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Your Essential Assignments. 1. Which type of natural selection does artificial selection resemble?
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I. Quick check:
1. Which type of natural selection does artificial selection resemble?
2. What effect does: a) inbreeding; b) outbreeding have on the genetic diversity of a population?
3. Give two possible explanations of hybrid vigour in plants produced by a cross between two different strains of pure-breeding plants.
II. Fill in the missing words:
| Term (verb) | Noun | Adjective |
| suit | ....... | ....... |
| resist | ....... | ....... |
| interact | ....... | ....... |
| value | ....... | ....... |
| cultivate | ....... | ....... |
| desire | ....... | ....... |
III. Use monolingual English dictionary and write down what could the words given below mean:
breeding, desirable, seed, cultivation, stem, crop.
IV. Match these words with their definitions:
| decrease | A. | the seeds of crops | |
| modern | B. | living in natural state, not changed or controlled by humans | |
| famine | C. | the preparation and use of land for growing crops | |
| yield | D. | to go down to a lower level | |
| grain | E. | happening because someone has made it happen and not as a part of a natural process | |
| hybrid | F. | physical and mental energy | |
| 7. | domestic animal | G. | breeding between closely related individuals |
| 8. | wild | H. | time belonging to the present time |
| 9. | cultivation | I. | to plant seeds on a piece of ground |
| artificial | J. | to produce crops, profits | |
| vigour | K. | a thing, place activity, etc. that you get something from | |
| 12. | pollinate | L. | an animal or plant produced from parents of different breeds or types |
| 13. | inbreeding | M. | an animal lives on a farm or in someone’s home |
| 14. | sow | N. | no food for a long time and many people or animals die |
| 15. | source | O. | to make a flower or plant produce seeds by giving it pollen |
V. Find English equivalents to the following word combinations:
| № | Russian term | English equivalent |
| 1. | разводить животных и растения | |
| 2. | постепенное изменение в генотипе | |
| 3. | возделывание пшеницы | |
| 4. | процесс отборного размножения | |
| 5. | тесно связанные между собой особи | |
| 6. | сохранить желаемые характеристики | |
| 7. | опыляться естественным путем | |
| 8. | происходящий в гомозиготных условиях | |
| 9. | гибридная сила | |
| 10. | зависит от | |
| 11. | особые комбинации | |
| 12. | присутствуют в гомозиготных условиях | |
| 13. | дикие разновидности растений |
VI. Give Russian equivalents to the following English terms:
| № | English term | Russian equivalent |
| to produce specific desirable qualities | ||
| selective breeding | ||
| artificial selection | ||
| to sow seeds | ||
| pest resistance | ||
| genetically different plants | ||
| to be exposed to new diseases | ||
| have no resistance | ||
| to develop domestic and farm animals | ||
| genetically distinct strains | ||
| the mixing of alleles | ||
| the descendants of hybrids | ||
| to maintain sources of genetic diversity | ||
| future breeding programmes |
VII. Find synonyms among the pool of words:
| Pool of words | Synonyms |
| 1)1.harvest /2.stock /3.crop /4.yield /5.strain /6.breed | |
| 2) 1.seed /2.vigour /3.strength /4.grain | |
| 3)1.retain /2.sow /3.decrease /4.keep /5.plant /6. reduce | |
| 4) 1.distinct /2.diversity /3.different /4.variety |
VIII. Answer the following questions. Use all information given before:
1. How long have humans been breeding animals and plants selectively to produce specific desirable qualities?
2. What does selective breeding mean?
3. What type of natural selection is artificial selection similar to?
4. Describe how wheat cultivation began.
5. What does inbreeding involve?
6. Why is inbreeding carried out?
7. What does outbreeding involve?
8. How is the offspring from outbreeding called?
9. What is called hybrid vigour?
IX. Match the sentence halves. Make complete sentences:
| 1. | Artificial selection is therefore similar to directional selection, in that selection pressure brings about | A. | to try and retain the desirable characters in future generations. |
| 2. | In selective breeding, particular individuals are chosen and allowed | B. | closely related individuals which by chance, possess some desirable character. |
| 3. | Inbreeding involves breeding between | C. | crossing individuals from genetically distinct strains. |
| 4. | Inbreeding is carried out | D. | to breed, whereas others are prevented from breeding. |
| 5. | Outbreedinginvolves | E. | a gradual change in the genotype of a group of organisms. |
| 6. | If the parental stocks are pure breeding, | F. | the vigour decreases as the plant become more homozygous again. |
| 7. | If the descendants of F1 hybrids are continually inbred, | G. | on the availability of genetically distinct animals and plants. |
| 8. | Outbreeding depends | H. | the offspring are called F1 hybrids. |
X. Read and translate the short text without any dictionary:
Fact of life:
With the advent of genetic engineering. Artificial selection has entered a new phase. It is now possible to breed clones of cattle and sheep which have genes for producing specific human proteins. What is more, nuclei of two different species can be combined to form a completely new type of animal. In this way, a hybrid that combines the characters of a sheep and a goat has been formed: this new species has been dubbed a “geep” by the popular press. Plants can also genetically engineered to incorporate characters of a number of different species, for example, potatoes with a high starch content and high productivity can be genetically engineered to produce the beta-carotene of green vegetables and the vitamins of citrus fruits. One day it might be possible to design foods on a computer by choosing characteristics from a palette of tastes, colours, textures, and nutrients.
XI. Food for thought:
The dog is thought to have been the first domesticated animal. For at least 12 000 years, it has been subjected to artificial selection. Dogs have been bred to do specific types of work (for example, Labrador retrievers for retrieving fishing gear, Old English sheepdogs for rounding up sheep, and poodles for retrieving ducks) or for show. Suggest why pedigree dogs bred for show tend to have more genetic disorders than mongrels and cross-breeds (for example, highly inbred pedigree Labradors often have hip problems, St Bernards suffer eye problems, and Pekineses pften have respiratory problems).
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