Friday Random 10

• Stephen Longfellow Fiske, "Eagle Fly"
• Johnny Cash, "Guess Things Happen That Way"
• Dar Williams, "Bought and Sold". Takes on Wal-Mart and weapons manufacturers in the same song.
• Collin Raye, "I Know That's Right". If this song doesn't make you feel good, nothing short of drugs will!
• Mariah Carey, "Hero"
• Julia Ecklar, "Ladyhawke!". Ever heard of filk? Nice example -- a fantasy song.
• Leslie Fish, "Sequoia sempervirens". Yes, it's a song about a tree and yes, I'm enough of a nerd to properly format the Latin name.
• Julia Ecklar, "Survivor's Song". The thoughts of a nuclear war survivor. Powerful!
• John Lennon, "Imagine". A perfect contrast with the previous song.
• Gaia Consort, "Evolve" (live version). I blogged about this one. You can hear it here.

The Beauty of Evolution

There's a lovely post on Pharyngula about the evolutionary connection between fish gills and our thyroid glands. Fish use their gills not just for gas exchange but also to control the concentration of salts in their bodies. So what does a fish do when it finds itself on land and needs to regulate calcium in its blood? Read the post to find out!

Nature Green in Leaf and Shoot

Debates about the nature of ecological communities have shaped many aspects of the science. Ecologists of the late 19th and early 20th centuries generally saw communities as highly interdependent systems or even superorganisms whose composition was shaped by biotic interactions and coevolution. The contrary view, that the physical environment in a location pretty much controlled what plants lived there, gained ascendency later. This idea, modified to included the effects of chance and some competition, is still dominant today. However, mutualism is finally beginning to get some recognition as an important factor determining community composition. (The word "mutualism" refers to an interaction between two species that benefits both of them -- what laypeople typically think of as "symbiosis".) The debate is not merely academic. It has real consequences for conservation and restoration of damaged ecosystems.

The May 2006 issue of Frontiers in Ecology and the Environment contains a review paper by Francisco M. Padilla and Francisco I. Pugnaire about the use of nurse plants in ecological restoration. This approach involves planting the plants you want next to larger plants already growing in the area. (Yes, I get paid for each use of the word "plant".) The nurse plants may shield the target species from harsh weather, bring up water and nutrients, protect against grazers and attract pollinators. However, this approach doesn't always work. Environment matters, as does the identity of the nurse and target plants.

Nurse plants are most helpful in harsh environments like chapparral and alpine tundra. In easier conditions, competition between the two plants trumps any beneficial effects. For the same reason, nurse plants are more useful in dry years than wet years. This counterintuitive effect may occur because the deep roots of the nurse plant bring up water and the shade it casts helps the establishing seedling conserve water.

The species of the nurse and target plants also makes a difference. Plants that release growth inhibitors into the soil don't make good nurse plants. (Duh.) Late successional species benefit more from having nurse plants than early successional ones. And, although the authors don't discuss this, I'd bet pairing close relatives will increase competition and reduce beneficial effects.

The importance of this synthesis goes beyond practical restoration work to providing key insights for community ecology. If nurse plants matter in restoration succession, they probably also make a difference in natural succession. Since these interactions show at least some species specificity, we can draw a similar conclusion about species interactions in succession and ecosystem development. Finally, both biotic interactions and physical conditions make a difference; indeed, physical conditions can determine the nature of the interaction between nurse and target plants. The same effect can be expected in the wild.

No Cats were Harmed in the Making of This Website...

But you should check it out anyway! I refer to Cat Flinging: An Illustrated History of Catflinging in Europe and North America, the first scholarly work on this much under-appreciated sport. An excerpt:

The cat is much like the bagpipe in that there are few people who are entirely indifferent toward either. (The similarity does not end there, however, a fact that will be documented hereinafter.) For the sake of illustration, let us assume it possible to create a list objects in the environment ordered according to their ability to engender collective indifference in the human observer. At the top of our indifference index one would probably find such things as tofu and Ed Sullivan, objects with the capacity to engender violent indifference. The cat and the bagpipe, however, would have their place at the bottom, somewhere in the vicinity of Monte Python and chewing tobacco. It is perhaps largely the cat's low indifference index that best explains the controversy surrounding the art of cat flinging.

What Kind of Whole is North Korea?

According to this, North Korea might be among the few states -- perhaps the only one -- that might be said to form a real whole. Seems fragile.

Wife Swap Leads the Way

One of my guilty pleasures is watching the ABC reality show Wife Swap with my mom. For those who don't know how Wife Swap works, the show has the wives in two families change places for two weeks. For the first week, each woman lives by her new family's rules; at the beginning of the second week, she gets to make some changes. Usually, both families come away having learned something, or at least give the impression of having done so.

The episode I saw today, which originally aired on November 28, 2005, featured two families, the Stonerocks and the Finleys. Both families learn to pay more attention to their childrens' needs, but the key theme in the episode is religion. The Finleys are hard-core atheists, while Jeff Stonerock preaches in what looks like a pretty fundamentalist church. Kelly Stonerock takes over Reggie Finley's Infidel Guy radio show while Amber Finley hires a secular tutor for the homeschooled Stonerock kids. Predictably, fur flies.

For me, the key moment came when Amber discussed discrimination against atheists with Jeff, explaining that she rarely goes out because of it. That topic NEVER comes up on TV. Later, when the families meet, they again discussed prejudice against atheists/agnostics/Brights and the religious Stonerocks sympathized, telling the Finleys, "We are on your side". The show's finale? Jeff Stonerock preaches a sermon at his church, saying that atheists are worthwhile individuals and God loves them and Christians equally. Amen to that! :-)

Seriously, I hope today's show starts to open a discussion of the civil rights of secular individuals. Religion is here to stay, and so is doubt. With tolerance, reason and separation of church and state, we can get along while disagreeing and build a better society for everyone.

Networks in Epidemics and Ecology

Tara Smith at Aetiology has a neat post about networks, particularly in disease transmission. Studying networks allows you to see and analyze how entities, like people in a society or species in an ecosystem, interact. Sometimes, you discover neat and useful patterns. For example, many infectious diseases, including HIV in America, are primarily spread by hyper-connected individuals. Other times, a person does more than their share of disease transmission by simply shedding more of the infectious agent than other people. SARS is an example of this.

To me, the coolest application of network science is to ecological networks such as food webs. Neo Martinez, Jennifer Dunne and their colleagues at PEaCE Lab have done some fascinating work on food web structure. One of their basic results shows that you can create realistic food webs using very simple rules -- animals have a certain size and eat things that are a given fraction of that size. Their simulations also show that the ability of a food web to withstand species extinctions depends on how richly interconnected the species are.

A different approach to the study of ecological networks is that practiced by Bernie Patten and the Systems and Engineering Ecology group at the University of Georgia. Their work looks less at network structure than at dynamics and general principles. I'll be joining this group in mid-August, so expect more on ecological networks starting then.