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The history of the camel provides an example of how fossil evidence can be used to reconstruct migration and subsequent evolution. The fossil record indicates that the evolution of camelids started in North America (see figure 4e), from which, six million years ago, they migrated across the Bering Strait into Asia and then to Africa, and 3.5 ...
Its genetic material was most likely DNA, [15] so that it lived after the RNA world. [a] [18] The DNA was kept double-stranded by an enzyme, DNA polymerase, which recognises the structure and directionality of DNA. [19] The integrity of the DNA was maintained by a group of repair enzymes including DNA topoisomerase. [20]
A very large number of fossils have now been discovered and identified. These fossils serve as a chronological record of evolution. The fossil record provides examples of transitional species that demonstrate ancestral links between past and present life forms. [45]
The best time to extract DNA from a fossil is when it is freshly out of the ground as it contains six times the DNA when compared to stored bones. The temperature of extraction site also affects the amount of obtainable DNA, evident by a decrease in success rate for DNA amplification if the fossil is found in warmer regions.
Fossils of organisms' bodies are usually the most informative type of evidence. The most common types are wood, bones, and shells. [57] Fossilisation is a rare event, and most fossils are destroyed by erosion or metamorphism before they can be observed. Hence the fossil record is very incomplete, increasingly so further back in time.
The majority of human aDNA studies have focused on extracting DNA from two sources much more common in the archaeological record: bones and teeth. The bone that is most often used for DNA extraction is the petrous ear bone, since its dense structure provides good conditions for DNA preservation. [ 81 ]
The fossils themselves are referred to as the fossil record. The fossil record was one of the early sources of data underlying the study of evolution and continues to be relevant to the history of life on Earth. Paleontologists examine the fossil record to understand the process of evolution and the way particular species have evolved.
The hominoids are descendants of a common ancestor.. Homo sapiens is a distinct species of the hominid family of primates, which also includes all the great apes. [1] Over their evolutionary history, humans gradually developed traits such as bipedalism, dexterity, and complex language, [2] as well as interbreeding with other hominins (a tribe of the African hominid subfamily), [3] indicating ...