History of Biogeography
Biogeography can be traced (like most every other
discipline) to Aristotle….
In the 3rd Century B.C.,
he suggested a view of
a dynamic earth to help
explain variation in life
over space and time.
The development of
biogeography is linked
to the development of
evolutionary biology
and ecology. The
growth of these
disciplines, in turn, were
linked to the age of
European exploration.
Although the Darwinian
revolution was very
significant to the study
of biogeography, many
of the major ideas
predate Darwin.
Persistent themes in biogeography
1. Classifying geographic regions based on their biotas.
2. Reconstructing the historical development of lineages and
biotas, including their origin, spread, and diversification.
3. Explaining the differences in numbers as well as types of
species among geographic areas, and along geographic
gradients including those of areas, isolation, latitude, elevation,
and depth.
4. Explaining geographic variation in the characteristics of
individuals and populations of closely related species, including
trends in morphology, behavior, and demography.
Early biogeographers, or
“naturalists”, collected
information about the
diversity and distribution
of living things.
It was becoming clear
that a scheme for
classification was
necessary.
It was also becoming
clear that the diversity of
living things could not be
explained in a purely
Biblical way.
Carolus Linnaeus (1707-1778)
Developed a scheme for the classification
of all life.
This system is still in use today.
Linnaeus also had
ideas about
biogeography.
He thought that all life
had originated on the
slopes of a “Paradisical
Mountain”, where they
were adapted to a
particular habitat on the
slopes of the mountain.
They then dispersed to
occupy the various
habitats of the globe.
He hypothesized a
similar spread of
organisms following the
landing of Noah’s ark.
Ararat
Georges-Louis Leclerc, Comte de Buffon
(1707-1788)
Studied living and fossil mammals, and
arrived at conclusions different from
those of Linnaeus.
Hypothesized that life originated in a
region of northwestern Europe during
earlier times, then migrated into the New
World and the Southern Hemisphere,
changing over time.
“Man is totally a production of heaven; But the
animals, in many respects, are creatures of
the Earth only. Those of one continent are
not found in another; or, if there are a few
exceptions, the animals are so changed that
they are hardly recognized.”
A comparison of the ideas
of Linnaeus and Buffon.
Linnaeus believed that
organisms spread from
Mount Ararat, or another
low latitude mountain
following the Great Flood.
Buffon thought that life
originated in northern
Europe and spread
southward, and to the
New World.
Buffon’s view of the
change
(degeneration) of life
forms with time, and
his belief that New
World life forms were
somehow inferior was
one factor that led
Thomas Jefferson to
commission the Lewis
and Clark expedition
to survey the western
portions of the
American continent.
Buffon’s observations led to the first principle of
biogeography, known as Buffon’s Law. It states that
environmentally similar but isolated regions have
distinct assemblages of mammals and birds.
Sir Joseph Banks
Accompanied Captain James Cook on a
three-year voyage around the world from
1768 to 1771.
Collected ~3600 plant specimens, including
over 1000 previously unknown to science.
Affirmed and generalized Buffon’s Law
Johann Reinhold Forster (17291798)
Also circumnavigated the globe
with Cook.
Developed one of the first
systematic descriptions of the
world’s biotic regions.
Also worked to extend Buffon’s
Law to plants.
Noted the tendency for plant
diversity to decrease from the
equator to the poles.
Willdenow
Karl Ludwig Willdenow (1765-1812)
German botanist.
Described floristic provinces of
Europe.
Suggested many sites of origin,
perhaps mountains that were not
inundated in the Great Flood. After
the deluge, life spread from these
multiple sites.
His student, Alexander von
Humboldt (1759-1859) is viewed as
the father of phytogeography.
Humboldt concluded that, within
regions, plants were distributed in
floristic belts ranging up the sides
of tropical mountains.
Humboldt
The 19th Century – A Golden Age for Biogeography
200 years ago, biogeographers (although not called that at the time) had
made a pretty good start at describing the distribution of organisms on
the planet.
They had not done nearly as well in terms of describing the causes of
these distributions.
To answers these questions, they needed:
a. A better idea about the age of the Earth.
b. A clearer picture of the dynamic nature of the earth’s surface.
c. A better understanding of the origin and spread of biological diversity.
Help was on the way.
Adolphe Brongniart (1801-1876)
Paleobotanist of the 19th
Century who used the fossil
record to draw inferences
regarding ancient climates.
Found tropical fossils in
temperate areas. Concluded
that the earth’s surface had
been altered by the uplift and
erosion of mountains.
Charles Lyell (1797-1875)
Regarded as the father of geology.
Saw evidence of the dynamism of the
earth’s surface.
Developed the theory of
uniformitarianism, stating that the
processes that we see operating today
on the earth’s surface have always done
so.
Wrote Principles of Geology.
