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 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.”
Exploring human evolution via DNA was essential for twentieth-century evolution scientists. Charles Darwin, however, in The Origin of Species, never used the terms genetics, genetic, and genes until 1872, following the publication of the pea plantinheritance report of Gregor Mendel in 1866.
In his sixth edition, Darwin used the term “genetic” twice, but only to express a genealogical idea, not as a molecular term. In the words of American evolutionary biologist Richard Lewontin,
Darwin, Then and Now, the Most Amazing Story in the History of Science, chronicles Darwin's life, how he developed his hypothesis, specifically what he said, and what scientists have discovered since the publication of The Origin of Species in 1859.
The book traces the rise and fall of evolution's popularity as a scientifically valid theory. With over 1,000 references from Darwin and scientists, Darwin Then and Now retraces developments in the most amazing story in the history of science.
Darwin Then and Now is an educational resource focusing on understanding the intersection of evolution and science to develop basic skills for analyzing and assessing the theory of biological evolution.