The geographical distribution of organisms and their interactions with their environment.

Island biogeography

Definition of Biogeography

Biogeography is the study of the geographical distribution of organisms and their interactions with their environment. It can be divided into two main branches: ecological biogeography, which focuses on current distributions and how they are affected by environmental factors; and historical biogeography, which looks at past distributions to understand how species have evolved over time.

Ecological biogeography examines the relationship between an organism’s habitat preferences and its ability to survive in different environments. This includes looking at factors such as climate, soil type, topography, vegetation cover, competition from other species for resources or space, predation pressure from predators or parasites, and human activities that may affect a species’ range.

Historical biogeography uses evidence such as fossil records and genetic data to trace changes in species ranges over time. It also considers geological events like continental drift that could have caused large-scale shifts in populations across continents or oceans. By understanding both ecological and historical aspects of biogeography we can gain insight into why certain organisms live where they do today – providing valuable information for conservation efforts around the world.

Patterns of Biogeography

Biogeography is a complex field, and many factors influence the patterns of species distributions. One of the most important influences is plate tectonics, which can cause large-scale changes in landmasses over time. For example, the break-up of the single landmass Pangea into separate continents around 200 million years ago had a major impact on global biogeographic patterns.

This event caused some species to become isolated from each other as they were divided by oceans or mountain ranges, while others were able to disperse across new habitats that opened up due to continental drift. Additionally, climate change has been an important factor in shaping current biogeographic patterns; for instance, during ice ages certain areas became too cold for certain species to survive in and so their range shifted accordingly.

Finally, human activities such as deforestation and urbanization have also had an effect on biogeographical distributions by reducing suitable habitat for some organisms or introducing invasive species that compete with native ones. By understanding the factors that influence species distributions, we can gain an insight into why organisms live where they do and how environmental changes might affect that – insights which are vital to conservation efforts worldwide.

Biotic and Abiotic Factors

Biogeography is shaped by both biotic and abiotic factors. Abiotic factors, such as climate, soil type, and topography can influence the distribution of species by providing suitable habitats for them to live in or preventing them from entering certain areas. For example, a cold climate may limit the range of some species while allowing specialized species to thrive. Additionally, changes in these abiotic conditions over time can cause shifts in species distributions. For instance during an ice age many organisms would be forced to migrate southward due to colder temperatures.

Biotic factors also play an important role in biogeography; competition between different species for resources or space can lead to exclusion zones where one organism outcompetes another and prevents it from living there. Predation pressure from predators or parasites can also affect which organisms are able to survive in certain areas.

These relationships are two-way – if prey populations become too low then predators will have difficulty finding food and so their range will shrink accordingly. Additionally, human activities such as deforestation or urbanization can reduce suitable habitat for some organisms while introducing invasive species that compete with native ones – all of which shape current biogeographic patterns around the world today.

Island Biogeography

Island biogeography, also known as insular biogeography, is the study of species distributions in isolated communities. Robert H. MacArthur and E. O. Wilson developed a theory in 1967 that proposed that the biodiversity of an island was determined by immigration and extinction rates.

The key factors influencing these two rates were thought to be island size and proximity to other landmasses. Islands with closer connections to the mainland would have higher immigration rates. Smaller, more isolated ones would experience higher extinction rates due to limited resources or competition – in line with the species area relationship. This theory has been used to explain why some island ecosystems are so diverse while others remain relatively unchanged over time.

The rescue effect is an important concept in island biogeography which states that when a population becomes too small for its environment it can be “rescued” by immigrants from another area – allowing it to survive despite unfavorable conditions or low numbers of individuals within the original population.

This phenomenon has been observed in many different types of organisms including plants, mammals, reptiles, and insects – demonstrating just how powerful this process can be for maintaining biodiversity on islands around the world.

Continental Drift

Continental drift is the process by which continents move slowly over time due to plate tectonics. This movement can have a significant effect on biogeography, as it changes the environment and creates new opportunities for species to disperse or become isolated from one another.

For example, millions of years ago Australia was connected to South America and marsupial populations could migrate freely across the land mass. When the landmass separated, certain marsupials were confined to Australia. Those marsupials evolved under different environmental conditions than their ancestors.

Now, many different species of marsupial are found only in Australia, with unique and distinct marsupials being found in the modern continent of South America. Similarly, about 150 million years ago Pangea had separated into landmasses known as Laurasia and Gondwana. Laurasia contained what is now North America and Eurasia, with the exception of India.

All other land mass was part of Gondwana. It is thought that side-necked turtles evolved throughout Gondwana – they are now found in parts of South America, Africa, the Indian Ocean and Australia, but nowhere else.

