4 complaints you'll find under every science article- and why you should think twice about them

Science gets shared all over social media these days, and thanks to the wonder of the comments section, people get to have their say on it. Sometimes comments are a valuable part of the discussion, and scrolling down will reveal extra details, well-thought-out arguments and interesting angles on the information you’ve just read. On the other end of the scale, we have the cesspit that often forms underneath articles about any science considered “controversial” by some laypeople: think vaccines, GMOs and climate change. Great entertainment if you have a taste for melodrama. Not great if you get a headache from READING CAPSLOCK AND EXCLAMATION MARKS!!!! I'm not going to touch on those here, as plenty of other bloggers have dissected the strange and often illogical arguments used by those with a penchant for denying science. In the middle ground, we have articles about new scientific discoveries on news websites or popular science social media pages. It’ll be on something like animal behaviour, or healthy habits, or a promising new disease treatment. It’s great that people can interact with research and respond to it in this way, and negative comments aren’t always unjustified: the internet is full of bad science and badly-communicated science alike. However, even the best bits of research seem to attract whiny commenters, who often bring up the same old complaints. Here I’ve compiled some moans that I see very frequently underneath science articles, and some tips on how you can tell if they’re valid. Are you really battling against pointless, badly-done science, or have you simply misunderstood the intentions of some pretty decent research?

1)    “That’s so obvious! We didn’t need a study to tell us that!”

Why we write it: We’ve all done it: a science headline pops up proclaiming some apparently cutting-edge research, and your overwhelming reaction is “No shit, Sherlock”. Something like High Heels Are Bad For Your Feet, or Cats Recognise Their Owner's Voice. What next, a study on the faith of the Pope?

The other side of the story: We like to think that our everyday observations about the worlds’ workings are pretty accurate. Our brains are fantastic at making connections between different things, inferring cause-and-effect, grouping things into categories and predicting stuff. Trouble is, these connections are often wrong, and it takes science and all its tinkering under controlled conditions to untangle what’s real and what’s not. What if cats actually recognised us by smell, not sound, and they simply came to investigate the noise when we shout "I'm home!"? What if our experiences of having sore feet after wearing high heels led us to blame them for long-term damage, even if there was no true link? For every study that we roll our eyes at, there will be another that surprises us and challenges our established knowledge. For example, a recent analysis of research into human brain size found that it has no meaningful connection to IQ- an idea that goes against most people's idea of "common sense". It’s always worth checking!

How to approach the issue: If you’re not sure whether that study with the obvious outcome was a lazy attempt at science or not, think about the bigger picture. One of the most important steps in scientific research is testing your assumptions. For example, if I want to examine wild crocodile poo to find out whether they prefer to eat puppies or kittens, I first need to make damn sure that puppies and kittens both live in crocodile habitat, or my interpretation of my results will be wrong and my study will be a big waste of time.

"She's the fattest! Eat her!"

 Sometimes, the assumptions made by a field of research are so big that they need entire studies to themselves. If we didn’t check the things we consider to be common knowledge and ploughed on, only to later find out our assumption was wrong… all the work that we built upon it would become useless, or would at least need reinterpretation. Does the study sound like it could fit into a bigger scheme of research, or does it seem more like a publicity stunt?

    2) “X was good for us last week, and now they’re saying it’s bad! This is why you can’t trust science”

Why we write it: It seems like science cannot make its mind up about whether red wine and dark chocolate are edible angels or the Antichrist. One minute we’re dipping a whole bar of Green and Blacks into a pint glass of wine, fuelled by the promise of a long life and freedom of heart disease, the next we’re tipping the Pinot Grigio down the drain and sobbing because we’re told we’re going to die fat and diabetic and covered in tumours.

The other side of the story: You can (mostly) blame the media for this one. Yes, there is a grain of truth in it: there are a lot of conflicting studies about the health benefits or drawbacks of particular foods and lifestyles, scientists don’t always agree on the components of a healthy diet, and nutrition science has its fair share of problems. If you look closer, however, each identical headline probably has a slightly different study behind it, even the ones that appear to come to the same conclusion. One might be comparing antioxidant content (another group of substances with mixed evidence behind them), without looking at how this affects real people. Another might follow a group of people with varying chocolate consumption over time, and see what happens to them. A third might also follow a group of people, but build on the study design in some way (e.g. increasing the sample size). All of these studies will have their own advantages and flaws, and cannot paint a conclusive picture on their own. Yet the media will treat them all the same, jumping on their conclusions and sensationalising them, because we love that bollocks and will eat it up without thinking. Just look how excited the media got over a fake study that suggested chocolate was an effective weight-loss aid.

How to approach the issue: To find out whether the conclusions you’re reading are worth listening to or just an excuse to print a stock photo of a sexy lady eating chocolate, look for:

  1) Quotes from the scientists

  2) The type of study that was done

Bit far?

If you’re lucky, the article will have printed something that the actual researchers said about their study. Usually this is stuck right at the end, because it’s something boring like “Yeah, we found wine can be good for you, but only if you drink ONE of those small glasses like twice a week” or “These results are only preliminary, and we’ll need more work to determine whether these patterns are real or not”. If not, or if you’re unsure whether the article just lifted a tiny, out-of-context soundbite, see if you can find the actual scientific paper, or at least an analysis that isn’t in the Daily Mail.

