Category Archives: Opinions
When you think about contagious diseases, the image that’s conjured is probably not a romantic one. Spanish flu, polio, the Black Death – while they’ve all shaped our history, they’re not exactly prime fodder for light-hearted musicals or sitcoms. And while many of these diseases we’ve successfully conquered as a society, we still see many diseases that do not have a cure yet.Read more
Image credit: Movie poster advertisement for Tarantula (1955), Public Domain, Image Cropped
In the mid twentieth century, movies like ‘Tarantula’ and ‘Them!’ set the scene for what life would be like if giant bugs existed. Scenes filled with nightmares arisen from experiments gone wrong, children-stealing ants, great taglines like “Science’s Deadliest Accident”, and some unbelievably outdated special effects.
Luckily, giant bugs don’t exist… Anymore.Read more
How do we motivate people to protect ecosystems?
At this stage in the climate crisis, many of us are very aware that ecosystem destruction and biodiversity loss are huge problems, bringing about everything from rapidly expanding deserts to global pandemics. We are acutely conscious that something incredibly valuable is being destroyed, and we want to protect it.
However, there are also people who aren’t very aware of the scale of ecosystem destruction, and therefore don’t seem to be doing anything about it. Motivating these people to protect ecosystems – or at least stop destroying them – is a huge problem. A problem so big, some people have even tried to throw money at it.Read more
Would you rather stab, or be on the receiving end of a stab? This may seem like a confronting question, but it’s the dilemma many flatworms face when a mating opportunity arises.
Option 1: You are a flatworm and have just been stabbed by a stubby penis. You now have puncture wounds that must heal, after which you must carry fertilized eggs which you need to lay and protect upwards of 24 hours. Oh, the energy demands!
Option 2: Flatworm victory! You have successfully stabbed your opponent with your stubby penis before they could stab you. Your sperm has now fertilized their eggs. With this win, you move on with life and wait for your next mating “opponent”.
Which option do you choose? If you still can’t choose, it’s a good thing you aren’t a simultaneous-hermaphroditic flatworm. These flatworms have both fully functional male and female reproductive capabilities that can be used interchangeably, unlike other hermaphroditic species who switch back and forth during different phases of life. One might say these individuals have the capability to “choose” what role they want to play, male or female. Although, those forced into the role of reproductive female may disagree…
It is believed that individuals fight to “remain male” (i.e., not be fertilized) because sperm is biologically cheaper to produce than eggs, and males can produce more offspring than females over a lifetime. This type of fight has been thought to be “pure evolutionary selfishness”.
It was only discovered recently, after Dr. Leslie Newman and Dr. Nicholas Michiels spent 20 hours continuously watching pairs of captured flatworms. They observed that when an individual encounters another, both assume a fighting stance, curling their bodies back to display their penises. Next, they began to fight, each attempting to stab the other, which could last from 20 to 60 minutes.
Different species fight with different strategies. For example, racing-line flatworms (Pseudocerotidae bifurcus) use their penis to repeatedly strike at one another until one succeeds, injecting sperm under the skin of the other. Once the sperm is injected, it moves through the body to find and fertilize the eggs. Persian carpet flatworms (P. bedfordi, pictured above) instead use their penis like a water gun, ejaculating anywhere on their opponent’s body. With a sperm cocktail that dissolves flesh, it burns its way through various tissues until it reaches and fertilizes the eggs.
Penis fencing is the term scientists use to describe this behavior to “remain male”. This mating behavior isn’t seen amongst all flatworm species, only certain species within the family Pseudocerotidae. In the 1990’s there were only two species of flatworm known for this behavior, however as of 2020, the number has grown to 16.
