- •KAzan federal univeRsIty Essential English for Biology Students kazan
- •The Content
- •Init IV. Inheritance 67
- •Unit I. What is biology?
- •Text 1.1 The Characteristics Of Life
- •I. Quick check
- •III. Use monolingual English dictionary and write down what could
- •IV. Find English equivalents to the following word combinations:
- •VII. Answer the following questions. Use all information given before:
- •IX. Read and translate the short text without any dictionary:
- •X. Food for thought:
- •XI. Translate into English using all the active possible:
- •Text 1.2. What Do Biologists Do?
- •I. Quick check
- •II. Find synonyms among the pool of words:
- •IV. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Read and translate the short text without any dictionary.
- •IX. Food for thought.
- •X. Traslate into English using all the active possible
- •XI. Prepare a short presentation to answer the question:
- •XII. Write a letter to your tutor telling him or her which areas of Biology you would like to specialize in and why. Use these notes to help you.
- •XIII. Prepare a short presentation to answer the question:
- •Unit II. Сell
- •Text 2.1 Cell Theory
- •A typical animal cell
- •A typical plant cell
- •I. Quick check
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VI. Give Russian equivalents to the following English terms:
- •VII. Find synonyms among the pool of words:
- •VIII. Answer the following questions. Use all information given before:
- •X. Read and translate the short text without any dictionary:
- •Text 2.2. Introduction To Cell Division
- •Chromosomes form homologous pairs
- •I. Quick check:
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before.
- •X. Read and translate the short text without any dictionary:
- •Text 2.3. Microscopes
- •Magnification and resolution
- •The transmission electron microscope
- •The scanning electron microscope
- •I. Quick check
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before:
- •IX. Match the sentence halves. Make complete centences:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Unit III. Molecular biology of the gene
- •Text 3.1. Dna Structure
- •In summary
- •I. Quick check
- •II. Fill in the missing words:
- •III. Use a monolingual English dictionary and give the definitions of the words below:
- •IV. Find English equivalents to the following word combinations:
- •V. Suggest Russian equivalents for the following word combinations
- •VI. Fill in the gaps with the words and expressions from the text:
- •VII. Answer the following questions. Use all information given before.
- •VIII. Read and translate the short text without any dictionary:
- •IX. Food for thought:
- •X.Translate into English using all the active possible:
- •Text 3.2 Chromosomes
- •V. Answer the following questions. Use all information given before:
- •VI. Read and translate the short text without a dictionary:
- •VII. Food for thought:
- •VIII. Translate into English using all the active possible:
- •IX. Use a monolingual English dictionary and write down what could the words given below mean:
- •X. Read the text and render it in English:
- •XI. Prepare a short presentation reflecting the following issues:
- •Init IV. Inheritance
- •Text 4.1. Variation
- •I.Quick check
- •II. Using a monolingual English dictionary define the following genetic terms:
- •IV. Fill in the gaps with the words and expressions from the text:
- •V. Find English equivalents to the following word combinations:
- •VI. Answer the following questions. Use all information given before.
- •VII. Read and translate the short text without any dictionary:
- •VIII. Food for thought:
- •IX.Translate into English using all the active possible:
- •X. Meet essential targets reflecting the following issues:
- •Text 4.2. Down's Syndrome And Genetic Screening
- •Down's syndrome: trisomy 21
- •V. Fill in the gaps with the words and expressions from the text:
- •VII. Answer the following questions. Use all information given before.
- •VIII. Read and translate the short text without any dictionary:
- •X. Translate into English using all the active possible:
- •XI. Meet essential targets reflecting the following issues:
- •Unit V. Nervous and hormonal coordination
- •Text 5.1. Nerves And Hormones
- •I. Quick check
- •II. Using monolingual English dictionary write down what the words below mean:
- •V. Translate into English using all the active possible:
- •VI. Fill in the gaps with the words and expressions from the text:
- •VII. Answer the following questions. Use all information given before.
