An Ecosystem

VII. Read and translate the given text: a Brief Look at Chemistry

Chemistry is the study of molecules, atoms, and subatomic particles. A group of atoms of one kind makes a chemical element, and groups of chemical elements make chemical compounds. All matter is made up of chemical elements or compounds.

A chemical compound is a substance consisting of two or more elements chemically combined. Compounds have chemical formulas, which are a combination of the symbols for the elements in the compound.

Chemical elements have chemical symbols, and they appear in a chart called the periodic table. This chart is internationally understood; therefore, the symbol for a substance like oxygen will be represented by the letter О all over the world.

VIII. Answer the questions about the reading.

1. What does chemistry deal with?

2. What is the difference between a chemical element and the chemical compound?

3. What is all matter made of?

4. Letters of what alphabet are used for chemical symbols?

5. Who was the creator of the chart called the periodic table of elements?

6. What chemical elements do you know?

IX. Fill in the blank cells in the table using the periodic table of elements given on the next page:

Name of Chemical Compound	Chemical Formula	Elements
	H2O	hydrogen + oxygen
table salt		sodium + chlorine
methane	CH4
carbon dioxide
glucose sugar	C6H12O6
	SO2
nitrous oxide	N2O

10. Match each chemical element to its correct chemical symbol.

Chemical elements: Aluminum ______, Carbon _______, Chlorine _______, Copper _______, Fluorine _______, Hydrogen _______, Iron ______, Lead ______, Magnesium ______, Nitrogen _______, Oxygen ______, Phosphorous, _______, Potassium ______, Sodium ______, Sulfur ______, Zink ______.

Chemical symbols: O, K, Zn, Al, N, Na, Cl, C, Pb, Fe, Cu, S, P, Mg, H, F.

Energy and Matter

11. Read sentences 1 to 10. Fill in the blank with either the word energy or matter.

Energy is defined as the capacity to do some kind of work. Matter is the stuff that all things in this world are made of.

1. __________ is used for many purposes; for example, it is used to build shelters, to make food, and to keep our bodies alive.

2. These forms of ___________ are solids (wood, iron, granite), liquids (water, petroleum), and gases (oxygen, hydrogen).

3. In other words, __________ is needed to move something from one place to another or to change it from one form to another.

4. They can be changed and moved from place to place, yet __________ is neither created nor destroyed in the process.

5. _____________ is the stuff that all things in this world are made of.

6. The biggest source of for any ecosystem is the sun.

7. Everything on earth—animals, plants, rocks, soil, rivers, air—is composed of ___________.

8. _______________ has three basic forms.

9. ______________ is defined as the capacity to do some kind of work.

10. It cannot be recycled; therefore, the earth continuously receives and uses ___________ from the sun.

11. Arrange each of the following lists from general to specific. Write 1 for the most general, 2 for the choice in between, and 3 for the most specific.

1. Amazon ____, ecosystem ____, rainforest ____;

3. matter ____, liquid ____, water ____;

2. rosy periwinkle ____, plant ____, flower _____;

4. hydrosphere _____, biosphere ____, ocean ____.

XIII. In the accompanying short paragraph about physical factors, what sentence tells you the main idea of the paragraph? (The paragraphs in English usually begin with a general statement followed by specific details. The general statement at the beginning of each paragraph usually tells you the main idea of the paragraph. This sentence that states the main idea is called topic sentence.)

The physical factors of an ecosystem are important abiotic characteristics. These physical factors, sometimes called limiting factors, are different for every ecosystem and determine what living things will exist in that ecosystem.

Match the topic sentences to their correct paragraphs about limiting factors

a) Temperature can act as a limiting factor.

b) During the winter, some mammals become dormant, or hibernate.

c) Temperature may have a significant effect on the appearance of organisms.

d) Animals that maintain themselves at their optimum temperature are warm-blooded or homoeothermic.

1. __________ At this time, the body temperature (normally about 100°F) falls to 45°F or even lower. The heart beat of a ground squirrel drops from a summer average of over 200 beats per minute to an average of less than 20 beats per minute in the winter.

2. __________ For example, the distribution of the polar bear is limited to regions in which the temperature averages no higher than 32°F. On the other hand, the malarial parasite does not develop when the temperature goes below 77°F.

3. __________ In other words, the weather outside can change, but they will keep the same temperature. If this temperature regulator doesn't work, however, the animal will die. If a person is kept in cold weather for too long, the temperature of his/her body will fall. When a person's body temperature falls to 65°F, the heart will fail.

4. ____________ The Himalayan rabbit is mostly white but has black ears, tail, and feet. If the hair is taken from a white area, it will grow back white if the animal is kept at room temperature (68°F). However, if the animal is kept at a temperature below 50°F, the hair will grow black.

XIV. Now see if you can write your own topic sentences for these paragraphs about ecosystems.

1. ____________ For example, they both have long, cold winters. In addition, neither of these ecosystems has trees. The tundra has mostly low-lying plants, while the grassland has grasses.

2. ___________ The biotic component consists of all the living things in the ecosystem. The abiotic component consists of energy, matter, and physical factors. Physical factors include things like precipitation, wind, and soil. All of these elements help determine what occurs in a particular ecosystem.