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Text B. Modern Horses Have Many Origins

By Julia Karow

About 6000 years ago, somewhere in the Eurasian grassland steppe, man started to capture and tame wild horses--at least that's what remains from archaeological sites in Ukraine and Kazakhstan, tell scientists. Initially, people did not only use horses for transport, but also for food; at the time, dogs, cows, sheep and goats had already lived with humans for several thousand years. Now genetic evidence from modern and ancient horses, published in today's Science, completes the picture: the taming of horses did not occur in only one place, but in several, geographically distant locations.

Researchers from Sweden and the U.S. analyzed parts of the mitochondrial DNA of 191 domestic horses from ten different breeds, including the Icelandic Pony, the Arabian horse and the (American) Standardbred. They also included DNA sequences from 12,000 to 28,000-year-old horse bones found in Alaska and from 1,000 to 2,000-year-old horse remains from Northern Europe in the comparison. Mothers alone pass on mitochondria to their offspring, which is why the data represents only the maternal line. But the DNA samples from the modern horses differed so much from each other that they probably originated from several different groups of domesticated horses. And the genetic variation within each breed indicates that probably more female horses and only a few studs were used for breeding--a practice that continues today.

Rather than giving away domesticated horses, people in Eurasia probably taught each other techniques for capturing and keeping wild horses from their own area. That's why today's breeds still carry the genetic hallmarks of many different wild populations. (From Scientific American Online, January 19, 2001)

 

Exercise 5. Answer the following questions:

1. When was a wild horse population seen for the last time?

2. What methods were used to determine the time of horse domestication?

3. What genetic material was used in each study described in the texts?

4. When and where did domestication of horses start?

5. How was domestication of horses performed?

 

Exercise 6. Make up a list of the 10 key facts about studies of domestication. Agree on the final list of facts with the whole group.

Then summarize everything you now know about domestication of wild animals into one report.

 


Section 1. Recommended Report and Presentation Topics

 

 

1. Seizures: classifications, etiology, treatment.

2. Epilepsy.

3. Malignant tumours.

4. Unique abilities of the human body.

5. Unique abilities of the human brain.

6. Do fresh water and sea water animals drink?

7. What do marine organisms drink?

8. Why is water considered the most valuable resource of the future?

9. Water conservation.

10. Poisonous mushrooms.

11. Symbiotic partnerships inside the human body.

12. Do bacteria packed yoghurts really benefit our health?

13. Extreme bacterial habitats.

14. How did different breeds of domestic dogs originate?



15. Why were cats domesticated?


Section 2.

Unit 6. Brain

 

Iíll give you my opinion of the human race . . . Their heartís in the right place, but their head is a thoroughly inefficient organ.


Date: 2016-03-03; view: 117


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Text B. Gene Study Suggests Goats Got Around Through Early Human Commerce | Exercise 3. Now divide into pairs or small groups and read about each method. Then tell other students what you have read about. Try not to miss any detail.
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