Tucson is a great place to get outdoors, bask in the warm sun, and do some exploring. I took the opportunity to do some hiking with my undergraduate lab while I was back in town for Thanksgiving. We explored the Tucson Mountain range, not too far from the University of Arizona. While checking out some small caves a short hike from the trail, we discovered the awesome cave paintings of the Black Sheep Pictograph Site. These paintings of deer and big horn sheep have been well preserved in a small cave along a mountainous slope. These were painted by the Hohokam who inhabited the Tucson Valley; it seems like these animals must have been valuable food sources, yet I'm more curious about which plants they might have foraged for.
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Camelina is certainly a very interesting system for studying evolution, and much work has been done in it, although the majority of this work was done in the early 20th century in the U.S.S.R. and has yet to be rediscovered in the West. Ivan Schmalhausen was a Ukrainian born, Soviet evolutionary biologist, whose work was largely disregarded in the U.S.S.R. due to the subduing of ideas that digressed from Lysenkoism. Schmalhausen used the term "norm of reaction", originally conceptualized by the German, Richard Wolterck, to explain how genotypes can react to the environment to vary phenotype. He used Camelina as an example of this, as C. glabrata (now recognized as C. sativa), shows a tall, slender morphology when planted in flax fields. He claimed that the tall structure, narrow leaves and long internodes of another "species", C. linicola (now C. alyssum), were stabilized through genetic fixation, while these are plastic characters in C. glabrata. Nikolai Wasiljevich Zinger, a Russian botanist, worked on Camelina in his little known paper "On the Species Camelina and Spergula Which Infest Flax Sowings and Their Origin". Zinger's figure, shown below, illustrates the norm of reaction in both of these Camelina varieties, where, when sown densely (or with flax) they adapt a tall, slender morphology, and when planted alone they branch and increase overall density of leaves and fruits. However, the stabilizing selection that acted on C. linicola as a flax weed can be noticed, as when grown alone it retains its narrow leaves and sparse habit compared to C. glabrata. Schmalhausen used this example as evidence that some physical forms can be under dynamic selection, as seen by Camelina changing morphology based on its environment (5a to 6a and 1a to 8a), while some traits become stabilized and are no longer subject to change by environment, like those in C. linicola of slender leaves and sparse growth when compared to C. glabrata under "wild" circumstances (6a to 8a). Zinger also noted that the selection of seed size in C. linicola was dynamic, meaning that the size were readily changed, although able to revert. The process of winnowing (separating the seeds from plant material) in flax, unintentionally selects for Camelina seeds which are larger in size so as to mimic flax seeds, and in doing so are planted with the next season's flax crop. Schmalhausen recognized this dynamic selection as labile, meaning that the variable trait is not fixed, and is phenotypically plastic depending on environmental factors.
Schmalhausen claimed that the propensity for Camelina to adapt rapidly to new environments was due to a "preceeding preparatory evolution". I would attribute this to C. sativa's polyploid status which gives it a large "tool set" for adaptation and rapid evolution, which has allowed the colonization of new geographies (temperate, mesic environments) and specific niches (flax fields). Schmalhausen, I. I. 1949. Factors of Evolution. Blakiston, Philadelphia. (pp 1-95)
Google's Ngram viewer is a tool which shows prevalence of words used in Google's collection of digitized books. The graph above represents the percent usage of several common names of Camelina sativa (Gold of pleasure or false flax). What is particularly striking about this graph is the higher usage of "Camelina" in literature of the 1800's, with a steady decline for the last 60 years, and now it's starting to increase in use again. This highlights the fact that Camelina fell out of favor as an oil seed crop during the 1900's, only recently to be recognized as a viable biofuel crop. It is also clear that "gold of pleasure" was most widely used around 1780-1900, whereas "false flax" became a popular common name from about 1900-1960. Now, it seems that there is an even split between the two common names "gold of pleasure" and "false flax".
Above is a graph of the use of "Camelina" and its German common name "Leindotter", which appear to be used interchangeably in German literature. These trends reflect those of the English names; there is a slight reduction in use, but this time starting in the 1920's, and following through until about the 1980's when a resurgence of "Leindotter" occurred.