It’s also important to see whether these conclusions are from an individual study, or the Optimus Prime of scientific papers-- a meta-analysis. After a lot of papers have come out on a particular issue, an expert in the field will review all those studies. He or she will take the differences in method, sample size and any flaws into account, discard badly-done studies and compare similar ones. Say we’re doing a meta-analysis into the risk of heart disease and its association with consuming red wine mixed with melted chocolate. The researcher will compare the size of the positive and negative effects found in individual studies, and using lots and lots of statistics, will pull out an overall figure; let’s say that in this case, the risk of heart disease falls by 8% for every 100ml extra of choco-wine consumed in an average week (we can but dream). Of course, this method has its own flaws, and different meta-analyses may come up with different conclusions, but a news story about this kind of study will probably be a lot more reliable than one about a lousy study on 5 people done by students at the Université de Champagne.

    3) “Correlation does not equal causation”

Why we write it: There’s a time and a place for this complaint. If you’re having a great time shooting down crazy conspiracy theorists in the aforementioned cesspit-type comment sections, and they pull out an impressive-looking graph like this:

Remembering that correlation does not equal causation allows you to see the flimsiness of their point and counter it with this:

2000 internet points to you, ma’am.

The other side of the story: I get it, this phrase is really important, and something that we should teach kids in schools to keep in their bullshit-spotting toolkit forever and ever. It starts to get grating, however, when you get a keyboard scientist writing this under every science article in a lazy attempt to sound like a sexy, intellectual sceptic.  Yes, correlations are not very solid evidence on their own, but they DO have a place in scientific research. People often expect scientists to start working on a problem and not stop until they’ve solved it, tied off the loose ends and ironed out any conceivable problems that could ever arise. However, science doesn’t work like that. Funds tends to arrive in packages that allow a certain amount of research to be done: money for a PhD student to work for 3 years, for example. What the lab has to show after that money runs out will depend on the field and the subject. If it’s a particularly intensive and difficult-to-study topic in an early stage of investigation, you might just end up with little more than some hard-won but interesting correlations. IF BACKED UP WITH SUFFICIENT EVIDENCE- i.e. other explanations for the pattern have been properly explored and discarded- a correlation isn’t as useless as you might believe. They certainly don’t PROVE an association between two factors, but they’re a good first step and can highlight associations that might be worth investigating more thoroughly. A nice, well-argued correlation is good grounds for obtaining that next batch of funding.

How to approach the issue: Is anybody claiming that this correlation = causation? If so, whom? Scientists and research institution press offices are definitely not blameless when it comes to exaggerating the benefits or future reach of their findings, but even the most cautiously optimistic quote can be spun out of proportion by the media and overexcited internet personalities. Plus, scientists who work on obscure or early-stage research may have to search a long way from their actual work to find something that seems immediately relevant to the general public: bear this in mind when a wild headline turns out to be founded on a much less exciting, flimsy-looking correlational study. This may just be the early stages of their research. So yes, absolutely remember the old c≠c rule and apply it when deciding what to take away from a science story. But let’s add a new phrase to our repertoire: correlation does not (necessarily) equal a crappy study.

    4)      “What a dumb/pointless piece of research, why are my taxes funding this?”

Why we write it: People often have strong opinions on the kind of science that should be funded. Cancer treatments for children? Yes please! But spending $880,000 on the study of the mating behaviour of New Zealand mud snails? Or those stupid news stories that appear when some academics claim to have found the perfect formula for making a bloody cup of tea. And my taxes are paying them to do this?! How is this benefitting humanity?! How?!

The other side of the story: Those two despicable examples are from quite different sources. The tea formula is real and has been thought up several times by different people. It was of course widely reported in the media each time, because the concept of tea doesn’t take much explaining. Those crazy scientists, spinning on their spinny chairs in their fancy expensive science labs and thinking of rehashed publicity stunts to waste money and get attention. What are they like? Well this is what Daily Mail readers think of them:

Yeah, Roberto, fight the power!
You should join forces with Steve from Nottingham, he has a real problem with tea science.

With the help of Google, I can find at least 3 different “tea formulas” that have been created over the years. The first was created in 1980, with involvement from the Ministry of Agriculture, Fisheries and Food, to standardise the procedure for professional tea testers (now there’s a job to aspire to). The second was in 2011, by researchers at the University of Northumbria, and was sponsored by Cravendale (a milk company). The third, in 2014, was the result of a competition run at the University of Leicester maths undergraduates, again sponsored by building company Jelson Holmes (because builders love tea. Get it?). Cheap, unoriginal publicity stunts that prey on our country’s addiction to tea? In the latter two cases, yes. Waste of public funds? No, seeing as the latter two had no public money input, and the first was a legitimate attempt at industrial quality control. As in the second example, you’ll often find that silly headlines originate from work done by science students. There’s no harm in that: fun research projects are a good way for students to hone their skills, especially at the stage when they’re not skilled enough to get involved in the university’s main research areas. I fed squirrels in the park in my second year to learn about their caching behaviour: not worth a headline, but I’m sure if an article appeared in the paper calling me a “scientist” rather than a student, people would get cross about the apparent waste of money.

