Basic Concepts
voltagegate | July 13, 2007So far we have established that spiders are distinct from insects for two reasons: physiology (mouth parts, body plan, respiratory structures) and more importantly, evolutionary history (or phylogeny, as scientists call it).
But where did spider's come from? How did they come to speciate ?
The answer, like many in invertebrate paleontology, is cloudy. Organisms without hard, thick shells rarely become fossilized. In fact, for any organism's parts to become fossilized, even vertebrates, is a profound rarity, as Bill Bryson illustrates in A Short History of Nearly Everything:
Only about one…
voltagegate | July 12, 2007So how is it that spiders are more closely related to horseshoe crabs - marine arthropods that haven't changed much in the past 250 million years - than to a more obvious choice, the insects?
The answer to that question is more complex than you might think.
Up until the middle of the 20th century, before evolutionary theory was completely accepted by mainstream biology and supported by genetic analysis, taxonomists (scientists who place organisms in groups) classified organisms according to their modern anatomy. If organisms shared common physical structures (like chelicerae or mandibles)…
voltagegate | July 11, 2007I started this series of posts almost a year ago, incorporating some basics about taxonomy, evolution, and a little genetics while exploring my fascination with the Chelicerates. I'll be reposting the series, which is included in the Basic Concepts list, this week and next.
Perhaps nothing will spark a lengthy dissertation from an entomologist more quickly than calling a spider a "bug." And lengthy can be well, hours.
Truly, spiders do seem rather buggish; they're creepy, have loads of legs and the thick outer structure (an exoskeleton) that other bugs possess. In short, if it looks like it,…
jstemwedel | July 9, 2007Some months ago I made a (seemingly idle) threat to follow up my basic concepts posts on polar and non-polar molecules and intermolecular forces with a post on phase changes. Finally it's here!
Since the discussion here will be leaning on a number of the concepts discusses in the earlier posts, don't be afraid to click back to them to re-read any of the parts that seem rusty.
First, in this post I'll only be discussing the three phases of matter taken for granted in intro chemistry classes, namely, solids, liquids, and gases. I won't be getting into more exotic things like plasmas; there…
evolvingthoughts | June 6, 2007
In this post, I want to propose my own view, or rather the views I have come to accept, about the nature of science.
[Part 1; Part 2]
There are three major phases in the philosophical view of science. The first was around in the nineteenth century - science is the use of inductive logic based on data to draw conclusions about the laws of nature. Thick books described this in detail, and they are still worth reading, in particular a book by W. Stanley Jevons, The Principles of Science, published in the 1870s. But induction, as anyone who has studied Hume knows, is problematic. You simply…
evolvingthoughts | June 5, 2007
Philosophy of science deals largely with two general topics: Metaphysics and Epistemology. These are general topics of philosophy, and in the philosophy of science they deal only with the metaphysics and epistemology of science. So there are no overarching debates about how you can tell if you're dreaming, or whether we are all brains in a matrix-style vat. But there are local issues, as it were, that reflect these general concerns of philosophers.
[Part 1, Part 3]
Metaphysics covers many things
Metaphysics is a hard field to define. It is named after the book of Aristotle, which…
evolvingthoughts | June 4, 2007
This three-part series is a talk I gave a while back to some ecologists and molecular biologists. It is a brief overview of the aims and relationship between science and philosophy of science, with a special reference to the classification wars in systematics, and the interface of science and the broader community. I will present my own overview of the elements of science - as a dynamic evolving entity of knowledge gathering rather than as a timeless methodology or as a purely social movement.
[Part 2, Part 3]
It isn't often that an ornithologist gets to talk to birds. It's even less…
voltagegate | May 24, 2007Walking through a streamside copse of eastern hemlock in the ancient Appalachians is revealing for several reasons. First, the sheer size and age of these virgin stands can be humbling - at 45+ meters high, one tree may have been alive for more than 600 years. Second, a closer look at the forest's composition can tell ecologists two things: By assessing the pollen contained within pond sediment, you learn that these hemlocks started repopulating the eastern US about 12,000 years ago, following in the "footsteps" of the maple genus (Acer spp.) after the retreat of the massive glaciers covering…
voltagegate | April 20, 2007
Not a breath of air stirred over the free and open prairie; the clouds were like light piles of cotton; and where the blue sky was visible, it wore a hazy and languid aspect.
-Francis Parkman (Photo: Mongolian grassland)
Perhaps no where else on the planet can you find a better example of the rise and fall of ecosystems and the rise and fall of human cultures than on the North American prairie. So much of American history has taken place on the Great Plains: the emigration of nomadic peoples from Asia, their domination of the Plains and probable partial responsibility for the loss of most of…
evolvingthoughts | April 18, 2007
Some ideas one might think are pretty clear. The notion of an ancestor is one of them. But I am astounded how few people understand this simple idea in the context of evolution.
Ergo...
The basis for evolutionary thinking is the notion of an evolutionary tree, or a historical genealogy of species. It looks somewhat like the diagram in the header, which is a rendering of the first evolutionary tree from Darwin's Notebooks. One species is the ancestor of another if it is lower in the tree diagram.
That seems simple enough, right? Well ancestry has a few wrinkles.
The first wrinkle is…
evolvingthoughts | April 9, 2007
This is a guest post by Carl Bajema, a retired evolutionary biologist, first posted on the Richard Dawkins website on Darwin's birthday.
Happy 198th Birthday Charlie Darwin from Carl Bajema...
