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Evolution on Islands

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.

Fixity of species and common descent

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.

Nature of Science

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.

Mammal eggs and reptile placentas

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.

Fossils of live birth

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.

Full discussion:

Explore Evolution acknowledges the evidence of fossilized forms transitional between reptiles and mammals, but asserts that:

Intermediates between modern forms

Summary of problems:

Modern species and fossil evidence all give us insight into evolutionary history, and of the sequence of evolutionary changes leading from the common ancestors of modern species to the modern forms.

Dinosaur diaphragms

Summary of problems:

The dinosaur ancestors of birds probably did not have diaphragms. The one researcher cited to oppose this view also rejects the evidence that birds evolved from dinosaurs; his views on both topics have been widely refuted.

Full discussion:

Paleontologist Matt Wedel explains:

Bird diaphragms

Summary of problems:

The claim that air sacs in evolving birds would put a hole in the a diaphragm and lead to a nonfunctional, fatal intermediate, is based on selective quoting of a single sentence from a scientific publication from 1997; the conclusions in that publication are more complicated than one might guess from reading that single out-of-context sentence. Furthermore, Explore Evolution ignores more recent findings that have overturned the idea that the dinosaur ancestors of birds even had diaphragms to damage.


Summary of problems:

There are detailed, testable models of the evolution of dual-opening parabronchi in bird lungs from single-opening alveoli found in the reptilian ancestors of birds. Explore Evolution asks a number of questions about this transition, but then fails to offer students any means to answer any of them, or to discuss how a student or scientist might go about finding answers to these questions.

Full discussion:

Explore Evolution asks its readers:

Mammalian hearts

Summary of problems:

There are good examples of the functional intermediate stages in the evolution of the mammalian heart. Explore Evolution repeats inaccurate and long-debunked creationist claims about the impossibility of evolving a four-chambered mammalian heart from a three-chambered reptilian heart. Though extensive research exists into exactly how this transition took place, Explore Evolution ignores the research, and abandons intellectual inquiry in favor of creationist talking points.


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