Penny Thoughts

Month: March, 2014

Two-Headed Animals: Dicephalia From Sharks to People

In 2011, fishermen caught an adult bull shark in the Gulf of Mexico. The adult was pregnant, and they soon realised that one of the foetuses was a lot more interesting than first thought.

The foetus had developed normally in all aspects, except that it had two heads. This bizarre phenomenon is known as dicephalia, and is when a single fertilised egg develops into a foetus with two heads. Dicephalia is something that occurs across nature and we humans generally refer to it as conjoined twins.

So the idea of a two headed animal is not hugely novel, however, the occurrence of this phenomenon in chondrichthyes (cartilaginous fish) like sharks, rays and skates is very rare.

C. Wagner and his team from Michigan State University managed to get hold of this truly unique shark and tried to understand the mechanisms of development that caused this two-headed marine animal. They released a paper this week that discusses the finding of this unusual shark and delves deeper into the interesting science behind the development of dicephalia.

The two-headed foetus was not the alone in the womb, with other normal foetuses having been found. The foetuses had developed enough that they were severed from their umbilical cords and released back into the wild. The two-headed foetus died soon after it was severed from the mother and was preserved in 70% ethanol to enable the research on this unique creature.

Other Examples of Dicephalia

This finding got me delving into other dicephalic creatures that have been found, so I thought I’d share some of the cases with you. I find it all really interesting except some of the science behind it is pretty complex, so if you do end up looking into it I wouldn’t get too bogged down in all the detail.

This is Abigail and Brittany Hensel, these are the most well known human dicephalic twins. Each twin has its own set of main organs (heart, liver, lungs etc.) but can only control one half of their body. So each twin has control over one leg and one arm. This meant that learning movements that required coordination between both halves was very difficult as it requires cooperation. This meant that walking, running clapping etc were highly difficult things to master.

This two-headed albino Honduran milk snake is an example of dicephalia in reptiles. Other two-headed snakes have been known to live up to 20 years in captivity. However, in the wild it is likely that survival is reduced due to the difficulty that comes with two heads controlling one body.

Another two-headed reptile; but this time a baby tortoise. Apparently this individual shows little difficulty in carrying out normal functioning and just goes about its daily business like any other tortoise.

 

An example of dicephalia in felines. This pair are from Massachusetts and are called Frank and Louie. They hold the world record for the longest living two-headed cat. Seems a pretty niche category.. but I swear most world records these days are a bit ridiculous.

 

Hope you enjoyed looking at some of the world’s weird and wonderful creatures, even if they do have more heads than normal.

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Fracking 101: Are Flaming Taps the Future for the UK?

I’ve been seeing a lot of media coverage about fracking recently. It isn’t something that I’ve ever really delved into but with all the media attention recently I thought I would look a little into it. I knew very little about fracking and after doing a little research into the topic I found out some really interesting things. Also with the use of fracking being considered in the UK I thought I would do a fracking 101 post for those readers like me who are new to this idea. So let’s start with what fracking actually is. “Fracking” is actually the name for the process of hydraulic fracturing which involves pumping liquid into drilled holes in the earth. The liquid is injected at very high pressures leading to shale rock  deep into the earth’s crust fracturing and releasing natural gas. So fracking is a method of extracting natural gas locked up in the shale rock of the earth’s crust, but what is actually involved in the process? So obviously water is required; this is the core component of the liquid injected into the ground. However, I had no idea just how much water would be required, with 1-8 million gallons of water needed for just one fracking job. 1-8 million is one of those figures so large that you can’t really come to terms with it so I thought I’d help to visualise it. Let’s split the figure at 4 million gallons of water. That is the equivalent to filling 80 000 bath tubs, or a swimming pool the length of 4 football pitches, 200 ft. wide and 40 ft. deep. Basically, it is a hell of a lot of water. But it is not just water that is required in enormous amounts; “fracking fluid” is made up of water mixed with sand and a cocktail of 600 chemicals. 40 000 gallons of this chemical concoction are mixed with the 1-8 million gallons of water per fracturing job. This mixture of 600 chemicals is made up of some nasty products, many of which are carcinogens and human, animal and plant toxins. These include the (unfortunately) commonly known polluting culprits like lead, mercury and uranium but also many other hazardous chemicals including ethylene glycol, radium, methanol, hydrochloric acid and formaldehyde. These chemicals have numerous detrimental effects when existing in unnaturally high concentrations in the environment. Right, so once the fracking fluid has been mixed what is the process involved in extracting the natural gas?

The fracking can take place over land or ocean as long as the appropriate rock and gas stores are located there. The fracking fluid is pressure injected down a pipeline drilled into the ground at these sites. When it reaches the end of the pipeline the shale rock cracks due to the high pressure of the fracking fluid. This released gas enters the well and is extracted to fulfil our growing energy demands.

Like all other forms of non-renewable energy extraction and some renewable energy forms, there are many associated detrimental effects. These effects have been touched upon already but I’ll go into more detail as to the problems and risks involved. So firstly there is the massive water requirement. Water demand is ever growing for many reasons driven at their core by the world’s growing population. However, the ability to fulfil this demand is falling and it is predicted that water demand will be 40% higher than supply by 2030. This means that industries requiring huge amounts of water are becoming increasingly unsustainable. Therefore, practises like fracking need to consider new methods to reduce their water use or their future is hugely limited if not completely empty. The impending water crisis is predicted to lead to huge water deficiencies worldwide. Do we want our limited water to be driving frankly, unsustainable practices or nourishing the drought ridden landscapes and populations that are predicted to become increasingly common? The second issue I’d like to delve into a little further is the problem of contamination. It is known that methane and other chemicals from the fracking fluid can leak into nearby groundwater. This water can be extracted and used as the drinking water supply for nearby towns and cities. It is has been noted that methane concentrations in water supplies near to fracturing sites are 17 times higher than normal wells. In the documentary GasLand by Josh Fox there are numerous clips of people putting matches to their running taps and the water setting alight due to the presence of the flammable methane. If that is not enough of a visual representation of the effects of fracking, I don’t know what is. This documentary is incredible and I really recommend you watch it. Over 1000 cases of water contamination have been recorded near to fracturing wells. The consumption of the contaminated water has been known to cause numerous sensory, respiratory and neurological health problems in people in the affected areas. These contamination problems are further worsened by the fact that 50-70% of this toxic fracking fluid is left in the ground to continue leaching into surrounding rock and water. This fluid is not biodegradable so can remain for years polluting the earth 1000s of meters below our feet. Just because we cannot see the effects of this industry in plain sight doesn’t mean that this polluting activity does not affect us. The fluid that is removed is left in pits to evaporate. This releases VOCs (volatile organic compounds) including methane and formaldehyde which evaporate into the atmosphere and contribute to our already worsening problems of air contamination, acid rain and ozone pollution. So why is this important now? Practises like this cannot be maintained forever. With our ever increasing demand for energy and water not being matched by our earth’s dwindling supply, practises like this need to change.

Fracking is relatively common practise in the US and the government ruled in 2006 that methods like fracking were exempt from following the guidelines of numerous environmental safety acts. This alone shows how governments are putting money and unsustainable practises ahead of human and environmental wellbeing.

There is plan to potentially carry out fracking in the UK. Yes, energy demand is growing and needs to be fulfilled but is this short sighted approach to fulfilling that demand really going to help us in the long term? I found a really good website briefly outlining the facts and dangers involved in fracking which I would really recommend as a more visual and interactive representation of fracking.