I. Quick check. 1. What is meant by fitness in evolutionary terms?
1. What is meant by fitness in evolutionary terms?
2. Some individuals of the European swallowtail butterfly (Papilio machaon) pupate on brown stems or leaves; others pupate on green stems or leaves. Two distinct colour forms of the pupae are found, namely brown and green, with very few intermediates.
a. What type of natural selection does this example show?
b. Explain why the intermediate colour forms would be at a selective disadvantage?
II. Fill in the missing words:
| Term (verb) | Noun | Adjective |
| argue | ....... | ....... |
| occur | ....... | ....... |
| increase | ....... | ....... |
| compete | ....... | ....... |
| expose | ....... | ....... |
| survive | ....... | ....... |
| distribute | ....... | ....... |
| describe | ….. | …… |
III. Use monolingual English dictionary and write down what could the words given below mean:
species, existence, selection, environment, to occur, gene.
IV. Match these words with their definitions:
| outstrip | A. | a group of closely related organisms | |
| origin | B. | a living creature such as a dog or cat | |
| disease | C. | becoming firm, steady or unchanging | |
| selection | D. | the situation, place, or physical matter from which something begins | |
| species | E. | birth rate | |
| plant | F. | prevents something from continuing in its usual way and causes trouble | |
| 7. | animal | G. | an illness or unhealthy condition in your body |
| 8. | favourable | H. | to be greater in quantity than something else |
| 9. | natality | I. | an animal’s baby or babies |
| directional | J. | a small part of the material inside the nucleus of a cell | |
| stabilising | K. | a living thing that has leaves and roots and grows in earth | |
| 12. | disruptive | L. | to do something that produces an effect or change in someone or something |
| 13. | gene | M. | the careful choice of a particular person or thing from among a group of similar people or things |
| 14. | offspring | N. | suitable and likely to make something happen or succeed |
| 15. | affect | O. | pointing in a particular direction |
V. Find English equivalents to the following word combinations:
| № | Russian term | English equivalent |
| запасы еды | ||
| применить к ….. | ||
| происхождение видов | ||
| несмотря на | ||
| ограниченные ресурсы | ||
| факторы окружающей среды | ||
| недостаток света, воды, кислорода | ||
| высокая рождаемость | ||
| высокая смертность | ||
| приводит к естественному отбору | ||
| способность организма | ||
| генетические характеристики | ||
| в ответ на изменения в окружающей среде | ||
| давать начало новому виду | ||
| короткие сильные клювы |
VI. Give Russian equivalents to the following English terms:
| № | English term | Russian equivalent | |
| to over-run the planet | |||
| struggle for existence | |||
| selection pressures | |||
| environmental resistances | |||
| to expose to disease | |||
| changes in temperature | |||
| best suited to the environmental conditions | |||
| to give an advantage in … | |||
| the best chance of surviving and producing offspring | |||
| selective disadvantage | |||
| survival of the fittest | |||
| compared with other individuals | |||
| gradually change from generation to generation | |||
| to act on the phenotypes in a population | |||
| to become unable to interbreed |
VII. Find synonyms among the pool of words:
| Pool of words | Synonyms |
| 1)1.offspring /2.struggle /3.change /4.progeny /5.battle / 6. alteration | |
| 2)1.gradually /2.surroundings /3. steadily /4.environment | |
| 3)1.population/ 2.resource/ 3.reduction/ 4.inhabitants/ 5.supply/ 6.decrease | |
| 4)1.quickly/ 2.survive/ 3.superiority/ 4.fast/ 5.advantage/ 6.remain alive |
VIII. Answer the following questions. Use all information given before:
1. What might lead to famine, pestilence and war?
2. What is called selection pressures?
3. What environmental factors do selection pressures include?
4. What organisms will have the best chance of surviving and producing their offspring?
5. Why does the difference in natality and mortality result in natural selection?
6. What is meant by “survival of the fittest”?
7. How is fitness defined in evolution?
8. What are three types of natural selection?
9. What is the difference between them?
IX. Match the sentence halves. Make complete sentences:
| 1. | Those organisms best suited to the environmental conditions, with characteristics that give them an advantage in the “struggle for existence”, | A. | although the populations of some species may be increasing at any one particular time. |
| 2. | Environmental factors that keep populations in check | B. | results in natural selection. |
| 3. | Darwin argued that this difference in natality and mortality | C. | from generation to generation in response to changes in the environment. |
| 4. | In spite of reproducing quickly, no single species has completely over-run the planet, | D. | will have the best chance of surviving and producing offspring. |
| 5. | The “fittest” individual in a population is the one that produces | E. | in an unchanging environment. |
| 6. | Stabilising selection occurs | F. | are called selection pressures. |
| 7. | Natural selection by “survival of the fittest” means that the genetic characteristics of a population gradually change | G. | the largest number of offspring that survive to reproduce themselves. |
| 8. | Stabilising selectionhappens | H. | in the natural selection of birth mass in humans. |
X. Read and translate the short text without any dictionary:
Fact of life:
You may think that natural selection results in change and diversification. This is not always the case. For example, natural selection helps to keep the average birth mass for human babies around 3.3 kg. Not surprisingly, extremely small or large babies have low rates of survival under natural conditions.
XI. Food for thought:
The extinction of animal and plants species is of great concern today because it is accelerated by direct and indirect results of human activities. However, extinction is a natural process that has occurred since the dawn of life. The 20-30 million species that inhabit the Earth today represent only a minute proportion of all species that have ever existed. Suggest why more than 99.9 per cent of all species that ever evolved have become extinct by natural processes. Explain why the highest rates of extinction in recent times have occurred among species that live only on small oceanic islands.
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