Scientific Scribbles

The voice of UniMelb Science Communication students

How do taste buds change?

When I was a kid I accidentally ate cat food.

Not the little crunchy kibbles, which, admittedly, sometimes smell kind of tasty. I’m talking about the cold, slimy, wet gruel, that’s so sludgy you need a spoon to extract it from the can.

I say it was an accident, because in one hand I had a spoonful of peanut butter that I was eating out of the jar (all class), and in the other, I used a spoon to scoop out the cat food. I forgot which hand held which spoon, and in a crucial moment, I was distracted and put the wrong spoon in my mouth. Expecting crunchy, peanut buttery goodness, I got a mouthful of only what I can describe as death and decay in a foul fluid/solid form.

I honestly think I blacked out from the shock and horror, but recalling the memory from over 15 years ago still makes me gag and shiver. Until recently, the smell of tinned fish made my eyes water and the hairs on the back of my neck stand up in repulsion.

I already feel queasy – image by Dario Lo Presti via Flickr

 

I always wondered, after all of these years, why does that one memory still haunt me?

Putty-brains

Memory and learning both start as signals carried through the cells in the brain, called neurons. Think of neurons like roads, and the cars travelling along them carry signals and information around the brain. At every intersection between neurons is what we call a synapse.

Now here’s where it gets interesting: synapses can actually rearrange themselves to favor pathways that get a lot of use. It’s like the council realizing that one particular road gets a lot of traffic, and either widening the road, or making the lights favor traffic along that particular route. This is called neuroplasticity, and is the reason things can become “second nature” – the synapses have rewired to make brain signaling more streamline and effortless.

Neuroplasticity is the reason we can learn to juggle, why blind people may have better hearing, and why human brains can lose up to 1 cell per second and still function – the brain rewires itself!

“Neurons that fire together, wire together” 

In my fishy case, what must have happened is that I lived the traumatic memory over and over so many times, I’d unwittingly strengthened the “fish = repulsion” pathway in my brain. The neurons that screamed “GET THIS OUT OF MY MOUTH” when I accidentally ate the cat food was associated with all things fishy: the smell of fish, the sight of fish and the thought of fish.

Snapper out of it

I’d accepted this as a lifelong disposition, until in the last few years I started getting really dry skin. One of the best ways to fix that is to increase the amount of healthy fats in my diet. And one of the best sources of these fats are, you guessed it, fish. Obviously, fish oil capsules were a no-go (fishy burps? I’ll pass), so I had to think of ways to sneakily overcome my aversion.

Fish oil capsules can leave you with fishy breath – no thanks! – image by Fitness Twistme via Flickr

 

Armed with trusty lemon juice and copious amounts of beetroot, I managed to disguise some pan-seared salmon in a salad. As the months went by, I learned to eat the salmon from the pan, and then one day, I cracked open a tin of salmon, and miraculously, I didn’t keel over retching.

This was neuroplasticity in the making – instead of associating fish with that traumatic episode, my brain had rewired to think of fish as healthy and nourishing.

Tastebuds (and brains) change

This is also why as a kid you might have sipped wine, been disgusted by it and sworn you could never find pleasure in such vile fluid. But after trying it again here and there, usually at festive events like parties or barbeques, you eventually started to like the taste. That’s the “happy-event” neurons firing with the “taste of wine” neurons, and slowly building a happy train of thought.

Whilst I don’t think I’ll ever want to train myself into liking anchovies, I wonder what else my brain has secret vendettas against, and if I could train myself out of them.

So what bad habit or association are you going to train yourself out of? Or have you done so already?

 


Put your money where your data is – the science behind effective giving

When was the last time someone knocked on your door asking you to sign up to donate monthly to a charity? Or someone stopped you on the street asking for just a couple of coins? What did you say?

