The Ecology Book

205

Over billions of years layers of

cyanobacteria have fossilized to form

stromatolites—mounds of sedimentary

rock, as seen here at Hamelin Pool,

Shark Bay, Western Australia.

See also: The ecosystem 134–137 ■ Biodiversity and ecosystem function 156–157

■ A holistic view of Earth 210–211 ■ The Gaia hypothesis 214–217

THE LIVING EARTH

and carbon dioxide result from

biological processes, such as the

respiration of plants and animals.

He argued that living organisms

reshape the planet as surely as

physical forces, such as waves,

wind, and rain. He also introduced

the idea of three stages of Earth’s

development: first, the birth of the

planet with the geosphere, in which

only inanimate matter existed;

secondly, the emergence of life in

the biosphere; and finally the epoch

in which human activity changed

the planet forever—the noosphere.

Sphere interactions

Scientists believe the biosphere

has constantly changed. Oxygen

levels in the atmosphere began

to rise at least 2.7 billion years

ago, as microorganisms called

cyanobacteria multiplied. As

oxygen increased, more complex

life forms evolved that would shape

Earth in different ways, eroding

and remolding its surface, and

changing its chemical composition.

Gradually, elements of the

biosphere became part of the

lithosphere. Over millennia, dead

corals created reefs in shallow

tropical oceans. Similarly, the calcite

skeletons of trillions of marine

organisms fell to the ocean floor,

fossilized, and formed limestone. ■

Vladimir Vernadsky

Born in 1863, Vladimir

Vernadsky graduated from

St. Petersburg State University

aged 22, and did postgraduate

work in Italy and Germany,

where he studied the optical,

elastic, magnetic, thermal,

and electrical properties of

crystals. After the revolution

in Russia in February 1917,

Vernadsky became assistant

Minister of Education in the

provisional government. The

following year, he founded the

Ukrainian Academy of Science

in Kiev. Although his book

The Biosphere was not taken

seriously by scientists outside

Russia for many years, it later

became one of the founding

documents of Gaia theory.

In the 1930s, Vernadsky

advocated the use of nuclear

power, and played an advisory

role in the development of the

Soviet atomic bomb project.

He died in 1945.

Key works

1924 Geochemistry

1926 The Biosphere

1943 “The Biosphere and

the Noosphere”

1944 “Problems of

Biochemistry”

I look forward with

great optimism.

We live in a transition

to the noosphere.

Vladimir Vernadsky

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