While Camelina cultivation halted around the early 1900's in most Western nations, Russia continued to experiment using the cruciferous oil seed. This is reflected by the usage of the Russian word for Camelina (Рыжик), which only started to be used after 1900, and reached a peak around 1940-1980, this corresponds to the time in which usage of "Camelina" was decreasing in the West. Camelina is still grown in Eastern Europe and parts of Russia, but I'm not certain of the extent of use or what the applications are (other than as a cooking oil).
The prevalence of the word Camelina is much higher in Russia (although I'm sure there could be many biases responsible for this). During the 1960's, use in Russia was at about 0.000045%, whereas the same period in English literature, only 0.0000015%, or put another way, during this time Camelina was mentioned in Russian language books 30 times more than English language books. Saint Louis is undoubtedly the destination for plant science research. Proof of this is, in part, evident from the first ever Joint Fall Symposium "From Darwin to Borlaug" which included talks at the Donald Danforth Plant Science Center and Missouri Botanical Garden (October 8-10). This symposium included an impressive array of lectures from scientists from St. Louis and across the U.S, find a list of speakers here. These talks gave me some great exposure to plant evolution and its translation to crop improvement in a world looking to double agricultural productivity by 2030.
Consider that only 30 agricultural species provide us with about 95% of our food, and yet throughout human history, about 7,000 species have been utilized for food. About 120 species (out of ~20,000 medicinal plants) are utilized for modern pharmaceuticals. These disparities should highlight the sense of urgency which must be commanded in order to preserve and understand Earth's plant biodiversity. I've always found it curious that growing up in the United States, I'd heard so little about Soviet science. Certainly the Soviets conducted science in a totally different way than that of Americans, but what was behind the difference? The inclusion of Marxism in USSR science led to dialectical materialism, a philosophy which discounts mysticism and spirits while explaining nature through an organisation of lesser components comprising a whole. This philosophy, itself akin to communism, fit in nicely with the communist system and was a convenient way to justify advancement in the sciences. In the field of Soviet genetics, a specific brand of dialectical materialism had dismal results and led to the deaths of some of the world's most promising scientists, but how? It all started with the Ukrainian born Trofim Lysenko. Born in 1898, Lysenko grew to become a budding agronomist, first studying at the Kiev Agricultural Institute and eventually conducting research at an agricultural experiment station in Azerbaijan. He studied the vernalization (cold treatment) of wheat in order to enhance yields and bring agriculture to otherwise unarable land. Drawing from the work of Ivan V. Michuran (1855-1935), Lysenko gradually built his reputation as an agronomist working to stave off impending famines. Michuran emphasized the role of the environment in the fate and heredity of organisms, features that Lysenko would later adopt and exaggerate. The theory pioneered by Lysenko, coined as Lysenkoism, had several fundamental pillars:
At the time (1920-30's) agriculture in the USSR was in a state of disrepair. Already lacking quality arable land, and being subjected to extreme winters and droughts, the USSR struggled immensely to maintain sufficient wheat output and suffered devastating famines. Lysenko came to the rescue with vernalization, which he employed on winter wheat varieties in order to prevent the destruction of wheat crops by extreme cold. His experiments were often devoid of controls, adequate sample size, and statistical analyses. Ultimately this research appeared to be providing higher yields, but the application of vernalization, in reality, seemed to have minimal effects. This was thought to be, in large part, due to the unpopular collectivization of Soviet agriculture. Many disgruntled peasants preferred to conduct sabotage on their crops in order to preserve their property rights. The losses attributed to agricultural sabotage masked the potential effects that Lysenko's vernalization was also wrecking on crops. It is thought that his vernalization methods were mostly unsuccessful in practicality, because seeds sown in winter, (to be vernalized) were failing due to rot and poor climate. The Communist Party favored Lysenko's Marxist theory nonetheless, and he won the favor of Joseph Stalin. By 1940, Lysenko became the director of the USSR National Academy Institute of Genetics, and soon after, criticism of his theory was outlawed. At the same time some Soviet geneticists were skeptical of Lysenkoism and spoke out resulting in their ultimate demise. One such example is that of Nikolai Vavilov, a prominent Soviet scientist with great potential. Vavilov was interested in understanding the origin of crop species, he even described crop mimicry in weeds (Vavilovian mimicry), one of which is gold-of-pleasure's mimicry of flax seed. Vavilov was unfortunate in having expressed views opposed to Lysenkoism; he was arrested and died in prison of starvation in 1943. Sadly, Vavilov was only one of many to be sentenced during Stalin's brutal purge of "traitorous" scientists.
