The solitary sandpiper, Tringa solitaria, is a migratory bird. DNA barcoding shows that about 2.5 million years ago T. solitaria split into two subspecies, Tringa solitaria solitaria and Tringa solitaria cinnamomea. A subspecies is a population within a species that is genetically distinct and has some phenotypic differences, but is not yet reproductively isolated. T. s. solitaria breed in eastern North America whereas T. s. cinnamomea breed in western North America. Suggest and explain how the two subspecies T. s. solitaria and T. s. cinnamomea may have evolved from the original T. solitaria population.
Fig. 3.1 shows an American oystercatcher, Haematopus palliatus. The black oystercatcher, Haematopus bachmani, has entirely black plumage. DNA barcoding analysis suggests that the American oystercatcher and the black oystercatcher are not separate species. Suggest how DNA barcoding evidence could show that the American oystercatcher and black oystercatcher are not separate species.
Customs officers at airports can use a hand-held DNA barcoding device to identify biological specimens as they enter or leave a country. Suggest how this helps protect endangered species.