"The 'scientific dictatorship' strikes again. They won't dictate to me though." ~ Roberto, 2011

Concerns about the "mating snails" example are all too common with austerity on the rise, and it’s understandable. Dig a little deeper, however, and blue-skies research often isn’t as silly as it sounds. Mucking about to see how things work is a very important part of science, even though we might not see the benefits for some years. It’s called basic research, and it sets the scene for more complex (and hopefully applicable) research in future. Naturally, not every bit of basic research leads to a new medicine or piece of technology, but it’s almost impossible to tell which studies will! Rich Victorians with nothing better to do, like Charles Darwin, gave us some incredibly important basic research. Without Darwin and friends pootling around with dead birds and barnacles, we wouldn’t be able to comprehend how bacteria evolve to resist antibiotics, or understand the contents of our own genome. In the case of the aforementioned snail sex study, there are several ways it could go. Voyeuristically watching New Zealand mud snails make babies could inform methods to control it: it’s an invasive species in many regions, with effects all the way up the food chain. This species is also a good candidate for studying an extremely nasty human parasite called schistosomiasis that’s carried by snails in undeveloped tropical regions. In essence, this grumble is linked to my first point: science is a process that moves in incremental and non-linear steps, and if you take a snapshot of it at any one point in time, you’re going to capture different investigations at different stages. It’s then easy to point to finger at apparently “pointless” and “useful” research, when in fact they’re all part of the same machine. Cut out one part and soon many vital parts will come grinding to a halt. And trust me- scientists spend an enormous amount of their time writing proposals in order to get funding. It’s not easy: public funding bodies don’t hand out grants like they’re sweeties. Shoddy science obviously exists and gets funded on occasion, but we shouldn’t assume that every study is a waste of time just because its merits aren’t immediately obvious to us.

How to approach the issue: Again, because the bigger picture of science can be so confusing as to make good science look pointless and vice versa, it’s often hard to laypeople to figure out whether a piece of research is to be respected or ignored. If you still suspect that a science headline is a heap of decaying bollocks, chances are that actual scientists will think so too. Nothing riles up a scientist more than their field being misrepresented in the media, or a bad piece of research being paraded around without question. Go and look at blogs and articles written by or quoting (well-respected) scientists and science bloggers, and see what comments they have on that research. Hell, drop them a message and ASK for their point of view, they’ll be flattered! Here we have takedowns of:

1) The widespread misinterpretation of the WHO's categorisation of red meat as carcinogenic

2) A study that supposedly found that tardigrade genomes contain an enormous amount of foreign DNA

3) A study widely reported as showing vegetarianism to be more environmentally unfriendly than meat eating 

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I'll go back to talking about individual bits of interesting science soon- this was just something that struck me when looking at a popular Facebook science page and the reactions of many of its visitors! As long as it is done by fallible humans, the funding, execution, and reporting of science can never be perfect, but knowing a little more about how contemporary science is done can go a long way in understanding the research in the news, why it's there, and how truthfully it's being represented. Please don't be "that person" making a fool of themselves in comments sections!

Do cheetahs have backwards legs? A question from my six-year old self

You may have noticed that the topics for these blog posts are often inspired by misconceptions I had when I was younger. This entry is no different.

Cheetahs came somewhere at the top of my “favourites” list when I was little. I often tried to imitate them in my games, but found that I was clumsy and slow on all fours. Cheetahs could bend their hind paws forward underneath their chins, kicking their front paws back to meet them between each enormous, graceful bound. I tended to fall off the bed when I tried this.

Go on, give it a go.

In fact, cheetah’s legs seemed to be entirely backwards compared to my own, with their hind legs appearing to angle forwards and their arms bending backwards. I concluded that their knees and elbows were on the wrong way round, and that this was the secret to their immense speed. I was a little bit right, and a little bit wrong, as it turns out. Let me explain.

Here is a human.

Her thigh extends about halfway down her leg, and she stands on the soles of her feet, with her heel touching the floor. It works very well for her unusual upright style of walking. This should sound familiar- if not, I hope you've checked it out with your doctor. This leg design makes her a plantigrade. All primitive mammals were originally plantigrades, but we're in somewhat mixed company these days: bears, other primates, most rodents, raccoons and the weasel family. Big palms and a flat sole are great for gripping things, including trees and food. However, a lot of mammals have switched their adorable little grippy paws for running shoes, and changed the design of their legs in the process...

This is where my friend the cheetah comes in, but to demonstrate, I've hired a friendly dog who has similar leg anatomy.

Dogs, cats and a few other groups of mammals are digitigrades. They walk on their toes with their heels lifted off the ground (as if they're wearing massive high heeled shoes), and it was this heel that I mistook for a backwards knee. The knee is actually close to the body, at the end of a relatively short thigh. If you have a pet willing to be prodded, gently massage the section of the leg above the paw, and you'll feel clusters of bones and tendons similar to the ones in your hands and feet. So why the redesign?

Dogs and cats are predators, so running fast is a useful skill. Having small points of contact with the ground makes movement much more efficient, so they can expend less energy when chasing prey. It also lengthens the legs without any one bone becoming excessively long and potentially weak. This is such a good design that predatory dinosaurs evolved similar legs, and passed them onto their descendants: the birds. Most birds don't make use of this generous gift for its original speed-boosting purpose, but almost all have retained it.  Here is a flamingo to demonstrate. Flamingoes are often falsely thought to have backwards knees, but as you can see, the bend is simply its ankle.

Twins!

Unlike mammalian digitigrades, the ankle and foot bones are fused in the lower section of birds' legs, forming a single, unique bone called the tarsometatarsus. This might have made their dinosaur ancestors' legs stronger, reducing the risk of injury as they chased prey at high speed.

With the festive season fast approaching, you can also become an expert at bird anatomy by examining the remains of a turkey carcass (or bucket of fried chicken, if you prefer). The thigh, which is usually hidden under the living bird's feathers, is short and muscular. Attached to it is the cut commonly known as the drumstick, which is equivalent to your calves and contains the tibula and fibia bones. The tarsometatarsus and toes, whilst interesting, aren't usually present on the bird at the point of sale, unless your butcher was drinking Christmas cocktails on the job.

