Evolución (Continuación)

Durante el mes de enero se organizó en España un ciclo de conferencias que, bajo el título Lo que Darwin no sabía, se ha constituido en la primera gran ofensiva iniciada por los grupos religiosos ultraconservadores estadounidenses que pretenden, mediante la crítica de la Teoría Evolutiva, extender la idea de que el Creacionismo (en los últimos tiempos denominado Diseño Inteligente, DI) puede considerarse una teoría científica. Las "conferencias" no son tales, y mucho menos científicas; son actos propagandísticos perfectamente diseñados para persuadir a un público desprevenido y de profundas convicciones religiosas que suele ser el perfil de la mayor parte de los asistentes.…  Seguir leyendo »

El brillo de las estrellas que observamos en una noche despejada es resultado de emisiones de luz que tuvieron lugar en astros lejanos en un pasado muy remoto, e incluso algunos de los brillos que contemplamos actualmente pertenecen a estrellas ya extintas. De manera similar, los genes que portamos son el rastro heredado de antepasados que pertenecían a poblaciones que ya no existen. Alo largo de la vida, nuestro genoma va acumulando pequeñas diferencias, pequeños cambios. Algunas de estas mutaciones son responsables de nuestro envejecimiento y quizás del desarrollo de alguna enfermedad. Sin embargo, gran parte de ellas no provoca ningún efecto y una pequeña porción la transmitimos a nuestra descendencia.…  Seguir leyendo »

In our sound-bite political culture, it is unrealistic to expect that every complicated issue will be addressed with the nuance or subtlety it deserves. So I suppose I should not have been surprised earlier this month when, during the first Republican presidential debate, the candidates on stage were asked to raise their hands if they did not “believe” in evolution. As one of those who raised his hand, I think it would be helpful to discuss the issue in a bit more detail and with the seriousness it demands.

The premise behind the question seems to be that if one does not unhesitatingly assert belief in evolution, then one must necessarily believe that God created the world and everything in it in six 24-hour days.…  Seguir leyendo »

Los neandertales fueron la única línea humana típica de Europa: los verdaderos europeos. Aparecieron a partir de la evolución del Homo heidelbergensis hace 250.000 años. En su máximo esplendor ocuparon no sólo todo el continente, sino que llegaron al Próximo Oriente y a Uzbekistán, en Asia Central. Son centenares los yacimientos arqueológicos que presentan restos de su actividad a lo largo de una evolución de más de 200.000 años hasta el momento de su extinción, 25.000 años atrás. Precisamente es noticia reciente la datación del conjunto de la cueva Gorham en Gibraltar, donde hemos sabido que, como mínimo, hace 28.000 años aún vivían neandertales en el extremo sur de la península Ibérica cuando prácticamente todo el continente ya estaba ocupado por unos recién llegados, los Homo sapiens,nuestra especie, hace 40.000 años.…  Seguir leyendo »

Science Notebook by Terence Kealey, the Vice-Chancellor of the University of Buckingham (THE TIMES, 30/10/06):

When I was still at school a boy once rushed into the classroom crying that Darwin had been proved wrong — not by one of those lunatic creationists but by a fellow scientist. The scientist was Stephen Jay Gould and he worked as a biologist at Harvard.

Darwin had suggested that evolution was a gradual phenomenon, and that species were always changing to meet new environmental challenges. But Gould noted that the fossil evidence suggested that, actually, many species survived unchanged for hundreds of millions of years, and that stability, not change, seems to be the normal fossil record.…  Seguir leyendo »

By Lynne A. Isbell, a professor of anthropology at the University of California, Davis (THE NEW YORK TIMES, 03/09/06):

Snakes hit a nerve in people. How else to explain why the movie “Snakes on a Plane” became an Internet sensation months before it was released in theaters? The very idea was all it took to rouse attention.

That humans have been afraid of snakes for a long time is not a fresh observation; that this fear may be entwined with our development as a species is. New anthropological evidence suggests that snakes, as predators, may have figured prominently in the evolution of primate vision — the ability, shared by humans, apes and monkeys, to see the world in crisp, three-dimensional living color.…  Seguir leyendo »

By Olivia Judson, a research fellow in biology at Imperial College London, is the author of Dr. Tatiana's Sex Advice to All Creation. In June, her column The Wild Side will appear on the TimesSelect Web site (THE NEW YORK TIMES, 28/05/06):

Ever since scientists realized that the fossilized bones of ichthyosaurs and mastodons were relics of organisms past, debates have raged about what fossils mean for our understanding of the history of life on Earth, and especially of evolution. No longer. Fossils have become unnecessary to the argument: since we've learned to sequence whole genomes, we've had far more powerful ways to examine the past.…  Seguir leyendo »

By Dean Falk, chairwoman of the anthropology department at Florida State University, is writing a book on mother-infant communication (THE NEW YORK TIMES, 14/05/06):

On Mother's Day, it's customary to speak about the sacrifices our mothers made to improve our lives. But mothers also deserve credit for the pivotal role they've played in the story of human evolution. Prehistoric mothers did nothing less than seed the development of our species' remarkable intelligence.

The story begins at least two million years ago, when our brains started to grow larger, eventually making humans the most cognitively advanced species on earth. This evolution was not without its difficulties, particularly for mothers.…  Seguir leyendo »