Evolution of Penis Fencing
Species of flatworms can use sexual reproduction (need both gametes; sperm and egg), asexual reproduction (does not require both gametes, obtain all DNA from parent), or both. Those that use both, do so depending on which strategy is favoured by the environmental conditions. For example, sexual reproduction is favored under harsher, more unpredictable conditions, since genetically variable offspring are often better able to adapt and survive these conditions. Asexual reproduction may be favored when individuals are scarce, however it tends to be avoided as there is on average a 50% loss of genetic diversity per generation, subsequently increasing the probability of inbreeding in future generations. If asexual reproduction does occur, it can occur through budding or transverse fission. Budding occurs when ‘buds’ (i.e., outgrowth) grow out of the flatworm’s body until they are large enough to break off as new individuals. Fission, on the other hand, involves an individual being cut in half, with each half becoming a new individual.
A species may employ different hermaphroditic strategies of cross-fertilization depending on their ecological niche. These include delivery of sperm to a sperm-receiving organ of the mating partner, or hypodermic insemination of sperm into the cellular tissue by a modified penis that enables individuals to pierce the body wall of their partner. It is believed that the willingness to invest as little resources as possible into their offspring is very strong in hermaphroditic species, leading to these extreme mating behaviors such as penis fencing.
Yet penis fencing does not always occur when individuals meet. Four possible scenarios have been observed when individuals encountered one another:
- Both partners were receptive to mating and penis fencing was observed,
- Both partners were receptive but no penis fencing was observed,
- Only one partner was receptive and no penis fencing was observed however insemination was successful, and
- Neither were receptive to mating.
If penis fencing occurs, it typically leads to successful sperm insemination for one or both individuals. Number 3 may be the result of other mating behaviors. For example, mating Starry flatworms (P. stellae) will curl around each other, swimming in circular motions in attempts to inseminate each other.
Outcomes of Penis Fencing
A more recent study in 2020 found that penis fencing results in three outcomes; 1) both individuals were inseminated, 2) one individual was inseminated, or 3) neither were inseminated. These researchers found penis fencing to be more of a duel or contest mating ritual, rather than an aggressive, violent behavior as was originally thought. This is because they found different scenarios where penis fencing occurred that resulted in neither individual being inseminated, or where no penis fencing occurred resulting in at least one individual being inseminated. Although we may think of penis fencing a little differently now, one thing that will forever remain constant are the words of David Attenborough, “its only solace is knowing it’s young will carry the genes of a master swordsman”.
Jennifer Merems is a writer and researcher focusing on behavioral and nutritional ecology. She is currently a PhD candidate in the Department of Forest and Wildlife Ecology with the University of Wisconsin-Madison. You can learn more about Jennifer by following her on Twitter at @atyourcervid.
Baldrick: I have a plan, sir.
Blackadder: As cunning as a fox who’s just been appointed Professor of Cunning at Oxford University?
Baldrick: Yes, sir.
Even if you’re not familiar with the British classic Blackadder, if you’re an English speaker the expression “cunning as a fox” will need no explanation. Our fascination (or in some cases disregard for) the intelligence of animals, and our comparison of animals to our own levels of intelligence, have been a part of language for centuries.Read more
What even is a desert?
When you think of a desert, what comes to mind?
- A sweltering endless expanse of sand dunes
- A frozen ice sheet
- A rocky beach
- A dry mountain range home to cacti and venomous snakes
If you any or all of the above popped into your head, you’d be correct. On earth, roughly a third of all land is desert, but deserts are as diverse as the species that inhabit them. We often think of the merciless sun as a desert icon, yet it is in fact rainfall that is generally the only factor used to classify deserts. A desert is simply any place that receives less than 25 cm of rainfall in a year, which means that deserts are found on every continent, including Antarctica.
How do animals and plants survive in deserts?
Contrary to common belief, deserts can actually have an incredible amount of diversity, although they are not without their challenges. The dry conditions, paired with often extreme temperatures, mean that species that live in deserts have developed a variety of special adaptations that allow them to survive in such challenging conditions. That starts right at the base of the food web, with plants. Some desert plants have a waxy coating or unique leaf structure in order to prevent water loss, and species of cactus go the extra mile by not having any leaves at all. Other plants have widespread roots in order to reach as much underground moisture as possible. These adaptations allow the plants to go many months without any rain.
