“Sam May: Taking science classes requires right chemistry - Post-Bulletin” plus 4 more

Sam May: Taking science classes requires right chemistry - Post-Bulletin
Birds Provide Clues in How Humans Learn Speech - Kansas City infoZine
Good mutations: Stalking evolution through genetic mutation in plants - Scientific American
Four Springfield teachers reach a career high - MontgomeryNews.com
Studying Ancient Humans Using Modern Sequencing Techniques - Redorbit.com

Sam May: Taking science classes requires right chemistry - Post-Bulletin

Posted: 01 Jan 2010 08:10 AM PST

This year, I am taking physics.

Last week, I mentioned to my freshman biology teacher, Eric Stanslaski, that I believed physics to be easier than biology. He agreed with me, and we discussed why physics was easier.

The conversation led to the teaching order of biology, chemistry and physics. They are taught in that order, but we agree that it would be much more logical to teach physics first, then chemistry, and biology last. I had thought about the subject before and thought my logic was sound, but I was nevertheless surprised when I realized that a science teacher agreed with me.

There is a freshman prerequisite to biology, physical science, but this has a few weaknesses. For one, freshman who go right into the honors science class go to biology honors, skipping physical science completely. I am in this category. Also, physical science doesn't go into the same depth needed for biology.

I remember looking at covalent and ionic bonding in biology. It was meant to be mostly review, but there were many freshmen who hadn't taken physical science and sophomores who didn't know enough to understand. Therefore, we had to spend time going over the topic.

Chemistry provides good insight to the topics that physical science didn't fully explain. Sticking with covalent and ionic bonding, we spent a fair amount of time on the subject in chemistry. Had we taken chemistry first, we wouldn't have had to take extra time to review, and would have been able to get much deeper into the subject.

The relationship is similar with chemistry and physics. Physics, however, doesn't require the same level of previous knowledge that the other two do.

The difficulty factor isn't that significant, either. I personally think physics is easier than biology. Physics is a lot of math -- identify what number goes where in which equation, then solve.

Chemistry still contains a lot of math, but there is also a hefty dose of other material. For example, the layout and design process of the periodic table.

Biology doesn't have much math at all, but there is a lot of material, nonetheless. Remembering the different families of creatures in the animal kingdom, for example, or analysis of genetics.

Switching the order that these classes are taught could also serve to eliminate physical science completely, opening the way for students who didn't take biology honors in their freshman year to take any science class they want in their senior year that they otherwise couldn't have due to prerequisite requirements.

I've tutored students in physical science, so I've seen enough overlap from chemistry and physics to cover all of physical science. There are definitely outstanding benefits to changing the order of the science classes.

Sam May is a junior at John Marshall High School. To respond to an opinion column, send an e-mail to life@postbulletin.com.

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Birds Provide Clues in How Humans Learn Speech - Kansas City infoZine

Posted: 01 Jan 2010 03:53 AM PST

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... understanding how language develops, we need to look at all the evidence, and that includes what we can learn from biology," said Howard Nusbaum, Chair of Psychology and an expert on speech development. Researchers have long studied vocal ...

Good mutations: Stalking evolution through genetic mutation in plants - Scientific American

Posted: 01 Jan 2010 08:10 AM PST

plant mutation genetic evolution Thale cress (Arabidopsis thaliana) has one of the smallest genomes in the plant kingdom and is a laboratory darling around the world owing to its relatively short code. First sequenced in 2000, the humble weed has only 120 million base pairs in its genome (humans, by contrast have about 2.9 billion), but it still packs plenty of genetic mystique.

A new study has uncovered the rate of the plant's spontaneous mutations as they happen across generations—a finding that could help illuminate the evolutionary history of plants and selective breeding efforts in the future.

"While the long-term effects of genome mutations are quite well understood, we did not know how often new mutations arise in the first place," Detlef Weigel, director at the Max Planck Institute in Germany, and coauthor of the study which appeared online Thursday in Science, said in a prepared statement.

The group studied genetic changes of five different plant lines across 30 generations. After carefully comparing each full genome, they found that only about 20 base pairs had mutated in each line.

