Tuesday, June 27, 2006
This is something I never realised existed: a colour changing snake (Via). Here is the news release from the WWF:
"Gland, Switzerland – A new snake with the ability to spontaneously change colour has been discovered in the forests of the Heart of Borneo, one of the most biologically diverse regions on Earth, possessing staggeringly high numbers of unique species across all groups of plants and animals.
This ability of the snake to change colour is known from some reptiles, such as the chameleon, but scientists have seen it very rarely with snakes and have not yet understood this phenomenon.
The snake was discovered by a German researcher who described it with the collaboration of two American scientists.
“I put the reddish-brown snake in a dark bucket. When I retrieved it a few minutes later, it was almost entirely white,” said Dr Mark Auliya, reptile expert at the Zoologisches Forschungsmuseum Alexander Koenig in Germany, and a consultant for WWF.
Dr Auliya collected two specimens of the half-metre long poisonous snake in the wetlands and swamped forests around the Kapuas river in the Betung Kerihun National Park, an area in Kalimantan (the Indonesian part of Borneo) where WWF supports conservation work. The scientists named it the Kapuas mud snake.
The genus Enhydris, to which the new snake belongs, is composed of 22 species, only two of which are widespread. All the others have a very restricted range. The scientists believe this newly discovered snake might only occur in the Kapuas River drainage system.
In the last ten years, 361 new animal and plants species have been discovered on the island of Borneo. This amounts to three new species a month in an area only a little more than twice the size of Germany.
“The discovery of the ‘chameleon” snake exposes one of nature’s best kept secrets deep in the Heart of Borneo," said Stuart Chapman, WWF’s international coordinator of the Heart of Borneo initiative.
"Its ability to change colour has kept it hidden from science until now. I guess it just picked the wrong colour that day.”
However, WWF warns that the home of the new snake is threatened. Today, only half of Borneo's forest cover remains, down from 75 per cent in the mid-1980s.
But there is also hope that this trend could be halted as the three Bornean governments – Brunei Darussalam, Indonesia and Malaysia – recently launched the Heart of Borneo initiative, which aims to preserve approximately 220,000km2 of equatorial forests and numerous wildlife species."
Here is the paper describing the snake:
J. C. Murphy, H. K. Voris & M. Auliya.
A new species of Enhydris (Serpentes: Colubridae: Homalopsinae) from the Kapuas river system, West Kalimantan, Indonesia.
The Raffles Bulletin of Zoology (vol 53, p 271) (Free PDF)
‘Chameleon' snake can turn white in minutes (New Scientist)
A study in press at PNAS on the evolution of Andean Lupins suggests that it is environmental change, in this case the uplift of the andes that is a major driver of phenotypic evolution (1). The uplift of the Andes seems to have created island type conditions with many new ecological niches being formed creating opportunities for an adaptive radiation. There does not seem to have been any key evolutionary innovation in the Andean Lupins so the ecological niches created by the uplift of the Andes are the most likely cause of this rapid diversification in forms:
This study reminded me of a paper in the current issue of Antiquity (2) that suggests that human evolution could have been driven by the opening of the Great rift valley. Maybe major tectonic events have a more widespread effect on evolution than has been realised.
1) Island radiation on a continental scale: Exceptional rates of plant diversification after uplift of the Andes
Colin Hughes and Ruth Eastwood
PNAS published June 26, 2006, 10.1073/pnas.0601928103
2) Tectonics and human evolution
Geoffrey King and Geoff Bailey.
Antiquity Volume: 80 Number: 308 Page: 265–286
Wednesday, June 21, 2006
"Many species of beetles in the UK are in danger of dying out, a conservation charity has warned.
Buglife, which campaigns to protect endangered insects, says 250 of the UK's 4,000 species of beetle have not been seen since the 1970s.
The charity says it is vital for other animals that the variety of beetle-life is maintained, and "imperative" that action is taken now to protect them.
It warned that habitat decline meant many species may already be extinct.
Conservationists say beetles play a unique and vital role in the planet's ecosystems, including burying the corpses of dead animals and pollinating flowers.
But some species have not been seen for years in the UK. For example, the Sussex Diving Beetle which was common in the Lewis Levels in the 1970s but was last spotted in 2002.
Buglife director Matt Shadlow told BBC News the problems facing beetles had been indicated by research into other invertebrates, such as butterflies and moths, for which better data existed.
"The data on butterflies and moths suggests that 70% of the species that occur in the UK are currently in decline," he said.
"And in fact even with the butterflies, recent butterfly conservation data shows that in the last 10 years alone, we've lost a third of all our butterflies from the countryside.
"So other invertebrates seem to be suffering very badly. So it's not surprising that when we look at the beetles, we find that there's problems there as well."
He said it was "imperative" immediate action was taken to preserve the astonishing variety of British beetles before it was too late."
This is probably related to national insect week which started on monday, check out the website to see whats going on and if you can, do something to help our invertebrate friends.
