ecology
chaoticutopia | September 22, 2006Deep within the pockets of a Mandelbrot set, delicate branches display endless variations. When highlighted with the colors of autumn, (since today is, after all, the Autumnal Equinox,) patterns of exquisite beauty emerge:
These patterns can remind us of many forms in nature, including a grove of quaking aspen:
Quaking Aspen (Populus tremuloides)
Aspen are members of the poplar family, along with their cousins, the cottonwoods (featured in last week's fractal.) While they are known for their brilliant foliage in the fall, the species has another claim to fame: the world's largest organism…
tsmith | September 21, 2006 That's certainly the claim in a new New York Times editorial (via The Frontal Cortex). The author, Nina Planck (author of Real Foods: What to Eat and Why), claims that it's as easy as just feeding cattle grass, and poof!--E. coli O157 will vanish.
More on this and why organic farming won't necessarily stop such outbreaks after the jump.
Planck writes:
Where does this particularly virulent strain come from? It's not found in the intestinal tracts of cattle raised on their natural diet of grass, hay and other fibrous forage. No, O157 thrives in a new -- that is, recent in the history of…
clock | September 20, 2006Bird Moms Manipulate Birth Order To Protect Sons:
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Since 2002, Badyaev, Oh and their colleagues have been intensively documenting the lives of a population of house finches (Carpodacus mexicanus) on the UA campus.
Throughout the year, the researchers capture birds several times a week to band and measure them and to take DNA and hormone samples. During the breeding season, the researchers locate the nests, keep track of activity in the nest, follow nestling growth and development, and take DNA samples from the chicks.
The researchers have also been…
clock | September 20, 2006Team Describes Unique Desert Cloud Forest:
Trees that live in an odd desert forest in Oman have found an unusual way to water themselves by extracting moisture from low-lying clouds, MIT scientists report.
In an area that is characterized mostly by desert, the trees have preserved an ecological niche because they exploit a wispy-thin source of water that only occurs seasonally, said Elfatih A.B. Eltahir, professor of civil and environmental engineering, and former MIT graduate student Anke Hildebrandt.
After studying the Oman site, they also expressed concern that the unusual forest could be…
tsmith | September 18, 2006And who said spinach was boring?
If the ongoing E. coli outbreak due to spinach has done one thing, it's highlight the mystery that revolves around Salinas, California:
The sunny Salinas Valley holds a dark mystery: Why, in the past decade, have nine Escherichia coli outbreaks been linked to produce grown here?
It's still unknown why this fertile land has been hit by what an FDA official calls "significant" crop contamination.
Throughout the picturesque terrain here, questions swirl.
Has cattle waste contaminated irrigation water? Does contaminated soil blow in the wind? Do birds feeding on…
tfk | September 17, 2006Many years ago, the University of Chicago invited Amartya Sen, who had recently won a Nobel Prize in Economics, to come and speak. He appeared beside Gary Becker, a distinguished professor of the University's famed economic department, and an adherent to the "Chicago School of Economics." At one point, after the speeches, a question was posed about how the two would define the role of economics in society. Becker gave what is probably his standard Econ 101 introduction, explaining how economics studies how rational human behavior influences the aggregate behavior of markets, etc. After…
clock | September 11, 2006Destructive insects on rise in Alaska:
Destructive insects in unprecedented numbers are finding Alaska forests to be a congenial home, said University of Alaska forestry professor Glenn Juday, and climate change could be the welcome mat.
Warmer winters kill fewer insects. Longer, warmer summers let insects complete a life cycle and reproduce in one year instead of two, the forest ecologist said.
Warm winters also can damage trees and make them less able to fend off insect attacks by changing the nature of snow. Instead of light, fluffy snow formed at extreme cold temperatures, warm winters…
chaoticutopia | September 8, 2006Fractals are like landscapes. From a simple process, be it a formula or continental drift, one area can be strikingly different from another. This is true for my favorite type of fractal, a Julia set, "colored" with a bit of fractal Brownian motion:
Or the ripples on the Great Sand Dunes:
Stone, Steam and Sand: A Geologic Photo Tour of Southwest Colorado, Part III
In the first part of this series, I described the formation of the San Juan Mountains, and then a bit of the more recent history of the lands to the west of the range. The valley east of the San Juans had similar initial…
tfk | September 8, 2006On Fridays, we like to highlight some of the remarkable and beautiful things you find right under your nose.
This week, a reader sends in some photos of Lycoperdon pulcherrimum, Latin for "most beautiful wolf-fart."
What we see is the fruiting body of a fungus. Most of the biomass of fungi is below ground, thin threads called hyphae that reach out and absorb nutrients and break down dead material.
Some fungi grow into roots (forming what are called mycorrhizae) get sugar from trees and in exchange help extend their ability to gather water and nitrogen. There have even been studies showing…
mikethemadbiologist | September 8, 2006This paper on the ecology of vampires in Buffyville is hysterical--in a geeky sort of way. And it's a very good ecology primer too...
tfk | September 4, 2006In Science, two biologists reported on the effects of fishing in South American rivers. Removing a large fish, Prochilodus mariae, from the river causes rapid changes in how carbon (stored energy) passes through the river, decreasing the cycling of carbon. In fact, they explain, "Impacts of removing Prochilodus on carbon flow equaled or exceeded effects of removing [in different studies] all fish, invertebrates, shrimps, and predatory fish in other streams and lakes."
