Evolutionary Synthesis Essay

Evidence of common descent of living organisms has been found by scientists working in a variety of fields over many decades and has demonstrated common descent and that life on earth developed from a last universal ancestor, that evolution does occur, and is able to show the natural processes by which the biodiversity of life on Earth developed. This evidence supports the modern evolutionary synthesis, the current scientific theory that explains how and why life changes over time. Evolutionary biologists document evidence of common descent through making testable predictions, testing hypotheses, and developing theories that illustrate and describe its causes.

Comparison of the DNA genetic sequences of organisms has revealed that organisms

Such reconstructions, especially when done using slowly evolving protein sequences, are often quite robust and can be used to reconstruct a great deal of the evolutionary history of modern organisms . These reconstructed phylogenies recapitulate the relationships established through morphological and biochemical studies. The most detailed reconstructions have been performed on the basis of the mitochondrial genomes shared by all eukaryotic organisms, which are short and easy to sequence; the broadest reconstructions have been performed either using the sequences of a few very ancient proteins or by using ribosomal RNA sequence .

Phylogenetic relationships also extend to a wide variety of nonfunctional sequence elements, including repeats, transposons, pseudogenes, and mutations in protein-coding sequences that do not result in changes in amino-acid sequence. While a minority of these elements might later be found to harbor function, in aggregate they demonstrate that identity must be the product of common descent rather than common function .

Universal biochemical organisation and molecular variance

Sequence comparison is considered a measure robust enough to correct erroneous assumptions in the phylogenetic tree in instances where other evidence is scarce. For example, neutral human DNA sequences are approximately 1.2% divergent from those of their nearest genetic relative, the chimpanzee, 1.6% from gorillas, and 6.6% from baboons. Genetic sequence evidence thus allows inference and quantification of genetic relatedness between humans and other apes. The sequence of the 16S ribosomal RNA gene, a vital gene encoding a part of the ribosome, was used to find the broad phylogenetic relationships between all extant life. The analysis, originally done by Carl Woese, resulted in the three-domain system, arguing for two major splits in the early evolution of life. The first split led to modern Bacteria and the subsequent split led to modern Archaea and