Friday, June 26, 2009
Wednesday, June 24, 2009
Murcott believes that an improved public understanding of the publication process may be an important step in fostering a genuine appreciation of science as both a profession and as a human endeavor – a process fraught with enticing drama and plot-twists. He further suggests that improved access to peer-review by journalists may pave the way to better reporting. This improved access - he believes - will enable writers to go beyond the mere summarizing of findings and may open the door to stories with greater historical context and more gripping storylines.
On the whole I find myself in agreement with Toby; although improved access may be used by a few shady journalists for generating confusion and hype, most writers would apply the access towards positive objectives. Further, by making referee comments available reviewers will have greater enticement to be thorough, clear and balanced.
The essay is worth a look:
Murcott, T. (2009). Science journalism: Toppling the priesthood Nature, 459 (7250), 1054-1055 DOI: 10.1038/4591054a
Tuesday, June 23, 2009
Recently a paper was published in The Southwestern Naturalist discussing red-tails, such as this one, hunting down and feeding on American kestrels and barn owls!
I wonder what could be motivating these guys to take on such high risk prey items?
Bahm, M., & Sullivan, B. (2009). Interspecific Depredation of Raptors by Red-Tailed Hawks (Buteo jamaicensis) on San Clemente Island, California The Southwestern Naturalist, 54 (1), 85-87 DOI: 10.1894/MH-27.1
Sunday, June 21, 2009
Recently, a paper from the Proceedings of the National Academy of Sciences proposes that decision making, in regards to natural resource conservation, should be undertaken with consideration to both science and social impact. More specifically, the paper proposes that climate change is hastening the need for sound conservation strategies with respect to the managed relocation of species. Furthermore, they argue that despite a past hesitation to intervene, biologists should consider human-facilitated migrations as a viable option.
A myriad of authors from a variety of universities and governmental agencies participated in the study which qualitatively examined three cases where managed relocation was conducted or considered. From these case studies, the group developed a decision-making model that considers such action from the Focal impact, Collateral impact, Feasibility, and Acceptability to both ecology and public perception.
My opinion in the matter is that although the model may, or may not, be an adequate tool in achieving desired policy outcomes, the science of species introductions and relocations tends to demonstrate that the practice is wrought with unknown variables and is a high-risk endeavor. Because of this, I don’t like that the paper – though well intentioned – “pushes” managed relocation when it should only be “pushing” a decision making process. In my experience, those species found admirable to the public are not always the best candidates for relocation, and when public opinion enters into science, decisions can be made based on perception and misconceptions as opposed to on fact.
Just my opinion, I could be wrong…
Richardson, D., Hellmann, J., McLachlan, J., Sax, D., Schwartz, M., Gonzalez, P., Brennan, E., Camacho, A., Root, T., Sala, O., Schneider, S., Ashe, D., Clark, J., Early, R., Etterson, J., Fielder, E., Gill, J., Minteer, B., Polasky, S., Safford, H., Thompson, A., & Vellend, M. (2009). From the Cover: Multidimensional evaluation of managed relocation Proceedings of the National Academy of Sciences, 106 (24), 9721-9724 DOI: 10.1073/pnas.0902327106
Saturday, June 20, 2009
The royal fern is an Obligate member of the Osmundaceae Family, they have thick creeping rhizomes and roots that are black, wirily and clump into large masses. Leaves are bipinnately compound with alternating leaflets and display finely toothed margins.
This one was photographed about a week ago near the Suwannee River in Columbia County, Florida.
Wednesday, June 17, 2009
During the last few months, there’s been a variety of paleontology related research coming out of the Panama Canal's spoils; I’ve seen articles on paleoclimate, paleobotany and now vertebrate paleontology.
As copied from STRI materials (PDF available HERE):
Aldo Rincón, STRI paleontology intern, unearthed a set of fossil teeth in the Panama Canal that Bruce MacFadden, curator of vertebrate paleontology at the Florida Museum of Natural History, describes as belonging to Anchitherium clarencei, a three-toed browsing horse the size of the modern donkey, living 15 to 18 million years ago.