Historical Biogeography

Historical biogeography is the study of how species distributions have changed over time. It combines data about current species distribution with information about their evolutionary history to track species through space and time. It allows us to gain insight into the evolutionary history of a species, and can help us understand why certain organisms are found in certain areas today. Techniques used in this field include phylogenetics, which uses genetic data and diagrams known as phylogenetic trees to trace relationships between different species; and modelling, which uses computer simulations to predict future distributions based on past patterns. Historical biogeography also involves looking at fossil records and geological evidence such as plate tectonics to determine when and where species may have dispersed or become isolated from one another. By combining these methods with ecological studies, we can gain a better understanding of how current ecosystems came about and what factors influence their diversity.

Biogeographical Realms

Biogeographical realms are large-scale regions of the Earth’s surface that share similar climates, flora and fauna. They are divided by the World Wildlife fund (WWF) into eight major realms: Neotropic, Nearctic, Palearctic, Afrotropic, Indomalaya, Australasia, Oceania and Antarctic. Each realm is further subdivided into smaller biogeographic provinces or biomes.

The Neotropic realm includes Central America and South America. The Nearctic covers most of North America. The Palearctic encompasses most of Eurasia and North Africa. The Afrotropic realm includes Africa south of the Sahara Desert, the Indomalayan realm includes India and Southeast Asia. Australasia comprises Australia and New Zealand. Oceania includes Polynesia – except New Zealand – and the Fiji Islands. Finally, the Antarctic realm includes South Georgia as well as Antarctica

Each realm has its own unique characteristics due to its climate conditions as well as evolutionary history. For example, many species found in tropical rainforests can only be found within a single biogeographical realm such as the Neotropics or Indomalaya. Similarly, some species have adapted to extreme environments like deserts or high altitudes which may limit their distribution across multiple realms. By studying these patterns we can gain insight into how organisms interact with their environment on a global scale.

Biogeographical Regions

Biogeographical regions are areas of the Earth’s surface that share similar climates, flora and fauna. They are defined by their natural boundaries, which can be physical features such as trenches, mountain ridges or peaks. These regions are found within biogeographical realms, which are larger-scale divisions based on climate and evolutionary history. Examples of biogeographical regions include the Caribbean islands, Amazonia in South America, and the Everglades wetlands in Florida, USA: all of which can be found in the Neotropical realm. Each region has its own unique characteristics due to its climate conditions as well as evolutionary history. For example, some species may only be found within a single region while others have adapted to extreme environments like deserts or high altitudes which may limit their distribution across multiple realms. By studying these patterns we can gain insight into how organisms interact with their environment on a local scale and how they respond to changes over time. Additionally, understanding regional differences can help us better manage ecosystems for conservation purposes by identifying areas where certain species thrive or need protection from human activities such as deforestation or pollution.

Conservation Biogeography

Conservation biogeography is a field of study that combines ecology, geography and conservation biology to understand the distribution of species in relation to their environment. It seeks to identify areas where biodiversity is most threatened and develop strategies for protecting these regions. Conservation biogeography uses data from satellite imagery, remote sensing, GIS mapping and other sources to create models that can predict how species distributions will change over time due to climate change or human activities such as deforestation or pollution. These models are then used by conservationists and policy makers to inform decisions about land use management, habitat restoration projects, protected area designations and more.

By using this framework, we can better protect ecosystems from further degradation while also preserving the unique characteristics of each region’s flora and fauna. Additionally, it helps us identify areas with high levels of endemism (species found only in one location) which may be particularly vulnerable if not given special protection measures. Conservation biogeography provides an important tool for safeguarding biodiversity now and into the future so that our living world remains healthy for generations to come.


Climate Change and Biogeography

Climate change has a profound impact on historical biogeographic patterns. Now, human-driven climate change is having a profound effect on biogeography, with species ranges shifting in response to changing temperatures and precipitation patterns. As the climate warms, many species are moving towards higher latitudes or elevations in search of more suitable habitats. This range shift can have serious consequences for populations that are unable to adapt quickly enough; they may become isolated from other members of their species, leading to reduced genetic diversity and increased vulnerability to disease or predation. Additionally, as some areas become too warm for certain species, they may be forced into competition with new competitors for resources such as food and shelter.

In addition to range shifts, climate change can also affect the timing of seasonal events such as flowering or migration which can disrupt interspecies interactions and cause population declines if organisms cannot adjust their behavior accordingly. Ultimately these changes will have far-reaching implications not only for individual species but also entire ecosystems that rely on them for balance and stability. It is therefore essential that we take steps now to mitigate further damage by reducing our emissions and protecting vulnerable habitats.


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