Factors such as temperature, availability of light, water and minerals, soil type and drainage all affect the growth of plants and animals. In turn the living organisms affect their environment and each other. For example, many plants use animals to pollinate their flowers and disperse their fruits. The environment, the living organisms and the interactions between them form an ecosystem.
The basis of every ecosystem is the population of green plants, who trap the solar energy that powers the rest of the living community. Plants make their own organic material from water and minerals taken from he soil and carbon dioxide taking up from the atmosphere. This process is called photosynthesis. During it light energy is converted into chemical energy.
The plants provide herbivores (plant-eating animals) with food. Carnivores (flash-eating animals) feed on the herbivores and other carnivores feed on them. These different levels of feeding make up a food chain. Energy flows through the food chain with every part of this chain getting 10% less energy than the preceding part. This explains why there are fewer carnivores than herbivores. Some of this energy is lost during the metabolic processes of plants and animals. Animals also use energy in searching for food, in mating and other activities.
When a plant or an animal dies, worms, fungi and bacteria decompose them, returning the nutrients to the soil. These organisms are called decomposers and they the essential part of every ecosystem.
Here is an example of a food chain:
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solar energy energy lost energy lost
through natural through natural
processes processes
green plant herbivore carnivore decomposer
Wheat mouse fox worms
Ex.3. Answer the following questions:
1) How do latitude and climate affect wilderness types? 2)Which forests are called coniferous, deciduous, hard-leaved, rainforests? 3) How does precipitation affect wilderness areas? 4) What is a biom? 5) How many bioms are there on the Earth? 6) The wilderness isn’t static, is it? 7) What is the basic unit of diversity? 8) What factors affect the growth of plants and animals? 9) What forms an ecosystem? What is the basis of every ecosystem? 10)How does a food chain work? 11) Why are there fewer carnivores than herbivores?
Ex.4. Put down the following plants and animals into the columns of the table:
| plants | herbivores | carnivores | decomposers |
Grass, clover, oat, squirrel, nut, wheat, worn, whale, snake, shrimps, leaves, caterpillar, tit, algae, carrot, bacteria, fungi, pea, sparrow, rabbit, wolf, cow, cat
Ex.5. Make up food chains from the following components:
a. algae, man, fish
b. wolf, cabbage, rabbit, worms
c. snake, bacteria, grass, mouse
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