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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 ...
However, because evolution is a branching process that produces a complex bush pattern of related species rather than a linear process producing a ladder-like progression, and because of the incompleteness of the fossil record, it is unlikely that any particular form represented in the fossil record is a direct ancestor of any other. Cladistics ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
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.
Archaic biological features and organisms are succeeded in the fossil record by more modern versions. For instance, paleontologists investigating the evolution of birds predicted that feathers would first be seen in primitive forms on flightless predecessor organisms such as feathered dinosaurs. This is precisely what has been discovered in the ...
Othniel C. Marsh, America’s first paleontologist, was the first to provide solid fossil evidence to support Darwin’s theory of evolution by unearthing the ancestors of the modern horse. [328] In 1877, Marsh delivered a very influential speech before the annual meeting of the American Association for the Advancement of Science, providing a ...
The fossil record and faunal succession form the basis of the science of biostratigraphy or determining the age of rocks based on embedded fossils. For the first 150 years of geology , biostratigraphy and superposition were the only means for determining the relative age of rocks.
Professor of biology Jerry Coyne sums up biological evolution succinctly: [3]. Life on Earth evolved gradually beginning with one primitive species – perhaps a self-replicating molecule – that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.