Evidence of common descent
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Evidence of common descent of living organisms has been discovered by scientists researching in a variety of disciplines over many decades, demonstrating that all life on Earth comes from a single anc
Figure 1a: While on board HMS Beagle, Charles Darwin collected numerous specimens, many new to science, which supported his later theory of evolution by natural selection.
Figure 2a: In July 1919, a humpback whale was caught by a ship operating out of Vancouver that had legs 4 ft 2 in (1.27 m) long. This image shows the hindlegs of another humpback whale reported in 1921 by the American Museum of Natural History.
Figure 3a: An insect trapped in amber
Figure 3b: Fossil trilobite, Kainops invius, from the early Devonian. Trilobites were hard-shelled arthropods, related to living horseshoe crabs and spiders, that first appeared in significant numbers around 540 mya, dying out 250 mya.
Speciation
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Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as oppo
African pygmy kingfisher, showing coloration shared by all adults of that species to a high degree of fidelity.
Cichlids such as Haplochromis nyererei diversified by sympatric speciation in the Rift Valley lakes.
Rhagoletis pomonella, the hawthorn fly, appears to be in the process of sympatric speciation.
Gaur (Indian bison) can interbreed with domestic cattle.