Of course, predators aren't the only ones modifying their legs for speed, or Earth's great meat buffet would have been licked clean by now. Hoofed mammals, also known as ungulates, have gone one step further with the invention of the unguligrade foot design. Here, the animal walks on its toenails, which are modified into what we usually call a hoof. Many groups have a reduced number of weight-bearing toes, too. This is because running on two strong toes, for example, is more efficient and safe than running on four weaker ones. Come to think of it, ballet would be a lot easier if humans had hooves, but you'd have to sacrifice standing on two legs, which defeats the purpose somewhat.

I would like to apologise to all horse-kind for this picture.

In deer, cows, goats, sheep and antelope, the third and fourth toes of the foot are strengthened to form the classic cloven hoof, with the second and fifth toes showing up as non-weight-bearing dewclaws further up the leg.

Horses have gone even further, running on just a single, extremely strong third toe! The other toe bones are barely there, hugging against their massive neighbour.

Yes. That tiny little toothpick of a bone.

Interestingly, horses can suffer from a genetic condition known as polydactyly, meaning they're born with extra digits. On humans, this manifests itself as six-plus digits on a hand or foot- not always that noticeable unless you're counting- but it gets a little odd when you've only got one functioning toe to begin with. Check out this case of a Belgian foal with the condition.

So if ungulates have managed to evolve even longer, more efficient legs with hooves, why haven't predators done the same? There did once exist a group of hoofed predators called mesonychids, related to today's ungulates. They didn't have the extreme hooves of deer or horses, but a foot design more like that of a rhinoceros, with a flattened, blunt, toenail at the end of each toe. This makes a nice, sturdy surface for running on, but doesn't hold the animal's entire weight like other hoof designs. In rhinos, the toes don't touch the floor at all, and the rear of the "foot" is made of a fleshy pad of fat. It's anyone's guess what sort of footprint was left by a mesonychid on a muddy path, but maybe they had paw pads like a dog.

Sidenote- if somebody could please discover some fossil mesonychid footprints, that would be really cool

They had a superficial resemblance to wolves with freakishly large heads, shortish legs and a fairly inflexible spine, Their hooves might have been great for running, but they probably lacked the versatility of clawed paws; they wouldn't be good for hunting like cats' claws, for example, nor would they have been much use for digging. The reason for their eventual extinction ~30 million years ago is unclear, though they may have competed poorly with more modern predators. I like to think that in some alternative universe, the mesonychids survived and were domesticated into an adorable race of pseudo-puppies, clip-clopping behind their owners with oversized muzzles on their toothsome faces. Adorable.

So there you have it. The rest of the animal kingdom's legs and feet might appear pretty alien to us, but when you look closer, it turns out we're the unusual ones. Take off your socks, take a long hard look at your feet, and tell me they don't look weird to you now. You massive flat-footed freak.

Male Bees Don't Have Fathers: the ins and outs of sex determination.

What determines if we're male or female?

I’ll leave it to the rest of the internet to argue about the complexities of human gender. If you dare, just scroll down to the comments under any article about Caitlin Jenner, and you'll find it doing just that. I’m talking biological sex here: the bits and bobs that lurk in the abdomens and proverbial underpants of living creatures. Although the two sexes are almost universal in the animal kingdom, the mechanisms that control which individuals develop into which sex aren't. These systems have been mucked about to the extreme by evolution, and these are just some of the strange results.

Chromosomes: the birds, but not so much the bees.

However hazy and distant your last science lesson seems, you’re probably vaguely aware that human sex is (predominantly) determined by our chromosomes. We all inherit an X chromosome from our mothers, and depending on which sperm wins the race, dad donates an X or a Y. Two Xs is a recipe for a female reproductive system, and XY is a recipe for danglies galore. Now, not to dampen anyone’s proud masculinity, but the Y chromosome is tiny and a bit useless, with very few functioning genes on it. You may also remember that this leaves men more vulnerable to any dodgy recessive genes on their X chromosome. As females have two Xs, they’re more likely to inherit at least one normal version of the gene. This is why men are more prone to  problems such as red-green colour-blindness, which is caused by a faulty gene on the X chromosome.

We share very similar systems with other mammals and the odd species of insect, but birds have flipped it on its head. In the avian genome, a different pair of chromosomes wield the power of sex-determination: the Z and the W. In this system, Z is the normal-sized chromosome whereas W is its weedy counterpart, and whilst males have two Zs, females are ZW. As a result, female birds are at a greater risk of dodgy genes lurking on the Z – domestic hens are more susceptible than cockerels to a condition that makes them shake uncontrollably. However, savvy poultry breeders can use genes like these to find out the sex of their birds without paying for expensive genetic tests or waiting for them to grow up. A commonly-used gene can be found on the Z chromosome, where it causes newly-hatched chicks’ feathers to grow more quickly. When slow-feathering hens are crossed with fast-feathering males, all their daughters will inherit their father’s Z chromosome, along with his fast feather growth. Males will inherit slower-growing feathers, allowing the breeder to pick out the fuzzy females for the farm. 

Awww!
...Unless you're a male chick.

