Final answer:
Molecular phylogeny, or cladistics, uses DNA, RNA, and protein sequences to determine evolutionary relationships among species and forms the basis of modern classification systems in biology. It provides a more accurate picture compared to traditional methods based solely on physical appearance or behavior, leveraging molecular and morphologic information to build phylogenetic trees and cladograms with the help of computer programs like BLAST.
Step-by-step explanation:
The field of molecular systematics has greatly expanded with the advancements in DNA technology. This area of science utilizes molecular data, including DNA and RNA sequences, to construct phylogenies, which are hypotheses about the evolutionary history of species.
Physical appearance has been a traditional method for classification, but it can be misleading as it often involves character weighting and can reflect superficial similarities rather than evolutionary relationships. Molecular data, on the other hand, is less likely to be influenced by natural selection and therefore can provide a more accurate reflection of phylogenetic relationships. This information is obtained from various molecular comparisons such as amino acid sequences and nucleotide sequences, and from different types of genes differing in their evolutionary rates.
Computer programs are employed to aid in determining relatedness through DNA sequencing, and the combined molecular and morphologic information is leveraged for a more effective determination of phylogeny. BLAST is a common tool used to compare genes and construct cladograms to illustrate these relationships. Overall, molecular phylogeny or cladistics utilizes DNA, RNA, and sometimes protein data to recreate the evolutionary history of organisms, forming the backbone of modern taxonomic classification.