Charles Darwin and Gregor Mendel were both pioneers in genetic engineering and biology. Mendel observed genetic change in inheritance and Darwin observed species of animals in evolution. Both contributed hugely to the field of science and made substantial findings in the subject. Without their research, the world today would seem much scarier and different than how we know it now.
Charles Darwin (1809-1882) went on board the H.M.S. Beagle as the ship's naturalist and the voyage lasted 5 years, from 1831-1836. When comparing the flora and fauna of the Galapagos islands, Darwin found that the species were different from island to island. Also, he compared existing to extinct animals and saw that there was change over time. Before the voyage, Darwin had believed in special creation and the "fixity of species". However, after making his observations, Darwin dumped the "fixity of species" concept.
Mendel (1822-1884) discovered genetic changes could be passed on through work on pea plants.
His work was ignored until the early 1900s. Mendel discovered two laws: 1) the law of segregation, and 2) the law of independent assortment. The law of segregation states that half of the genes from one parent are carried by each gamete (sex cell). Each gamete has one allele (or one variation of a gene) out of two from the parent cell (each parent cell in a diploid species can have only two alleles at one gene locus -- i.e. genes come in pairs in diploid organisms). The law of independent assortment states that different gene pairs assort independently of other gene pairs into gametes. As it turns out, these two "laws" have several exceptions to them. For example, the second law only applies to genes that are far apart on the same chromosome or are on different chromosomes (Both definitions were copied...