Why I’m becoming vegetarian (and probably avoiding cheese, too)

August 15, 2011

There is a favorite saying of mine, “There are no twenty-dollar bills lying around on the street because someone’s picked them up already.” In other words, opportunities are hard to come by, because millions are trying at the same time, many more desperate, and what little low-hanging fruit there is has already been plucked.

So with this knowledge in mind, I was thoroughly astounded when I learned about the energy pyramid in ecosystems in my biology class. It states that on each successive level of the food chain, the total energy available in biomass decreases by a factor of approximately 10. In other words, the efficiency of energy transfer by predation is between 5-20%. And therefore, 80-95% of energy at a given level is unavailable at the next.

The reason for this is fairly obvious. Plants, producers at the lowest level of the pyramid, perform the process of photosynthesis to convert sunlight into glucose. This glucose then has two purposes – synthesis into carbohydrate polymers that “build” the plant (contribute to its edibleness) and fuel for cellular respiration, which provides energy for the everyday processes that a plant goes through. At the next level, primary consumers, herbivores, consume the edible parts of the plant, carbohydrate polymers such as starch and glucose, and then use that for the same two purposes – building biomass, or tissues such as muscle and bone, and energy for “maintenance.” So in each case, at each level, we see that an organism takes in energy, which it uses for (a) building biomass for other things to eat for energy, and (b) using energy to fuel processes to keep itself alive. As it happens, (b) is a need that is allocated 9 times more energy than (a).

But all of that is very intuitive. So the major question is…why should humans eat meat? And the simple answer is, that other than for the fact that it tastes really good, there is no good reason. In fact, there are a whole slew of reasons not to do so.

This argument doesn’t delve into ethical considerations, although I do digress to say that my math teacher did say that the reason he stopped eating meat at a young age was because he couldn’t bare to take away the “feeling of life” from any living creature. A puppy might not ponder the reasons and nuances of its existence (and humans don’t do this most of the time, either) but if you hold its head underwater, the puppy feels a very strong sense of “aliveness” coupled with a very strong sense that its “aliveness” is being threatened. So how could you take that away from something?

Of course, people say that it’s only “natural” for people to eat meat, but what’s “natural” about what we do anyway? Multiple levels of the food chain haven’t always been there – presumably there were once only producers and primary consumers (consumers of the lowest level, or vegetarians). At such a point, the “low-hanging fruit” was no longer the literal low-hanging fruit competed for with other herbivores but rather the defenseless herbivores themselves – another level of consumers could emerge, at 10% of the size of the lower energy level. And thus the energy pyramid would develop an equilibrium with each level no bigger than 10% of the level immediately lower and no smaller than 10 times that of the level above (there would be other restrictions as well, depending on resources such as water, space…)

Enter human civilization. As omnivores, humans are generally primary, secondary, or tertiary consumers. The problem is that humans possess far more total biomass than any other species of large mammals, and that our use of complex tools allows us to at least temporarily evade the limits imposed by the energy pyramid, especially predators to check population growth. The other problem is that humans, despite being perfectly able to subsist as primary producers, domesticate large amounts of primary consumers, which is extremely inefficient. It’s basically like going from “If life gives you lemons, make lemonade” to “If life gives you lemons, use those lemons to continually feed some large mammal for years before slaughtering and eating it.” It’s not very difficult to see which is more efficient.

Just for reference, here’s a graph that I found on the NY Times’ Green Blog. It plots the amount of CO2 emissions to produce different types of food:

Lamb’s not such a popular product, but the changes that even a meat-eater can make by switching from livestock to poultry are astounding!

Since I’m doing this from an environmentalist perspective, there’s no reason to be an absolutist. But if as a human race, we’re having trouble feeding each other and squandering our precious resources to add another extraneous level to the food pyramid, and we should really look into vegetarianism. The Amazon rainforest, a carbon sink, is slash-and-burn deforested (releasing CO2) at a startling rate to accommodate cows, which graze short-term on poor-quality soil while emitting methane, another greenhouse gas, resulting in a triple whammy for emission control efforts.

