1. Zoogeography
Zoogeography is the study or description of the geographical distribution of animals and how their past distribution has contributed to present-day patterns. Scientists in this field attempt to formulate theories that explain the present distributions as elucidated by geography, physiography, climate, ecological correlates (especially vegetation), geological history, the evolutionary theory, and an understanding of the evolutionary relationships of the particular animals under study.
2. Ecological Biogeography
This branch of Biogeography focuses on the study of distribution and diversity in the context of modern biotic and abiotic factors, with emphasis on:
- Why is a species confined to its present range?
- Why and how doesn't it expand its territory into other areas?
- What roles do climate, topography interactions with other organisms have on its distribution?
- Why do communities change as we go north or up a mountain?
3. Paleoecology
Paleoecology is the study of relationships between organisms and past abiotic and biotic variables. It is based on observations of long-term interactions between climates-vegetation- fire on vegetation dynamics in different World biomes.
There is increasing evidence from ancient sediment cores that a warming climate could make the world's arctic tundra far more susceptible to fires than previously thought. The findings are important given the potential for tundra fires to release organic carbon which could add significantly to the amount of greenhouse gases already blamed for global warming.
4. Historical Biogeography
It attempts to explain the origin of the different patterns of distribution of biota; tracing the origin, dispersal, and extinction of organisms, mainly in a historical context, and tries to answer questions such as:
- How did a species come to occupy its present range?
- What are a species' closest relatives and where are they found?
- How have historical events, such as continental drift and Pleistocene glaciation shaped the present distribution?
5. Vicariance Biogeography
This view is based on the continental drift and sea floor spreading. This theory by Wegener, led to the explanation of the origin of similar but widely isolated species. It attempts to answer the question: How has continental drift contributed towards present geographical distribution? It reveals that such distributions were part of a once continuous land mass that was split into continents that are now separated. The new resulting continents has led to species radiation, and therefore disjointed distributions.
6. Island Biogeography
According to MacArthur and Wilson (1967), the number of species living in an isolated space, such as an island, can be seen as a balance between the immigration of new species and the extinction of established ones. While the population is low, the balance will be non- interactive; i.e. different species multiply without interference. However, when populations are large enough, they interact and immigration and extinction result.
Distant islands will receive immigrants at a slower-rate than the islands near the mainland due to proximity to source areas. However, extinction rates will be the same for both, so that distant islands will hold fewer species. On large islands, immigration is high since the 'target' habitat is large. Extinction is also lower because delayed competition as there is more, to offer.
Thus, large islands will have more species than small ones. The concepts of island biogeography may be extended to any community in an isolated habitat including lakes, which are islands of water in a sea of land.
7. Phytogeography
Phytogeography is an area concerned mainly with the geography of the distribution of plant life. Phytogeography is central to understanding biogeography
- Plants are stationary landscape features which to a large extent mainly dependent upon the environment. Therefore, they are best indicators of the physical environment and as^ immobile entities; they provide a continuous picture of changes in environmental parameters and keep the history of a site compared to animals which are highly mobile.
- Plants also influence the environment more directly. They change the soil, help hold water in the soil, reduce soil temperature and increase humidity.
- Methodologically, plants are easier to deal with, for example, since they are immobile unlike the animals, which move around, they are better specimen for monitoring ' environmental dynamics of a site.
- Plants are a major component of the landscape (i.e. forests make the highlands what they are, grasses and shrubs make the Savannahs) and comprise the greatest biomass of the world biomes. They also serve as clue to animal distributions because they are a major a source of animal food.
francis1897 answered the question on February 27, 2023 at 07:24