Expanding the Panama Canal to make way for super-sized ships is providing geologists and paleontologists with rare finds. Carlos Jaramillo, STRI stratigrapher, has, in collaboration with the University of Florida and the Panama Canal Authority, organized a team of researchers and students who move in following dynamite blasts to map and collect exposed fossils.
"This is one of very few places in the tropics where we have access to fresh outcrops before they are washed away by torrential rains or overgrown by vegetation, and we expect the fossils that we have been salvaging to resolve some major scientific mysteries," said Jaramillo. "What geological forces combined to create the Panama land bridge? Were the flora and fauna of Panama before the land bridge closed similar to those of North America, or did they include other elements?"
The latest finding appears in the Journal of Paleontology, vol. 83: 489-492.
Gregory Retallack (University of Oregon) and Michael Kirby (STRI) have also been actively publishing on materials from the Canal’s excavations. I plan to post about some of their work over the next few days - so keeping it brief for now.
Sunday, June 14, 2009
Saturday, June 13, 2009
This one was photographed earlier this week near Big Shoals State Park in Florida.
Friday, June 12, 2009
First, Hyla versicolor a “gray treefrog” – this guy was about twelve feet up; couldn’t convince him to turn and smile…
And second, Tremella fuciformis, a.k.a. “snow fungus” – a variety of jelly fungi often used in Chinese cooking.
For more info on snow fungus checkout Kuo’s Tremella fuciformi page here: http://www.mushroomexpert.com/tremella_fuciformis.html
Monday, June 8, 2009
Sunday, June 7, 2009
In the paper The Role of Geography in Human Adaptation, Graham Coop (et al.) moves beyond expressed phenotypes and investigates the traces of human adaptation found in the genomes of extant and geographically diverse populations. By analyzing nonsynonymous SNPs, the study found that signals expressed in the genome can be used to predict the patterns found within specific loci. Essentially, the patterns they identified demonstrated that closely related populations possessed fewer genetic differences than would be expected having been subject to differing ecological pressures over the past 100,000 years. These apparently resilient genetic patterns - they suggest - are indicative of a selection pressure that “has been strongly constrained by the historical relationships and gene flow between populations.”
From the Introduction:
“…Humans have spread out of Africa to colonize almost all of the world's land mass, and in the process have experienced a vast range of new climates, diets and ecosystems. Humans have also encountered new pathogens as they moved around the globe and moved into close proximity with domesticated animals, and as human population densities increased.
These changes in human ecology suggest that there has been ample scope for the action of natural selection in recent human evolution. Moreover, most species, including humans, probably face various additional selection pressures on a persistent basis: e.g., due to sexual competition, viability selection and resistance to evolving pathogens. Hence, it seems reasonable that our genomes would show evidence for recent selection…”
Evidence for natural selection is exactly what they find, however they also conclude that the power of selection on humans can be very weak and therefore easily influenced by historic patterns of migration and genetic drift.
The paper is well worth a look…
Coop, G., Pickrell, J., Novembre, J., Kudaravalli, S., Li, J., Absher, D., Myers, R., Cavalli-Sforza, L., Feldman, M., & Pritchard, J. (2009). The Role of Geography in Human Adaptation PLoS Genetics, 5 (6) DOI: 10.1371/journal.pgen.1000500
Saturday, June 6, 2009
Though I would agree with the paper’s authors in that a biologist might find it “…suspicious that there would be any period of time, however remote, that normal biological and ecological principles did not apply,” I would also emphasize that ecological and biological interactions tend to be constructed from compounding processes that develop with specific respect to time. And, when we examine deep geologic time it’s important to bear in mind that although the rules of the game remain constant, the players may have been substantially different – different in quantity, diversity, intra/inter-population density, etc…
These factors are absolutely crucial in the advent of any competitive strategies, rather they are for energy acquisition as in predator-prey relationships, or locomotion/movement tactics as methods for searching and dispersal. The question isn’t so much “did predation arise through the interplay of natural forces” – we’re fairly confident of that – instead the question is, “what is the duration and timeline associated with these processes?”
