Archive for February, 2012

Mediterranean wildlife

Mediterranean wildlife

Limestone rock coastline of Istria, Croatia

Low rainfall and hot summers make the Mediterranean biome a hard place for animals and plants to thrive. Mediterranean plants are often adapted to conserve water and survive summer drought. Many African animals would probably suit the Med’s hot, dry summers – porcupines and fruit bats have crossed over – but are less able to cope with the cooler, wet winters. The original Mediterranean Sea dried up in the Miocene Epoch and stayed that way until a little over 5 million years ago when water poured in from the Atlantic. It lacks nutrients and is saltier than the Atlantic, but it’s still a biodiversity hotspot with many unique species.

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The pre-historic ” Age of ice “

Age of ice

Ice age

Technically we are living within an Ice Age, inhabiting a warm interglacial period that occurs between colder glacial periods. Today’s warm period is known as theHolocene and started about 11,500 years ago.

The last glacial period peaked about 20,000 years ago: the climate was cooler and ice sheets covered large areas of land. It would have been a dramatically different landscape from today’s and a harsh place to live.

Imagine a world inhabited by herds of giant woolly mammoths and rhinoceroses, alongside deer with antlers spanning over four metres. A place where ourancestors relied on hunting and gathering as a way of life.

Wht are . . . . Monocotyledons ?

Monocotyledons

Wheat growing in a Gloucestershire field

Monocotyledons (liliopsida) are traditionally one of the two main groups of flowering plants, the other being the dicotyledons. What distinguishes the monocots is the single leaf in the seed (cotyledon) and flower petals in multiples of three. There are over 60,000 recognised species contained within some of the largest families of flowering plants such as the orchids (20,000 species) and grasses (10,000 species). Most of the agriculturally and economically important plants are in here from rice, wheat, barley and sugar cane to palms, bamboo and bananas.

An Animal or a Flower ?

Bee orchids

Close-up of a bee orchid flower

Bee orchids are fascinating and beautiful plants that certainly live up to their name: each flower looks like it has a female bee or wasp resting on it. These modified petals also smell like female bees, emitting enticing chemical signals. These remarkable adaptations are in fact an effective deception to lure a real bee to come and mate.

In most bee orchid species the excited male insect becomes covered in pollen, in turn pollinating the next orchid he visits; a few species, however, are still self-pollinating. These Mediterranean masters of mimicrygrow either singly or in small groups in meadows, woodland edges or even by the side of the road.

Mozambican poachers get 25 years in South Africa court

Rhinos in Kruger National Park,SA, file

Some game farms in South Africa have resorted to de-horning rhinos before poachers get to them

Three Mozambicans have been sentenced to 25 years each in a South African court for rhino poaching, according to the South African national parks body.

The men were found guilty of illegally hunting rhino in the Kruger National Park in July 2010.

The head of SANParks, David Mabunda, said the sentence was harsher than other similar cases.

In 2011, a record 450 rhino were killed in South Africa, according to the Department of Environment Affairs.

“This is an indication that, as a country, we are taking more stringent measures in the fight against rhino poaching,” Mr Mabunda said in a statement.

Aselmo Baloyi, Jawaki Nkuna and Ismael Baloyi were found guilty on four charges, including illegal hunting of a rhino and possession of a prohibited firearm.

They were caught with two freshly chopped rhino horns, an assault rifle, a hunting rifle and an axe.

Mr Mabunda said that last year 232 suspected poachers were arrested, including 26 who died in fights with the authorities.

Large syndicates are involved in this multi-billion dollar trade worldwide – exporting the horns from Africa to parts of Asia and the Middle East.

South Africa has been the focal point of poaching because it has the largest population of rhinos in the world, with 1,916 black rhinos and 18,780 white rhinos.

Poachers use a chainsaw to cut away a rhino’s horns, after darting it with a tranquilizer – drugged and helpless the animal bleeds to death, says the BBC’s Pumza Fihlani in Johannesburg.

The country’s government has commissioned a study into whether legalising trade in rhino horn could help to bring down poaching.

Male spiders break off sex organ to boost paternity

Nephilengys malabarensis

The red box shows a broken male organ lodged in the female spider

Some male spiders voluntarily “castrate” themselves during sex in order to increase their chances of fathering offspring, a new study shows.

The males break off the entire sex organ while it is still in the female, allowing it to keep injecting sperm long after they have scuttled away.

A quick getaway is understandable; the females often eat their male mates.

Writing in Biology Letters journal, a team now says castration increases the amount of sperm transferred.

This boosts the chances of paternity from this pairing, explaining a behaviour had been a puzzle to biologists because, on the face of things, it renders the spiders sterile.

