30 January 2011

Methylated cobrox

One of my all-time favorite TV shows is The Man From U.N.C.L.E. from the mid-1960s. I didn't watch TV in the 60s. I discovered The Man From U.N.C.L.E. many years later and got hooked on it only within the last year when I learned that the entire show was available on Netflix. Despite its primitive special effects, outdated gadgetry and the often silly plots, I get a kick out of watching the U.N.C.L.E. agents Napoleon Solo and Illya Kuryakin carry on their perennial fight against the bad guys of T.H.R.U.S.H.

In the episode I watched last night, The girls of Nazarone affair, a flower vendor is killed and Illya, posing as a doctor, examines him and determines that a poison had been delivered to the victim via the pin on a corsage. Illya later informs Napoleon that the poison was "methylated cobrox". Subsequently, Napoleon and Illya find pins, also dipped in methylated cobrox, sticking out of their pillows in their hotel room.

There is no such chemical as methylated cobrox or even as cobrox as far as I can tell. In fact, a Google search for "methylated cobrox" returned no hits. This post has apparently become the only page on the Internet that now mentions methylated cobrox.

Was the poison needed in the show so unrealistic that it needed to be invented with a new, made-up name? Or was it considered unethical to name a real poison in a TV show back in the 1960s? People, on the other hand, smoked incessantly on TV and in the movies. It probably didn't dawn on the makers of TV shows that cigarettes were killing innumerably more people in real life than could the imaginary methylated cobrox ever do in movies.

26 January 2011

Frozen Vertigo

A few nights every winter, the outside temperature where I live goes below -10° C, but not too far below; the lowest temperature I've measured in my yard within the last 3 years was -14° C. When the National Weather Service predicted that the temperature last Sunday night would be -14° C, I decided it was time again to repeat an annual experiment.

The tiny land snail Vertigo pygmaea is an inhabitant of my backyard and a frequent subject of the posts on this blog. When I collected live snails one spring that I had marked the previous fall, I determined that the species survived the winters (see this post). Otherwise, how would the snails be always out there?

The purpose of the annual experiment I carry out whenever the temperature goes below about -10° C is to determine if the little Vertigo will survive having their tails frozen off*. So last Sunday, I retrieved 8 adult and one juvenile dormant Vertigo from the yard and placed them in a small plastic container. Then I put the container on my front porch with the probe of a thermistor thermometer in it. Here is a picture of the set-up. The snail container, not quite visible in this photo, was below the wad of cotton.

The lowest temperature recorded during the night was -13.1° C. Early Monday morning I brought the snails indoors and wetted them before I left for work. In the evening, 8 of them, including the juvenile, had revived.

In North America, the range of Vertigo pygmaea extends into Canada, where the winter temperatures go much below -10° C. However, wherever there is snow cover throughout most of the winter, the ground temperature will be much less than the air temperature (see this post). Therefore, to determine the lowest temperature Vertigo pygmaea can withstand, I need to repeat my experiments either somewhere where the winters are colder than here and there is no snow or under artificially lowered temperatures.

*I don't actually know if the snails survive or resist freezing.

24 January 2011

Solutions of relative growth

I have been reading Julian Huxley's 1932 classic* Problems of relative growth. It is all about the growth of different body parts relative to each other and the consequences of such growth. But what exactly are we talking about?

Generally speaking, an animal's body may be taken to be compartmentalized. Compartments may be the individual organs, such as the nose, the heart and the penis, or different parts of the body, such as the head, the torso and the appendages.

The growth of all the compartments during the ontogeny of an animal at the same rate is called isometric growth. Isometric growth does not change the shape of the animal; the adult has more or less the same shape as the baby or even the late-stage embryo.

The growth of the compartments at different rates relative to each other is called allometric growth. Allometric growth changes the shape of the animal; the adult is not only bigger than the baby but it also has different proportions.

Here is a crude drawing that contrasts isometric and allometric growths. The terms in parentheses, isogonic and heterogonic, were what Huxley used for isometric and allometric, respectively. Huxley's terminology has since fell into disuse.

The "animal" in the drawing consists of 4 compartments. If it undergoes isometric growth, all compartments grow at the same rate and the overall shape stays the same. If it undergoes allometric growth, on the other hand, compartments, and even different regions of some compartments, grow at different rates. For example, the orange and the yellow compartments grow faster in one direction than in the other. That process eventually changes their shapes. At the same time, the yellow compartment grows at an equal rate in every direction, while the blue compartment grows at a very slow rate. The net result of all these growth processes is that the overall shape of the adult animal is different than that of the baby.

How do we apply these ideas to the growth of snail shells? That will be the subject of a future post.

*Actually, the 1972 Dover edition.

