title: Some thoughts on evolution.
abstract: The sparsity of transitional forms and the abrupt appearance of higher taxa in the fossil record are enigmas for the neo-Darwinian theory of evolution. If the cell is considered to be a steady state system then mutations affecting non-regulatory proteins will have far less effect on the steady state than mutations affecting regulatory proteins. This latter type of mutation, when expressed in multicellular biological systems, is a sufficient explanation for the discontinuities observed between species. Such a mechanism, however, has its own implications for any theory of evolution.
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002454:Cell Differentiation; D004777:Environment; D005815:Genetic Code; D009154:Mutation