CK-12 Foundation
Ck 12: Biology: Natural Selection
[Free Registration/Login may be required to access all resource tools.] Describes how natural selection changes allele frequency.
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Evolution: The Theory of Natural Selection (Part 1)
These pages are part of a site called Evolution that accompany a textbook by the same name. Mark Ridley is the author. This section has an advanced discussion of determining allele and genotype frequencies using the Hardy-Weinberg ratio.
CK-12 Foundation
Ck 12: Life Science: Evolution Acts on the Phenotype
[Free Registration/Login may be required to access all resource tools.] Natural selection acts on the phenotype (traits or characteristics) of an individual. On the other hand, natural selection does not act on the underlying genotype...
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Evidence for Evolution: Formation of New Species
These pages are part of a site called Evolution that accompanies a textbook by the same name. Mark Ridley is the author. These pages offer an explanation of speciation using reproductive isolation and differences in phenotype.
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North Dakota State Univ.: Mendel's Law of Ind. Assort.
Mendel's second law and how he arrived at it through his experiments. Includes vocabulary and examples.