23 January 2011

Natural selection in the pot?

We have been growing these annual vinca plants for several years by bringing their pots inside at the onset of winter. But early yesterday morning, while the outside temperature was still below freezing, the pots were taken out to allow for a house renovation project to commence. When they were brought back in several hours later, it appeared that several of the plants in the largest pot had succumbed to the elements. Those are the ones with drooping leaves in the photo.

But there were survivors. So, now the question is why some plants died and some survived.

The distribution of the survivors suggests that location within the pot was irrelevant. So we can assume that air and soil temperatures were more or less uniform. Presumably, the plants were not genetically identical; some may have descended from one plant that was the original occupant of the pot and others from other original plants that occupied different, but nearby, pots (incidentally, they do seed well). It is, therefore, possible that we witnessed a selection event: the survivors had the right phenotypes coming from the right genotypes that enabled them to survive the freezing temperatures.

We should have flowers soon.

19 January 2011

Archaeo+Malacology Group Newsletter No. 18

The AMG Newsletter No. 18 is available here.

An interesting article in this issue is about unidentified objects from the Middle East that were made by apparently pouring molten lead or other metals into empty bivalve shells. Henk Mienis writes that because of their considerably variable weights, these objects could not have been used as standard weights. And the lack of holes thru them rule out their use as sinkers. The mystery remains.

There are also 2 articles on the land snail Papillifera papillaris, which has become quite a popular subject for the newsletter. In one of them, the editor Janet Ridout-Sharpe writes about the 2nd record of that species in England.

Issue No. 17 had featured an illustrated article by me and Mienis that was the 1st ever for the newsletter. However, the lack of illustrations in the present number shows that the practice hasn't caught on yet. Maybe slowly?

17 January 2011

Not exactly a frozen print

Sometimes the absence of something is the presence of information.

16 January 2011

Time travel achieved

I went to a local wine shop last night and had at good time. So time flew and I was apparently sent back a hundred years. I didn't notice anything significantly different, though. Perhaps the beer and the goat cheese I had consumed had numbed my senses.

I did consider asking the cute bartender out, but when I suspected that she was destined to become my grandmother, I changed my mind.

14 January 2011

I have Lindholmiola lens in my mind

Lindholmiola lens is a common and often abundant land snail species in western Turkey. I have a large number of shells of it in my collection collected during the last 12 years.

The shapes, especially the spire heights, of the shells of Lindholmiola lens are quite variable.

These 2 specimens were from the same locality. The one on the left has an elevated spire, while the one on the right has a flat top with almost no spire.

I have been wanting to study the variability of shell characteristics of Lindholmiola lens. Once I decide what to measure on each specimen, and once I have plenty of free time in my hands, I will commence the project.

13 January 2011

Where and how did slugs evolve?

Slugs are snails that changed their body plans and lost their external shells during evolution. I don't yet know the answer to the question posed in the title, but the late Alan Solem, in his 1974 book The Shell Makers: Introducing Mollusks, claimed that slugs evolved "under conditions of plentiful moisture and scarcity of calcium".

I don't find Solem's meager arguments in support of his hypothesis very convincing. Many species of slugs are native to areas where moisture is not plentiful, but calcium is abundant. For example, slugs live in western Turkey where the summers, under the influence of the Mediterranean climate, are bone dry, while limestone rocks provide an unlimited supply of calcium.

I am inclined to believe that if slugs can and do survive in places where moisture is not always plentiful, then the plentifulness of water couldn't have been a critical factor during their evolution.

The question boils down to this: if species A evolves into species B as a direct result of the influence of the environmental condition X, can species B continue to survive at the same location (and without undergoing further evolution) if the environmental condition X ceases to exist?

12 January 2011

Cold juncos at the feeder

This bird, and several others like it, were at the feeder during this morning's feeding frenzy. I believe it is a dark-eyed junco (Junco hyemalis). They were quite competitive and were constantly chasing each other from the feeder even when unoccupied perches were available. At some point, a male and a female cardinal joined them.

The juncos that were not at the feeder often sat in the snow covering the railing of the adjacent deck. Here is one that was all puffed up. It was indeed cold and windy.

10 January 2011

How my weight fluctuates during a day

About a month ago we bought a digital bathroom scale and retired the mechanical one after 22 years of faithful service. Ever since then the new scale has provided us with numerous occasions of weighty fun.

One project I did was the monitoring of the variations of my weight during 3 days. I am presenting the results as a graph with all weights expressed as percentages of each day's highest weight.

A person's body weight almost continuously changes: every inhalation increases the body weight, while every exhalation lowers it. Of course, such minuscule weight changes would be almost impossible to monitor against the much larger total body weight. But more significant changes in weight result from the meals and liquids consumed, profuse sweating and, of course, urination and bowel movements.