At this risk of sounding overly critical, I think that there may be a disconnect between the paper’s introductory assumption that predation arose in less than about 1–3 billion years, and the bulk of the paper’s data which argues that predation is the result of natural processes. Somewhere during the read, it seems to me, the perspective of time is lost...
It’s not unreasonable to suggest that at some point in deep geologic time there existed an "original" population of protozoans (or other unicellular critters), and that this population consisted of numerous, multiplying individuals whom expended energy. Due to the physical constraints of chemistry and the physiology of biological metabolism, generating energy requires the continual acquisition and consumption of resources from the surrounding environment. Unfortunately, the surrounding environment doesn’t possess unlimited resources, thus populations do not experience unbounded growth and reproductive autonomy - there are restrictions to population size.
As the population of protozoans reproduced and expanded, shortfalls in available resources would cause the population to undergo a “leveling out effect” (or rather, enter a state of oscillation) in which the number of individuals present would hover near the environment’s carrying capacity. At this point, the population either randomly fluctuates near this carrying capacity, while awaiting its inevitable demise at the hand of environmental change; or, the individuals in the system attempt to locate new, or alternative, resources through the mechanisms of natural selection.
In order for the population of protozoans to track down additional resources, they must either expand their range through greater exploration and dispersal; or, change in such a way as to enable the consumption of other, more prevalent resources – through predation or otherwise. Either of these options, range expansion or the processing of alternative foodstuffs, require morphological adaptation, the most basic of which is simply growing bigger.
Individual protozoa are far too small to be effective range expanders; therefore an increase in an individuals overall size (as well as propulsion) would be necessary to maximize travel efficiency. Likewise, in order to process new foodstuffs an organism must develop both a new means of acquisition (or gathering) and a new means of metabolizing the “foodstuffs” once they are found. To a certain degree, this implies a change in morphology and physiology – new parts and the metabolism to support those new parts are needed.
(NOTE: Perhaps a population can expand a range over multiple generations, but on my assessment adaptations “for the good of” a species or population don’t have as much explanatory torque; that’s another topic though - my point here is that individual protozoa would have some difficulty exploring the seas in search of palatable sustenance.)
As an organism grows bigger - increases its volume - it must do so while obeying certain physical and biological principles. For instance, any increase in total volume must be accompanied by a proportionately greater increase in available surface area. The surface of an organism is where energy absorption and environmental interaction occurs, consequently surface area must increase to permit inclusion of ample energy, to facilitate ecological interaction and to sustain the internal components. (For example, if an organism were spherical, volume would increase as the cube of the radius, whereas the surface area would only increase as the square of the radius; so, in order to maximize energy absorption the organism must either develop in an elongate fashion, or develop additional specialized structures such as appendages, trichomes, folded skin, etc.).
Such a drive to acquire resources may have enabled protozoa (or other unicellulars) to grow or adapt in a way as to permit phagocytotic predatation, but to the best of knowledge, that isn’t in doubt - what is uncertain is the timing of such events. How long did it take for the “original population” to reach a point of ecological pressure sufficient to drive a transition towards predation – how much TIME ???
To end on a positive note however; throughout the paper the authors emphasized the need for scientists studying the biologic systems of deep geologic time to account for established biologic and ecologic principles during their research – this point is clearly supported by the current paper and I think that it will be well received by most!
de Nooijer, S., Holland, B., & Penny, D. (2009). The Emergence of Predators in Early Life: There was No Garden of Eden PLoS ONE, 4 (6) DOI: 10.1371/journal.pone.0005507
Saltwater false willow
Baccharis angustifolia is an Obligate perennial shrub and member of the Asteraceae Family; it displays erect slender stems with narrow, single veined, succulent leaves that alternate. Saltwater false willow can commonly be found near the Atlantic and Gulf coastal plains.
This one was photographed two weeks ago near the Chassahowitzka National Wildlife Refuge.