"The probability that any letter of the genome changes in a single generation is thus about one in 140 million," Michael Lynch of the Department of Biology at Indiana University in Bloomington and study collaborator, said in a statement.

Locating these small numbers required some high-powered sequencing. "To ferret out where the genome had changed was only possible because of new methods that allowed us to screen the entire genome with high precision and in very short time," Weigel said. Despite the new sequencing capabilities, the team still rechecked each letter's position 30 times to make sure suspected mutations were being accurately assessed. As high-throughput sequencing becomes more widely available, researchers should be able to conduct more mutation-rate studies. One ongoing study at Michigan State University that is tracking evolutionary change in E. coli, for example, has analyzed hundreds of mutations across 40,000 generations of the bacteria.

The new findings might prove to be more than a simple gee-whiz figure. This study revealed that mutations were occurring at about the same rate across the full genome—not just in specific parts. This might help explain why efforts to keep some plants at bay with single-gene-targeting herbicides are often only briefly successful. It should also hearten researchers who are searching for ways to improve crops—making them more drought-tolerant or better producers—to know that these mutations are likely already occurring. But to truly expedite strategic breeding for many crops, full genome sequencing, as was recently accomplished for corn, will be crucial to giving horticulturalists a genetic map to different traits.

The group has also been able to use the findings to peer back into Arabidopsis thaliana 's genetic past. Previously, researchers had speculated that it and its closest relative, Arabidopsis lyrata, had split about five million years ago. The new genetic data suggests a divergence at least 20 million years ago.

Although these results are from a lowly mustard relative, the data might also have implications for understanding human genetic change.

"If you apply our findings to humans, then each of us will have on the order of 60 new mutations that were not present in our parents," Weigel said. A study published in Current Biology in August estimated that each individual had something more along the lines of 100 to 200 new mutations. Whatever the exact number, the modest mutation rate can have a big impact when spread across some six billion individuals. And even though natural selection usually appears to work on a relatively slow timescale, with so many mutations, nature can be assaying new combinations all the time. "Everything that is genetically possible is being tested in a very short period," Lynch said.

Image courtesy of Wikimedia Commons/Suisetz

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Four Springfield teachers reach a career high - MontgomeryNews.com

Posted: 01 Jan 2010 05:54 AM PST

Newly board-certified teachers in the School District of Springfield Township are, from left, Joyce Huff, Lori Pinelli, Rosemarie Becker and Debbie Smith. Staff photo by BOB RAINES

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By Amanda Glensky
Staff Writer

Four teachers from the Springfield Township School District have met what are viewed as the highest teaching standards in the country, an intense process they said made them focus and reflect on how they teach and how they impact their students.

As of 2009, middle school librarian Rosemarie Becker, fifth-grade teacher Lori Pinelli and high school biology teacher Deborah Smith are now National Board Certified Teachers.

Enfield first-grade teacher Joyce Huff earned recertification in 2009. She was first National Board certified in 2000, making her the first teacher in the district and one of the first in the state to earn the honor, she said.

The National Board for Professional Teaching Standards, which developed this certification, is a nongovernmental organization that works to "advance the quality of teaching and learning," according to its Web site.

The Springfield teachers said the process, which takes from about one to three years to complete, required completion of portfolios, assessments, measuring student success and critiquing videos of themselves teaching.

The teachers said it was an involved process, but worth the end result because it made them better at what they do.

"It was a very reflective process in which I had to think about what I do with students and how effective I am," said Becker, certified in library media, K-12. "I have made changes in some of my teaching practices and have created some new practices based on the work that I did. So, I think the process was very positive."

Becker, who has been at the middle school for 17 years and a school librarian for 20, said the requirements challenged her in the areas of technology, literature and library administration to measure the result on student learning of what she does.

"I love my job and I want to be vibrant and effective in it. Working on National Board Certification was simply a challenge I wanted to take," she said.

Pinelli, certified in early adolescent math, said the process required her to think about "evidence of learning" in the classroom. She had to look past a student's grades and figure out how she could fill the gap between the grade and 100 percent, she said.

