July 3, 2008, 9:17 PM CT

Species Have Come and Gone

View a video interview with researcher John Alroy of the National Center for Ecological Analysis and Synthesis.

Diversity among the ancestors of such marine creatures as clams, sand dollars and lobsters showed only a modest rise beginning 144 million years ago with no clear trend afterwards, as per an international team of researchers. This contradicts prior work showing dramatic increases beginning 248 million years ago and may shed light on future diversity.

"Some of the time periods in the past are analogies for what is happening today from global warming," says Jocelyn Sessa of Penn State. "Understanding what happened with diversity in the past can help us provide some prediction on how modern organisms will fare. If we know where we have been, we know something about where it will go".

Using contemporary statistical methods and a paleobiology database, the scientists report in the July 4 issue of Science, a new diversity curve that shows that most of the early spread of invertebrates took place well before the Late Cretaceous, and that the net increase through the period since, is proportionately small relative to the 65 million years that elapsed. The research team was led by John Alroy of the University of California at Santa Barbara.

One key to the new curve is the Paleobiology Database, (http://paleodb.org/cgi-bin/bridge.pl) housed at the National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara. Prior research was based on databases of marine invertebrate fossils that recorded only the first occurrence of an organism and the last occurrence of the organism. There was no information in between for the organism......... Posted by: Janet      Read more         Source

July 3, 2008, 8:53 PM CT

Agriculture and frog sexual abnormalities

A farm irrigation canal would seem a healthier place for toads than a ditch by a supermarket parking lot.

But University of Florida researchers have found the opposite is true. In a study with wide implications for a longstanding debate over whether agricultural chemicals pose a threat to amphibians, UF zoologists have observed that toads in suburban areas are less likely to suffer from reproductive system abnormalities than toads near farms where some had both testes and ovaries.

"As you increase agriculture," said Lou Guillette, a distinguished professor of zoology, "you have an increasing number of abnormalities".

Guillette is one of several UF authors of a paper on the research appearing in the online version of the journal Environmental Health Perspectives The lead author is Krista McCoy, who did the work as part of her UF School of Natural Resources and the Environment dissertation.

Several past studies have suggested a link between herbicides usually used in farming and sexual abnormalities in tadpoles and frogs. Such deformities may be responsible for declines in frogs documented in areas affected by agricultural contaminants, such as Sierra Nevada, Calif., McCoy said. Amphibians are declining worldwide and agricultural chemicals are considered to be one likely cause, she said. Others include pathogenic infections and habitat loss......... Posted by: Kelly      Read more         Source

July 3, 2008, 3:32 PM CT

A very notable birth at the Los Angeles Zoo

To kick off the Los Angeles Zoo's summer activities, the Zoo is cutting admission prices for the July 4 weekend. From Friday, July 4, to Sunday, July 6, 2008 everyone can slash $4 off the price of Zoo admission! In addition to the discount, guests will also be able to buy a delicious BBQ meal, get free samples of Nestle Juicy Juice and enjoy the music of a local surf band. Take advantage of this special holiday deal to visit all of the Zoo's adorable babies!

The Zoo has also had a flurry of spring births. One of the most notable was the birth of two male peninsular pronghorns on March 25, 2008. These fawns are the first of their kind ever born at a Zoo. As per Senior Animal Keeper Kelley Greene, "the brothers have been pulled for hand rearing to ensure that they are given every opportunity to thrive." When the pair is old enough, they will be sent to the Living Desert in Coachella Valley, Calif.

The parents of these two healthy boys were just fawns themselves when they arrived at the L.A. Zoo in July of 2006. These pronghorns originally came here from a breeding center in Mexico and are the first of their species to be on exhibit outside of their home country. The older pronghorns are located in the North American section of the Zoo.

Typically, a pronghorn mother will have one or two fawns weighing in at around seven or eight pounds. When they reach adulthood, pronghorns weigh up to 125 pounds and reach a height of 35 inches. The females are commonly 10 to 25 percent smaller then males......... Posted by: Kelly      Read more         Source

July 2, 2008, 10:27 PM CT

Ethanol byproduct produces green results

Commercial flower and plant growers know all too well that invasive, ubiquitous weeds cause trouble by lowering the value and deterring healthy growth of potted ornamental plants. To control weeds, a number of commercial nursery owners resort to the expensive practice of paying workers to hand-weed containers. Some growers use herbicides, but efficacy of herbicides is questionable on the wide range of plant species produced in nurseries, and a number of herbicides are not registered for use in greenhouses.