Genetic halflings

Ants, bees and wasps are generally pretty strange, and their sex determination system is no exception. Many species live in vast colonies in which only a single individual – the queen—is in charge of breeding. It’s a big responsibility; the kingdom needs an army of daughters and only a handful of sons to succeed, and so leaving her offspring’s sex to chance just isn’t an option for the queen. Thankfully, she can control whether her eggs hatch into sons or daughters, simply by choosing whether to add sperm. Although pretty celibate during their reign, queens attract lots of male attention when they leave their natal nest, and they nurture the resulting sperm for the rest of their lives. If a queen chooses to add sperm to an egg, it will become a female, with a set of chromosomes from each parent. Eggs that don’t receive sperm develop into males, inheriting just a single set of chromosomes from their mother. That’s right—male ants, bees and wasps might have plenty of half-sisters, but they don’t have fathers. True mummy’s boys indeed.

Hot girls wanted

Not all animals have their sex determined at conception. For some species, environment can also have a powerful effect on sex, during development or even in adulthood.

Some reptiles lay eggs that develop into males or females depending on their incubation temperature. This system is mostly found in crocodiles and chelonians (turtles, tortoises and terrapins), and it varies between species. In snapping turtles, females develop when eggs are either kept very cool, or very warm, whilst males hatch at intermediate temperatures. In many other species, warmer clutches hatch into females, whilst eggs in a cool nest will find themselves with a lot of brothers. This system appears to work through a temperature-sensitive enzyme called aromatase, which can convert testosterone into oestrogen under the right conditions. As different females will choose different sites to lay their eggs, the sex ratio stays fairly even. However, the temperature parameters may need to adjust as climate change takes hold, or there'll be a lot of horny female tortoises looking for mates.

"Hey babe."

One fish, two fish, girl fish, dude fish

Fish are even more flexible, with many species able to casually change sex in adulthood to cash in on breeding opportunities. This is usually a one-way system, with most or all young fish hatching as one sex, and changing permanently if the opportunity arises. For example, wrasse are mostly born female, and live in colonies led by a dominant male. The male bullies his wives to keep their stress hormones up, inhibiting sex change to ensure he has plenty of mates and no competition. However, if he dies, the females don’t rejoice and live happy lives free from bullying and oppression. The largest one simply becomes male, and begins the reign of terror all over again. The opposite is true in the more peaceful society of the clownfish, where all fish are born male, but happily become female if their mate dies. Unlike the wrasse, older clownfish are better off using their large bodies to make lots of eggs instead of fight, and so becoming female is the coveted goal. The fish don’t wait around: in some species, transforming individuals show dramatic shifts in behaviour almost immediately after the social setup changes. Alterations in colour and size follow as the old sex organs shrink and new ones awake from dormancy, and within a week, the fish is making eggs or sperm like a pro.

What IS plankton?

Any documentary or article on ocean life is bound to mention plankton at some point. It’s a fundamental part of our ocean ecosystems that sustains countless billions of invertebrates, fish, seabirds and marine mammals- and by extension, us! Yet we seldom talk about plankton outside its role in sustaining larger, flashier organisms. Plankton never asked to get eaten by a whale, but it rarely gets its time in the spotlight unless it’s being swallowed by something. As a result, many people aren’t all that sure what plankton actually IS.

It's this guy... right?

In fact, plankton is so little-discussed that you could be forgiven for thinking that it’s the name of a single, tiny and very abundant species floating in our oceans. As a child, my mum described plankton to me as “a mixture of plants and animals”, and I therefore imagined it as the lovechild of a shrimp and Bulbasaur, with clusters of green bulbs on its back and rows of tiny legs. Yet in reality, when a whale takes an enormous mouthful of plankton-rich seawater, it isn’t the equivalent of swallowing a tonne of homogeneous steak. This is more of a varied and colourful stew, with countless ingredients from multiple kingdoms of life. “Plankton” is not a biological classification like “mammal” or “rodent”: it’s a title earned through lifestyle. If you are a living thing that drifts in the water column, then congratulations: you are plankton. There are some very strange organisms under this vast umbrella term that really do deserve a closer look… although you may need to pack a microscope.

Plankton both directly and indirectly support some of the largest animals on our planet. But it’s not just big creatures that eat plankton- there’s an entire food web within the planktonic world itself, and photosynthesising organisms, or phytoplankton, are at the bottom of it. However, you won’t find anything particularly leafy floating in the soup: the oceans are the realm of algae. We often think of algae as simply being tiny plants, but they actually belong to an entirely different kingdom of life to the terrestrial plants we are familiar with. All land plants- mosses, trees, flowers, conifers, grasses- evolved from an ancestral aquatic alga that adapted to dry land around 450 million years ago, and very few of its descendants have made the transition back to the sea. Under the microscope, algae have an enormous diversity of shapes and forms compared to their larger terrestrial cousins.

Algae. It's all green and same-y.

Some exist as single cells. Others form bizarrely-shaped colonies. Some are bioluminescent, and light up the sea during large nocturnal gatherings. While most drift benignly in the water column, other groups use flagellae (tails) to propel themselves through the water, and may even supplement their photosynthesising by hunting smaller microorganisms. This is no homogeneous field of daisies.

Yep, allllll green and same-y. 

