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Explore Evolution claims that some current evolutionary biologists think that mutations that result in major changes in morphology (such as the mutations in the Hox gene Ultrabithorax, which produce the four-winged fruit fly) are necessary to explain morphological evolution. Modern evolutionary biologists do not suggest mutations in the genetic toolkit must have dramatic effects (as discussed elsewhere in this critique). Explore Evolution falsely asserts that evolutionary developmental biologists doubt the role of mutation in development.
The four-winged fruit fly is a classic example of how creationists misinterpret the genetic analysis of development. Developmental geneticists try to understand the role of a gene by modifying a gene and analyzing the consequences, so it is of little consequence that four winged flies would not survive in the wild. The importance of the four-winged fruit fly is that it demonstrated that a few mutations in a single gene were able to transform an entire structure.
Explore Evolution insists, contrary to the consensus of developmental biologists, that we don't really know what controls development or whether that mystery force could mutate:
Explore Evolution claims:
Explore Evolution completely ignores studies showing that mutations in both protein coding sequences and in non-coding cis-regulatory element sequences (CREs) are responsible for changes in morphology. Explore Evolution muddies the distinction between mutations which affect protein structure and function, and mutations which affect when and where genes are turned on or off.
In its discussion of DNA and mutations, Explore Evolution asserts:
In claiming that developmental processes are too integrated to allow change, Explore Evolution ignores over 10 years of research in evo-devo on the modularity of development. Evolutionary developmental biologists who study Hox genes think that mutations in the CREs of target genes for Hox genes are more likely to be more important for morphological evolution than mutations in Hox genes themselves.
Compensatory mutations are mutations that correct a loss of fitness due to earlier mutations. In some cases, such mutations bring their own fitness costs, but often they do not. Even when they do, it is irrelevant to the power of mutation and selection to produce novelty.
Explore Evolution claims:
The discussion of Richard Goldschmidt and his saltational model of evolution is largely copied (without credit) from an essay by "creationist anatomist" David Menton. Goldschmidt's ideas were widely criticized when first publicized, and their reputation has not improved with time. There's no particular reason to cover them in a modern biology textbook at all.
Evolutionary biology does not require that organisms be able to accumulate unlimited mutations. Organisms can and do accumulate large numbers of mutations. Explore Evolution is deeply misleading about the role of mutations and adaptations.
Explore Evolution claims that
Mutations can improve normal protein function resulting in increased fitness relative to the environment. Many mutations work by generating more effective enzymes or through novel catalytic mechanisms. Explore Evolution is wrong to claim that mutations must impair a protein's normal functioning and impose a fitness cost.