"It does make you a better teacher as you grow throughout the process," said Pinelli, who came to the middle school in 2003. "It was tough — it was very stressful — but, I think there were a lot of positive things to come out of it."

The teachers also said the chance to work with their colleagues both within and outside of Springfield was rewarding.

Deborah Smith teaches anatomy and physiology, honors and academic biology, AP biology and environmental science at the high school, where she has been working for 19 years.

Huff, who has been a teacher in Springfield for 20 years, is National Board Certified as an early childhood generalist, meaning she can teach all subjects to students from 3 to 8 years old.

To earn recertification, she had to prove she has grown as a teacher and made a difference in the profession and to her students, she said.

If teachers do not submit enough documentation, they cannot receive the credentials, she said.

"It's an honor, and it's also a way for me to prove that I am a true professional. This means a lot to me," she said. "It's a chance for me to reflect on how I teach, too. I have to analyze what I do and answer to myself why I do it and how I can do it better."

The teachers will be recognized at the next school board meeting on Jan. 5.

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Studying Ancient Humans Using Modern Sequencing Techniques - Redorbit.com

Posted: 01 Jan 2010 06:23 AM PST

Posted on: Friday, 1 January 2010, 08:26 CST

DNA that is left in the remains of long-dead plants, animals, or humans allows a direct look into the history of evolution. So far, studies of this kind on ancestral members of our own species have been hampered by scientists' inability to distinguish the ancient DNA from modern-day human DNA contamination. Now, research by Svante Pääbo from The Max-Planck Institute for Evolutionary Anthropology in Leipzig, published online on December 31st in Current Biology — a Cell Press publication — overcomes this hurdle and shows how it is possible to directly analyze DNA from a member of our own species who lived around 30,000 years ago.

DNA — the hereditary material contained in the nuclei and mitochondria of all body cells — is a hardy molecule and can persist, conditions permitting, for several tens of thousands of years. Such ancient DNA provides scientists with unique possibilities to directly glimpse into the genetic make-up of organisms that have long since vanished from the Earth. Using ancient DNA extracted from bones, the biology of extinct animals, such as mammoths, as well as of ancient humans, such as the Neanderthals, has been successfully studied in recent years.

The ancient DNA approach could not be easily applied to ancient members of our own species. This is because the ancient DNA fragments are multiplied with special molecular probes that target certain DNA sequences. These probes, however, cannot distinguish whether the DNA they recognize comes from the ancient human sample or was introduced much later, for instance by the archaeologists who handled the bones. Thus, conclusions about the genetic make-up of ancient humans of our own species were fraught with uncertainty.

Using the remains of humans that lived in Russia about 30,000 years ago, Pääbo and his colleagues now make use of the latest DNA sequencing (i.e., reading the sequence of bases that make up the DNA strands) techniques to overcome this problem. These techniques, known as "second-generation sequencing," enable the researchers to "read" directly from ancient DNA molecules, without having to use probes to multiply the DNA. Moreover, they can read from very short sequence fragments that are typical of DNA ancient remains because over time the DNA strands tend to break up. By contrast, DNA that is younger and only recently came in contact with the sample would consist of much longer fragments. This and other features, such as the chemical damage incurred by ancient as opposed to modern DNA, effectively enabled the researchers to distinguish between genuine ancient DNA molecules and modern contamination. "We can now do what I thought was impossible just a year ago – determine reliable DNA sequences from modern humans - but this is still possible only from very well-preserved specimens," says Pääbo.

The application of this technology to the remains of members of our own species that lived tens of thousands of years ago now opens a possibility to address questions about the evolution and prehistory of our own species that were not possible with previous methods, for instance whether the humans living in Europe 30,000 years ago are the direct ancestors of present-day Europeans or whether they were later replaced by immigrants that brought new technology such as farming with them.

The authors include Johannes Krause, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Adrian Briggs, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Matrin Kircher, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Tomislav Maricic, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Nicolas Zwyns, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Anatoli Derevianko, Russian Academy of Sciences, Novosibirsk, Russia; Svante Paabo, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.

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