A phenotype results from the expression of an organism's genes as well as the influence of environmental factors and the interactions between the two. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorph.The genotype of an organism is the inherited instructions it carries within its genome.he concept of phenotype can be extended to variations below the level of the gene that affect an organism's fitness. For example, silent mutations that do not change the corresponding amino acid sequence of a gene may change the frequency of guanine-cytosine base pairs (GC content).
President Woodrow Wilson persistently vetoed the Immigration Act of 1917, however Congress overrode his veto and put this law into effect in May 1917. This act increased the head tax on each adult immigrant to $8, barred most Asian immigrants, and required all adults to take a literacy test.
In 1846, during the Mexican War, the House of Representatives considered an appropriations bill designed to provide $2,000,000 for negotiating with the Mexican government. Wilmot introduced a rider to that measure, which was derived from the Northwest Ordinance, barring slavery from any territory acquired from Mexico.The bill containing the Wilmot Proviso passed the House in 1846 but the Senate failed to take any action on it.Passed again by the House in 1847, the proviso was defeated largely by the opposition of Senator John C. Calhoun of South Carolina.he Wilmot Proviso would have prevented slavery's expansion into any of this new territory. The House of Representatives approved the appropriations bill and, as a result, the proviso on August 8, 1846, but the Senate adjourned beforWilmot Proviso would have prevented slavery's expansion into any of this new territory.