Ecology 7th Edition by Manuel Molles

Exercise 2

Most examples of regional and latitudinal variation in species richness cited in this chapter have been terrestrial. Consider regional variation in marine biotas. Like birds on land, fish are one of the best-studied groups of marine organisms. Moyle and Cech (1982) cite the following patterns of fish species richness:

As you can see, fish species richness decreases northward on both coasts. However, the Pacific coast generally supports a larger number of species. This contrast may be another situation requiring historical- and geographic-level explanations. Explore and explain this contrast in species richness using information from the fields of marine biology, oceanography, and ichthyology. Moyle and Cech (1982) and Briggs (1974) are good starting points.