National Insect week
Thursday, June 15, 2006
Its a book on fungi in german, notable because it contains the first description of several species and genera of fungi. It also has a few nice illustrations that have been hand tinted:
The discovery of the oldest true orb weaving spider has been announced in Biology letters. It was found in amber from northern spain and extends the range of the orb weavers back to the early Cretaceous. This means that the radiation of spiders occurred at the same time as that of angiosperms and the pollinating insects which form a major part of spider diets.
Oldest true orb-weaving spider (Araneae: Araneidae)
David Penney and Vicente M. Ortuño.
Biology Letters, DOI: 10.1098/rsbl.2006.0506
Early web-spinner found in amber: BBC News story
Tuesday, June 13, 2006
Ciliates are a large group of unicellular eukaryotes that have a highly unusual genome architecture. They have two, a micronucleus (MIC) and a macronucleus (MAC). The MIC is where genes are stored and it is passed on during sexual reproduction but it does not produce mRNA. The MAC is not passed during sexual reproduction, it is much larger than the MIC containing several copies of each gene and it is derived from the MIC (1). Ciliates normally divide asexually and in that case both nuclei are duplicated and one copy is passed on to each daughter cell. The reason for this genome architecture seems to be the very large cell size of Ciliates making it necessary to produce large amounts of proteins from each gene; this makes it necessary to have several copies of each gene from which mRNA can be produced.
It has been hypothesized that this unusual genome causes the ciliates to evolve much faster than other organisms. A fast rate of evolution has been found in histone H4 but as this gene is related to chromosome structure this fast rate of evolution could be a cause of the strange genome rather than a consequence of it. Now the rate of protein evolution has been compared between ciliates and other organisms and within ciliates with different amounts of genome processing (2). It was indeed found that genome processing did dramatically increase the rate of protein evolution, and the more extensive the processing the faster the rate of evolution.
It is not immediately obvious just how the unusual genome architecture of ciliates causes this fast evolutionary rate. The model proposed in the paper is this:
(Click for bigger)
“Genome architecture drives protein evolution in ciliates through the impact of selection operating on processed chromosomes in a somatic nucleus that divides by amitosis. Each ciliate contains a germline micronucleus, with a canonical eukaryotic genome, and a somatic macronucleus, represented by a large polyploid nucleus. A. If a deleterious mutation occurs (shown as an X), the chromosome carrying that mutation can be lost following unequal assortment during amitosis of the macronucleus. While this mutation may eventually be completely eliminated from the macronucleus, it will be present in the micronucleus. B. During subsequent rounds of asexual division, the micronucleus will acquire additional mutations. Given sufficient time and/or population size, one or more of these mutations may be compensatory. After conjugation, individuals with compensatory mutations can increase in frequency in the population. C. These processes are exaggerated in ciliates with extensively fragmented genomes, where every allele and locus is able to assort independently.”
Its and interesting theory although a lot more data will have to be accumulated before it is validated or another explanation can be found for the rate of evolution in Ciliates.
Although ‘Developmentally Regulated Genome Rearrangements’ seem very odd, they are fairly common (3). For example Genome-wide rearrangements has been found in Nematodes, Copepods, Hagfish Foraminifera and Ciliates and Targeted rearrangements are found in places like the vertebrate immune system. It is likely that this phenomenon does have an effect on the rate of evolution and it seems that this area of study will reveal interesting results.
1) Carolyn L. Jahn and
GENOME REMODELING IN CILIATED PROTOZOA
Annual Review of Microbiology Vol. 56: 489-520
2) Rebecca A. Zufall, Casey L. McGrath, Spencer V. Muse, and Laura A. Katz
Genome Architecture Drives Protein Evolution in Ciliates
MBE Advance Access published on
4) REBECCA A. ZUFALL, TESSA ROBINSON, AND LAURA A. KATZ
Evolution of Developmentally Regulated Genome Rearrangements in Eukaryotes
JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL) 304B (2005)
Thursday, June 08, 2006
The research team has a Pilbara wiki and they have a good info so i will just quote from them:
"The ancient reef is cut off one end by a fault, and at the other as it disappears into what would have been deep water, not liked by the microbial communities that created the stromatolite structures, just like modern ones.
“If you start at the deep water end and trace it along the reef system, the numbers of stromatolite shapes increase and become more complex and varied, just as occurs in biological reef systems throughout the geologic record,” she says. “It is a classical biological response to the environment.”
Her other lines of evidence include the individual structures and the association of morphologies (shapes), the spatial distributions, and the way those relate to the palaeo-environment. Analysis of the rare earth element chemistry (with Balz Kamber, Laurentian University) confirms the deposition of the fine-grained sedimentary rocks known as chert and carbonate that make up the stromatolites happened in a marine environment.
“If you take a vertical section through time there is a brief change from the high temperature hydrothermal and volcanic deposition that dominated the Pilbara at the time to a shallow marine environmentt in which life flourishes virtually immediately, “ she remarks. “And then back again to another volcanic and hydrothermal episode, when the stromatolites disappear. This speaks volumes about the conditions that may have nurtured early life” From Here
Another paper recently described structures called 'endolithic microtubes' in the Strelley Pool chert (3) that they interpreted as being of microbial origin providing futher independant evidence of the biological origin of these fossils. So overall i think the case biological origin for these structures is fairly solid.