But algae aren’t the only tiny sun-worshippers in the sea. Some forms of bacteria- called cyanobacteria- can also photosynthesise. In fact, they pretty much invented photosynthesis, and they changed the world forever by doing so. About 3 billion years ago, oxygen was almost non-existent in Earth’s atmosphere, and any that appeared was quickly taken up by the vast amounts of iron in the crust, creating iron oxide, or rust. As cyanobacteria evolved and became more and more successful, their photosynthesis produced vast amounts of oxygen. This caused mass rusting of the planet’s iron reserves, creating huge depositions of iron oxide that appear as striking bands of bright orange in the Earth’s crust. Once the iron sinks were exhausted, oxygen began to accumulate in the atmosphere-- great news for our very distant, microscopic ancestors, as it led to the evolution of mitochondria (our cells’ powerhouses) and bigger, more complex bodies. However, a vast number of oxygen-intolerant species were lost forever in one of Earth’s largest mass extinction events, and the planet underwent a reverse greenhouse effect, becoming swamped in snow and ice for the next 300 million years. Not bad for an organism that looks like a Smurf’s nose hairs.

Feeding on this garden of freaks is a whole host of animals and single-celled organisms, collectively called zooplankton. Some are instantly familiar to us: many kinds of tiny crustaceans live as plankton, including krill, the staple food of the blue whale. Others, however, are downright weird. Amongst many examples are tiny flying slugs known as sea angels…

…amoebae with shells…

…the adorably-named tintinnids…

… and gigantic strings of clear jelly called salps.

Fun fact: the two creatures in this picture are more related than you'd think

But whilst all of these creatures typically spend their whole lifecycles as planktonic nomads, many others come along for the ride exclusively during their youth. You see, childhood works a little differently in the oceans. Land animals have had to invent all sorts of ingenious ways to stop their developing young from drying out, mostly by confining their most vulnerable growth phases to a nice damp waterproof capsule, such as an egg or uterus, until they can survive in the outside world. However, to marine creatures, the seas are just one big bath of amniotic fluid into which they can cast their offspring without a care. Many therefore undergo bizarre planktonic larval phases that just aren’t visible in their land-dwelling relatives, simply because they would usually be confined to eggs or their pregnant mothers.

Take snails, for example. Land snails hatch as miniature shelled versions of the adults, but their marine cousins go through multiple larval stages that look nothing like the creatures they will eventually become. The second of these incarnations is called the veliger. 

Um...what?

It flies through the water on hairy wings, and undergoes a painful-sounding developmental process in which all of its organs twist 180 degrees relative to the rest of its body, so that it can fit into its developing shell. As a result, its anus ends up in a fairly inconvenient place...

All right when you're stretched out, not so great when you're napping inside...

The larvae don’t join the plankton crowd as a kind of self-discovery gap-year experience before they settle down. Having a tiny, mobile larval stage is a great way for creatures that are slow or fixed to the sea floor to exploit new parts of the ocean. This specialised dispersal phase means that some species apparently regress to a simpler form upon reaching adulthood. For example, larval sea squirts bear a striking resemblance to tadpoles, with eyes, rudimentary “brains” that control their movement, complete but non-functioning digestive tracts, and a spine-like structure called a notochord that marks them as close relatives of the vertebrates. But when they find a suitable place to live, they plant themselves headfirst into the ground, and absorb all of these complex features to begin life as simple, filter-feeding adults, leaving no trace of their relatively advanced place on the tree of life. 

Pretty, but brainless

Meanwhile, some larvae show a remarkable amount of ingenuity when searching for a new home. Rather than drifting aimlessly and risking settlement in an unsuitable spot, coral larvae listen for the sounds of distant reefs with the fringe of fine hairs (cilia) on their bodies. They can distinguish the typical sounds of a busy reef from other ocean noise with astonishing precision, allowing them to swim towards their nearest friendly neighbourhood.

Who knew mouldy gherkins were so smart?

 For many larvae, navigating towards a suitable permanent home is a race against time: while some are equipped to feed, many carry a limited supply of yolk for energy, and will eventually die if they stay adrift for too long. Fish, for example, undergo a larval stage in which they lack fins, scales or swim bladders, and rely on a distended belly full of yolk for sustenance. 

At least you can sort of TELL that they're fish.

As with other plankton, they must navigate a whole suite of dangers during this time, including adult fish, jellyfish and indiscriminate filter feeders like basking sharks. Unsurprisingly, creatures with planktonic offspring must produce a vast number of eggs if any are to survive their dangerous childhood in the ocean’s great microscopic buffet.

Plankton might not have the dangerous sex-appeal of a great white shark. Tourists seldom spend hundreds of pounds to go on boat trips to see them. Doctors’ waiting rooms don’t contain tanks of exotic and colourful plankton to calm the nerves of their patients. Although in our heart of hearts we know that they’re by far the most important inhabitants of the ocean, sometimes it’s hard to appreciate plankton beyond their supporting roles as snack bar and crèche to our favourite ocean creatures when they’re so incredibly tiny. Even so, their unfathomable yet practically invisible diversity is surely worth celebration of its own. Each teaspoon of seawater is home to an otherworldly soup of nomadic baby animals, alien algae and single-celled oddities, as different from each other as you are from the banana in your lunchbox or the bacteria on your skin. If you find yourself struggling for inspiration, just remember: if you don’t have a microscope handy to picture them, your wildest imagination might be just as accurate.

Why are we so obsessed with robins?

 

Last week, it was announced that the humble robin, darling of Christmas card manufacturers worldwide, has won a poll to find Britain’s unofficial “National Bird”. Beating off its closest rival the barn owl by over 5000 votes, it confirmed what a love affair we Brits have with the little red bird. It’s strange that, for a nation with more soft spots than a furniture shop when it comes to wildlife, we seem to have a particularly soft one for robins. What makes them so appealing to us? Do they deserve their fuzzy, friendly, somewhat festive reputation, and is there anything particularly British about a bird that ranges as far afield as Siberia and North Africa?

