Tuesday, January 31, 2012

"Science" Programming

PhD Comics hits another one out of the park. This one is so true. I'm going to date myself by starting a sentence with "When I was a kid..."

When I was a kid the science channels had actual science and animal shows on them. Shows featuring Mr. Wizard showing some kid how science is cool, lions chasing down antelope on the Serengeti, weird and wonderful insects, crocodiles leaping from the water at wildebeest, etc. etc. etc. These days I've just resorted to calling Animal Planet, "Pet Planet" instead (not that I have anything against pets, I just don't need to watch a psychic communicate with a dog).

(via PhD Comics)

Sunday, January 29, 2012

Science vs. Skeptics

An interesting infographic. A concise layout of some of the arguments from global warming deniers/skeptics vs. the consensus from the science community. Science isn't exactly known for short explanations about things, to the point where concise often looks like brushing off the issue. But this gives you a nice starting point for looking in to the issue and learning about the actual data, as well as some good discussion points.


(via visual.ly)

Saturday, January 21, 2012

The Math of Being a Plant: Fibonacci Numbers

Another really cool video from ViHart about Fibonacci numbers in the structuring of plants.

Mind = Blown

Bring on the Stupid

Have you ever tried to talk to a guy when he's talked to a pretty woman? It's like talking to a brick wall. He's got eyes, and other parts, only for her. If a bomb were to drop at his feet he might not even notice. It is so common an occurrence that books and movies frequently feature men who are trying hard to impress a beautiful woman and in so doing manage to be at their clumsiest, most forgetful, and dumbest. So I suppose that it was only a matter of time before there was a study about it.

A couple of previous studies have shown that men's cognitive performance is depleted after a short interaction with an attractive woman, particularly if the man is trying hard to impress her. This behavior has been shown to be taxing on the brain because they are trying so hard to control and manage their behavior. Merely anticipating an interaction with a woman can render a man virtually brain dead. Then there's what are called "pseudo-interactions" in which a man and woman do not communicate face-to-face (telephone, Internet, texting, etc.). In our technologically advancing world, these pseudo-interactions are becoming more and more commonplace. Anticipating an interaction and pseudo-interactions are similar in that men frequently know little to nothing about they woman they are (or will be) corresponding with, and if they have not yet met he has no idea if she is attractive or single or whatever. One of the aims of the paper in today's post was to determine if men's cognitive performance decreased after one of these pseudo-interactions with a woman. The second part of the study looked at anticipation and a man's motivation to make a good impression.

The first experiment expected that men would perform worse on simple tasks after a pseudo-interaction with someone of the opposite sex than after a pseudo-interaction with someone of their own sex. They found that women were not influenced. Men, however, showed a decline in cognitive performance after interaction with a woman even though there was no actual face-to-face contact, and they didn't even know what she looked like. The second experiment expected that men (but not women) would perform worse at simple tasks if they anticipated a mixed-sex interaction than if they anticipated a same-sex interaction. Again, females were not influenced. They found that just the anticipation of interacting with a woman influenced a man's cognitive performance, and it wasn't in the positive direction.

What did we learn from this study? Something as small as mentioning a female name instead of a male name is enough to make men dumber (at least temporarily). Add to that, sitting in the same room with a woman, talking to her on the phone, chatting with her online, or just anticipating that he might meet up with a woman is enough to render a man thinking-impotent.

Guys, it's truly amazing you function at all.

Read the complete study here:
Nauts, Sanne, et al. (2010) The mere anticipation of an interaction with a woman can impair men's cognitive performance. Archives of Sexual Behavior: published online 01 November 2011. (DOI: 10.1007/s10508-011-9860-z)

Friday, January 20, 2012

One-Third for the Birds

For this post I was looking for something a little different. Not so much a weird topic, but more like a topic that I haven't really posted on before. I came across an interesting article about predator-prey relationships as they relate to population sizes. It is one of those basic dynamics that is taught in almost every biology and/or ecology class there is, and rightfully so, because when you get down into it it is actually pretty interesting, no to mention really important.