There are microfossils from the area discovered by Schopf but these are more dubious.
There are older fossils dating to nearly 3.5 billion years ago in the Pilbara Supergroup belonging to the Dresser Fromation. In the light of this research these can also probably be more confidently called biological in origin. If this is the case I think these are the oldest currently known visible traces of life on earth.
1) Fossil evidence of Archaean life
J. William Schopf
Phil. Trans. B. Volume 361, Number 1470 / June 29, 2006
2) Stromatolite reef from the Early Archaean era of Australia
Abigail C. Allwood, Malcolm R. Walter, Balz S. Kamber, Craig P. Marshall and Ian W. Burch
Nature 441, 714-718 (8 June 2006)
3) A fresh look at the fossil evidence for early Archaean cellular life
Martin Brasier, Nicola McLoughlin, Owen Green, David Wacey.
Phil. Trans. R. Soc. B. Volume 361, Number 1470 / June 29, 2006
Pilbara Wiki - excellent resource with things like images, and maps and a reef FAQ.
Biologists in California have rediscovered the record breaking millipede Illacme plenipes notable for having the largest number of legs in the animal kingdom with some specimens having up to 750 legs! although the recently found ones have only a maximum of 666 legs.
The species was first discovered in 1926 but none have been found since. The current specimens comes from a tiny area only 0.8 km2 in San Benito County. Lets hope their habitat is now preserved. This also illustrates the amazing biodiversity of the California Floristic Province and will hopefully stimulate interest in conservation of this amazing area.
Biodiversity hotspots: Rediscovery of the world's leggiest animal
Paul E. Marek and Jason E. Bond
Nature 441, 707 (8 June 2006) | doi:10.1038/441707a
The supplementary information has a a video a PDF with electron micrographs and is available free to everyone: Link
Friday, June 02, 2006
"Passive TV viewing related to children's sleeping difficulties
A recent Finnish randomized population-based study shows that TV-viewing, and particularly exposure to adult-targeted programs, such as current affairs programs, TV series and police series and movies, markedly increases the risk of sleeping difficulties in 5-6 year old children. Also passive exposure to TV increases sleeping difficulties.
Questionnaires concerning TV viewing, sleep disturbances, and psychiatric symptoms were administered to 321 parents of children aged 5-6 years, representing the typical urban population in three university cities in Finland.
The results of the study have been published recently in the Journal of Sleep Research.
1. All the families that participated in the study had at least one TV set. In 21% of families, there was a TV set in the children's room. On average, the TV was switched on for 4,2 h a day. Children actively watched TV for a mean of 1,4 h a day and were passively exposed to TV 1,4 h a day.
2. Both active TV viewing and passive TV exposure were related to shorter sleep duration and sleeping difficulties, especially sleep-wake transition disorders and overall sleep disturbances.
3. There was also a clear association between the contents of actively viewed TV programs and the sleep problem scores. Watching adult targeted programs, such as current affairs programs, police series, movies, series, was related to an increased frequency of various sleeping difficulties.
4. Watching TV alone was related to sleep onset problems.
5. Watching TV at bedtime was also associated with various sleeping problems, especially sleep-wake transition disorders and daytime somnolence.
6. Particularly high passive exposure to TV (>2,1 h/day) and viewing adult-targeted TV programs were strongly related to sleep disturbances. The association remained highly significant when socio-economic status, family income, family conflicts, the father's work schedule, and the child's psychiatric symptoms were controlled for statistically. The adjusted odds ratios were 2.91 (95% CI 1.03-8.17) and 3.01 (95% CI 1.13-8.05), respectively. There was also an almost significant interaction between passive TV exposure and active viewing of adult programs (AOR 10.14, 95% CI 0.81-127.04, p=0.07). By contrast, active TV viewing time and the viewing of children's programs were not correlated with sleep problems.
Most of the previous research has concentrated on active TV viewing while passive TV exposure has only rarely been considered. Passive TV exposure can be particularly harmful to young children because it increases the risk of children coming into contact with programs intended for adults.
Quality sleep is essential for children's wellbeing and health. Therefore reducing the quantity of passive TV exposure and limiting children's opportunities to watch adult-targeted programs might help to reduce children's sleeping problems and increase average sleep duration, which could further lead to beneficial changes in children's daytime behavior. Parents should be advised to control the quantity of TV viewing, to monitor the program content viewed, and to limit children's exposure to passive TV. Watching TV at bedtime should be discouraged." (LINK)
I have mentioned before that watching television may be linked to a decline in childrens abilities. The mechanism of this could well be sleep deprivation as sleep is important for memory consolidation and other brain processes. There is also the link between sleep and obesity - if children sleep less they are more likely to get obese. It could well be that the increase in obesity in recent years is due in part to the widespread lack of sleep in children.
Refs:TV exposure associated with sleep disturbances in 5- to 6-year-old children
E. JUULIA PAAVONEN, MARJO PENNONEN, MIRA ROINE, SATU VALKONEN and ANJA RIITTA LAHIKAINEN
Journal of Sleep Research
Volume 15 Issue 2 Page 154 - June 2006, doi:10.1111/j.1365-2869.2006.00525.x