Organisms with their intricate adaptations for surviving and reproducing could not have evolved by chance alone. Both creationists and evolutionary biologists agree with this conclusion. Charles Darwin understood that the designs we observe in nature could not have been produced by undirected random processes alone.
Selection was widely understood before Darwin's time to be strictly a negative…
jstemwedel | April 7, 2007PRESS CENTER | UPDATED BRACKET
Janet: Welcome to team coverage of the much anticipated Chair Bracket match between Kuhn and Theory!
Ben: Yes, I think we can agree on our assumptions that this will be quite a battle.
Janet: I certainly hope so, Ben. Otherwise, we're going to spend the whole game talking past each other!
Ben: Before the gladiators take the field, let's take a quick look at how they got here. In first round play, Kuhn surprised the crowd by trouncing Popper, while Theory squeaked by Experiment by a single point.
Janet: The second round saw another trouncing at the hands of…
jstemwedel | March 30, 2007The pregame show has already started on the Acid vs d-orbitals game, but we've just received another set of predictions about this game and the Fossil Fuels vs. Erlenmeyer Flask match (hmm, should I say "match" there?) from the Molecule of the Day guy. Adjust your best accordingly!
Acid vs d-orbitals:
I have to agree with Derek Lowe - d orbitals for sheer utility. They inform huge swaths of chemical usefulness, notably in the case of metal catalysts. Acids might pull ahead for reasons of recognition, and the second row of the periodic table might be more comfortable territory to relative…
jstemwedel | March 29, 2007You've been waiting patiently. It's almost here!
PRESS CENTER | UPDATED BRACKET
GAMES TO BE PLAYED NEXT WEEK (April 2nd to 6th, 2007)
While the first two rounds of chemistry play were hosted here, Acid vs. d-orbitals will be hosted by The World's Fair and Fossil fuels vs. Erlenmeyer flask will be hosted by Page 3.14. (If you haven't already, check out the pre-game prognostication here and here. I heard a rumor that more is on the way.)
Next week, it's time for me to put on my philosophy of science hat and cover (with Ben Cohen) the Kuhn vs. Theory game, to be hosted right here.
Other…
jstemwedel | March 26, 2007As we head into the Science Spring Showdown Sweet Sixteen, it seemed prudent to turn to some experts for their predictions on the two remaining games in the chemistry region, Acid vs. d-orbitals and Fossil fuels vs. Erlenmeyer flask. (Of course, we won't soon forget the exciting first and second round games that brought these four teams to the Sweet Sixteen.)
Here's what some members of the chemical cognoscenti have to say:
Acid vs. d-orbitals:
While professing not really to understand the American basketballesque nature of the tournament, Propter Doc was willing to call this one as follows…
voltagegate | March 24, 2007From a human perspective, deserts, like tundras, seem barren and desolate, inhabited by organismal oddities, pressed into their respective niches by patch of bad luck, or a salt flat, as it were. But thinking beyond our prejudice, seeing through the eyes of a camel or transpiring through the stomata of a saguaro cactus, some conception of deserts as biologically viable and diverse regions of the planet can be gained. Life may not be particularly abundant in most of these areas, but it is varied, unique and beautiful.
For the most part, deserts occur in a consistent band at 30 degrees north…
jstemwedel | March 20, 20071st ROUND RESULTS | PRESS CENTER | PRINTABLE BRACKETS
Welcome to coverage of the 2007 Science Spring Showdown second round play in the Chemistry region. The fans in Chemical Arena resorted to a face centered cubic strategy to pack themselves into the stands. You could almost feel the electricity in the air as the products of the first round match-ups were poured into the separatory funnel of the second round. The fans and the teams shook things up. Which teams came out in the top layer, and which saw their hopes of going all the way drained out?
Acid: 105
Ethanol: 87
In one of the most…
jstemwedel | March 19, 2007PRESS CENTER | PRINTABLE BRACKETS
Even given a weekend to come back to equilibrium, some chemistry fans are still perturbed by some of the results of first round play in the MORTAR AND PESTLE bracket. FTIR's upset win over NMR has many a Monday morning spectroscopist splitting his peaks trying to analyze what went wrong. And while Ethanol is a perennial powerhouse in this conference, many tournament watchers had anticipated celebrating Caffeine at their Monday morning lab meetings.
Friday's games were just the first step in a mutli-step synthesis of a tournament champion. Tomorrow, just…
voltagegate | March 18, 2007A cheetah crouches, shoulders hunched, barely visible through golden stems. The antelope on the edge of the herd has stopped chewing, and scans the horizon with a nervous eye. As it takes a step forward to rejoin the safety of the group, the cheetah makes her move, bounding with impossibly huge leaps towards her prey. The entire herd is on the move with her first step, but the stray is dangerously lagging behind. It flies only for a few seconds before the cheetah leaps one final time, clinging to the young antelope's rump with all her strength, pulling the animal to the ground for the coup de…
jstemwedel | March 16, 2007PRESS CENTER | PRINTABLE BRACKETS
The March weather in California has taken a turn for the beautiful this afternoon, but to chemistry conference fans, the natural beauty of the great outdoors is no match for the beauty of the competitions inside the Chemical Arena. The crowds donned their safety goggles and souvenir nitrile gloves and piled in to observe the action. The press box was a flurry of strip-charts and lab notebooks. After some excited play, here are the first round results:
Entropy: 117
Enthalpy: 84
While Entropy was the favorite of the odds makers going into this game, Enthalpy…