Transcript The Science of Biogeography

Biogeography
Chapter 1
Diversity on the Earth
► Between
5 – 50 million species of plants,
animals, and microbes on the Earth
► Less than 2 million have been formally
described
Biogeography
► Biogeography
is the science that attempts
to document and understand spatial
patterns of biodiversity.
► It is the study of the distribution of
organisms, both past and present, and of
related patterns of variation over the Earth
in the numbers and kinds of living things.
Questions Asked by Biogeographers
► Fundamental
Biogeographic Question: How
are organisms distributed, over the surface
of the Earth and over the history of the
Earth?
► Interested in more process based issues of
how natural systems function rather than
simple distribution.
My Questions in Biogeography
► What
role does disturbance play in
succession?
► What drives biodiversity?
► How will the natural systems react to global
climatic and environmental change?
► What is necessary for ecosystem health?
 Starts dealing with conservation biology issues
and rebuilding and maintaining ecosystems and
biodiversity.
Specializations in Biogeography
► Phytogeography
– The study of plants
► Zoogeography – The study of animals
► Microbial Biogeography – Little Studied
Approaches to Biogeography
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Historical Biogeography – Reconstruct the origins,
dispersal, and extinctions of taxa and biotas
Ecological Biogeography – Accounts for the present
distributions in terms of interactions between organisms
and their physical and biotic environments
Paleoecology – Bridges the gap between these two
fields, investigating the relationships between communities
(abundance, distribution, and diversity of species) and
abiotic conditions (climate, soils, water quality, etc.).
Analytical Biogeographers - Develop general
mathematical rules of how geography effects the evolution
and distribution of plants and animals
Conservation Biogeography - Work on the protection
and restoration of natural environments
Methods of Biogeographers
► Field
Based
 Descriptive – Document ranges of species
 Process Driven – Examine the processes of a
system
► Conceptual
– Using theoretical models
► Experimental – Manipulating the system to
test hypotheses
Relationship to Other Sciences
► Biogeography
is a synthetic discipline
 Draws from Geography, Ecology, Population
Biology, Systematics, Evolutionary Biology,
Genetics, and Geology
Philosophy of Science
► Scientists
try to understand the natural
world by explaining its enormous diversity
and complexity in terms of general patterns
and basic laws.
 Examine the relationship between pattern and
process
 Pattern – Non-random, repetitive organization
►The
occurrence of pattern implies causation by some
general process.
►Searching for mechanistic explanations
Philosophy of Science
► Inductive
Reasoning – From specific observations
to general principles.
► Deductive Reasoning – From general constructs to
specific cases.
► Karl Popper (1968) introduced
Hypothetico-Deductive Reasoning – A good
scientific theory contains logical assumptions and
consequences, and if these can be proven wrong,
then the theory itself must be flawed.
 Theories can be tested by setting up alternative,
falsifiable hypotheses.
 If a theory has withstood the severest empirical tests,
then it is considered corroborated but can never be
proven true.
Famous Biogeographers
► Charles
Darwin
► Alfred Russel Wallace
► Joseph Dalton Hooker
► George Gaylord Simpson
► Ernest Mayr
► Robert MacArthur
► Edward O. Wilson
Growth of the Field
► Many
early writers did not refer to their
work as Biogeography. We can see the
development of Biogeography as a field of
study through its publications (per Biosis).
1400
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Publications
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0
1975
1985
1995
Biogeography Search
Searched on “Biogeography” in Biological
Abstracts database 1/16/05
100000
86002
90000
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55200
60000
50000
Publications
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9763
36
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1900-1975
1976-1985
1986-1995
1996-2005
Biogeographic Techniques
► Simulation
modeling
► GIS
► Statistical
Analysis
 multivariate and geospatial statistics
► Remote
Sensing
► Submersible vessels
► Automated ground-based data collection systems
► Radioisotopes
► Stable isotopes
► Molecular biological techniques
► Genetic tools
Scale Issues
Fluid Dynamics
Patterns on the Landscape
Gross Primary Productivity
Levels of GPP
Red (highest), Orange, Yellow, Green, Blue (lowest)