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 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).

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

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)