BiogeographyBiogeography

Chapter 1 Chapter 1

Diversity on the EarthDiversity on the Earth

►Between 5 – 50 million species of Between 5 – 50 million species of plants, animals, and microbes on the plants, animals, and microbes on the EarthEarth

►Less than 2 million have been formally Less than 2 million have been formally describeddescribed

BiogeographyBiogeography

►BiogeographyBiogeography is the science that is the science that attempts to document and understand attempts to document and understand spatial patterns of biodiversity. spatial patterns of biodiversity.

► It is the study of the distribution of It is the study of the distribution of organisms, both past and present, and organisms, both past and present, and of related patterns of variation over of related patterns of variation over the Earth in the numbers and kinds of the Earth in the numbers and kinds of living things.living things.

Questions Asked by Questions Asked by BiogeographersBiogeographers

►Fundamental Biogeographic Question: Fundamental Biogeographic Question: How are organisms distributed, over How are organisms distributed, over the surface of the Earth and over the the surface of the Earth and over the history of the Earth?history of the Earth?

► Interested in more process based Interested in more process based issues of how natural systems function issues of how natural systems function rather than simple distribution.rather than simple distribution.

My Questions in My Questions in BiogeographyBiogeography

►What role does disturbance play in What role does disturbance play in succession?succession?

►What drives biodiversity?What drives biodiversity?►How will the natural systems react to How will the natural systems react to

global climatic and environmental global climatic and environmental change?change?

►What is necessary for ecosystem health?What is necessary for ecosystem health? Starts dealing with conservation biology Starts dealing with conservation biology

issues and rebuilding and maintaining issues and rebuilding and maintaining ecosystems and biodiversity.ecosystems and biodiversity.

Specializations in Specializations in BiogeographyBiogeography

►PhytogeographyPhytogeography – The study of – The study of plantsplants

►ZoogeographyZoogeography – The study of – The study of animalsanimals

►Microbial BiogeographyMicrobial Biogeography – Little – Little StudiedStudied

Approaches to BiogeographyApproaches to Biogeography► Historical BiogeographyHistorical Biogeography – Reconstruct the origins, – Reconstruct the origins,

dispersal, and extinctions of taxa and biotasdispersal, and extinctions of taxa and biotas► Ecological BiogeographyEcological Biogeography – Accounts for the – Accounts for the

present distributions in terms of interactions between present distributions in terms of interactions between organisms and their physical and biotic environmentsorganisms and their physical and biotic environments

► PaleoecologyPaleoecology – Bridges the gap between these two – Bridges the gap between these two fields, investigating the relationships between fields, investigating the relationships between communities (abundance, distribution, and diversity communities (abundance, distribution, and diversity of species) and abiotic conditions (climate, soils, of species) and abiotic conditions (climate, soils, water quality, etc.).water quality, etc.).

► Analytical BiogeographersAnalytical Biogeographers - Develop general - Develop general mathematical rules of how geography effects the mathematical rules of how geography effects the evolution and distribution of plants and animalsevolution and distribution of plants and animals

► Conservation BiogeographyConservation Biogeography - Work on the - Work on the protection and restoration of natural environmentsprotection and restoration of natural environments

Methods of BiogeographersMethods of Biogeographers

►Field BasedField Based Descriptive – Document ranges of speciesDescriptive – Document ranges of species Process Driven – Examine the processes Process Driven – Examine the processes

of a systemof a system

►Conceptual – Using theoretical modelsConceptual – Using theoretical models►Experimental – Manipulating the Experimental – Manipulating the

system to test hypothesessystem to test hypotheses

Relationship to Other Relationship to Other SciencesSciences

►Biogeography is a synthetic disciplineBiogeography is a synthetic discipline Draws from Geography, Ecology, Draws from Geography, Ecology,

Population Biology, Systematics, Population Biology, Systematics, Evolutionary Biology, Genetics, and Evolutionary Biology, Genetics, and GeologyGeology

Philosophy of SciencePhilosophy of Science

►Scientists try to understand the natural Scientists try to understand the natural world by explaining its enormous world by explaining its enormous diversity and complexity in terms of diversity and complexity in terms of general patterns and basic laws.general patterns and basic laws. Examine the relationship between pattern Examine the relationship between pattern

and processand process Pattern – Non-random, repetitive Pattern – Non-random, repetitive

organizationorganization►The occurrence of pattern implies causation by The occurrence of pattern implies causation by

some general process.some general process.►Searching for mechanistic explanationsSearching for mechanistic explanations

Philosophy of SciencePhilosophy of Science

► Inductive Reasoning – From specific Inductive Reasoning – From specific observations to general principles.observations to general principles.

► Deductive Reasoning – From general Deductive Reasoning – From general constructs to specific cases.constructs to specific cases.

► Karl Popper (1968) introduced Karl Popper (1968) introduced Hypothetico-Deductive Reasoning – A good Hypothetico-Deductive Reasoning – A good scientific theory contains logical assumptions scientific theory contains logical assumptions and consequences, and if these can be and consequences, and if these can be proven wrong, then the theory itself must be proven wrong, then the theory itself must be flawed. flawed. Theories can be tested by setting up alternative, Theories can be tested by setting up alternative,

falsifiable hypotheses.falsifiable hypotheses. If a theory has withstood the severest empirical If a theory has withstood the severest empirical

tests, then it is considered corroborated but can tests, then it is considered corroborated but can never be proven true.never be proven true.

Famous BiogeographersFamous Biogeographers

►Charles DarwinCharles Darwin►Alfred Russel WallaceAlfred Russel Wallace► Joseph Dalton HookerJoseph Dalton Hooker►George Gaylord SimpsonGeorge Gaylord Simpson►Ernest MayrErnest Mayr►Robert MacArthurRobert MacArthur►Edward O. WilsonEdward O. Wilson

Growth of the FieldGrowth of the Field

33

358

1238

0

200

400

600

800

1000

1200

1400

1975 1985 1995

Publications

►Many early writers did not refer to Many early writers did not refer to their work as Biogeography. We can their work as Biogeography. We can see the development of Biogeography see the development of Biogeography as a field of study through its as a field of study through its publications (per publications (per BiosisBiosis).).

Biogeography SearchBiogeography Search

36

9763

86002

55200

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

1900-1975 1976-1985 1986-1995 1996-2005

Publications

Searched on “Biogeography” in Biological Abstracts database 1/16/05

Biogeographic TechniquesBiogeographic Techniques► Simulation modelingSimulation modeling►GISGIS► Statistical Analysis Statistical Analysis

multivariate and geospatial statisticsmultivariate and geospatial statistics► Remote SensingRemote Sensing► Submersible vesselsSubmersible vessels► Automated ground-based data collection Automated ground-based data collection

systemssystems► RadioisotopesRadioisotopes► Stable isotopesStable isotopes►Molecular biological techniquesMolecular biological techniques►Genetic toolsGenetic tools

Scale IssuesScale Issues

Fluid Fluid DynamicsDynamics

Patterns on the LandscapePatterns on the Landscape

Gross Primary ProductivityGross Primary Productivity

Levels of GPPRed (highest), Orange, Yellow, Green, Blue (lowest)