History, Evolution, and The Darwin Debate

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Evolution today

January 28th, 2009 · No Comments

Birds Survived Mass Extinction That Wiped Out Dinosaurs Because Of Their Larger Brains
ScienceDaily (Jan. 28, 2009) — The Cretaceous–Tertiary mass extinction 65 million years ago may have wiped out the dinosaurs, but those that survived – the ancestors of today’s birds – may have done so because of their bird brains.

Extending Darwinism
Is there more to heredity, natural selection, and evolution than genes and DNA?

I and several other biologists believe the MS is in need of serious revision. Growing evidence indicates there is more to heredity than DNA, that heritable non-DNA variations can take place during development, sometimes in response to an organism’s environment. The notion of soft inheritance is returning to reputable scientific inquiry. Moreover, there seem to be cellular mechanisms activated during periods of extreme stress that trigger bursts of genetic and non-genetic heritable variations, inducing rapid evolutionary change. These realizations promise to profoundly alter our view of evolutionary dynamics.

Collectively, the processes that we believe have been neglected in evolutionary studies are known as epigenetic mechanisms. Epigenetics is a term that includes all the processes underlying developmental flexibility and stability, and epigenetic inheritance is part of this. Epigenetic inheritance is the transmission of developmental variations that have nothing to do with changes in DNA base sequences. In its broad sense, it covers the transmission of any differences that do not depend on gene differences, so it encompasses the cultural inheritance of different religious beliefs in humans and song dialects in birds. It even includes the developmental legacies that a young mammal may receive from its mother through her placenta or milk &mdash transmitted antibodies, for example, or chemical traces that tell the youngsters what the mother has been eating and, therefore, what they should eat. But epigenetic inheritance is commonly associated with cellular heredity, in which differences that arise among genetically identical cells are transmitted to daughter cells.

Biologists have long suspected that mechanisms for epigenetic cell heredity must exist. Take, for example, our own embryonic development, when cells assume different roles. Some become kidney cells, others liver cells, and so on. Although they have the same DNA, liver cells and kidney cells look different and have different functions. In biologist jargon, they have the same genotype but different phenotypes. Moreover, they “breed true”: Kidney cells generate more kidney cells, and liver cells generate more liver cells, even though the stimuli that induced the different phenotypes in embryonic precursor cells are long gone. There must be some epigenetic mechanisms to ensure that a cell “remembers” what it was induced to be and transmit this “memory” of its altered state to daughter cells. This much is obvious. But surprisingly, we now know that cellular epigenetic variations are transmitted not only within organisms, but sometimes also between generations of organisms, via their sperm and eggs.

On the evolution of Darwin
Among a glut of new works on the great naturalist, Philip Ball finds the claim that a hatred of slavery motivated his studies
New Scientist says Darwin was wrong

Creationism to be taught in La. public schools
“Evolution is not a science. It’s as much a science as Christianity is. The majority of America is Christian, and we should acknowledge that in school,” said Sam Huff, LSU geography freshman.
Apparently, lawmakers in Louisiana agree with Huff.
According to local reports, the state’s top school board approved a policy on Jan. 15 to aid in teacher compliance with a new state law concerning the teaching of evolution in Louisiana’s public schools. The Louisiana Science Education Act, which was overwhelmingly passed by the state legislature last June without serious debate, claims to promote “students’ critical thinking skills and open discussion of scientific theories.”

The Act expressly allows teachers to provide supplemental reading material for their students, outside of state-approved textbooks, for the purpose of critiquing established scientific theories.

Natural Selection Not The Only Process That Drives Evolution?
ScienceDaily (Jan. 28, 2009) — Why have some of our genes evolved rapidly? It is widely believed that Darwinian natural selection is responsible, but research led by a group at Uppsala University, suggests that a separate neutral (nonadaptive) process has made a significant contribution to human evolution.

Ancient Wounds Reveal Triceratops Battles
ScienceDaily (Jan. 28, 2009) — How did the dinosaur Triceratops use its three horns? A new study led by Andrew Farke, curator at the Raymond M. Alf Museum of Paleontology, located on the campus of The Webb Schools, shows that the headgear was not just for looks. Battle scars on the skulls of Triceratops preserve rare evidence of Cretaceous-era combat.

Newborn Infants Detect The Beat In Music
ScienceDaily (Jan. 27, 2009) — Researchers at the Institute for Psychology of the Hungarian Academy of Sciences and the Institute for Logic, Language and Computation of the University of Amsterdam demonstrated that two to three day old babies can detect the beat in music.

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