Clipmarks | Aribeth's Evolution/Biology collection

Regulating Evolution

Tue, 22 Apr 2008 08:15:08 GMT

clipped by: wildcat

Because genes encode instructions for building animal bodies, biologists once expected to find significant genetic differences among animals, reflecing their great diversity of forms. Instead very dissimilar animals have turned out to have very similar genes.

Mutations in DNA “switches” that control body-shaping genes, rather than in the genes themselves, have been a significant source of evolving differences among animals.

If humans want to understand what distinguishes animals, including ourselves, from one another, we have to look beyond genes.

At first glance, the list of animals could suggest any zoo. There’s an elephant, an armadillo, an opossum, a dolphin, a sloth, a hedgehog, big and small bats, a couple of shrews, some fish, a macaque, an orangutan, a chimpanzee and a gorilla—to name a few of the more familiar creatures. But this menagerie is not at all like any zoo that has been constructed before

It is a “virtual” zoo that contains only the DNA

sequences

of those animals

Tags: genomes, diversity, variety, nature, mutations

1st time Darwin's Papers Online 4 Free

Thu, 17 Apr 2008 10:48:48 GMT

clipped by: syncopath

Clip Source: darwin-online.org.uk

Charles Darwin's Papers Online

For decades available only to scholars at Cambridge University Library, the private papers of Charles Darwin, one of the most influential scientists in history, can now be seen by anyone online and free of charge. This is the largest ever publication of Darwin papers and manuscripts, totalling about 20,000 items in nearly 90,000 electronic images.

This vast and varied collection of papers includes the first draft of his theory of evolution, notes from the voyage of the Beagle and Emma Darwin's recipe book.

These online images are scans from copies of early black and white microfilms produced by the Cambridge University Library Imaging Service, mostly in the 1990s. For online publication now a slight colour tint has been added to many and the brightness and contrast have been digitally enhanced.

First sketch of the theory of evolution, 1842

Theoretical notebooks

Drafts of Descent of Man

Review of Origin of Species, 1859

Human Evolution & Intelligence StudiesTrending Away From Reductionism

Tue, 08 Apr 2008 10:58:35 GMT

clipped by: Silkweaver

Clip Source: memebox.com

How strong are your genes? How smart are you? People have traditionally estimated answers to these questions based on genetic surveys and IQ Tests, which can provide valuable answers, but stop well short of factoring in the system(s) surrounding us.

Right now, we may be on the verge of a perspective shift that will help us to fill in a few more gaps and better our systems definitions. Both human intelligence and evolutionary studies appear poised for a due emphasis shift from reductionism (the focus on individual human agents and single brains) to a more holistic (the focus on large groups and the surrounding bio/info/tech structures) approach.

a new model, which demonstrates that environmental factors play a much larger role in the evolution of cognition than previously thought.

“industrialization’s rising cognitive demands

could in fact be the kind of widespread

changing environmental factor that could account for the higher IQ scores across so many nations.” (cont.)

Tags: evolution, human intelligence, cognitive development

Genes. Memes and Co-Evolution

Tue, 25 Mar 2008 17:16:26 GMT

clipped by: abailart
clipper's remarks: whole paper at site

Clip Source: www.susanblackmore.co.uk

The meme is an evolutionary replicator, defined as information copied from person to person by imitation. I suggest that taking memes into account may provide a better understanding of human evolution in the following way. Memes appeared in human evolution when our ancestors became capable of imitation. From this time on two replicators, memes and genes, coevolved. Successful memes changed the selective environment, favouring genes for the ability to copy them. I have called this process memetic drive. Meme-gene coevolution produced a big brain that is especially good at copying certain kinds of memes. This is an example of the more general process in which a replicator and its replication machinery evolve together. The human brain has been designed not just for the benefit of human genes, but for the replication of memes. It is a selective imitation device.

Most simply put, we have coevolution between replicators and their copying machinery

Tags: susan blackmore, meme/gene, replicators, culture and biology

On The Origin of Species: 150 years old

Sat, 09 Feb 2008 23:02:44 GMT

clipped by: JohnWaterman

Clip Source: www.guardian.co.uk

150 years ago, Charles Darwin unveiled his theory of natural selection. To mark this anniversary we bring you the definitive guide to the naturalist's great book, with extracts from key chapters and essays from leading scientists and thinkers

Why Darwin matters

The proof's in our genes

Keeping faith with natural selection

Extracts

Where do new species come from?

The struggle for existence

The driving force behind evolution

Why is the fossil record gappy?

At home with the Darwins

It ain't necessarily so ...

Feb 9 2008:

Everyone has heard of Charles Darwin. Yet a good part of what most people think and believe about the man is wrong. John van Wyhe clears up some of the myths

The book that changed the world

Feb 9 2008:

On the Origin of Species, an instant bestseller, drew both applause and fury, writes Tim Radford

How Darwin anticipated the "intelligent design" argument

Schizophrenia: The Curse That's Almost a Blessing

Wed, 14 Nov 2007 19:57:25 GMT

clipped by: Mohir
clipper's remarks: A recent study may have found what kind of process goes awry in schizophrenic brains. Researchers found that DISC1 regulates the migration of new neurons in the adult brain. When the levels of DISC1 were reduced in mice during adult neurogenesis, the newborn neurons sped up and overshot their intended targets within the hippocampus, When the neurons finally reached their destinations, they forged an unusual number of connections with neighboring cells, a series of events that might give rise to the abnormal—and quite crippling—brain functions associated with schizophrenia, according to Hongjun Song, a Johns Hopkins neurologist who also worked on the study. It is possible, Song says, that further research will lead to a drug that treats schizophrenia by restoring normal neurogenesis.

So what evolutionary advantage could schizophrenia-related genes bring to people who have some of the genes but not the disease? For now, this remains one of the many open questions.

Clip Source: discovermagazine.com

Schizophrenia: The Curse That's Almost a Blessing

The disease may be the twisted flipside of an evolutionary boost.

For years, scientists struggled to identify an adaptive advantage that might explain schizophrenia’s persistence. Researchers from various disciplines volleyed ideas back and forth. Some argued that the genes implicated in the disease promoted creativity; others believed that schizophrenics were frustrated cult leaders—unorthodox thinkers constitutionally “engineered” to lead segments of humanity to break off from the herd, but who lacked the charisma to effect much change. None of the theories gained much traction.

Tags: psychology, brain, schizophrenia, evolution