Modern human mothers are probably happy that they typically have one, maybe two babies at a time, but for early hominids, low birth numbers combined with competition often spelled extinction.

"The lineages of primates have some traits that make it hard for them to respond to rapid perturbations in the environment," says Dr. Nina G. Jablonski, professor of anthropology and department head at Penn State. "Through time we see a lot of lineages become extinct when environments where the species are found become highly seasonal or unpredictable."

Primates evolved in the Paleocene and Eocene when worldwide climate was less seasonal. The beneficial environment allowed primates to evolve as relatively brainy animals that reproduce slowly.

A scientific panel revealed today that rising global demand for healthy seafood has exceeded wild capture fisheries' ability to provide all fish meals demanded by consumers. Aquaculture -- or the farming of seafood -- is helping to fill the gap between sustainable wild supplies and the public demand for seafood. Research unveiled at the AAAS Annual Meeting demonstrated the enormous potential for sustainable growth of healthy farmed seafood production, notably through advancements in feed efficiency and the ability to expand production in marine environments.

The notion that more information about the science of human-caused climate change will spur effective problem solving by American society is just flat wrong, according to a University of Colorado at Boulder climate policy analyst.

Even the 2007 Intergovernmental Panel on Climate Change report released Feb. 2, which painted a bleak global portrait of rising seas and temperatures due to human activity, is unlikely by itself to lead to meaningful mitigation or adaptation anytime soon, said Lisa Dilling of CU-Boulder’s Cooperative Institute for Research in Environmental Sciences. “Most people still don’t feel the immediacy of the problem,” she said.

An international team of researchers from 19 countries has identified one gene and a previously unidentified region of another chromosome as the location of another gene that may contribute to a child's chances of having autism.

The findings, based on genetic samples from nearly 1,200 families with two or more children who have autism, were published today in Nature Genetics by more than 120 scientists from Europe and North America who make up the Autism Genome Project.

The project was launched in 2002 by scientists at 50 institutions to share data, samples and expertise in an effort to speed up the process of identifying susceptibility genes, those that heighten a child's risk of having the developmental disorder.

Though the cell membrane is a protective barrier, it also plays a role in letting some foreign material in — via ion channels that dot the cell’s surface. Now new research from the Nobel Prize-winning laboratory that first solved the atomic structure of several such channels shows that their function is controlled in part by a complex interaction between a channel’s voltage sensor and the cell membrane immediately adjacent to it.

The cell membrane is a specialized environment, home to a variety of proteins that enable the cell to interact with its environment. One specific family of proteins, voltage-gated channels, are especially important in conducting signals along and between nerve cells.