Monday, December 24, 2018

The Big Little World of Robert Hooke

In England in 1664, the scientific world was amazed to see Robert Hooke’s book Micrographia. Hooke was one of the first people to make expert use of early microscopes. The intricate drawings in this book remain some of the best art in the world today. Hooke opened up our vision to a big little world too small for the unaided eye to see.

Most biology textbooks contain the drawing that he made of a thin slice of cork. Rather than being a solid material, it consisted of lots of tiny cubicles, which reminded Hooke of the monastery cells in which monks lived. This observation began the scientific search that eventually led to the cell theory: that all organisms consist of cells. 

But Hooke did not just look at organisms, nor did he just look: he also asked questions about what he saw. One of his drawings was of “gravel in urine,” or kidney stones. When you look at them microscopically, you can see that the smaller ones are crystalline. This helped to explain where they came from: from minerals dissolved in the urine which occasionally crystallize. And because they are crystals formed in the urine, rather than actual gravel, they can be dissolved back into the liquid and thus, perhaps, eliminated. “How great an advantage it would be,” he wrote, “to such as are troubled with the Stone, to find some [liquid] that might dissolve them without hurting the bladder...” This possible solution to kidney stones would not have occurred to someone who did not look at them closely, so someone who just assumed they were gravel.

He also asked questions about the “cells” in the cork. (He was well aware that no one had ever described them before: “...indeed the first microscopical pores I ever saw, and that perhaps were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this.”) He deduced that these cells, which contained air that could not escape from them, were the reason that cork could float and why it was springy. He even deduced that there were also “channels or pipes through which the...natural juices of Vegetables are convey’d, and seem to correspond to the veins, arteries and other Vessels of nutrition in sensible creatures...”

Hooke also rhapsodized about the amazing quantity of tiny objects, such as the cells of cork, of which “a Cubick Inch” could contain 1259712000, or “twelve hundred millions.” It was “a thing almost incredible, did not our Microscope assure us of it...”

How could he be sure that his observation of cork cells was not a mere anomaly of cork? He also looked at (but did not draw) cells in “the pith of an Elder, or almost any other Tree, the inner pulp or pith of the Cany hollow stalks of several other Vegetables: as of Fennel, Carrets, Daucus, Bur-docks, Teasels, Fearn, some kinds of Reeds, &c.”

He also closely observed sensitive plants (a branch and leaf of which appears right under his drawing of cells) to try to figure out why and how the leaflets closed when touched.

His drawings of small arthropods revealed a new world of awe to his readers. Although creatures such as the flea can be very ugly, one must admire the intricacy of their adaptations, which allow them to suck blood and to avoid being scratched away or swatted.

Hooke also wrote about the things he saw through the telescope, and drew craters and mountains of the moon.

The beginning of science is thoughtful observation. The microscope and telescope extended our observation to the very small and the very large and allowed us to ask new questions that we could not have imagined. Thank you, Galileo, and thank you, Robert Hooke.

Wednesday, December 19, 2018

Plants Will Save the World! Or Not

An old acquaintance of mine (well, no older than I am) responded to a message that I had posted on Facebook, in which I said I had my students do a project in which they increased their health and reduced their carbon footprints. My friend wanted to know why anyone would want to reduce their carbon footprint. Plants need carbon dioxide, so if we put as much carbon into the air as possible, we are feeding the plants, right? He was puzzled that I, as a botanist, did not seem to understand this.

He even had a scientific source for his views. He referred to the work of Sylvan Wittwer, a horticulturalist whose research showed that plants grow better in higher carbon dioxide. From this, Wittwer concluded that rising carbon dioxide levels in the air was a good thing.

In the narrow sense, Wittwer was right. Back in graduate school, I worked on experiments with Fakhri Bazzaz (University of Illinois, later Harvard) that proved this very thing. They were greenhouse experiments. But later outdoor experiments, using Free Air Carbon Enrichment (FACE) reached similar conclusions. What happened is that, at first, plants grow more when they have more carbon, but then the growth enhancement slows down. Just one example of this is a 2006 article by Stephen Long and Donald Ort, from the University of Illinois where I got my Ph.D. Unfortunately, I cannot provide the full text, since it is available only to members of AAAS. But you can read the abstract. Here is a photo of one such experiment. It was led by my fellow graduate student from Illinois in the 1980s, Rick Lindroth.

The problem with saying that plants will grow more and cleanse the air of excess carbon is that plants need lots of things other than carbon dioxide in order to grow. They need light, which on this planet is usually abundant. But they also need soil with water and nutrients. A lot of places on Earth have droughts and soil erosion, and in those places the plants cannot make use of any extra carbon dioxide. Most of all, plants need to not be destroyed if they are to grow and absorb carbon dioxide. A lot of forest and grassland is being destroyed. Forests grow back, but we are destroying them faster than they can grow back. Apparently the plants grew quite well in Wittwer’s greenhouses, but in the great outdoors, they frequently do not.

The results are clear. Carbon dioxide levels have been increasing. When measurements began in the 1950s, carbon dioxide levels were less than 300 parts per million. Today, they exceed 400. These numbers sound small but carbon dioxide is very good at holding in the atmospheric heat. Carbon dioxide is the main reason that Venus is hotter than Mercury despite being further from the sun.

If plants are going to save the world, why are they not doing so now? They seem to be totally incapable of absorbing the surplus carbon dioxide we have already put in the air. If plants are going to save the world, when are they going to start?