- •VIII. Find English equivalents to the following word combinations and make up sentences with them:
- •IX. Read and translate the short text without any dictionary
- •X. Food for thought.
- •XI. Prepare a short presentation on 2 or 3 glands reflecting the following issues:
- •Text 5.2. Setting up a nerve impulse
- •Investigating nerve impulses
- •Ion channels and action potentials
- •I. Quick check
- •II. Using monolingual English dictionary write down what the words below mean:
- •V. Answer the following questions. Use all information given before:
- •VI. Translate into English using all the active possible:
- •VIII. Read and translate the short text without any dictionary
- •I. Quick check:
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Text 6.2. Natural Selection
- •I. Quick check
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Text 6.3. Artificial Selection
- •I. Quick check:
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Text 6.4. Human Evolution: Primate Ancestors
- •I. Quick check:
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •IV. Match these words with their definitions:
- •V. Find English equivalents to the following word combinations:
- •VI. Give Russian equivalents to the following English terms:
- •VII. Find synonyms among the pool of words:
- •VIII. Answer the following questions. Use all information given before:
- •IX. Match the sentence halves. Make complete sentences:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Unit VII. Photosynthesis
- •Text 7.1. Photosynthesis: An Overview
- •I. Quick check:
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Text 7.2 Factors Affecting The Rate Of Photosynthesis
- •I. Quick check:
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Text 7.3. Photosynthesis In Different Climates
- •I. Quick check
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Answer the following questions. Use all information given before:
- •X. Read and translate the short text without any dictionary:
- •XI. Food for thought:
- •Unit VIII. Structure and transport in plants
- •Text 8.1 The Leaf
- •I. Quick check
- •II. Use monolingual English dictionary and write down what could the words given below mean:
- •VIII. Match the sentence halves. Make complete sentences.
- •IX. Answer the following questions. Use all information given before.
- •X. Read and translate the short text without any dictionary.
- •XI. Food for thought
- •XII. Translate into English using all the active possible.
- •Text 8.2. The Stem
- •I. Quick check
- •III. Use monolingual English dictionary and write down what could the words given below mean:
- •IV. Find English equivalents to the following word combinations:
- •VII. Answer the following questions. Use all information given before:
- •IX. Read and translate the short text without any dictionary:
- •X. Food for thought:
- •XI. Translate into English using all the active possible.
- •Supplementary reading Texts for Reading, Retelling and Discussing
- •Extract from a lecture about immunization
- •Quick check:
- •Griffith's experiment: transformation of pneumococci.
- •Quick check:
- •Quick check:
- •Quick check:
- •Suggested Answers and Solutions
- •Glossary of Biological Terms
- •Appendices
- •Book Presentation (Useful Language)
- •Phrases to Be Used in Discussion
- •References – Список использованной литературы
- •Web – Resources and Support Web links to some useful and helpful resources:
Text 6.2. Natural Selection
■ Essential targets:
By the end of this text you should be able to:
explain what is meant by “ survival of the fittest”;
distinguish between directional selection, stabilising selection, disruptive selection.
Pre-reading
■ With a partner consider the following questions and try to answer them. Then scan the text to check your answers.
1. What is natural selection?
2. What environmental factors effect on surviving and producing offspring?
■ Read the given text and make your essential assignments:
Survival of the fittest
Darwin had the idea that natural selection is the mechanism that drives evolution after reading An Essay on the Principal of Population by Thomas Malthus, a clergyman and political economist. Malthus argued that, in time, the growth of human populations will outstrip the food supply, and that this will lead to “famine, pestilence, and war”. Darwin applied this idea to populations of other animals and of plants. In his book on the origin of species, Darwin wrote: “There is no exception to the rule that every organic being naturally increases at so high a rate that if not destroyed, the Earth would soon be covered by the progeny of a single pair”. In spite of reproducing quickly, no single species has completely over-run the planet, although the populations of some species may be increasing at any one particular time. Darwin concluded that populations are kept in check by a “struggle for existence” as they compete for limited resources and are exposed to disease. Environmental factors that keep populations in check are called selection pressures or environmental resistances. These include:
disease
competition for resources such as food and a place in which to live
predation
lack of light, water, or oxygen
changes in temperature.