Most people think they know predator-prey relationships. One thing eats another thing. The organism doing the eating is the predator and the one that is eaten the prey. That is perfectly true. Now think about it in terms of evolution. The predator and the prey evolve together, what is usually referred to as the "evolutionary arms race." If the predator does not catch any food then it does not survive; those that evolve better ways to catch food survive (speed, stealth, smell, sight, etc.). If the prey gets caught by the predator then it (obviously) does not survive, and so it evolves better ways to evade predators (camouflage, speed, poison, etc.). It is important to point out that both the predator and they prey are both adapting, a type of co-evolution. Next, think about the system in terms of population. The interaction of predators and prey greatly affect their population sizes, often on several levels within the food chain/web (or tropic pathway/cascade). When predators eat prey they: (1) decrease the population size of the prey, (2) survive, thereby not decreasing their own population, and (3) are healthy, and alive, enough to breed additional predators, increasing their population. So when there are lots of predators you see a big dip in the size of the prey population. You will can make the same types of conclusions when you take the point of view of the prey. When prey is eaten by the predator: (1) they are removed from the population, decreasing population size, (2) are no longer healthy and alive to reproduce, (3) release their food source (if there is one) to increase their population, and (4) by decreasing their population there is that much less food for their predators. These interactions can result in very predictable, natural boom and bust cycles within these populations and is more the focus of today's topic. If you want pictures and graphs then check out the classic lynx-hare relationship and the Lotka-Volterra Model.

A new paper published in Science takes a look at the role of top predators in marine ecosystems. These upper tropic level (UTL) species include seabirds, marine mammals, and large predatory fish. All groups that have been depleted due to human activities. Fisheries impacts cause direct mortality in the targeted species and indirect, often more subtle, mortality lower down in the food chain/web. Fisheries that specifically target lower tropic level (LTL) species (small fish, squid, crustaceans, etc.) threaten those higher tropic level species by directly removing their food sources. However, it can be very challenging to assess the impacts of fishing on food webs, an ecosystem level approach. Think about it: all those predator-prey interactions in the ocean. That's tough. Often what you see is studies, even large ones, taking on a big chunk of the system, modeling how it works based on gathered data, and drawing conclusions or feeding it into an even bigger model. This study in Science specifically looks at seabirds.

Figure 1: A map of the distribution of
seabird and prey species. (click for
larger view)

Seabirds are a good system because they are conspicuous members of the marine ecosystem globally, have been studied and measured for decades, can reflect change at several scales, long-term breeding datasets from several species in several environments exist, and data from systems where prey availability has been measured suggests that seabirds can be used as indicators for forage fish population fluctuations. This study looked at the response between seabird breeding success and forage fish abundance across various species and ecosystems. The modellers compiled 438 data points spanning 15 to 47 colony-years per breeding site, in a total of seven marine ecosystems spanning 19 time series, 14 seabird species and their prey. They crunched a whole lot of numbers, using statistical methods that I'm not going to mention here, to quantify the fluctuations in food abundance and breeding success.

They found something that you usually don't see when you crunch that much data - all their species showed the same response. The results showed that the number of fledglings per breeding pair started to decline and was more variable when their forage fish food source dropped below one third of its maximum observed amount. The prey becomes scarce and as a result the hunting becomes more inefficient. The birds do not have enough food to successfully raise that many young.

Sure, there are the normal high and low cycles that I mentioned at the beginning, and those are natural. However, adding high rates of fishing from humans into it and, as with many other systems, we exacerbate the problem or collapse the system completely. The fish populations never recover from low seabird numbers because predation and habitat destruction by humans still puts a large amount of pressure on the fish, causing chronic food scarcity for the birds. And, as this study shows, this scarcity can have long-term affects on breeding success, can reduce survival in adult birds, and may affect the trajectory of their populations. The thresholds revealed by this study should inform management objectives in balancing predator-prey interactions, a "keep one-third for the birds" approach. If done well, these management decisions can sustain healthy UTL predator populations, maintain LTL fish populations, and could be applied to other marine ecosystems.

Read the paper here:
Philippe M. Cury, et al. (2011) Global seabird response to forage fish depletion -- One-third for the birds. Science: 334(6063), 1703-1706. (DOI: 10.1126/science.1212928)

And a write-up in ScienceNOW called "A Surprising Threshold for Seabird Survival"

Learn more about predator-prey interactions at
University of Michigan's Introduction to Global Change Curriculum's "Trophic Links: Predation and Parasitism"
New England Complex Systems Institute (NECSI)'s Predator-Prey Relationships page
University of Wisconsin-Madison's SSCC page on Predator-Prey Models (Warning: Contains potentially scary math)
A neat demo from Wolfram of a Predator-Prey Model of foxes and rabbits

Also, revisit my post called "To Eat or Not to Eat, That is the Fishy Question" to learn more about how to purchase seafood from green stores or restaurants and guides on choosing the correct seafood.

(image from readysetwhoa.wordpress.com)

Friday, January 13, 2012

The Math of Being a Plant: Spirals

This is really interesting. ViHart shows us how the math of spirals applies to plants, all through doodling.

