Covering, appeared, change, combining, accidentally, life, delicate, emerged, circle

1) The biosphere is the part of Earth's outer shell.

2) The idea of biosphere originated rather casually more than a century ago.

3) The biosphere is the global ecological system integrating all living beings and their relationships.

4) Over nine-tenths of the total biomass on Earth is plants, on which animals depend very heavily for their existence.

5) The number of individual species is constantly in some degree of flux.

6) Part of the biosphere containing the highest concentration of living matter is the Earth’s thin and fragile “film of life”.

7) The biosphere is a complex system of energy use and material cycling.

8) The idea of biosphere originated rather casually more than a century ago.

9) Life is thought to have occurred about 3.9 to 3.5 billion years ago.

5. Finish the sentences using the text.

1) The biosphere is the part of Earth's outer shell …

2) From the broadest geophysiological point of view, the biosphere is …

3) Currently the entire Earth contains …

4) Over nine-tenths of the total biomass on Earth is …

5) More than 2 million species of …

6) The number of individual species is constantly …

7) The total number of species is presently …

8) Biosphere is a relatively thin life-supporting layer around the Earth …

9) Part of the biosphere containing the highest concentration of living matter …

10) The biosphere is a complex system of …

11) We can divide the biosphere into …

12) The biotic part of the biosphere consisting of fauna and flora …

13) The idea of biosphere originated rather casually …