Breaking off the tip of the palp during sex is fairly common in spiders. It is thought to function as a “plug” to stop other males from later mating with the same female, and potentially fathering offspring with her instead. It also makes sense in light of the female propensity for cannibalising males after sex.

But full emasculation was not considered necessary for making an effective plug.

So scientists had come up with other theories to explain the behaviour, known as the “eunuch phenomenon”.

These have included the so-called better fighter hypothesis; eunuchs are more aggressive and agile compared with males sporting intact organs.

Arms raceBut Daiqin Li, from the National University of Singapore, and colleagues decided to test whether castration resulted in continued sperm transfer to females of the Nephilengys malabarensis species.

They dissected the spiders and counted sperm from the reproductive parts under a microscope.

Their results show that sperm transfer from the broken palp continued after sexual intercourse had been terminated. The longer the broken spider organ was left lodged in the female before its removal, the more sperm were transferred.

They also discovered that while the percentage of organ breakages initiated by the female spider and those initiated by the male spider did not differ greatly, those initiated by the female generally resulted in a shorter intercourse time and fewer sperm transferred.

This reduces the male spider’s reproductive potential.

So the authors think that voluntary castration evolved as a response to both female cannibalism of male spiders after sex and to counter the female’s desire to control the duration of sexual intercourse.

Breaking off the whole palp allows sperm transfer to continue after the male spider has bolted and allows males to monopolise the female for longer.

But writing in Biology Letters, the team does not rule out that other benefits, such as the enhanced aggressiveness of castrated spiders, further justify the cost of sterility.

Science decodes ‘internal voices’

Scans showing brain activity when speaking/listeningThe studies focused on a part of the brain associated with sounds called the superior temporal gyrus

Researchers have demonstrated a striking method to reconstruct words, based on the brain waves of patients thinking of those words.

The technique reported in PLoS Biologyrelies on gathering electrical signals directly from patients’ brains.

Based on signals from listening patients, a computer model was used to reconstruct the sounds of words that patients were thinking of.

The method may in future help comatose and locked-in patients communicate.

Several approaches have in recent years suggested that scientists are closing in on methods to tap into our very thoughts; the current study achieved its result by implanting electrodes directly into a part of participants’ brains.

In a 2011 study, participants with electrodes in direct brain contact were able to move a cursor on a screen by simply thinking of vowel sounds.

A technique called functional magnetic resonance imaging to track blood flow in the brain has shown promise for identifying which words or ideas someone may be thinking about.

By studying patterns of blood flow related to particular images, Jack Gallant’s group at the University of California Berkeley showed in September that patterns can be used to guess images being thought of –recreating “movies in the mind”.

All in the mind

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The development of direct neuro-control over virtual or physical devices would… improve quality of life immensely for those who suffer from impaired communication skills”

Mindy McCumberFlorida Hospital

Now, Brian Pasley of the University of California, Berkeley and a team of colleagues have taken that “stimulus reconstruction” work one step further.

“This is inspired by a lot of Jack’s work,” Dr Pasley said. “One question was… how far can we get in the auditory system by taking a very similar modelling approach?”

The team focused on an area of the brain called the superior temporal gyrus, or STG.

This broad region is not just part of the hearing apparatus but one of the “higher-order” brain regions that help us make linguistic sense of the sounds we hear.

The team monitored the STG brain waves of 15 patients who were undergoing surgery for epilepsy or tumours, while playing audio of a number of different speakers reciting words and sentences.

The trick is disentangling the chaos of electrical signals that the audio brought about in the patients’ STG regions.

To do that, the team employed a computer model that helped map out which parts of the brain were firing at what rate, when different frequencies of sound were played.

With the help of that model, when patients were presented with words to think about, the team was able to guess which word the participants had chosen.

They were even able to reconstruct some of the words, turning the brain waves they saw back into sound on the basis of what the computer model suggested those waves meant.

Plots of predicted spectrograms (PLoS Biology)The technique hinges on plotting brain activity across a number of frequencies

“There’s a two-pronged nature of this work – one is the basic science of how the brain does things,” said Robert Knight of UC Berkeley, senior author of the study.

“From a prosthetic view, people who have speech disorders… could possibly have a prosthetic device when they can’t speak but they can imagine what they want to say,” Prof Knight explained.

“The patients are giving us this data, so it’d be nice if we gave something back to them eventually.”

The authors caution that the thought-translation idea is still to be vastly improved before such prosthetics become a reality.

But the benefits of such devices could be transformative, said Mindy McCumber, a speech-language pathologist at Florida Hospital in Orlando.

“As a therapist, I can see potential implications for the restoration of communication for a wide range of disorders,” she told BBC News.

“The development of direct neuro-control over virtual or physical devices would revolutionise ‘augmentative and alternative communication’, and improve quality of life immensely for those who suffer from impaired communication skills or means.”