I know I normally say ‘sorry, no’. I’m sure most people say the same – but there are a variety of reasons – if you’re being really honest – why you don’t wish to give your money away. Let’s think about these for a minute…

poverty

Image courtesy of Luis Felipe Salas via Flickr

Perhaps you cant afford it – if you’re living off your pay week to week, donating money to charity just isn’t an easy option.

Perhaps you already donate to one charity and so you don’t feel the need to give more.

Or perhaps you just don’t believe that your small contribution will really make a difference – and that you could spend that $30 on yourself far more effectively than a charity could use it to help thousands of people.

 

If this last option sounds like you, then I have good news; evidence is here to help!

 

Over the last few years charities and organisations asking for donations have realised that showing the effectiveness of donations/ dollar based on evidence is a very powerful way to send money where it’s most needed – because that’s what donors want to know – that their money is saving as many people as possible.

 

Imagine being told that your $100 can buy a single life-saving blood donation for one fatally wounded person in Vietnam OR it can buy 1000 condoms for women in Somalia.

You may be tempted to decide your money is best spent on saving the one fatally wounded person – sure you’ve actually saved a life with your donation right? Well, consider that the use of condoms can prevent transmission of many sexually transmitted infections that are lethal for women in poor countries who don’t otherwise have access to contraception or treatment. So, statistically, you can save more lives (more than 10!) by donating your money to providing condoms.

Condoms

Condoms save lives

Image sourced via robertelyov @ flickr

Does this surprise you? It made me think twice about where my money was being sent. So if all the choices seem too overwhelming there are now fantastic resources to help us find out how to donate money most effectively.

 

Let me introduce:

Effective Altruism – an Australian social movement of people dedicated to improving the world by linking donors with effective charities

And

GiveWell – a nonprofit dedicated to finding outstanding giving opportunities through in-depth analysis with a focus on global poverty

Poverty

People in poverty can benefit greatly from effective donations

Image courtesy of Sean Ellis via Flickr

 

These organisations use a combination of criteria to determine the effectiveness of charities including:

Evidence of effectiveness – looking for charities that implement rigorously studied programs with benefits that can be spread to large populations

Cost effectiveness – estimates of cost per life saves or cost per total economic benefit

Room for more funding – asking where any additional funds be spent

Transparency – continual review of strengths and concerns as well as progress over time

 

Personally I really like this approach to giving because finally you can be confident that your money, whether its $20 or $20,000 is going to be used in the most effective way and thus have the largest possible positive impact. If that’s not an inspiring way to use data I don’t know what is!

 

 

 

 


The slippery slope of global oil supplies

Imagine one day you woke up and suddenly aeroplanes were grounded, cars were stalled and plastic no longer existed. How would the world continue to function without these crucial inventions?

Didn't get LOST

Could this be the future of air travel without oil?
image courtesy of Timo @ Flickr

Well, this is the future facing us if we run out of oil supplies and don’t adopt a sustainable replacement.

 

Where does oil come from?

At the moment, crude oil (our source of unrefined petroleum) is sourced from both conventional land and offshore sources as well as unconventional tight oil sources including shale using a controversial process called fracking (fracturing rock with pressurised liquid) as well as coal liquefaction.

 

As crude oil supplies are not renewable we are naturally working with limited stocks and the point at which supplies begin to dwindle has long been anticipated and termed ‘peak oil’.

 

Over at least the last five years, global oil production has reached over 80M (yes that’s M for Million) barrels PER DAY.

 

It’s not yet clear if we have reached peak oil as global demand continues to grow however just 3 months ago, large oil company Saudi Aramco’s chief executive Amin Nasser was quoted as saying “If we look at the long-term situation of oil supplies the picture is becoming increasingly worrying” and suggested that the world may indeed be facing an oil supply shortage.

 

This shortage is also a result of lack of investment and fresh discoveries because financial investors are focusing elsewhere on more sustainable alternatives.

Remaining

An offshore oil refinery

Image courtsey of Thomas Hawk via Flickr

 

So what happens when oil runs out, or becomes too expensive?