Friday, June 5, 2009
Recently, alterations in climate have facilitated a “butterfly effect” in which expansion in the home ranges of two species has resulted in a chain of events that may ultimately lead to designation of a new butterfly species. As chance would have it, one of the two affected species, an Eastern Tiger Swallowtail butterfly, was photographed in my backyard yesterday.
Swallowtails belong to the Papilionidae family of butterflies and are characterized by their robust size, contrasting coloration and antenna-like tails. Their elongate tails mimic the appearance of antenna and redirect the focus of predators away from the head and towards the rear of the butterfly, thereby improving the probability of escape.
Yesterday, this male Eastern Tiger Swallowtail (Papilio glaucus) was photographed in my yard just after emerging from his chrysalis (three photos same specimen):
Common throughout the eastern United States, P. glaucus has a home range that is naturally bounded by ambient temperature (requires warm temperatures to reproduce) and although the pictured specimen will undoubtedly enjoy the opportunities provided by the numerous black cherry trees (Prunus serotina) in my yard – one of the staples of the swallowtail’s diet – and the warm Florida clime, even greater opportunities exist for his kin to the north.
Recently, research conducted by Michigan State University has shown that climate change has allowed the Eastern Tiger Swallowtail to travel further north than was previously tolerable. In taking advantage of its new habitat, the Eastern’s range now overlaps with the territories of the Canadian Tiger Swallowtail (Papilio canadensis) and has resulted in increased rates of hybridization between the two. The hybrids, though not yet reproductively isolated, exhibit some rather distinguishing characteristics that lead the folks at MSU to think that speciation may be at hand.
As with most plant feeding insects, butterfly-to-host plant adaptations are highly specialized towards specific plant species or plant groups. The reason for this is that plants characteristically produce chemicals that either deter or attract insects based on the defensive and mutualistic needs of the plant itself; if butterflies are to take advantage of a plant as a food source they must first adapt tolerances or immunity to the toxic compounds produced by that particular plant as defensive measures. In regards to the swallowtails specifically, although both the Eastern and Canadian feed on a variety of trees (polyphagous), they are very particular about the trees used to oviposition their eggs; the Eastern has a preference for tulip trees and the Canadian is a fan of quaking aspen. One of the distinguishing characteristics exhibited by the hybrid swallowtails is a shift in this ovipositional preference.
Although the northern most range of the Eastern has expanded, its plant of choice, the tulip tree (Liriodendron tulipifera), immigrates a bit slower and is still found only to the south – thus not accessible to the hybrids. In addition, the aspen tree (Populus tremuloides) preference of the Canadian isn’t passed on to the hybrids – i.e. no genetically transmitted tolerance to aspen chemicals. Left with little recourse, the hybrids have begun to oviposit on Fraxinus americana, the white ash tree. White ash isn’t toxic to either hybrid parental species, nor, are they specialized towards it…
This case serves as an excellent example of an ecology-linked evolutionary dynamic in which novel environmental conditions are driving divergent speciation through a compounding process. More to the point, at present a change in climate has resulted in the expansion of the swallowtail’s biogeographic distribution, thus amplifying the frequency of hybridization with similar species, and in turn increasing transmission of a trait-linked behavioral phenotype permitting unique insect-to-host plant combinations. Taken together these changes are pushing the Eastern-Canadian swallowtail hybrids towards reproductive isolation and the advent of a new Papilionidae species.
Sort of like a “butterfly effect”…
Mercader, R., Aardema, M., & Scriber, J. (2008). Hybridization leads to host-use divergence in a polyphagous butterfly sibling species pair Oecologia, 158 (4), 651-662 DOI: 10.1007/s00442-008-1177-9
Thursday, June 4, 2009
Having watched the first three episodes, posts from the blogosphere, such as those on Pharyngula and Ecographica, seem to make up a sizable portion of the included content.
Definitely worth checking out! I've embeded Episode III below for your viewing pleasure.
Monday, June 1, 2009
The article is presented from an honest and well-balanced view and is well worth a quick look. The news page also has video and graphics detailing the issue.
You can link to the article HERE.