Part IV

How do Ecosystems Work?

I. Read the text and render it:

In the biological world you are one of two things, either a producer or a consumer (Only rarely can you be both). Producers are the organisms that support the entire living world through photo synthesis. Plants, algae, and cyanobacteria are the key producers of energy – rich organic materials. They are also called autotrophs (from the Greek root “troph” – to feed, nourish), because they literally nourish themselves photosynthetically that is, by using sunlight and atmospheric carbon dioxide to make the food materials they need to survive. Consumers feed on plants and other organisms and are called heterotrophs, because they are nourished by consuming other organisms.

Consumer organisms that feed exclusively on plants are called herbivores. Cattle, deer, elk, and tomato hornworms are examples. Those consumers that feed exclusively on other animals, such as the mountain lion, are carnivores. Those consumers that feed on both plants and animals, such as humans, bears, and raccoons, are omnivores.

A series of organisms, each feeding on the preceding one, forms a food chain. Two basic types of food chains exist in nature: grazer and decomposer. Grazer food chains are so named because they start with plants and grazers organisms that feed on plants.

In the second type – the decomposer, or detritus, food chain organic waste material is the major food source.

Detritus is organic waste which comes from plants and animals and is consumed on two levels. In the grasslands of Africa, for instance, a wildebeest that dies of old age is consumed by vultures, hyenas, and the larval of various flies. These are called detritus feeders, or macroconsumers. The actual process of decomposition is carried out primarily by microscopic bacteria and fungi, known as microconsumers. All of these organisms, microscopic or not, derive energy and essential organic building blocks from detritus. In the process they liberate carbon dioxide, water, and other nutrients needed by plants to make more plant material and maintain the perpetual cycle.

II. Study the vocabulary:

1. a producer – поставщик, производитель

2. a consumer – потребитель

3. algaeplomalga– морская водоросль

4. cyanobacteria – цианобактерин

5. autotrophs – питающие сами себя

6. literally – буквально, дословно, точно

7. carbon dioxide – углекислый газ

8. heterotrophs – питающиеся за счет других

9. cattle – крупнорогатый скот

10. deer – олень

11. elk – лось

12. tomatohornuorms– рогатые червяки (улитки), живущие на

томатах

13. grazer – пасущиеся животные

14. decomposer – разлагающиеся организмы

15. organic waste material – органические отходы

16. wildebeest– южно-африк.: гну (животное)

17. vultures – гриф (птица)

18. hyenas – гиена

19. larvae, pl om larva – личинка

20. fungi,pl om fungus– гриб

21. liberate – выделять

22. perpetual cycle – вечный круг

III. Study the following definition:

1. herbivore,n – a plant – eating animal

2. racoon,n- a nocturnal North American animal having grayish

brown fur and a bushy tail with black rings

3. carnivore,n - a flesh – eating animal

4. omnivore,n - animals that eat both plants and animals

IV. Explain the difference between “producers” and “consumers”.

V. Give your own examples of herbivores, carnivores and omnivores. Discuss it with your groupmates.

VI. Find the passage describing detritus, translate it into Russian.