Here are my theories on why we’re so hung up on the robin, and the little biological quirks that have moulded this bird into our firm favourite.

    The eyes have it

We humans are suckers for a big pair of eyes. Puppies, kittens, sugar gliders and tree frogs- large eyes instantly melt our hearts and inspire feelings of nurturing and empathy. Although its eyes aren’t as appealingly huge as the barn owl’s, robins sport a pair of intelligent-looking dark eyes that take up far more of their face than those of similar birds. Let’s compare it to the dunnock, a bird so similar in body and bill shape that it is often mistaken for a “female robin” (in fact, males and females both sport a red breast).

Oh Grandmama!

Whilst the comparatively large eyes of robins may help them when it comes to encouraging regular restocking of the bird table, their real purpose is to allow a longer working day. Robins are one of the first birds you’ll hear during the dawn chorus; by getting up in low light and singing before other birds (and in modern times, the rush hour), they’re more likely to be heard by their audience. In fact, getting their message across is very important to robins…

     Homebodies

There are few birds that defend a territory more fiercely than the robin. The idea that bulls can be riled up just by the colour red may be a myth, but it’s definitely true for robins. The colour of their fronts is a literal red flag to these birds, to the extent that they will try to murder the crudest of robin dummies placed in their territory, even a red cloth. 10 percent of all adults die in territorial disputes, and the colour association is so deeply ingrained that young robins don’t develop red feathers until maturity, or they’d risk being pummelled, too.

Pictured: young robin discreetly getting changed

Unusually amongst birds, both male and female robins hold separate territories all year round, and only come together to raise offspring. This means that robins are one of the few birds that keep singing during the winter, brightening the UK’s famously dull weather and likely cementing their association with Christmas (the practice of putting them on Christmas cards dates back to the Victorians, when postmen were nicknamed “robins” because of their red uniforms). Although their bloodthirsty nature goes against our somewhat sentimental view of the robin, the result is that we tend to become familiar with just one or two robins that live on our home patch. Many gardeners suspect that the same bird always watches them at work, and they’re probably right. Compare this to birds such as blue tits, which move from place to place and turn up erratically in flocks to feed, and you’ll see why it’s easier to foster a relationship with your local robin. This bond is also aided by their noticeably bold behaviour…

     Gardener’s little helper

One of the main reasons we love robins is that they’re so feisty and confident. These are birds that can be trained to eat from your hand, and will often come to feed from the bird table the moment that it’s filled, without waiting for the obliging human to move away! Those who enjoy gardening will also be familiar with the intent watchfulness of robins, particularly during any activity that involves disturbing the soil. Why are they so brash, when most birds will skulk for a good 10 minutes after you’ve gone inside just to ensure it’s safe?

It’s not that they love us back, sadly—in fact, many individuals would probably starve if not for their boldness. Robins are predominantly insectivorous—that is, they mostly eat invertebrates such as worms, insects and spiders. In a cool climate such as the UK, these foods can be hard to come by, especially during winter. We have very few specialist insectivores in this country, and many of them migrate in winter (e.g. swallows) or suffer population crashes during bad weather (e.g. Dartford warblers). Whilst robins do supplement their diets with fruits during winter, their ability to live closely to humans and exploit novel food sources gives them access to the high-protein, high-fat foods that they prefer, such as mealworms and fat balls. Their attentiveness towards gardeners is just another clever ruse to get food, and is a habit that was probably around long before us. All sorts of invertebrate treats get stirred up by large animals like us as we move through vegetation or dig in the soil. By being unafraid to snatch these from under our feet, robins save themselves a lot of effort and searching time, and have made a real success of themselves as a result.

"You're going inside?! Fine, I'll do it myself"

However, natural selection appears to have purged this ancient behaviour from robins on mainland Europe. In fact, our perky, bossy little robin is almost unrecognisable: far from there being one in every urban garden, they skulk in woodlands and are very nervous of humans. This is because small songbirds have been hunted and eaten by humans  on the other side of the Channel for centuries, putting bolder individuals at a distinct disadvantage and leading to the spread of more cautious bloodlines. Whilst songbirds have featured on British menus in the past, the harming of robins has long been frowned upon thanks to folklore that depicts them as gentle, sympathetic creatures. The robin’s breast, far from being a violent symbol, was said to be stained red by the blood of the dying Christ as the bird tried to free him, or scorched as it flew into the fiery pits of Purgatory to deliver water to suffering souls. All these noble acts made it very bad luck to kill a robin, and so the cheeky behaviour that we know and love today has been preserved.

Slugs and snails and evolutionary tales

Is a snail just a slug with a house on its back?
Or is a slug just a naked snail?

There’s no denying that slugs and snails are closely related. Both have a healthy appetite for greens, hold a reputation for being slow, and leave a slimy trail wherever they wander. But which one came first? 

Slugs and snails belong to a big group of animals called the molluscs. Their relatives include limpets, mussels, oysters, squids and octopuses, and the long-extinct ammonite. What you’ll notice about most of these animals is that they have a shell. The world’s first mollusc probably possessed one, and aeons later, just a handful of its descendants have done away with their portable houses. Shells are the key to molluscs’ success: although they evolved in the sea and need to stay moist, many groups have conquered shorelines and dry land thanks to their shells, which provide a damp hiding-place for their vulnerable bodies. They also make a great defence against predators, as anyone who’s ever tried to prise a limpet off a rock will know.

The ancestor of slugs was probably very snail-like, but over millions of generations, their shells became smaller and less important. Some species even carry around an adorable little remnant of their former shells, like a tiny backpack. 

