The Ecology Book

F

or centuries, scientists

in the Western world tried

to reconcile the findings

of geologists and fossil hunters

with literal interpretations of

biblical stories about Creation

and the Great Flood. In 1654, for

example, Archbishop Ussher dated

Earth’s creation to October 22,

4004 BCE. A series of discoveries

challenged this narrative and led

to new ideas about the dynamic

history of life on Earth.

Evidence in the rocks

Two Scottish geologists—James

Hutton and Charles Lyell—

advanced our understanding of

Earth’s age. In Theory of the Earth

(1795), Hutton argued that the

repeated cycles of sedimentation

and erosion necessary to create

thousands of feet of rock strata

must indicate a truly ancient origin

for the planet—an idea which Lyell

developed further in the 1830s.

Soon after, Swiss-American

geologist Louis Agassiz proposed

that the topography of some regions

had been shaped by glaciations.

Hutton and Lyell also noted that

fossils of animals and plants

vanished from the geological

record. Lyell believed this to be

evidence of extinction, challenging

the prevailing belief that species

were immutable.

Fossils also offered clues to

movements of Earth’s continents.

German meteorologist Alfred

Wegener noted that similar fossils

could be found on both sides of the

South Atlantic, even though they

were thousands of miles apart. In

his 1912 theory of continental drift,

Wegener cited this as evidence that

continents were once joined and

had broken away. It was not until

the 1960s that a viable mechanism

was found for such movement.

Geophysicists discovered patterns

of magnetic anomalies running in

parallel stripes on either side of

ocean ridges and identified the

process of seafloor spreading—hot

magma bubbling up through cracks

in the oceanic crust and forming

new crust as it cools and moves

away. This gradual process shifts

and shapes continents.

The birth of biogeography

In the Age of Exploration from the

16th century on, scientists began to

study the geographical distribution

of plants and animals. By the 1860s,

Alfred Russel Wallace viewed these

patterns, clearly defined by physical

barriers such as mountains and

INTRODUCTION

1840

Louis Agassiz shows that

an ice sheet once covered

Switzerland, and suggests

that an ice age occurred

in recent geological history.

1896

Svante Arrhenius is the

first to argue that carbon

dioxide emissions can lead

to global warming.

1869

The father of biogeography

Alfred Russel Wallace

reports a clear evolutionary

division in fauna species

on neighboring islands.

1912

Alfred Wegener presents his

theory that Earth was once

a single landmass from

which continents

drifted apart.

196

1926

Vladimir Vernadsky’s

book The Biosphere explains

how atmospheric gases are

created by biological

processes.

1935

Arthur Tansley coins the term

“ecosystem” to describe

an interdependent

community of biological and

nonbiological components.

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