 

Commuting without the use of petroleum is possible thanks to electricity and steam power however petrol based vehicles are still the majority and the norm for transport and freight around the world.

Additionally the use of plastic in packaging and preserving food as well as in medical equipment and research around the world means oil supply is a relevant and pressing issue for people and governments across the world.

 

The International Energy Agency suggest this oil shortage is a huge problem for the worlds economy as large shifts in demand and supply create economic instability however BP claim that technological advances mean the world has energy resources to supply us for decades to come and we need not be concerned about the shortage of oil.

From an environmental perspective, this enforced shift to alternative / renewable resources to replace fossil fuels is a rather promising outcome.

 

Where is new technology at right now?

At this stage, many alternative fuels such as biodiesel and bio-alcohol have been developed. Battery, solar and wind power technology are also rapidly improving in their cost and capacity and many would argue a combination of these technologies would easily provide the energy demands of the current global population.

The major hurdle to making this switch away from oil reliance appears to be belief and commitment to policy change by governments and influential companies.

Sunset on the wind farm

A windfarm – one alternative source of energy

Image courtesy of brian.abeling via flickr

 

So what does the future look like?

 It appears that crude oil will last the world another decade or two and in the meantime, with development of alternative technologies full-steam ahead (pun absolutely intended) hopefully the transition to more sustainable energy supplies will be the easiest and most logical option for governments and large companies to choose in the future.


The plight of plants

 

There’s no way of softening the blow, plants just aren’t as “cool” as animals. At least, that’s what most people think. People all over the world are suffering from what scientists are calling “plant blindness.”

Look at this picture – what do you see? You’d probably say, “an iguana.” You miiight say, “an iguana in a tree.” You probably don’t know what kind of tree though. But don’t worry, neither do I, because whoever took the photo didn’t think it was important enough to write down in the description.

A camouflaged iguana at the Parque Nacional do Pantanal Matogrossense — By Giovanna Colombi – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=49832734

This tendency not to notice plants is a problem because it can lead to not valuing plants. In the US, 57% of endangered species are plants, but only 4% of money used to protect species is spent on plants. That’s a big gap. And this a bigger problem than you might think. We rely on plants for food, air, fresh water, psychological wellbeing and other ecosystem services. If we don’t protect our plants, these things go out the window.

So why don’t we tend to notice or value them? There may be an evolutionary explanation – generally, animals have been more important to pay attention to as they have presented significant threats or a significant food source. That, and plants are don’t grab attention by moving.

But it could also be a learned behaviour – for example, school textbooks might devote less time to plants. This creates a zoocentric culture – one focused on animals. But there are some societies that are more plant focused. For example, the Maori people have a creation story in which people and plants are united by genealogical descent. And for Aboriginal Australians, everything in the world is alive, and even plants have their own sense of autonomy, their own personhood.

A red river gum (Eucalyptus camaldulensis). It is probably a normal sight in Australia, but to indigenous Australians it was important for medicine as well as canoe-making. — fir0002 | flagstaffotos.com.au [GFDL 1.2 (http://www.gnu.org/licenses/old-licenses/fdl-1.2.html)], via Wikimedia Commons
So how do we foster this kind of closeness to plants in western culture? Well, people value animals because they can relate to them. Scientists have concluded that to cure plant blindness, we have to create empathy with plants.

One experiment showed that when people were asked to take the perspective of a group of trees that had been cut down, people empathised more with the trees. They were also more willing to engage in environmentally protective behaviours.

Documentaries like Michael Pollan’s “the botany of desire” or David Attenborough’s “Kingdom of plants” go a long way in providing people with a plant’s eye view of the world. Maybe we can unlearn our plant blindness and appreciate these important organisms just as much as animals.