The true body weight of a person would have to be measured with no clothing and no food or waste in the stomach and the intestines and no urine in the bladder. At the same time, the person would have to be properly hydrated. This is much easier said than done.

The closest weight to the true weight can probably be obtained by monitoring the change of the body weight during a day.

The conclusion I reach from the graph above is that my body weight is at its lowest in the mornings and at its maximum at night right before I go to bed.

But what causes the body weight to decrease during the night? Some nights I get up to pee, but that can't be the sole cause of the weight loss during the night. One of my morning measurements were taken before breakfast and even before I sat on the toilet, but it was still 0.5 kg less than the previous night's maximum—too much to have resulted from one night time trip to the bathroom. That leaves us with the weight lost via breathing. I will try to tackle that in some other post.

So which of these weights come closest to my the true weight? Perhaps the weight given by the first reading of a given day.

09 January 2011

Frozen olive oil for breakfast

We often have these olives (with red peppers) for breakfast. The olive oil they are in is almost always frozen when the container is removed from the refrigerator. This is what the contents looked like this morning.

Olive oil is a mixture of numerous oils and other oil-soluble chemicals from olives. Because it is a mixture of a more or less variable composition, olive oil does not have a definite freezing point. My 1944 edition of Lange's Handbook of Chemistry (no, I didn't buy it in 1944) states that olive oil becomes turbid at 2°C and precipitates at -6°C. I measured the temperature inside our freezer several times in the past: it fluctuated around 3°C, although on one occasion it was down to 0.5°C.

What we had in the olive container this morning was certainly a semi-solid substance—its state was beyond turbid.

Ten seconds of microwaving restored the oil's fluidity and we had a nice breakfast indeed.

08 January 2011

Rush hour philosophy

This is one of the entrances to the Metro (subway) station in Silver Spring, Maryland. Note the 2 clumps of green plants behind the 2 trees on the muddy mound of soil. Until about 3 years ago that entire mound was covered with those plants. Then, the start of a construction on the other side of the station, where the main entrance is, caused a large increase in pedestrian traffic in and out of this entrance.

Since the rushing commuters, I am among them, often tend to take the shortest paths to their destinations, instead of walking around the plant bed, we started cutting across it with total disregard for the plants underneath our shoes. Seeing this, the station management removed a section of the plants and laid down a gravel path for us. That worked for a while, but during heavy rains the path, being lower than the surrounding mound, began to get flooded. So we started trampling over the plants again.

Now the only remaining plants are the ones behind the trees. They have survived, because the trees would block the way of anyone attempting to walk across those plants.

In nature and also in our lives, unforeseen circumstances often dictate the outcome of crucial events. A chance event, not always a growing treen but sometimes a a falling one, for example, determines who survives and who doesn't.

04 January 2011

Where is the rest?

This bird fragment was on a sidewalk yesterday. It must have been left over from a predator's meal. The perennial question, where do dead birds go?, now has another answer: sometimes they are ripped apart and scattered all over the place.

02 January 2011

Biological safety factors

I have been reading up on the safety factors built into animal bodies. The underlying idea, borrowed from engineering, is simple. Its most general expression may be as follows. If the maximum possible output of an animal for a particular function is M, while the average required output is A, then the safety factor (SF) for that particular function is given by:

SF = M / A

So, if SF is about 1.0, then there really is no safety factor. If the required output happens to exceed the average output, the animal will not be able to keep up with demand and its survival will be jeopardized. On the other hand, safety factors greater than 1.0 assure that if the required output ever exceeds the average, the animal will still survive.

Of course, there is a cost to keeping a safety factor much larger than 1.0. Therefore, evolution settles not for the best, but for an optimum somewhere between just enough and the best.

A good review on this topic was written by Jared Diamond*. According to Diamond, pancreas has one of the highest known biological safety factors, which is 10. From an evolutionary stand point, this is obviously good; one can survive long enough to reproduce even when one's pancreas is seriously damaged. But in the case of modern humans who are usually living far beyond their allocated lifespans, a damaged, but functioning pancreas is not necessarily a good thing. Diamond explains:

...malabsorption, due to decreased absorption of ingested food by pancreatic proteases and lipases, is not observed until pancreatic enzyme output has dropped to only 10% of normal peak values. That is why pancreatic cancer is so insidiously difficult to detect: patients show no telltale symptoms of malabsorption until 90% of pancreatic function has been destroyed, by which time the cancer has usually metastasized to other organs.
I will write more about this subject in the future.

*Diamond, J. 2002. Quantitative evolutionary design. Journal of Physiology 542:337–345.