Enter "dried distillers grains with solubles", or DDGS. DDGS, a byproduct of converting corn to fuel ethanol, is typically used as livestock feed. Rick A. Boydston, Harold P. Collins, and Steve Vaughn, of the U.S. Department of Agriculture, undertook a research study on the use of DDGS as a weed deterrent on potted ornamentals. The study results, reported in the February 2008 issue of HortScience, reviewed the use of DDGS as a soil amendment to suppress weeds in container-grown ornamentals.

Scientists applied DDGS two ways: to the soil surface, and mixed into the potting media of transplanted ornamentals. Applied to the soil surface after transplanting, DDGS caused no injury to plants. As per Dr. Boydston, an agronomist with the Agricultural Research Service (ARS), "grains applied to the surface at rates that gave good coverage of the soil (800 and 1600 g/m2) reduced the number of common chickweed and annual bluegrass. Weed control was not perfect, but could reduce the amount of hand-weeding typically required"......... Posted by: Erica      Read more         Source

July 1, 2008, 9:53 PM CT

Crossed (Evolutionary) Signals?

What do humans and single-celled choanoflagellates have in common? More than you'd think. New research into the choanoflagellate genome shows these ancient organisms have similar levels of proteins that cells in more complex organisms, including humans, use to communicate with each other.

As per a paper published last week in the Proceedings of the National Academies of Science, these findings help confirm choanoflagellates' role as an evolutionary link between single-celled and multi-celled organisms. They also contend that these insights into the organism's genome may mean that the proteins used to help cells communicate may have other roles as well. The scientists are from the University of California, San Francisco and the European Molecular Biology Laboratory in Heidelberg, Gera number of.

Choanoflagellates, or at least their ancestors, have long been suspected as being the bridge between microorganisms with only one cell and metazoan, or multi-cellular organisms. There are a number of clues that lead to this conclusion, including the fact that choanoflagellates are similar to the individual cells in ocean sponges and unlike most other flagellates, they use their flagellate, or tail, to push themselves through water, rather than being pulled by it.

By analyzing the recently-sequenced choanoflagellate genome, the scientists discovered another similarity between choanoflagellates and most metazoans--their genetic code caries the markers of three types of molecules that cells use to achieve phospho-tyrosine signaling proteins......... Posted by: Janet      Read more         Source

July 1, 2008, 9:48 PM CT

Plants in the fourth dimension

As anyone who has suffered from jetlag knows, we have internal clocks that tell us when to sleep and wake, and we can be miserable when these are disrupted. The daily cycles of a number of organisms are well known, but what has not been clear is whether these cycles are just responses to external cues of light, dark, heat, and cold, or if there are internal clocks that are set and reset by environmental signals. In animals, circadian rhythms are known to be important for maintaining a multitude of physiological processes. They may be even more critical for plants, which grow in a number of different light and temperature environments that not only vary with latitude but also with subtle differences within just a few feet. Plants respond to changes in light and temperature, opening flowers at dawn and closing them at night or blooming in the right season. However, they also have endogenous circadian ("around the day") rhythms with roughly 24 hour periods that are regulated by numerous genes that interact in complex pathways and cycles like exquisite 18th century clocks. These clock genes have been intensely investigated over the last 20 years, but we still do not fully understand the molecular mechanisms that make them run. Knowledge of these oscillations and the genes that regulate them could help us adjust the growth, development, and yield of crops under climatically variable conditions......... Posted by: Erica      Read more         Source

July 1, 2008, 9:26 PM CT

Human influences challenge penguin populations

The ecology of penguins makes these iconic swimming and diving seabirds of the Southern Hemisphere uncommonly susceptible to environmental changes. Pronounced warming in the Antarctic, as well as commercial fishing, mining, and oil and gas development at lower latitudes, has led to declines in a number of species, as per P. Dee Boersma, of the University of Washington in Seattle. In the July/August 2008 issue of BioScience, Boersma provides a first-person account based on 30 years of studying the birds. Counts of the penguin populations at the 43 remaining breeding "hotspots," even once every five years, could provide valuable insights into the variability of the ocean ecosystem and the populations' viability, Boersma writes. Yet counts are carried out only rarely, if at all.