The removal of one species from one side of a river reduced flow of organic material by 60%, and changed the sort of growth…
tfk | September 3, 2006Saying "This compares with any treasure anywhere in the world,":
Gov. Kathleen Sebelius and the Nature Conservancy on Friday announced the donation of a conservation easement encompassing 10,000 acres [of tallgrass prairie in the Flint Hills].
The tallgrass prairie once stretched in a giant sea of grass from Alberta down to Texas, a continuous swath of grass across the continent. Pioneers describe having to stand in their stirrups to see over the grass. Giant herds of bison migrated across it, with native people and the prairie wolves trailing the herds.
A prairie lives in its roots, with…
clock | August 30, 2006
Re-post from May 17, 2006, under the fold...
When teaching biology, one has to cut up the syllabus into edible and digestible chunks, and it makes sense to cover various subdisciplines in separate lectures. As you know, I strive to find ways to make connections to students so they don't leave with a sense that all those subdisciplines are disconnected from each other, almost like separate sciences.
One obvious way to do it is to place everything heavily into an evolutionary context. Another way - and the two go hand-in-hand - is to find really cool diseases, like malaria, in which findings…
tfk | August 27, 2006Ask A ScienceBlogger:
The destruction of the rainforest was a hot-button topic in the early '90s, but I haven't heard anything about it in ages. Are the rainforests still being destroyed wholesale? Are they all gone? Is it still important? Is the coffee I drink making it worse, and is "free trade" and/or "shade grown" coffee any better?
It is still a problem, and I've been remiss in not answering this question.
The simplest guide can be seen in this satellite image of the border between Haiti and the Dominican Republic. On the Haitian side, where forests nationwide have declined 5% between…
tsmith | August 23, 2006So, you may or may not be aware of the latest "challenge" to evolutionary theory--DI Fellow Jonathan Wells' new book, "The Politically Incorrect Guide to Darwinism and Intelligent Design." Following in the footsteps of Tom Bethell's "Politically Incorrect Guide to Science" (whose terrible chapter on AIDS I reviewed here), the book is just all shades of terrible. (As has been pointed out by many others who've read books in the "Politically Incorrect" series, they should just drop the pretense of "Politically"--simply "Incorrect" sums them up much better). I'll have a more comprehensive…
clock | August 18, 2006One of the several hypotheses floating around over the past several years to explain the phenomenon of repeated wake-up events in hibernating animals although such events are very energy-draining, is the notion that the immune system needs to be rewarmed in order to fend off any potential bacterial invasions that may have occured while the animal was hibernating:
Now, a group of researchers provided a mathematical model that supports this hypothesis:
"A habit in some animals to periodically wake up while hibernating may be an evolutionary mechanism to fight bacterial infection, according to…
tsmith | August 10, 2006So it would seem.
West Nile is spreading beyond birds, horses and humans. A squirrel has tested positive for the virus and hundreds more are showing the same symptoms
People are finding squirrels in their yards or parks that look like they've been injured because they aren't able to walk. In some cases they're disoriented, running around in circles or shaking. Now it's believed they're suffering from West Nile.
(More below...)
West Nile virus (WNV) is another arbovirus; that is, a virus that's transmitted by an arthropod (in this case, the mosquito). Typically, the virus cycles between birds…
clock | August 10, 2006A nice new study on ecological aspects of circadian rhythms:
To a tiny tadpole, life boils down to two basic missions: eat, and avoid being eaten. But there's a trade-off. The more a tadpole eats, the faster it grows big enough to transform into a frog; yet finding food requires being active, which ups the odds of becoming someone else's dinner.
Scientists have known that prey adjust their activity levels in response to predation risk, but new research by a University of Michigan graduate student shows that internal factors, such as biorhythms, temper their responses.
Michael Fraker, a…
clock | August 10, 2006As the temperatures rise, different organisms respond differently. Some migrate to higher latitudes or altitudes. Others stay put but change the timing of reproduction and other seasonal activities. As a result, ecosystems get remodeled.
So, for instance, insect pollinators and flowers they pollinate may get out of sync.
Animals tend to use photoperiod as a major clue for seasonal timing, with temperature only modulating the response to some extent.
Plants, on the other hand, although they certainly can use photoperiod, are much more strongly influenced by temperature. Non-biologists who…
clock | August 10, 2006This is interesting:
Landscapes And Human Behavior:
On Arizona State University's (ASU) Polytechnic campus, graduate student families in the cluster of six houses abutting lush lawns and ornamental bushes spend time together talking while their kids play outside. Meanwhile, the families in a nearby cluster of six homes barely know each other. But that may be in part because their homes sit on native Sonoran desert, not nearly as conducive to recreation as the lush microclimate researchers created in the first neighborhood. Social scientists and biophysical ecologists are finding that…