Biogeography
Biogeography is a fundamental branch of Physical Geography, and a fundamental field in Biology as well. It deals with the study of the distribution of species and ecosystems in geographical space, and through the geological timescale. It is Biogeography that explains “how and why particular species live in a particular geographical location”, and what are those factors, which make a specific geographical region favourable for particular types of organisms. In biogeography, we focus on why the living organisms live where they do and how these patterns change. In biogeography, we need to utilise evolutionary biology, physical geography, geology, taxonomy, paleontology, and ecology to understand the factors that influence the distribution of species. The plausible factors that influence biodiversity are evolution, continental drift, climate, and habitat.
Branches of Biogeography
Biogeography is a broad field, but it is divided into two main subfields.
- Ecological Biogeography: The goal of ecological biogeography is to understand the distribution patterns of species and ecosystems in relation to ecological factors, like climate, habitat features, species interaction, and disturbance. It explains how, at various geographic scales, ecological processes influence the spatial distribution of organisms and communities. Fundamental elements of ecological biogeography are;
- relationship between species and environments
- biogeographic mechanism
- slopes in biogeography
- community-based ecology
- Historical Biogeography: The goal of historical biogeography is to comprehend the past processes and events that have influenced the distribution of species in various geographical areas. It looks for the past causes (geological events, climate shifts, evolutionary processes, continental drift) of the current pattern of species and ecosystems.
History of Biogeography
Biogeography is a derivative discipline, with elements of evolution, geography, ecology, climatology, genetics, and phylogenetics. Here, we are going to deliberate on the historical roots of the discipline, major determinants in early development, and evolution from a descriptive endeavour to a rigorous scientific discipline. This historic background of biogeography can be segmented into three periods.
- Age of Exploration (1700 to 1900)
- Age of Integration (1900 to 1960)
- Age of Maturity (1960 to present)
Age of Discovery
Biogeography, the study of the geography of life, emerged as a recognizable science as plant and animal collections grew during the eighteenth‐century age of exploration. The foundation of biogeography, that geographically disjunct regions with similar environments have distinct plants and animals, appeared as Buffon’s Law in 1761. While being further developed within both evolutionary and ecology frameworks by late nineteenth‐century naturalists, including Wallace, Sclater, and Darwin.
Age of Integration
The “Age of Integration” in the history of biogeography generally refers to the period between 1900 and 1960. This era followed the initial age of exploration (1700–1900) and was characterised by the synthesis of
Age of Maturity
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- Plate Tectonics Revolution: The acceptance of continental drift in the late 1960s/early 1970s fundamentally altered historical biogeography. It provided a mechanism for explaining disjunct species distributions, linking Earth’s geological history with biota evolution.
- Theory of Island Biogeography (1963): Robert MacArthur and Edward O. Wilson proposed that species richness on islands represents a dynamic equilibrium between immigration and extinction, largely determined by island size and distance from the mainland. This theory propelled the use of mathematical modeling in ecology.
- Ecological and Conservation Focus: The discipline expanded to focus on mechanisms limiting species distributions, including habitat fragmentation and environmental change. This fostered the growth of conservation biogeography to manage biodiversity.
- Molecular Phylogenetics: Recent decades have integrated DNA analysis to reconstruct the evolutionary history and dispersal patterns of organisms, transforming historical biogeography from purely fossil-based studies.
- Macroecology: Modern biogeography includes the study of large-scale, often global, patterns of biodiversity, looking at relationships between organisms and their environment on a massive scale.
Components of the Study
Scope of Biogeography
Nature of Biogeography
Application of Biogeography in Modern World