Animals deal with a lack of rainfall in a different way. Desert tortoises can get water from their food, store it in their body, go months without drinking, and have highly concentrated urine in order to decrease the amount of water they lose over that time period. Reptiles such as lizards have a thick layer of skin that prevents water loss. In Antarctica, a cold desert, penguins are able to take in saltwater and then secrete excess salt, avoiding the need to find freshwater.
What happens when deserts get even dryer?
Animals and plants have both developed unique ways to survive in extreme conditions. However, these extremely specific adaptations might not protect every desert species from the impacts of climate change.
One very important impact of climate change is desertification, which is land degradation that takes place in dry areas and turns fertile land into a desert. Desertification makes an area less habitable for animals, plants, and people. Over the next century, climate change is predicted to lead to decreased rainfall in some areas, along with increased drought (and more severe drought) and higher temperatures. This, coupled with our clearance of vegetation that moderates extreme heat and retains water, means that even more of the planet will become desert. Although desert species are adapted to tough conditions, many species are essentially already living on the edge, and even more severe conditions might push them over the edge. For non-desert species, it will have an even bigger impact.
Desertification leads to a decrease in biodiversity (which here means variety/number of different species in an ecosystem), and can lead to extinction for species that can’t relocate or tolerate harsher conditions. For people, it leads to a decrease in usable land.
In these deserts, often the only way humans can survive there is by having a system to bring in water from somewhere else. In the western United States, 40 million people across 7 states and 30 native tribes rely on water from the Colorado River, and have developed detailed agreements to determine how the water is distributed. As populations grow and available water decreases, there will come a time when there isn’t enough water for everyone, and that time might come earlier than people thought. This summer, the US government directed states to find ways to decrease their water use over the next year. If they don’t, the government will make emergency cuts to water allowances in order to ensure that the water reservoirs don’t get too low.
Currently, there are more than a billion people that live in deserts. As deserts become harder to live in, not everyone has the means to relocate to somewhere better. People living in deserts will have to cope with less fresh water, poor sanitation, malnutrition, an increase in diseases, and more.
So what can we do in order to survive in these deserts?
Even though there already isn’t much water in deserts, people living there will have to find ways to use even less water in order to preserve what we have. Indigenous people have been successfully living in deserts for thousands of years, using strategies like moving to cooler areas during the hotter seasons and only growing crops that suit the environment and season. If we want to succeed, we should listen to indigenous communities and adopt these strategies.
We’ll also need to take steps to become more sustainable so that we can share resources like water and ensure that no one has to go without it. We can adapt our infrastructure by taking actions such as installing rainwater harvesting systems and increasing available shade. Living in the desert is incredibly challenging, and it’s not going to get any cooler, but if we learn from those that’ve been here longer than us, we can make the desert our home as well.
Holly Albrecht is currently an educator/zookeeper, and holds a Bachelors degree in Conservation Biology from the University of Arizona. She is passionate about ichthyology, herpetology, and using education/outreach to get people interested in conservation and the natural world.
This week has seen Europe hit by heatwaves of an intensity that would have seemed more at home in the USA’s dust bowl or Australia’s Great Red Centre. Fires have raged across Spain and France, people have been evacuated from and lost their homes, and thousands have died as temperatures seared great swathes of the continent.
While some have sneered at the UK cowering in the face of such heat, there’s no doubting that 40 degrees is pretty scorching, especially in a country where the infrastructure just isn’t built to take it. The full ramifications of these heatwaves are yet to be seen, but the loss of life, and financial costs rising from damage to property and infrastructure, plus the health issues caused by ongoing drought and heatstroke, are only likely to rise as the week goes on.
Now that we’ve covered the depressing stuff that’s happening currently, let’s focus on the future. Is this the new norm?Read more