Essay on Evolution

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Essay on Evolution

There are many mechanisms that lead to evolutionary change. One of the most important mechanism in evolution is natural selection which is the differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. Natural selection occurs when a environment makes a individual adapt to that certain environment by variations that arise by mutation and genetic recombination. Also it favors certain traits in a individual than other traits so that these favored traits will be presented in the next generation. Another mechanism of evolution is genetic drift. Genetic drift is a random change in a small gene pool due to sampling errors in propagation of alleles or
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Some bacteria had genes that coded for enzymes that specifically destroyed certain antibiotics such as ampicillin. From this incident, scientists were able to deduce that natural selection helped the bacteria to inherit the genes for antibiotic resistance. Scientists have also been able to use biochemistry as a source of evidence. The comparison of genes of two species is the most direct measure of common inheritance from shared ancestors. Using DNA-DNA hybridization, whole genomes can be compared by measuring the extent of hydrogen bonding between single-stranded DNA obtained from two sources. The similarity of the two genes can be seen by how tightly the DNA of one specie bonds to the DNA of the other specie. Many taxonomic debates have been answered using this method such as whether flamingos are more closely related to storks or geese. This method compared the DNA of the flamingo to be more closely related to the DNA of the stork than the geese. The only disadvantage of this method is that it does not give precise information about the matchup in specific nucleotide sequences of the DNA which restriction mapping does. This technique uses restriction enzymes that recognizes a specific sequence of a few nucleotides and cleaves DNA wherever such sequences are found in the genome. Then the DNA fragments are separated by electrophoresis and compared to
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