Dennis Avery, Director of the Centre for Global Food Issues, said that “The world must create five billion vegans in the next several decades, or triple its total farm output without using more land.” The clock’s ticking. So yours truly has decided to make a small sacrifice with huge power-of-ten payoffs. Because even if there seem to be no 20-dollar bills lying around on the ground, going vegetarian seems to be a climate change-curbing low-hanging fruit that’s just dying to be plucked.

“Why do we have to know this?”

July 26, 2011

I’ve been in enough science classes from elementary through high school to know that there’s almost always that one kid who doesn’t really seem to belong in the class but’s there anyway for some inexplicable reason, if only to interrupt the teacher’s enthralling PowerPoint presentation on double fertilization in angiosperms with that question. THAT QUESTION. The question that renders self-confident and well-informed science teachers mumbling and sheepish. Sometimes they ignore it, and sometimes they offer something like, “It’s important even if you don’t like it that much.”

So even though a lot of people would dismiss the occasional “Why do we have to know this?” as absurd and immature, I think that an even higher portion of the population would occasionally, when memorizing the multiple steps of fungus reproduction or glycolysis in biology, poring over solubility charts in chemistry (exceptions included!), or wrestling with free-body diagrams in order to set up the correct equations in physics, wonder why they’re doing this and not something much more directly linked to future success, like, say, liberal arts.

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Reflections on some pop sci books

June 27, 2011

Over the course of the last two weeks or so I’ve forayed into reading popular science books on physics for the first time. Namely, I read A Brief History of Time by Stephen Hawking and then The Fabric of the Cosmos by Brian Greene. Both dealt with relativity, quantum and particle physics, and cosmology. Greene’s book went further, introducing the “time’s arrow” concept and also discussing superstring theory and ending with some speculations on the future of physics research (a few up-and-coming experiments, and teleportation, wormholes, and time travel).

Overall, I think that Greene is a better writer. Both authors are respected physicists at the forefront of their profession, although I think there is no doubt that Hawking is in a class of his own. Despite superior intelligence, this detracts from Hawking’s writing since he seems extremely eager to highlight his own discoveries, relevant as they are, in order to give himself credit. Greene does mention his own work but he comes off as much less intimidating to the reader. Even with ideas that he himself labels difficult to explain without the math, he comes off as lucid and easy to understand. I was also thankful for extensive endnotes which gave fuller explanations to advanced or “mathematically inclined” readers, as well as pointers to further reading.

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What is it that computers CAN’T do? A simple introduction to Turing’s Halting Problem

May 29, 2011

(This is the first in a series about computationally insolvable problems, with a focus on Turing machines and the halting problem)

As a modern society, we rely on faster and more powerful computers in greater and more diverse areas of our life with every successive generation. In fact, some people believe in (and are working hard towards) the possibility of a technological “Singularity” by the 2030’s, when artificial intelligence will have surpassed human intelligence sufficiently to recursively self-improve (eg. A slightly smarter-than-human AI will make an AI slightly smarter than itself, which will in turn improve its own design, etc) and when the future will become extremely difficult to predict.

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Three and a half important facts about the theory of evolution

May 28, 2011

I was recently reading The Mind’s I, an anthology of reflections on souls, self, and consciousness compiled by two of my intellectual heroes, Professors Douglas Hofstadter and Daniel Dennett. I’m about 150 pages and all I can say is that it’s definitely a must-read. But I’ll talk about that more in some other post.

One of the pieces featured in the book was an excerpt from Richard Dawkins’ The Selfish GeneAfter reading it, I kind of kicked myself. I’d never really been interested in Dawkins before, since to me he was just that “atheist guy”; now I would revise that mental reference to read “that guy who really knows his evolutionary biology and now uses his immense prestige in the scientific community as well as his high name recognition to widely promote his views regarding religion.”

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