The Monty Hall Problem
The Monty Hall paradox is a probability puzzle based on the American television game show Let's Make a Deal, the one with the three doors, where 1 door contains a highly coveted prize and the other two, useless stuff. Monty Hall was the name of its first host. Watch this little video from ASAP Science (I recommend all their videos) carefully, more than once, you will see that the results appear impossible but they are verifiably true. If at first you don’t get, don’t worry, many mathematicians and scientists did not get either and it was for a while a subject of controversy. Check out the Wikipedia entry as well, if you still have doubts, it is very comprehensive.
Why am I interested in the Monty Hall paradox? Because I’m reading THE DRUNKARD’S WALK: How Randomness rules Our Lives by Leonard Mlodinow. It’s a great book about how our brains are really bad at grasping randomness and probabilities. It is a great book full of history, with anecdotes from the now long dead mathematicians and gamblers who contributed greatly to development of the mathematics of randomness), full of probabilistic puzzles, and examples from real life in which an understanding of probability and randomness could prove crucial. These include not only gambling but also risk assessment, in finance as well as in medicine, and the administration of justice. Read-this-book-now.
The Orion Bullets. Image Credit: GeMS/GSAOI Team, Gemini Observatory, AURA. Explanation: The “bullets” are hot gas clouds about ten times the size of Pluto's orbit, show in blue in the false color image. They travel at hundreds of kilometers per second! The image was created using the 8.1 meter Gemini South telescope in Chile with a newly commissioned adaptive optics system (GeMS).
Find more fantastic images of our universe in the group The Daily Cosmos, and join the group if you haven’t already done so!
Earth-sized planets are plentiful. The Kepler space telescope, launched in 2009, is an endless source of fascinating discoveries since it was launched in 2009. The number of extrasolar planets, or exoplanets, keeps growing. Our galaxy contains around one hundred billion planets. Can you wrap your head around that number of planets? I can’t. I can only drop my jaw in awe. And small planets, the size of Earth, are not that rare; the total tally is now up to 2740. Most sunlike stars have planetary systems orbiting them and about 15% of them are Earth-sized. Most are too close to their stars and thus too hot to be fit life. But at the current rate of discovery, we still don’t know for sure how many these Earth-sized planets are in the Goldilocks or habitable zone.
ENDLESS FORMS MOST ELUSIVE
Giant squid caught on film. We atheists have a reputation for worshipping Chthulu, and quite frankly, I fail to understand how one CANNOT be fascinated with sea monsters. The giant squid (genus Architeuthis) is one of those real sea monsters that scientists have been trying to capture on film, alive, for a long time. Every time one is even partially spotted, dead or alive, it makes the news. Check out this image grabbed from footage (not yet released) of one of these giant cephalopods, captured in July 2012 but analyzed this past week, in the North Pacific, off the coast of Chichi Island, at a depth of 630 meters (2,066 feet). This particular specimen is “only” 3 meters long (~10 feet). The scientists in the submersible followed the animal for a while, until it disappeared into depths where it could not be followed. The creature was missing its two longest arms; otherwise it would have been be 8 meters (~26 feet) long. This is the first time a live giant squid has been filmed at such depths, its natural habitat, with very little oxygen and tremendous water pressure. The Discovery Channel will air special documentaries on this finding later this month, which is why the footage has not been released yet.
ENDLESS INSECT FORMS, MOST BEAUTIFUL AND MOST CREEPY
A butterfly’s long life in the fast lane. The “rule” in biology is that the more energy an animal burns, the shorter its lifespan. This is because burning a lot of energy results in the production of free radicals, which are unstable compounds that damage cells. But in nature, there seem to be exceptions for everything. The beautiful Glanville fritillary butterfly (Melitaea cinxia) appears to be one of them. Researchers measured the energy expenditure of this insect, and found the individuals that with the highest metabolic rate during flight also lived the longest. The finding was valid both in a lab setting and in its natural habitat in Finland. In this case, the connection between oxidative stress and lifespan seems to be reversed. It’s possible that only the fittest butterflies can fly at top speed and thus the effect of accumulating free radicals is dampened. The fastest fliers are probably genetically superior and could have access to better nutrition. A more exciting possibility, and one that warrants further research, is that these fast fliers evolved ways to protect themselves from the high metabolic rate and energy expenditure.
A very clean zombie cockroach. As I’m sure most of you know, there are species of parasitic wasps that lay their eggs inside the bodies of other live insects, who get eaten from the inside out by the larva when the egg hatches. One of these species is the strikingly iridescent emerald cockroach wasp (Ampulex compressa). The female wasps finds and stings a cockroach (Periplaneta americana), then drags the roach into her burrow and deposits an egg in its body cavity. German scientists placed a transparent panel through the roach’s side so they could watch the larva in action inside the zombie roach body. They noticed the larva coating the inside of the roach with a liquid coming out of their mouthparts. The scientists analyzed the liquid and found two compounds, mellein and micromolide, that slow the growth of bacteria, in particular Serratia marcescens, a bacterial species commonly found in roaches, that can quickly kill insect larvae. The larva disinfects the roach regularly so bacteria cannot accumulate inside the host’s body. It is a brilliant solution to avoiding microbial colonization in the zombie roach, since were it to happen, the larva would perish as well. The scientists think that the “disinfecting behavior” could end up being common among parasitic insects since they all need to solve the potential problem of bacterial growth inside the host.