Salamanders just aren’t that into you

Mole salamanders are native to North America and also adorable — By Greg Schechter from San Francisco, USA (Mole Salamander (Ambystoma talpoideum)) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
A type of mole salamander has found a way to achieve the perfect society – all female. At some point, about 2 million years ago, a hybrid of different mole salamander species started reproducing in a way that only produced females. This is really, really rare. In fact, this ancient family is the oldest known line of all-female vertebrates (animals with spines).  They’re basically the amazons of the amphibian world.

These salamanders can be found in North America and they belong to the genus Ambystoma, which includes the famous axolotl. They may look like wet lizards, but they’re actually amphibians, with many spending their lives both in and out of water.

Most salamanders begin life as a tadpole in the water and eventually grow legs and live on land. But the axolotl is special. They spend their lives as aquatic creatures. They never grow up, like the Neverland’s lost boys of salamanders. — By Orizatriz (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
A quick sex-ed lesson:

This unique line of mole salamanders is what you call “unisexual,” meaning they have only one sex, female. They have the advantage that every individual in the species is able to bear offspring. But there’s a reason that unisexual lines aren’t common in animals.

Most unisexual species reproduce through asexual reproduction. This is when an organism’s offspring are exact genetic copies of itself. This is different to sexual reproduction where the genes of the parents of a bisexual species combine in different ways to create offspring with a very different sets of genes. Genes are the biological “code” for what makes us… us. Brown hair, short, skinny, purple feathered or blue tongued – all of that is decided by genetics.

This is how cells divide and make copies of themselves. Asexual reproduction is essentially this on a large scale. — By Mysid, translated in greek by Badseed [Public domain], via Wikimedia Commons
But if we could just copy ourselves, why bother with sex? I hear you ask. Sexual reproduction allows for a species to be more resilient to *bad things.* For example, imagine there’s a crash (this is the correct group term) of feathered rhinos. If a disease came along that only affected purple feathered rhinos, all the green, magenta and orange feathered rhinos would be fine. But if they were all purple-feathered… You get the picture. In terms of evolution, there’s safety in diversity!

It’s always ladies night at the mole salamander bar

So the question is, if this line of all-lady mole salamanders reproduce asexually, why hasn’t some obnoxious disease wiped them out?

It’s because they’ve found a unique way to diversify their offspring.  These unisexual salamanders use a technique called kleptogenesis – they’re sperm stealers. They breed with other similar Ambystoma such as the blue spotted salamander or the tiger salamander, taking their pick of the gene pool. This is an advantage as they are able to mate with five different species, increasing the range of habitats they can be in, so long as there is a sperm donor present.

A blue spotted salamander (Abystoma laterale) — By Fyn Kynd Photography from Searsmont, Maine, United States (Blue-spotted Salamander – Ambystoma laterale) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
Most of the time the genetics of the male are rejected, and the sperm is only used to initiate the development of the female’s eggs. However, occasionally as much as 25% of the genetics from the sperm donor will be used to form the new offspring. This is how these incredible creatures have managed to have genetic diversity without using standard sexual reproduction.

Doing it better

Not only are these salamanders of interest to scientists for their fascinating reproductive habits, but they have another interesting quirk.  Most salamanders can regenerate their tails after they lose them to escape a predator. But scientists have found these unisexual salamanders are able to regenerate their tails 1.5 times faster than normal salamanders. The reason for this is unknown, but this makes them even more interesting to research as unlocking the secret to regeneration is of prime interest.

Clearly, there are benefits to this unique society of salamanders. And perhaps there are more secrets they can tell us as scientists continue their research.

Newts are famous for being able to regenerate not just tails, but body parts as well! They aren’t in the same genus, but just in case you didn’t know, I wanted to point out that newts are a kind of salamander! The more you know. Another fun fact, the “eye of newt” joked about as a witches brew ingredient? That’s actually just an old name for mustard seeds. Don’t worry newts, you’re safe. — By Christian Fischer, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1194676

 


Number of posts found: 2420

Authors