Lysenko came to embody the perfect Soviet scientist, and he went on to proliferate a range of pseudoscience and outlandish claims. He once claimed to have discovered a method of fertilizing fields without the use of fertilizers, and even that he could force wheat to produce rye seeds. The death of Stalin in 1953 hailed a new era, one in which criticism was gradually accepted and overtime Lysenko's power diminished. The Soviets cut their losses, admitted the blemish that was Lysenkoism and eventually shifted their focus to adopting American agricultural techniques and Mendelism. Lysenko continued his research, but much of the attention was drawn away from it. Lysenko died in 1976, and by that time he had published over three hundred papers. Admittedly, not all of Lysenko's work was bogus, but his theory of heredity through environment had long been known to be baseless (especially in Western genetics). What lessons are to be learned from Lysenko? Firstly, experiments should be unbiased, include controls, rigorous statistics, and allow for negative results. Secondly, Lysenkoism is a prime example of the utmost importance of separation of science from idealism and politics. Graham, L., (1987). Science, philosophy, and human behavior in the Soviet Union. New York: Columbia University Press. Levins, R., & Lewontin, R. (1985). The Problem of Lysenkoism. The Dialectical Biologist. Lysenko, T. D. (1946). Heredity and its Variability. I spent my weekend at Council Bluff Lake in the Mark Twain National Forest. I did a little bit of botanizing, but the flora of Missouri is still a bit foreign to me. While I think plants are awesome, I've got a sweet spot for my amphibian friends as well. Turning over rocks and logs near small ponds and streams around the lake yielded a surprising number of salamanders. I rejoiced the opportunity to do some herping in such a diverse area as the Ozarks.
Today was the 5th annual SLEEC retreat at the Saint Louis Zoo. Presenters from Washington University in St. Louis, Missouri Botanical Gardens, Saint Louis University, University of Missouri-St. Louis, and Southern Illinois University Edwardsville gave talks on a variety of fascinating topics. Talks ranged from evolution in Anolis lizards to the ecology of religious beliefs, even lessons learned from global whaling negotiations. For the event I presented a poster detailing my undergraduate work at the University of Arizona, a great opportunity to introduce my work to new colleagues.
If you're in the Saint Louis area and interested in evolution, check out the SLEEC website. Ernst Haeckel (1834-1919) proposed the famous "Ontogeny recapitulates phylogeny" hypothesis which states that the history and evolution of an organism (phylogeny) is parallel to its development at the embryo stage (ontogeny). Frustrated by the fact that few scholars of his era understood even the most basic aspects of ontology, Haeckel set out to convince the scientific community that his theory could explain the evolution of man. This interesting theory has long been controversial and is now considered to be without merit. In light of the evidence for evolution at the time, it seems natural for such a theory to come about; long before the discovery of DNA there were few other places to look other than the morphological features of organisms to the naked eye. Haeckel studied embryogenesis as a way to gain insight to the history and relationship of organisms. His belief was that the development of embryos could tell a story about the position of an organism in relation to all others, as evidenced by the fact that early stages of human, dog and horse embryos are nearly identical. Furthermore, the gill-like fissures and folds of human embryos led Haeckel to postulate a fish-like ancestor of humans. While he was a proponent of Darwin's theory of a singular ancestor to all life, he favored a Lamarckian view of the evolution of individual species. There is much to be learned from Ernst Haeckel's work, and he's nonetheless a prominent scientist that contributed immensely to the study of invertebrates. And at the very least he put out some of the most amazing biological illustrations. |
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November 2019
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