Plants need carbon, and we need water. But you can’t make us healthier by drowning us in water. You can’t make plants grow more by gassing them with carbon, except sometimes in a greenhouse.

Another problem is bias. Wittwer helped to start two major think tanks. One of these is the Greening Earth Society, which is sponsored by the Western Fuels Association. The other was the Center for the Study of Carbon Dioxide and Global Change, which does not reveal its funding sources but IRS records showed that at least one source was ExxonMobil. The very purpose of these think tanks is to convince people, mainly politicians, that global warming is nothing to worry about and we should use as much oil as possible right now. They fund only research that is consistent with this view.

Having bias does not mean that you are a liar. We all have biases, as I explain in Chapter 13 of my new book, Scientifically Thinking. But there is certainly pressure for scientists whose work is funded by oil companies to reach conclusions those companies would like. You would have to be nearly superhuman in your fairmindedness if your funding sources did not influence your conclusions.

One would think that the Center for the Study of Carbon Dioxide and Global Change would gleefully promote the conservation and replanting of forests and grasslands, in order to get them to grow back faster and absorb more carbon dioxide. I asked the lead scientist of that organization if his organization promoted conservation and reforestation. He answered that taking a stand one way or the other on reforestation was outside the mission of his organization. I took this to mean that his oil donors did not want him to say that we should save and replant forests, even if he personally believed it. Your funding sources not only influence your conclusions but limit what you can say. This man struck me as being honest, as honest as he was permitted to be.

My own research shows that buds of deciduous trees in Oklahoma have opened earlier in the spring by about one to three days per year over the last dozen years. This is associated with one component of global warming. Earlier budburst is not necessarily a bad thing, but it is a sign of global warming. This graph shows the earlier budburst dates in four major species of deciduous trees. Lower numbers on the y axis mean earlier budburst.

Budburst did not occur earlier each year, but over the twelve year period, the odds of this result occurring by chance were (by statistical analysis) less than one in ten thousand.

I have received no funding for this research, not from science agencies, nor from environmental groups, nor from oil companies.

So, what is my bias? Of course I have one. But it is not what you might think. I am a botanist. I love love love plants, starting with the green chlorophyll that absorbs sunlight all the way up to the whole organism and the whole forest.

In the photo on the top, green chlorophyll glows red because it absorbs visible white light but emits red light by fluorescence. The photo on the bottom is a water oak leaf, which is a photosynthetic factory filled with veins that deliver water and take away precious sugar.

I would love to be able to tell everyone, plants will save the world! They will scrub the excess carbon out of the air. Unfortunately, I have to dejectedly accept the conclusion that they will not. This is the conclusion I reached in Chapter 3 of my earlier book, Green Planet. The subtitle of that book shows clearly that I really hoped that plants would rescue us from the greenhouse effect: How Plants Keep the Earth Alive.

It is with a heavy heart that I must report to you that the research conducted by a handful of oil-funded scientists is incorrect, and global warming is real, getting worse, and very dangerous.

Wednesday, December 12, 2018

The Terrorist Attack in Strasbourg

Last night, a terrorist attack in Strasbourg left two dead, one brain-dead, and twelve injured. This attack has shocked people around the world. French police responded immediately and are looking diligently for the shooter, whose identity is known and whose face has been broadcast everywhere.

Very quickly les citoyens strasbourgeoises created memorials to the slain.

(Photos from 

This was the same response that I saw in July 2016 when the citizens of Strasbourg created memorials for the victims of the terrorist attack in Nice.

While the horror of this attack cannot be ignored, I must remind my readers that there were more people killed, thirteen in all, on October 27 at a bar in Thousand Oaks, California. That was the 307th mass shooting in America. America has so many mass shootings that people here and around the world quickly forget them.

Friday, December 7, 2018

Mix Together Religious Zeal and Scientific Ignorance, and What Do You Get?

You all already know the answer to this question. I want to give you a particularly vivid example.

In eighteenth-century France, as in other places in Europe, Catholics massacred a lot of Protestants, and the reverse was often true as well. One of the worst massacres was in August, 1572, when French Catholic mobs murdered thousands of Protestant Huguenots in the St. Bartholomew’s Massacre. Historical summaries generally say the triggering event of the massacre was the attempted assassination of the Admiral de Coligny. But there was more to the story. I cannot find this information online, but I distinctly remember reading in a book in 1976 (written by Henri Noguรจres) that one of the triggering events was the flowering of a crabapple tree. Crabapple trees usually bloom in spring. When some of them bloomed in late summer in Paris, many people, already stirred up by religious zeal, took this to be a miracle; if a miracle, then a message; if a message, then from God; if from God, it meant that they were supposed to go kill Huguenots.

This event, however, was all based on ignorance—in this case, botanical ignorance. If crabapple (or Bradford pear) trees experience a summer drought, and then rain begins to fall, the rain serves as a trigger that makes the trees bloom. This is because the trees do not have heat and cold sensors; to a tree, winter is dry (because the water is frozen) and spring is wet. Therefore, many trees will respond to a dry midsummer followed by a wet late summer as being winter followed by spring. This is why the crabapple trees bloomed in Paris in August 1572.

When the trees bloomed, the religious zealots did not know why. And if they do not know why, then it must be a miracle. This was their religiously deluded line of reasoning. Who knows how many people lost their lives because some religious zealots did not know enough botany!

This is my six hundredth post.