929 Alexander Fleming observed that molds can produce a substance that prevents the growth of bacteria. His discovery, an antibiotic is called penicillin, was later isolated and produced commercially to protect people against the harmful effects of certain microorganisms and used for different therapeutic purposes. In the 1940s microbiology expanded into the fields of molecular biology and genetics. Scientists found that DNA (deoxyribonucleic acid) could be removed from living cells and spliced together in any combination. They were able to alter the genetic code dictating the entire structure and function of cells, tissues, and organs.
Задание 1. Найдите в тексте английские эквиваленты следующим словам и словосочетаниям:
микробиология, микроскоп, развитие, столетие, ученые, микробы, вакцинация, защищать, вирус, бешенство, вирусные инфекции, вторая половина 19 века, вызывать болезнь, рост микробов, функции клеток, ткани, определенная среда, антибиотик, различные виды пенициллина, биология, генетика, ДНК, кислота, изучать.
Задание 2. Согласитесь или не согласитесь со следующими утверждениями:
1. Microbiology began with the development of the microscope in the 15th and 16th centuries.
2. In the late 1800s Edward Jenner conducted the first vaccinations, using cowpox virus to protect people against smallpox.
3. The French scientist Louis Pasteur developed methods of culturing and identifying microbes.
4. During the second half of the 19th century, Pasteur and his contemporary Robert Koch provided final proof of the germ theory of disease.
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5. Today several kinds of penicillin are synthesized from various species of the mold Penicillium.
Text 3
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Animal Kingdom
All living things are divided into five kingdoms. Bacteria belong to the kingdom Monera, while the plantlike algae and animal-like protozoa are members of the Protista. The fungal kingdom includes molds, yeast, and mushrooms, and the kingdom Plantae includes all multicellular plants. The largest kingdom, however, is the Animalia. Its members range from very simple invertebrates, such as sponges, to highly complex mammals, such as whales, monkeys, and humans. Animals display some key differences that distinguish them from other living things. For example, what is the difference between a horse and grass? A horse moves around in the pasture eating grass. It trots toward you when you offer it a lump of sugar and shows pleasure when you stroke its head. The grass, however, is rooted to one place. It does not respond behaviorally to people or to the horse in any way.
Most animals move freely from place to place and can sense their surroundings; that is, they can taste, smell, hear, see, and touch. Certain simple animals, such as the corals and barnacles, spend most of their lives fastened to one spot, but they are able to swim freely when they are young. Even these rooted animals have parts that move in order to capture food. Plants, however, cannot shift around at their own will. They react to heat, light, chemicals, and touch, but their responses are involuntary and automatic, quite different from those of animals.
All living things are made up of cells of protoplasm. They may consist of a single cell, as does an amoeba, or billions of cells, as do trees and horses. The cell wall of a plant is composed of a woody material called cellulose. No true animal contains cellulose. Animal cells are bounded by a membrane composed chiefly of fat and protein.
Задание 1. Подтвердите или опровергните следующие утверждения:
1. All living things are divided into five kingdoms.
2. Bacteria belong to the kingdom Protista.
3. The kingdom Plantae includes all multicellular plants.
4. The largest kingdom is the Animalia.
5. All living things are made up of cells of protoplasm.
Задание 2. Ответьте на следующие вопросы:
1. How many kingdoms are all living things divided into?
2. What kingdom do bacteria belong?
3. What is the largest kingdom?
4. What are all living things made up of?
5. Are animal cells bounded by a membrane composed chiefly of fat and protein?
Text 4
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