“Honesty” in animal communication and evolution. The “handicap principle”, first proposed by evolutionary biologist Amotz Zahavi in 1975, establishes that when an animal signals or “advertises” their fitness to members of the other sex, to rivals, or to predators, it comes at a cost to the animal. For example, the beautiful tail of the male peacock signals his good genes, since the long tail is a “handicap”, in that it makes him more vulnerable to predators. It’s as if the peacock is trying to say to the peahen: “hey, in spite of this huge tail I have escape predators, therefore I’m healthy and fast and I will give our offspring very good genes”. So for a peacock that is not very strong or fast, it would not pay to have a very big tail because it would be easier prey. The idea is that it pays to be “honest” in your communications. Interestingly, the best strategy for animal communication can be studied using game theory. In the evolutionary game, where the payoff is offspring, being “dishonest” does not pay: if there were no correlation between beautiful tails and fitness, the peahens would end up ignoring that signal. But a new study suggests perfect honesty is not the optimal strategy either, as previously assumed. Scientists used computer simulations of populations under selective pressure to model communication, and they found that “partial honesty” is the best or most stable strategy, at least in theory. They need to now go to the field and see if the data confirms the mathematical model. But there are already good indicators that at least in some species, the model will be correct because not all signals are costly. For example, baby birds of certain species with nests that are not easy to reach can afford to be loud in begging for food without attracting predators, so the signal is “cheap”. So even chicks that were not hungry will beg. Parents should then not always feed a begging chick, and they should never feed a chick that is not begging. Researchers have actually observed that boobies sometimes ignore intensely begging chicks for up to 20 minutes, which would be consistent with the partial-honesty model. Check out the article to read about different scenarios, it’s fun to speculate. The field of animal communication is fascinating to me.
BRAIN AND MIND
Spatial ability as a testosterone side effect. Carl Zimmer wrote a fascinating post about a real difference in the way the minds of women and men work: spatial ability. It is basically the only difference that has been repeatedly measured with confirming results: males have on average a slightly better capacity with spatial tasks, especially the ability to note that a geometric figure is the same if rotated 180 degrees. Of course, there are overlaps and many women do better than men, but there is a statistically significant difference nevertheless, and it can be detected even in babies. Evolutionary biologists have speculated that it could be an adaptation: males need to navigate a bigger territory than female. If that was the case, other mammal species in which males forage or hunt over a larger territory should show spatial ability dimorphism. But it turns out that the most likely explanation is testosterone! If you castrate male rats, they no longer have an edge over females on navigating a maze. It appears that better spatial ability is actually a side effect of testosterone, just like acne. And nobody would argue acne was selected for, that it had an evolutionary advantage. What has an evolutionary advantage is plenty of testosterone, because the hormone is directly related to reproduction. We do not know what is it about testosterone that results in slightly better spatial ability (though we know why a lot of testosterone gives you acne), but it is not likely to be an adaptation, but a spandrel. A spandrel is a term borrowed from architecture, that in evolutionary biology means a characteristic that is the byproduct of another, evolutionarily selected for, trait.
Rita Levi-Montalcini, great lady of science, dies at age 103. Dr. Levi-Montalcini was a personal hero of mine. She was a pioneer in cell biology at a time when the vast majority of famous scientists were men. Her innovative research earned her a Nobel Prize in 1986, for the co-discovery (together with Stanley Cohen,when she was working in the US) of nerve growth factor, a protein critical to the survival of neurons, and recently found to also be present in large quantities in semen, responsible for inducing ovulation in some mammal species. I had commented about her almost 2 years ago in our site, when she was 101 years old. She an Italian Jew by birth (though she was never religious), and she was the target of anti-Semitic laws implemented by Benito Mussolini in 1938. She left Italy for Belgium in 1939, not wanting to expose her non-Jewish colleagues to the consequences of allowing a Jew to work in their labs. She soon was back in her native Turin where she conducted research in her own bedroom, using chicken embryos, since she could not do so at the university. These were the initial experiments leading to the discovery of nerve growth factor. She was a person of incredible optimism, and often said she ended up getting a Nobel Prize because she had faced persecution and discrimination, not in spite of it. She managed to find the good in the bad, she had a great sense of humor, was very unassuming and very, very active until her very old age. She famously said, when asked about aging: "The body can do what it wants. I'm not my body, I am my mind". She also said, on the subject of aging: "It's better to add life to your days, than days to your life." Talking about being a role model for women, she said: "The women who have changed the world never had any need to show anything other than their intelligence." To read about her life work, here is a great article in Scientific American, reprinted today, from 1993: "Finding the Good in the Bad."Addio, grande donna della scienza, non ti dimenticheremo mai. Goodbye, great lady of science, we will never forget you.