Biogeography Chapter 2 The Age of Exploration ► The Early European explorers and naturalists traveled the Earth collecting specimens and describing the patterns of their distribution.

Chapter 2
The Age of Exploration
► The
Early European explorers and
naturalists traveled the Earth collecting
specimens and describing the patterns of
their distribution.
Carolus Linnaeus (1707-1778)
Developed the system of binomial
nomenclature to classify all organisms. He
noticed that species where well adapted for
the locations where they where found, but
he believed that species where immutable
and created as they where by God.
He described 6000 species in his Species
Comte de Buffon (1707-1788)
Buffon suggested that species and climate
where mutable and he postulated what
later became known as Buffon’s Law.
“Environmentally similar but isolated
regions have distinct assemblages of
mammals and birds.”
Hypotheses for the Origin of All Species
Linnaeus thought that all life
survived the biblical flood on
the slopes of Mount Ararat.
At successively higher
elevations was a series of
environments ranging from
desert to tundra. Each region
with species perfectly adapted
to the environment but
Buffon noted that migration
across different environments
would not be possible, so
suggested the origin of all
organisms to be at the North
Pole and migrations
proceeded from that place.
James Hutton (1726-1797)
Realized that given the gradual nature of geologic
processes, the Earth must be much older than a
few thousand years old. Only an ancient Earth
could account for the formation and erosion of
mountains, the submergence of ancient
landmasses, and the migrations or replacements of
entire biotas that where documented in the fossil
Johann Reinhold Forster (1729-1798)
He Circumnavigated the globe with
Captain Cook and presented one of the
first systematic world views of biotic
regions. He extended Buffon’s Law to
plants. He also provided important early
insights into what became Island
Biogeography Theory and Species
Diversity Theory.
Sir Joseph Banks (1743-1820)
One of the explorer/naturalist who
traveled for three years with Captain
James Cook on the Endeavor (1768-1771)
and collected 3600 plant specimens
including 1000 species not known to
Alexander von Humboldt (1769-1859)
The Father of Phytogeography. He
extended Buffon’s Law to plants and most
terrestrial animals. He noted that Forster’s
floristic zonation also occurred with
changes in altitude as well as latitude.
Augustin de Candolle (1778-1841)
Swiss botanist noted that not only are
organism distributions controlled by
light, heat, and water but they
compete for these resources. He
brought in the concept of the habitat
of a species. He added to Forster’s
ideas on Island Biogeography that
besides island size, species numbers
are controlled by island age,
volcanism, climate, and isolation.
Theoretical Advances in the
Nineteenth Century
► Better
estimate of the age of the Earth.
► Understanding of Plate Tectonics.
► Better understanding of the mechanisms
involved in the spread and diversification of
species – dispersal, vicariance, extinction,
and evolution.
Charles Lyell (1797-1875)
Father of Geology and influenced
the development of Biogeography
with his book Principles of Geology
in 1830. Realized from the fossil
record that climate is mutable.
Lyell also documented that sea
levels had changed and that the
Earth’s surface changed with the
lifting up of mountains and the
erosion of the same. He provided
evidence for the process of
Four British scientists who,
in the mid-nineteenth
century, revolutionized our
understanding of the history
of the Earth and the
distribution of its organisms.
They were close friends and
much can be learned from
their personal letters as well
as their formal publications.
A) Charles Darwin,
B) Joseph Dalton Hooker,
C) Philip Lutley Scalter,
D) Alfred Russel Wallace
Charles Darwin
In 1831 set sail for a 5-year surveying voyage
on the HMS Beagle with Robert Fitzroy. He
observed fossils of extinct fossils in Argentina,
seashells at high elevations in the Andes, and
observed different forms of animals on
different islands. These observations lead to
his idea that geographic isolation facilitates
inherited changes within and between
In 1845 he wrote a manuscript on evolution by
natural selection but he withheld it from print
for 15 years to gather more evidence. Darwin
also proposed that the spread and eventual
isolation and disjunction of biotas resulted
from long-distance dispersal.
Darwin’s Voyage on the HMS Beagle
Alfred Russel Wallace
Wallace independently wrote up his
ideas on evolution by natural selection.
His work prompted Darwin to publish
his 15 year old manuscript on the topic
and their papers where read together
before the Linnaean Society of London
in 1858.
Louis Agassiz (1807-1873)
Agassiz was a Swiss-born naturalist who
trained most of North America’s leading
zoologists and geologists from his
professorship at Harvard. His studies
into glacial deposits lead him to the
postulation of past ice ages. He was an
ardent opponent to many of Darwin’s
ideas and his students supported the
idea of the emergence of land bridges
for the dispersal of organisms.
Proposed Land Bridges by the Extensionsists
“Rules” of Biogeography
Allen's Rule state that certain extremities of animals are
relatively shorter in the cooler parts of a species' range
than in the warmer parts.
Bergmann's Rule asserts that geographic races of a
species possessing smaller body size are found in the
warmer parts of the range, and races of larger body size in
cooler parts.
Gloger's Rule states that dark pigments increase in races
of animals living in warm and humid habitats.
The Egg Rule states that the average number of eggs in a
set, or clutch, laid by songbirds and several other kinds of
birds increases as one moves north in latitude.
Cope’s Rule the evolution of a group shows a trend
toward increased body size.
C. Hart Merriam (1855-1942)
Confirmed that elevation changes in
vegetation type and plant species
composition are generally equivalent to the
latitudinal vegetation changes found as one
moves toward the poles.
Merriam’s Life Zones
Latitude and Altitude
Ernst Mayer (1893-1969)
Mayer made major contributions to the fields
of systematics, evolution, and historical
biogeography. He developed the biological
species concept which states that a
species is definable as a group of
populations that is reproductively isolated
from all other such groups.
George Gaylord Simpson (1902 – 1984)
Simpson, among other paleontologists,
described the origin, dispersal, radiation,
and decline of land vertebrates. They
showed that new groups increase in number
of species, radiate to fill new ecological
roles, expand their geographic ranges, and
become dominant over and contribute to the
extinction of older forms.
Alfred L. Wegner (1880-1930)
German meteorologist who revitalized Antonio Snider-Pelligrini’s 1958 idea of
continental drift. Wegner’s observations where based on the geological and
biological evidence.
Continental Slope Fit
Fossils of Mesosaurus
Wegener’s matching of mountain
ranges on different continents
Paleoclimatic evidence for
Continental Drift
Development of Plate Tectonics
► In
1963 Fred Vine and D. Matthews tied the
discovery of magnetic stripes in the ocean crust
near ridges to Hess’s concept of seafloor
Robert H. MacArthur (1930-1972)
Published with E.O. Wilson Island
Biogeography. One of the most influential
modern ecologists.
E. O. Wilson (1929 – Present)
On Human Nature (1978) won the
Pulitzer Prize
Biophilia (1984) suggests that human
attraction to other living things is innate
Consilience (1998) urges wider
integration of the sciences
The Diversity of Life (1992)
The Ants, with Bert Hölldobler (1990;
Pulitzer Prize)
The Future of Life (2002)
Recent Growth of Biogeography in
OCLC – First Search

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