Antarctic Sauropods: No Longer a Cold Case

Credit: Charles R. Knight; (inset) Cerda/Naturwissenschaften
Saurischia  is one of the two orders of dinosaurs. The name translates to "lizard-hipped," meaning that the pelvis of these animals consists of three elements: the ilium, ischium, and pubis. The orientation of the pubis, in particular, is such that it points downward and forward at an angle to the ischium.. The saurischian dinosaurs are then divided into two major groups: Sauropoda (large herbivores) and Theropoda (bipedal carnivores). Sauropoda is the second most diverse group of dinosaurs with more than 150 valid recognized species. This group of dinos also includes the largest terrestrial vertebrates to have ever existed, with the smallest growing to 20 feet long. Typically, the animals in this group had very long necks and tails, relatively small skulls and brains, and thick, pillar-like legs. They were a long-lived group, evolutionarily speaking, spanning 100+ million years, appearing in the Late Triassic and becoming widespread during the Mesozoic. They fed on various plant species of the time, either aquatic or terrestrial, and were very likely gregarious, forming herds. To this day, sauropods are some of the most recognizable dinosaurs there are. They are an extremely widespread group and have been found on every continental landmass except Antarctica. Until now.

A new paper in the journal Naturwissenschaften reports on a new sauropod fossil find in Antarctica. Consider your average paleontological expedition: the hiking, the fossil hunting, the hammering, the tiny little brushes. Now consider all of that in the frozen land that is Antarctica. Despite these arduous collecting conditions, there have been some important fossil finds on this continent in the last couple of decades, particularly in the James Ross Basin. If you are familiar with Antarctic geography, or just search for Google a map of it, then you'll notice that the James Ross Basin is located in the Weddell Sea, adjacent to the northern part of the Antarctic Peninsula. Yep, that's marine. However, there are exposed areas on James Ross, Vega, Snow Hill, Seymour, and Cockburn islands that expose shallow marine shelf deposits of the Upper Cretaceous and Paleogene sedimentary sequence and the fossils buried within it. This is where the new bone was located.

Figure 2 *
The new sauropod fossil is from the tailbone of a sauropod exhibiting common characteristics of advanced titanosauriform sauropods (Titanosauria), particularly lithostrotian titanosaurs. Titanosauria includes over 40 known species that range in size from dwarf (size reduction through evolution) to gigantic (including some of the heaviest of the dinosaurs). These dinosaurs had small (even when compared to other sauropods), wide heads with large nostrils and spoon-like teeth. They had relatively short necks (again, in comparison to other sauropods) and long whip-like tails. Titanosaurs also had slimmer hips but a wider chest, giving them a wide-gauged stance, resulting in broader tracks. Lithostrotian titanosaurs originated during the Early Cretaceous and were the predominant group of sauropods until the mass extinction at the end of the Cretaceous. They have been found on all continents, but are particularly abundant in South America.

So how did this species get to Antarctica? The scientists have two hypotheses:

1. The presence of the titanosaur is a result of a dispersal event from South America through a paleoisthmus (a long ago land bridge) between Patagonia and the Antarctic Peninsula during the Late Cretaceous . This is a hypothesis that has already been proposed for hadrosaur dinosaurs in Antarctica.

2. Titanosaurs were already present in Antarctica during the Early Cretaceous or earlier. This hypothesis is supported by evidence of lithostrotian titanosaurs in the Albian of Australia and is consistent with studies showing many dinosaur clades spreading across Pangaea or Gondwana prior to the continental fragmentation during the Cretaceous.

Can they put a name to this new dinosaur? Not yet. They really only have 1 bone of 1 dinosaur. The important, take-home point of this paper is that a group of dinosaurs has been found on a continent for the first time. It will be interesting to see what other dinosaurs once lived on this very large continent.

Here's the paper:
Cerda, Ignacio A., Ariana Paulina Carabajal, Leonardo Salgado, Rodolfo A. Coria, Marcelo A. Reguero, Claudia P. Tambussi, Juan J. Moly. (2011) The first record of a sauropod dinosaur from Antarctica. Naturwissenschaften: 99(1), 83-87. (DOI: 10.1007/s00114-011-0869-x)

Learn more about sauropods at...
The University of California's Museam of Palentology's "The Sauropod Dinosaurs" page
Evolution & Phylogeny of Titanosauria

And more about this discovery here:
ScienceShot article "Giant Dino Lived in Antarctica"
Science Daily's article "Plant-Eating Dinosaur Discovered in Antarctica"