Why would any self-respecting mollusc evolve to go naked, though? Despite their usefulness, there are some situations where having a shell is a bit of a drag. Shells can only protect you from a certain amount of attack before they break, and some predators have evolved clever ways of getting into them.

The "whack it til it breaks" method

The "gravity-assisted" method

Growing a stronger shell isn't always an option, as it requires a lot of nutrients like calcium, and for mobile molluscs like snails, carrying such a heavy load can only make them slower! Therefore, sometimes the best strategy is to hide away from predators in cracks and crevices. Whilst snails can get into some very snug spots, the streamlined bodies of slugs are much better adapted to burrowing and fitting into small gaps. This is why they often turn up uninvited in people’s houses, by squeezing underneath doors, up plugholes, and through holes made for wiring or pipes in walls. 

"Honey, I'm home!"

Fitting into tight spaces also helps slugs to find somewhere cool and shady when the sun is bright, getting around the loss of their climate-controlled shells. But slugs can’t stay under cover forever. They have to emerge to feed, potentially making them vulnerable to predators. I say "potentially", because slugs don't have many enemies thanks to their rather unpleasant defense strategy. Anyone who allowed creepy crawlies to explore their hands as a child will know that the slime of slugs and snails feels very different. Whilst a snail trail easily rubs or washes off your skin, handling a slug will make you feel as if a tube of PVA glue has been emptied over your hands, and as the slime easily absorbs water, it needs more than a good rinse to wash it off. Eating a slug with its tough, rubbery skin and mouth-clogging, grooming-resistant slime is not an appetising experience for most animals, so the majority leave them in peace.

Slugs aren’t the only mollusc to ditch their shells for a different lifestyle. During the Jurassic period, the sea was full of ammonites; like snails, these animals retreated into their shells and sat tight when under attack, sacrificing their ability to swim fast. However, only one of their descendants has kept its shell to this day—the rare but beautiful Nautilus.

Cuttlefish and squid have shrunk their shells and relocated them to the inside of their bodies, with some species using them as a buoyancy device—this is the cuttlefish “bone” that you can find washed up on beaches. Meanwhile, the octopus family has gone one step further, getting rid of their shells entirely. This makes them masters of changing shape and fitting into impossibly small spaces, giving them the upper hand both in hiding from predators and ambushing prey.

These amazing animals show that there’s a lot to be said for coming out of your shell. Whilst most of their relatives still cling to the comfort and safety of their ancestral defenses, slugs demonstrate that with a bit of ingenuity (and a whole lot of natural selection), life in the nude isn’t so bad after all. Why more people haven't adopted them as their inspiration in life...

...I have no idea.

Sprout Science

A lot of things cause arguments at Christmas time. Bad gifts, cooking disasters and a room full of relatives who spend the rest of the year apart for a reason… yet few things divide opinion as greatly as the humble Brussels sprout. Some view them as an essential part of Christmas dinner, and wonder out loud why they’re not eaten all year round. The remainder silently wonder what their ancestors were thinking when they made these little Grinch-green blobs a tradition. Yet dig a little deeper, and the Brussels sprout is a pretty interesting vegetable. If you find yourself spending less time eating them than staring at them as they go cold on your plate, why not at least appreciate these little vegetables for their trivia?

A Sprout Family Christmas

Sprouts smell like cabbages. They taste like cabbages. They look like miniature cabbages. So it’s fair to assume they’re related to cabbages. You’d be right- they’re actually the same species. A large number of our traditional green vegetables are descended from a single wild species, called Brassica oleracea, or wild mustard.

Yum?

 By selectively breeding different parts of the plant to grow large and edible, humans have created a diverse range of vegetables collectively known as brassicas. For example, the roots of one lineage have been bred to swell up and form the vegetables we know as turnips. Cauliflower, as suggested by its name, is literally a bunch of tiny flowers, as is broccoli. Breeding for exaggerated stems makes kohlrabi, whilst cabbage and kale are different varieties of leaf, and mustard is obtained from plants bred for particularly pungent seeds. Brassicas are essentially the domestic dogs of the vegetable world; a collection of artificial “breeds” so distinct from one another, you’d be forgiven for thinking they were different species.

The Brussels sprout is descended from the buds of the plant, and the way in which they grow is unfamiliar to most people. They bud out of a thick central stem, growing in a spiral formation from top to bottom.

Here’s a fine specimen out the garden. Notice how the older sprouts towards the base have opened into perfect little cabbage-y florets as they move beyond the bud stage to become fully-formed leaves.

An acquired taste?

What makes sprouts and other brassicas divide opinion so much? If your rejection of sprouts leads others to call you a fussy eater, it might not be your fault-- the distastefulness might actually be written into your genes. Our tongues are covered in taste receptors, and the most diverse group of these are the TAS2 receptors, which allow us to detect a whole host of different bitter compounds. Though having a complex appreciation of the least popular flavour out there might seem pointless, it’s actually paramount to our survival: most poisonous substances are bitter, so it pays to be able to detect them. One gene coding for a particular TAS2 receptor comes in two forms, and which variety you have determines your ability to taste certain harmless but bitter compounds commonly found in brassica vegetables. People who carry the sensitivity gene will experience sprouts as being unpleasantly bitter, to the bafflement of non-carriers. This effect is enhanced in young children who carry the sensitivity gene, as they can detect much lower concentrations of the bitter compounds than adults. This is partly why some kids learn to love-- or at least tolerate-- sprouts as they get older.