Those organisms best suited to the environmental conditions, with
characteristics that give them an advantage in the “struggle for existence”, will have the best chance of surviving and producing offspring. Their high natality (birth rate) gives them a selective advantage. On the other hand, those will unfavourable characteristics are more likely to die. Their high mortality (death rate) gives them a selective disadvantage. Darwin argued that this difference in natality and mortality results in natural selection. As environmental conditions change certain characteristics within a randomly varying population are favoured, and natural selection occurs. This has become known as the “survival of the fittest”.
In evolution, fitness is defined as the ability of an organism to pass on its alleles to subsequent generations, compared with other individuals of the same species. The “fittest” individual in a population is the one that produces the largest number of offspring that survive to reproduce themselves. Natural selection by “survival of the fittest” means that the genetic characteristics of a population gradually change from generation to generation in response to changes in the environment. As we shall see in the following spreads, natural selection affects a gene pool by increasing the frequency of alleles that give an advantage, and reducing the frequency of alleles that give a disadvantage. (A gene pool is all the genes and their different alleles present in an interbreeding population.)
Three types of natural selection
Natural selection is not always a mechanism for change. There three
different types: stabilising selection, directional selection, and
disruptive selection. These are three different ways in which
natural selection acts on the phenotypes in a population (the
observable characteristics such as colour or height). Typically, the
frequency in the population of each phenotype has a normal
distribution, described by a bell-shaped curve.
Stabilising selection happens in an unchanging environment. Extremes of the phenotype range are selected against, leading to a reduction in variation (more individuals tend to conform to the mean). Stabilising selection occurs in the natural selection of birth mass in humans.
Directional selection favours one extreme of the phenotype range and results in a shift of the mean either to the right or to the left. This type of selection usually follows some kind of environmental change. The long neck of the giraffe is thought to have evolved in this way. Probably, when food was in short supply, only the tallest individuals could reach enough food to survive. They passed on their genes to the next generation.
Disruptive selection selects against intermediate phenotypes and favours those at the extremes. This leads to a bimodal distribution (the distribution curve has two peaks or modes) and two overlapping groups of phenotypes. If the two groups become unable to interbreed, then each population may give rise to a new species. Disruptive selection may have contributed to the evolution of Darwin’s finches. Because there were few other birds to compete, finches with short strong beaks had exclusive use of nuts as a food source, while those with long slender beaks had almost exclusive use of insects. Those finches with an average, unspecialised beak were more likely to have been in completion with other species of bird and would have reproduced less successfully.
■ Glossary of essential terms for you to know
№ |
English term |
Russian equivalent |
1 |
natural |
естественный |
2 |
selection |
отбор |
3 |
growth |
Рост |
4 famine |
голод |
|
5 |
pestilence |
Чума |
6 |
progeny |
потомство |
7 |
origin |
происхождение |
8 |
to increase |
увеличиваться |
9 |
disease |
болезнь |
10 |
lack of sth |
недостаток ч.-л. |
11 |
condition |
условие |
12 |
to suit |
подходить |
13 |
natality |
рождаемость |
14 |
mortality |
смертность |
15 favourable |
благоприятный |
|
16 |
fitness |
приспособленность |
17 |
frequency |
частота |
18 |
disruptive |
разрушительный |
19 |
curve |
изгиб |
20 |
either….or |
Или…..или, либо……либо |
21 |
in response to |
в ответ на …… |
22 |
to occur |
происходить |
23 |
to give rise to давать начало чему-либо |
|
24 |
finch |
зяблик |
25 |
beak |
Клюв |
26 |
insect |
насекомое |
■ Your Essential Assignments