Text b. Water purification

Exercise 6. Before listening to the text answer the following questions:

1. Why does purification of drinking water present an urgent problem in many regions of the world?

2. What methods of water purification do you know?

Exercise 7. Explain the following terms which will be used in the text:

Transition metals Dissolved metals	Pollutant / contaminant Reactivity	Ferrates Ferric chloride
alacrity – быстрота, живость flocculating agent – осаждающее вещество, коагулянт to precipitate – 1) давать осадок, оседать; 2) провоцировать bleach – отбеливатель caustic soda – гидроксид натрия

Exercise 8. Listen to the text (Script 4) to check your answers in Exercise 7. Describe the new method of water purification developed by Luke Daly, the boss of Ferrate Treatment Technologies of Orlando, Florida.

Exercise 9. Listen to the text again and answer the questions:

1. What beneficial properties of ferrates were used?

2. How do ferrates purify water?

3. What obstacle did the researchers have to overcome?

4. How was it overcome?

5. How efficient is the Ferrator machine?

Unit 3. Fungi

Lexis: Mycology / Phytopathology / Ecology Listening: 2 texts

Text a. Plant communications

Exercise 1. What do you know about different types of ecological relationships – symbiosis, mutualism, parasitism, commensalism, amensalism. Describe each type in detail. Give examples of species which form such relationships.

Exercise 2. Listen to the text (Script 5) and describe how different plant species can communicate to warn each other of danger and predator intrusion.

alarm, alert – тревога, сигнал тревоги aphid – тля wasp – оса volatile compounds – летучие соединения stalk – стебель leaf blight – пятнистость листьев broad bean – кормовые бобы to ward off, to repel – отпугивать, отгонять mesh – ячейка сетки to infest – заражать to sever – отсекать, отрезать leguminous – бобовые культуры

Exercise 3. Put the words in brackets in the correct word form. Listen again to the first part of the text (Script 5.1) and check your answers.

The experiment which (1. suggest)____________ this was following up the (2. discover)____________, made in 2010 by a Chinese team, that when a tomato plant gets (3. infect)____________ with leaf blight, nearby plants start (4. activate)____________ genes that help ward the (5. infect)____________ off - even if all airflow between the plants in question has been (6. eliminate)____________. The (7. research)____________ who (8. conduct)____________ this study knew that soil fungi whose hyphae are symbiotic with tomatoes ((9. provide)____________ them with minerals in exchange for food) also form a network (10. connect)____________ one plant to another. They (11. speculate)____________, though they could not prove, that molecules (12. signal)____________ danger were passing through this (13. fungus)____________ network.

Dr Johnson knew from his own past work that when broad-bean plants (14. attack)_________ __________ by aphids they (15. respond)____________ with volatile chemicals that both irritate the parasites and attract aphid-hunting wasps. He did not know, though, whether the message could (16. spread)____________ tomato-like, from plant to plant. So he (17. set)____________ out to find out - and to do so in a way which would show if (18. fungus)____________ were the messengers.

Exercise 4. Listen again to the second part of the text (Script 5.2) and put the stages of the experiment in the correct order. Describe each stage in detail:

a. The central plant was infested with aphids.

b. The scientists tested the chemicals on wasps and aphids.

c. The scientists measured the amount of time.

d. The scientists set up eight "mesocosms".

e. The beanstalks grew for four months.

f. The beanstalks were covered with bags.

g. One mesh was rotated.

h. The scientists collected the air inside the bags.

i. The insects were placed in a two-chambered apparatus.

j. The beanstalks in each mesocosm were either surrounded by a mesh or left to grow freely.

Exercise 5. What do the following figures refer to in the text:

3 1/2 – 1 1/2 1 3/4 – 3 1/4 3 1/2

Exercise 6. Answer the questions using information from the text:

1. What experiments demonstrated that plants could communicate even without airflow?

2. How do plants spread the message of predator threat?

3. What strategies can plants employ to ward off predators?

4. How do plants and fungi benefit from the underground network?