Life originated in “a warm little pond,” Charles Darwin wrote to Joseph J. Hooker, the founder of geographical botany within Darwin’s circle of colleagues. How, where, and when the first species got started, however, completely escaped Darwin.
In contemplating the origin of life dilemma, Darwin noted in his autobiography –
“The mystery of the beginning of all things is insoluble by us, and I, for one, must be content to remain an agnostic.”
Scientists last week proposed new evolutionary relationships among all 9,993 of the world’s known living bird species. In a letter published in the prestigious Nature journal, scientists reported on the use of DNA-sequence data to create a radiating phylogenetic tree, a revolutionary new bird tree of life (pictured left).
Walter Jetz (pictured right), an evolutionary biologist at Yale University in New Haven, Connecticut, was the leading author of the letter entitled “The global diversity of birds in space and time.” In an interview with science writer Virginia Gewin for Nature News, Jetz explains –
“This is the first dated tree of life for a class of species this size to be put on a global map.”
As the novelty generating the flight of birds, the feather, the most complex integumentary structure found in vertebrates, has long intrigued and fascinated naturalists.
Since Charles Darwin published The Origin of Species in 1859, however, the origin of the feather emerged as a contentious issue. The newfound association between feathers and dinosaurs has only intensified the problem.
The junk DNA theory was introduced in 1972 by evolutionary geneticist Susumu Ohno in the paper entitled “So Much ‘Junk’ in Our Genome.”
The junk comprises sections in the genome with no discernible function, it was thought. Previously, in 1970, Ohno gained notoriety for his gene duplication-driven theory presented in his book Evolution by Gene Duplication.
“Human evolution is the lengthy process of change by which people originated from apelike ancestors,” explains the Smithsonian Institute exhibit (pictured left) entitled “Introduction to Human Evolution.” Continuing their explanation –
“Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.”
