Biogeography, contrary to what readers of Explore Evolution might think, encompasses more than just adaptive radiation on islands. Studying the biogepgraphic effects of rivers and mountain ranges also informs our understanding of evolution. Our understanding of relationships between distantly related groups is often informed by comparing the distributions of modern species and their fossil ancestors with our understanding of continental drift.
Studying the biogeographical links between different parts of the world can deepen our understanding of the evolutionary relationships between different populations within a species, between different species, and among higher taxonomic groups. Because different groups diversify at different rates, the evolutionary history of a single species revealed by biogeography might help clarify the relationship between entire families of some different group. These testable predictions about biogeography are powerful tools for scientists.
In discussing dissent in science, Explore Evolution continues to misrepresent the nature of science itself. Science is treated as a courtroom trial with scientists serving as "expert witnesses" and students acting as juries, selecting their preferred outcome from several debating advocates. The "Case for"/"Case against" structure of the book is held out as an example of how science works and should work, with disagreeing voices presented without a context of experimentation and hypothesis testing.
Summary of problems:There are mammals that lay eggs. There are reptiles that have a rudimentary placenta. A May, 2007 errata from the authors corrects only one of the four major errors in these two sentences.
Full discussion:This is one of the most baffling claims in the entire textbook. Here is the original text from EE:
Summary of problems with claim:
Fossils are not the only evidence that mammals have a common ancestor with reptiles, and living transitional forms exist illustrating the evolution of the organ systems they cite as examples.
Explore Evolution acknowledges the evidence of fossilized forms transitional between reptiles and mammals, but asserts that: