Why biogeography matters

Another theme I will discuss in this blog is biogeography. Biogeography is the study of where organisms live and why they live there.

Why are biologists interested in biogeography?
Evolutionary biologists believe that organisms have been limited in their dispersal to different environments by barriers. For example, shellfish that live in the Pacific off the coast of Central America have difficulties dispersing to the Atlantic due to the Isthmus of Panama. In fact, scientists think that the formation of the Isthmus of Panama some 3.5 million years ago created a barrier to dispersal for marine organisms while simultaneously allowing for increased dispersal for terrestrial organisms, leading to the Great American Interchange of North and South American fauna.


Biologists and paleontologists study the geographic distribution of living and fossil organisms, plate tectonic movements and the relationships of these organisms in attempts to understand why animals live where they do today. We believe that the evolution of organisms paired with plate tectonic theory, the rising and lowering of sea levels and each species’ ability to disperse best explains the geographic distribution of life.

Creationists need to think about the distributions of living and extinct animals in the context of Noah’s Flood. If the ark contained all terrestrial animals that have ever lived, then Creationists need to ask themselves: 1) how did all of the animals find their way to the ark (i.e., did they all live in the Middle East)?, 2) how did the animals reach the areas of the globe that they did (e.g., how did sloths get to South America)?, and 3) why do some animals that are very similar to each other live in only very specific parts of the earth as opposed to possessing a circumglobal distribution?

Though Creationists typically think of evolutionary theory in the context of things like fossils, biogeography is a very important aspect of the history of life and needs to be properly understood in order to consider evolutionary theory vs. creationism.

Questions for creationists

If life evolved, what would you predict in terms of biogeographical patterns? If life was created within the past 6,000-10,000 years how would it be different? How may that be altered when factoring in Noah’s Ark?


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