The stage was set for the contribution of
four British naturalists.
Charles Darwin
1809-1882
Through a series of events,
Darwin sailed as an amateur
naturalist on the H.M.S. Beagle
in 1831.
For a more detailed history of
Darwin’s life, take a look at the
linked PowerPoint.
The Beagle circumnavigated the globe on its five
year voyage.
The voyage had a tremendous
influence on Darwin.
Darwin, in turn, had a tremendous
influence on biogeograhy and biology
in general.
Darwin explained the spread and
eventual isolation of taxa as the
result of long-distance dispersal.
His arguments threatened to
overturn the “steady state” ideas
that were entrenched in
biogeography.
One of the leading
proponents of these ideas
was Louis Agassiz (18071873). Agassiz believed that
species were unchanging,
and so were there
distributions.
However, Darwin’s views
gained support and eventually
won out.
The views of the “dispersalists” were
challenged by the “extensionists” of the
late 19th Century.
They had to propose a variety of
vanished land bridges to account for the
observed distributions of terrestrial
organisms.
(Note the connection between South
America and Africa present in all of
these proposed land bridges. That will
be significant later)
One of the leaders in the extensionist camp
was Joseph Dalton Hooker. Hooker was a
great friend of Darwin (actually referred to
sometimes as “Darwin’s bulldog” as a result
of his ferocious defense of the theory of
evolution). He was also a very influential
botanist who traveled extensively and
collected plants from around the world.
Hooker felt that long-distance dispersal was
an insufficient explanation for the distribution
of many organisms.
He wrote that the evidence supported…
“the hypothesis that of all being members of
a once more continuous extensive flora…that
once spread over a larger and more
continuous tract of land,…which has been
broken up by geological and climatic causes.”
When no evidence of vanished
land bridges emerged, the
extensionist movement lost
momentum.
Still, Hooker’s contributions to
biogeography were significant.
You have probably noted
the fact that botanists
made most of the early
contributions to
biogeography?
Why do you think that was
the case?
The impact of zoologists began to increase as the 19th Century
progressed. Darwin was one example.
Philip Lutley Sclater was another.
Sclater was an ornithologist who described
over 1000 species of birds. His writings
had a major impact on zoogeography.
He proposed a scheme that divided the
earth into biogeographic regions. His work
provide the basis for the biogeographic
regions recognized today.
Sclater’s scheme of
terrestrial
biogeographic
regions.
The most significant figure,
however, in the history of
zoogeography, and biogeography
in general, is….
Alfred Russel Wallace (1823-1913)
Wallace is often considered the
father of zoogeography.
Wallace wrote three of the most significant books in
the history of the science:
The Malay Archipelago (1869)
The Geographical Distribution of Animals (1876)
Island Life (1880)
The authors of your text list, on page
27, a number of biogeographic
principles advocated by Wallace. Read
through them.
Many of these ideas remain central to
the study of biogeography today.
One of Wallace’s early contributions was the
recognition of a distinct break in the faunal
compositions between the islands of Bali and
Lombok in the East Indies.
This break is known today as Wallace’s Line.
Also, in the 19th Century,
other biogeographers
contributed some
generalized “rules” regarding
animal distributions.
Bergmann’s rule states that the
size of warm-blooded vertebrates
tends to be larger in cooler
climates. Why might that be?
Allen’s rule says that the extremities of such
species tend to be larger in warmer climates and
smaller in cool climates.
Cope’s rule states that the
evolution of a group is often
accompanied by an increase
in size.
However, this increase in
size often brings with it an
increased susceptibility to
extinction.
It’s important to remember that all of these rules are generalizations, and
that there are many exceptions.
C.H. Merriam’s “life
zones” illustrated the
relationship between
climate and
vegetation.
Life zones can be
seen both in relation
to elevation…..
….and to latitude.
In the early decades of
the 20th Century,
paleontologists
contributed greatly to our
understanding of the
origin, dispersal, and
ultimate decline of many
groups of vertebrates.
Much debate focused on “centers
of origin”, the place where a group
developed.
Four major developments revolutionized biogeography in the
latter part of the 20th Century:
1. The acceptance of plate tectonics.
2. The development of new phylogenetic techniques.
3. New ways of conducting ecological research.
4. Investigations in the factors limiting distributions.
We will talk in detail about each of these in later chapters.
The acceptance of plate tectonics as
a mechanism driving continental drift
has completely changed the way in
which we view distributions today.
Perhaps the most significant event
in ecological biogeography was the
publication of a monograph on
island biogeography by E.O. Wilson
and Robert MacArthur. In this
seminal work, they proposed
theories to explain the number of
species found on islands.
The effect of
various events on
the science of
biogeography can
be seen by
looking at the
number of
publications in
the field in
relation to the
timing of events.