Look Alikes Aren't Always CopyCats

Dolphins and sharks look alike and live in the ocean, but most people regard them as different types of animals: dolphins are mammals with hair and mammary glands so they are more like us than sharks which have gills and are more like other fish.

Scientists call this phenomenon convergent evolution, and there are examples of it in all forms of life. Bats and birds fly and have wings, cacti and euphorbias have spines and grow in deserts, and koalas and humans have finger prints. These organisms are considered by science to have acquired these traits independently of each other - sometimes in response to similar environments.

For the scientist it can be exciting to identify examples of convergent evolution. However a recent study of giant plants suggests that the designation may be given erroneously if not enough lines of inquiry are pursued.

The giant Lobelia is found globally. Its range includes eastern Africa, the Hawaiian Islands, South America, French Polynesia and southeast Asia. Lobelias are most often found as small, herbaceous plants commonly used as ornamentals. So when the various populations of giant Lobelias were discovered spread across the world, it was assumed that this was an example of convergent evolution: that the herbaceous Lobelia will evolve the giant form in response to particular environments.

Alexandre Antonelli published in BMC Biology that all the giant Lobelias are actually related to each other. Scientists call this a monophyletic group meaning they come from a common ancestor and more importantly the giant form of the plant evolved once and all the giant Lobelias today come from that originating population. Antonelli used molecular analysis to establish this close relationship. He found that the giant Lobelias probably came from eastern Africa between 25 and 33 million years ago.

He concludes his paper stressing that there be careful analysis before making assumptions about morphological development and convergent evolution in all organisms.

Click here to read the original article

copyright 2009 Brendan Craughwell. All rights reserved. SCIENTIFIC STATION is a trademark of Brendan Craughwell. All rights reserved.

Obese? Not Me! Tell the Fat Guy.

Overweight, Normal, or Underweight most of us mis-perceive our actual body size.

Tiffany Powell reported at the American Heart Association Science Sessions that obese people who mis-perceive their ideal body size have double trouble: they already have increased risks associated with obesity and they think they are smaller than they should be.

5893 people who participate in the Dallas Heart Study were asked to self-identify their body size as below normal, normal, or above normal. The difference in perceived body size was compared with the subject's actual body size.

Those with below normal or normal body sizes generally self-identified as being larger than their ideal. Those with above normal body sizes saw themselves as being below their ideal.

The people who underestimated their larger than ideal body size were more likely to be female, African American, had a higher body mass index, higher systolic blood pressure, and higher insulin resistance.

Powell concluded that addressing this mis-percerption may be important in preventing and treating obesity.

Click here it read the research abstract

copyright 2009 Brendan Craughwell. All rights reserved. SCIENTIFIC STATION is a trademark of Brendan Craughwell. All rights reserved.

Last Chance for a World Without HIV and AIDS - Scientific Station™ - 20 November 2009

Read the research article

Last Chance for a World Without HIV and AIDS by Brendan Craughwell

Robert Smith and fellow researchers in Canada propose in the journal BioMedical Central that we may now have our last, best chance at eradicating HIV and AIDS.

And the way to get rid of it. . .money.

$60 billion dollars has been raised to spend on treating HIV and AIDS for the next 20 years. This money will be held in reserve and released incrementally.

The researchers developed a mathematical model demonstrating that with population growth and global migration HIV will perpetuate itself in humans despite this 20 year plan.

However, the model predicts that if the plan is modified and funded at $63 billion over 5 years, eradication may be possible.

This linear differential equation model divides the world by regions and directs the spending in each region to achieve a 2/5 reduction in the HIV infection rate by focusing on education and condom distribution.

Eradication must occur on a global scale to be effective.

Should these interventions not be made, the model predicts that in twenty years HIV eradication will no longer be possible due to the high cost of dealing with a larger world population.

copyright 2009 Brendan Craughwell. All rights reserved. SCIENTIFIC STATION is a trademark of Brendan Craughwell. All rights reserved.

I'll have a TofuPup, but does it taste like fish now? - Scientific Station™ - 17 November 2009

Soybeans are used for a variety of foods: tofu, soy milk and edema-me. Lines of genetically engineered soybeans have been developed to manufacture a precursor of one of the Omega-3 fatty acids used to promote heart health.

Stearidonic acid also called SDA is converted into this Omega-3 in our bodies.

We usually get this particular Omega-3 from fish. William Harris of the Stanford Medical School tested whether or not SDA from these soybeans worked as well as fish oil at raising our blood Omega-3 levels. His finding is that SDA derived from modified soybeans produces statistically significant increases in blood Omega-3 levels.

This means soybeans may become a major source of Omega-3 in our diets in the future.
Regulatory testing is still underway for the soybeans, so it will be a few years before it hits the shelves.

This study did not address the taste of the oil.

copyright 2009 Brendan Craughwell. All rights reserved. SCIENTIFIC STATION is a trademark of Brendan Craughwell. All rights reserved.

Look Me In The Eye! - Scientific Station™ - 14 November 2009

Look me in the eye

Attention seeking at first glance seems to be a purely human quality. However our reliance on vision is rooted in primate evolution. Seeing has helped us find better food, safer housing, and more attractive mates.

Vision has become so important to us that we first seek out others' eyes in new situations. It worries us when others do not return our glance.

Jeffrey Klein, Stephen Shepherd and Michael Platt published a review in Current Biology examining the neural circuits that mediate visual information and influence our social attention.

Not only who looks at us, but who we are looking at and how "betrays much about our own identity" the authors write "who we are, where we come from, our gender, age and social status" are all on display in our gaze.

Click here to visit the original article


copyright 2009 Brendan Craughwell. All rights reserved. SCIENTIFIC STATION is a trademark of Brendan Craughwell. All rights reserved.

Womb Acoustics - Scientific Station™ - 5 November 2009

When do we learn to talk? Just published research suggests human fetuses in their third trimester are acquiring language they hear from their families.

copyright 2009 Brendan Craughwell. All rights reserved. SCIENTIFIC STATION is a trademark of Brendan Craughwell. All rights reserved.

Hungry, Hungry Lions - Scientific Station™ - 3 November 2009

How many people did the lions who hunted the Uganda Railroad construction in 1898 eat?

Using carbon and nitrogen isotope ratios from the killer lion carcasses, an article in the Proceedings of the National Academy of Sciences estimates the lions at 35 people in 1898.

copyright 2009 Brendan Craughwell. All rights reserved. SCIENTIFIC STATION is a trademark of Brendan Craughwell. All rights reserved.