The task is urgent, because a number of populations seem to be in rapid decline even as some temperate populations have expanded their range southward. Rapid reductions of sea ice off Antarctica in recent years threaten Adlie and emperor penguins, which need ice, but may benefit some populations of relatively ice-intolerant gentoo and chinstrap penguins. Increased snow and rain, another result of the changing climate, reduce breeding success in some gentoo and Adlie penguins.

Temperate penguins, such as Galpagos, Peruvian, and African species, are all declining. Mining of guano, egg harvesting, commercial fishing, and oil spills are the chief causes, as per Boersma, eventhough tourism and increasingly severe El Nio events, probably resulting from climate change, are also partly responsible......... Posted by: Kelly      Read more         Source

June 26, 2008, 9:25 PM CT

'Early bird' project really gets the worm

Researchers from the LSU Museum of Natural Science, or MNS, recently participated in a project joining together the most prominent ornithological research programs in the world. This study the largest study of bird genetics ever completed has not only shaken up the avian evolutionary tree, but completely redrawn it. The results of this massive research project, which relied heavily upon the LSU MNS' genetic resources collection, will be published in Science on June 27.

The results of the study are so broad that the scientific names of dozens of birds will have to be changed, and biology textbooks and birdwatchers' field guides will have to be revised.

LSU participants in the study include: Fred Sheldon, director of the LSU MNS; Ben Marks, recent graduate of LSU's biological sciences doctoral program; and Chris Witt, former LSU graduate student and current assistant professor in the Department of Biology and Museum of Southwestern Biology at the University of New Mexico.

For more than five years, the Early Bird Project, funded by the National Science Foundation's "Assembling the Tree-of-Life" research program, has been collecting DNA sequence data from all major living groups of birds.

"One thing that makes this project unique is its breadth; both in its taxonomic scope and in terms of the amount and type of data we collected," said Marks......... Posted by: Kelly      Read more         Source

June 26, 2008, 8:52 PM CT

What It's Like to Be a Bat

Not a number of people think about what it's like to be a bat, but for those who do, it's enlightening and potentially groundbreaking for understanding aspects of the human brain and nervous system.

Cynthia Moss, a member of the Neuroscience and Cognitive Science program at the University of Maryland, College Park, Md., is one of few scientists who spend time trying to get into the heads of bats.

Her new research suggests there is more to studying bats than figuring out how they process sound to distinguish environments. Partially supported by the National Science Foundation, her research paper appears in the June 18 online edition of the Proceedings of the National Academy of Sciences.

"For decades it's been recognized that a bat's voice produces sounds that give the bat information about the location of objects," says Moss. "We're now recognizing that every time a bat produces a sound there are changes in brain activity that may be important for scene analysis, sensorimotor control and spatial memory and navigation".

The research could help neurobiologists understand mechanisms in the human brain and ultimately benefit human health, but that may not happen for some time as more studies are needed.

Moss and her colleague, Nachum Ulanovsky from the Weizmann Institute of Science in Israel, evaluated more than 100 studies and determined the brief calls emitted through a bat's mouth or nostrils and their returning echoes play a pivotal role in motor control and have other behavioral implications......... Posted by: Kelly      Read more         Source

June 25, 2008, 10:26 PM CT

Where Are You Now, My Love?

Having a good nose is essential to a Japanese beetle's survival. The beetle's sense of smell helps it avoid enemies and zero in on a mate. Meanwhile, the potential mate is programmed to release sex pheromones in exactly the right proportions. Like cheap perfume, there is such a thing as too much: Excessive pheromones can get the attention of a passing fly, leading her to the beetle. The fly can then lay her eggs on the beetle's back, setting up emerging fly larvae for their first meal (fresh Japanese beetle).

If all of this isn't challenging enough, the male beetles have to track females while they're both flying. This requires a mechanism within the males that loses the pheromone scent from a moment before and picks up the latest scent as the females move through the air.

This mechanism is well understood by Walter Leal, a chemical ecologist at the University of California, Davis. With funding from the National Science Foundation, Leal has isolated, identified, cloned and expressed a pheromone-degrading enzyme that allows receptors in the beetle's nose to lose the pheromone scent from the female's earlier locations as she moves to new places.

Isolating this enzyme offers the potential to eliminate entirely the beetle's reception of the pheromone scent, making them unable to find females, mate and reproduce. This potential could be useful to agricultural pest control, since the Japanese beetle is an invasive species responsible for millions in damages to crops each year......... Posted by: Kelly      Read more         Source