* Figure 2 from the paper showing the discovered sauropod fossil: "Lithostrotian gen. et sp. indet. MLP 11-II-20-1 caudal vertebra centrum, photograph (a–c) and interpretative drawing (d–f) in anterior (a, d), right lateral (b, e), and posterior (c, f) views"

(first image from ScienceShot, credit with photo, link above)

Wednesday, January 4, 2012

This Year in Pictures

I've been absent for a few weeks. You know how it goes: travel, family, holidays, family, travel. But I'm back to the blog for the new year and would like to share with you The Year in Pictures from Science. These are pictures from ScienceSHOTS that accompany published papers/studies that are equally as fascinating as their pictures. Here are a few of the amazing pictures that caught my eye, and I'll link to the rest at the end of the post.

This photo accompanied a story about detecting tiny amounts of gasses, toxic gases in particular. Scientists have improved the sensitivity of gas detection 1000 times over, not to mention being much cheaper and simpler in it's methodology. The applications of this improvement range from better security operations to carbon dating. The article will appear later this month in Physical Review Letters.

Meet Metridia longa, a copepod of the northern seas. This creature was part of a study the feeding habits of tiny marine crustaceans. They were originally thought to collide with their food rather than seeking it out. This study showed that copepods exhibited an "attack response" when algae floated close to it, creating suction to draw in its prey. This newly described behavior could help explain how copepods survive in the ocean, particularly when food is scarce. You can find the report online in Biology Letters.

We don't typically think of wasps having different faces, they sort of all look the same to us. But a picture like this shows us our mistake. Scientists taught paper wasps (Polistes fuscatus) to associate certain wasp mugshots with safety and others with danger in an electrified maze. They found that wasps recognized the faces and applied associated knowledge to get through the maze, with the antennae of the reference wasp being particularly important. The report is published online in Science.

The fairy wasp (Megaphragma mymaripenne) is one of the world's smallest creatures at only 200 micrometers in length. This picture compares the minuscule wasp to a paramecium and an amoeba. As it turns out, you can't evolve down that small without losing some parts of yourself. Scientists compared the neurons of adult and pupae fairy wasps and found that more than 95% of the adult neurons lacked a nucleus. This shed some light on brain and neuron development itself in that a complete set of neurons need to grow but far fewer are required to live. The article can be found in this month's Arthropod Structure & Development.

Researchers looked into the mating habits of female mouse lemurs (Microcebus murinus) and why they chose to mate with multiple males. The assumption was that the females were being sexually harassed causing them to breed with several partners. After raising some females on fattening diets, making them larger than males and able to defend themselves better, they found that the ladies kept to their multiple partner strategy, even increasing the number of male partners. They concluded that this is of some as yet unknown evolutionary advantage to the females or that maybe these girls are just having some fun. Read more about it published in the Proceedings of the Royal Society B.

How do geckos stick to surfaces? It was thought that molecular interactions between microscopic branching hairs on the footpads and the surface were the reason. Then some scientists noticed that geckos leave footprints. This residue consists of phospholipids (fats) that help protect these little hairs from wear and provide a liquid-like layer that makes the toes cling better. This paper is published in the Journal of the Royal Society Interface.

At the end of last year, scientists found three Bornean rainbow toads, a species only known from a few sightings, in the trees between  Malaysian and Indonesian Borneo. The Sambas Stream Toad (Ansonia latidisca) is listed as endangered but the area in which it is found is not currently protected. This toad joins the Rio Pescado stubfoot toad (Atelopus balios) of Ecuador as the only two of Conservation Internationals "Top 10 Most Wanted" frogs to be found.

If you known anything about dinosaurs then you know that meat-eating dinosaurs were prone to evolving away their fingers. The earliest carnivorous dinosaurs had 5 fingers, 4 of which were functional, then later ones had only three, and later meat-eaters (like T. rex) only had two. Researchers have now found the first known dinosaur with only one finger. Linhenykus monodactylus was found in ~80 million year old rock in Inner Mongolia. It was about a meter tall and belonged to the family of dinosaurs called alvarezsauroids. The paper can be found in the Proceedings of the National Academy of Sciences.

This beautiful picture of M51 was taken by Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and shows the two dusty spiral arms that swirl around the core of the galaxy. The small, bright specs in the photograph are newborn stars that have never been seen before because their light is too obscured by the surrounding dust. Discrete dust clouds can also be seen which is amazing for a galaxy that is 37 million light-years from Earth!

You can find many more wonderful images by going to the ScienceNOW This Year in Pictures webpage. Along with each picture you can find information on the study and links to the articles.
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