This Week in Evolution

I liked this essay comparing areas in evolutionary biology where there is genuine controversy -- i.e., where people who are actually collecting data and publishing on a topic disagree -- vs. the phony controversies imagined by creationists. Group selection may still almost qualify as a controversy, a question I may address in a later post, but age of the earth, common ancestry of all species (at least those studied so far!), and the power of natural selection to solve difficult problems are not at all controversial among those actively publishing on related topics.

The question of how much exposure high school students should have to genuine scientific controversies seems a bit more complex to me. I agree that helping students get enough of the basics to understand active controversies in any depth is a big challenge. On the other hand, I've been amazed how many high school students (and their parents) think that the only definition of "research" is looking up information in a library or on the web. If we want students to understand that scientific research is an exciting, ongoing activity, some kind of exposure to areas where scientists disagree seems essential. Areas of research that are easier to understand, like the mindless screening of drugs, don't convey the intellectual excitement of real science.

Here's a seminar class I've thought about for either high school seniors or first-year college students. First, let's set the minimum standard for a scientific controversy as: at least two conflicting points of view, each represented by data-containing papers from at least two nonoverlapping groups, in journals with an impact factor of at least 1.0. Each week we consider one question, such as:
1) What causes AIDS?
2) What is killing amphibians around the world?
3) How old is the earth (within 10%, say)?
4) What living species is the closest relative of chimpanzees?
Students get points for showing that each topic was controversial, at least at one time, with a big bonus for whoever shows controversy most recently. Then we could make a time-line, showing when each question was settled (pending new data, of course!).

Posted by R. Ford Denison at 11:21 PM | Permalink | Comments (0)

Each generation tends to resemble the previous one, so evolution of whales from land animals, for example, took many generations. One limitation on the power of natural selection is that each generation must be viable. Some creationist suggested that the problem is analogous to "evolving" a sentence one letter at a time to make a substantially different sentence, while requiring that each intermediate step be a valid sentence. The Mosquito Eater has solved this challenge. Cool!

But we no longer need to rely on imperfect analogies to biological evolution. Molecular tools now make it possible to explore multistep evolution experimentally, as I discussed in an early post.

Posted by R. Ford Denison at 05:09 PM | Permalink | Comments (0)

That's the title of an essay by my colleague Scott Lanyon. He notes that "development" refers to changes within an individual, whereas changes in the genetic composition of a population are known as "evolution." Apparently some public officials were afraid to say that a fish population could "evolve" resistance to a newly arrived pathogen, so they say they hope resistance will "develop." This is confusing, because individual susceptibility to pathogens can develop, increasing or decreasing with age, but that's not what they were talking about.

I used to run into a similar problem when I worked in an agronomy department. Some of the people I interacted with would say that an herbicide had "broken down", when actually the weed species it once killed had evolved resistance to it. The change was in the weeds, not in the pesticide. This misuse of the English language is particularly harmful because herbicides do break down (chemically degrade), which is usually a good thing; we don't want them polluting lakes, for example.

Populations evolve, but don't worry, fish and weeds didn't evolve from apes.

Posted by R. Ford Denison at 10:19 PM | Permalink | Comments (5)

Reminder: generic comments on evolution not tied to a particular post, unsupported assertions, tirades, philosophical or religious discussions, etc. are welcome in the comments section of the Troll Refuge but not elsewhere. Repeat offenders will be banned. If anyone feels like arguing with a creationist, who claims that evolution can't create new KINDS -- is this an acronym, or is he just shouting? -- I just moved his comments there, along with my response.

Also in the Troll Refuge, Hermione Granger, founder of Save the Trolls, weighs in on the faith vs. skepticism debate.

Posted by R. Ford Denison at 11:11 PM | Permalink | Comments (0)

There are hundreds of papers published each month whose authors find evolution useful in explaining their results. One would think that, if "intelligent design" has any scientific merit, there would be a significant number of papers each month presenting evidence of supernatural intervention by an intelligent designer. Surely the many religious scientists, in particular, wouldn't fail to publish results that turn out to support intelligent design, even if that wasn't the original focus of their research.

However, I haven't seen even one paper on intelligent design so far this year that meets the basic scientific criteria in my first post. Maybe I've missed some? Let's check the Discovery Institute web site.

Continue reading "This year in intelligent design" »

Posted by R. Ford Denison at 06:16 PM | Permalink | Comments (3)

As explained in the first entry, this blog has a narrow focus: current, peer-reviewed papers in major journals, containing new data on evolution. I may occasionally cover other topics, such as advice on science fairs or grad school, but I reserve my blog-given right to delete off-topic comments -- except in this Troll Refuge.

Comments immune from deletion outside the Troll Refuge are either:
1) narrowly focused on the particular paper-of-the-week, or
2) suggestions for papers to discuss that meet the criteria in my first post.

Continue reading "Troll refuge may prevent local extinction, scientist says" »

Posted by R. Ford Denison at 03:50 PM | Permalink | Comments (9)

In general, I don't want to waste time responding to tired old creationist criticisms of evolutionary theory that have already been refuted elsewhere (such as here or here) -- criticisms backed by new data would be another story -- but I do need to address one issue that could undermine my ability to find a paper to discuss each week. Some creationists have suggested that scientists are increasingly rejecting evolution. Actually they've been saying this for a long time. Is my paper pipeline drying up?

Continue reading "Evolution triumphs over photosynthesis" »

Posted by R. Ford Denison at 11:52 PM | Permalink | Comments (6)