Tag Archives: evolution
I like to think that when people visit Ecology for the Masses, they come to quench their insatiable curiosity about the ecological world and all its mysteries, and just want a well-reasoned, accessible answer to their issues (and also to figure out whether birds are reptiles of course).
But of course sometimes someone who isn’t looking for top-shelf ecology content and comics (thank you Tanya) stumbles across our site. And thanks to the magic of WordPress I often get to see what strange question brought them to the site. So because it’s the first Monday back for the year (and my first day of work in two weeks) let’s have a look at and try to answer some of the weirder search terms that brought readers to Ecology for the Masses this year.
1. Evil looking duck
If you’ve met me for more than 20 minutes or read my take on ducks, you’ll know that I consider every duck to be an evil-looking duck. Hey Hey It’s Saturday fans probably share my opinion (90s Aussie kid joke). But if I really had to pick a more objectively evil-looking quacker, it’s probably the Bullockornis. Quacker might be a false tag here, as these massive flightless prehistoric birds weren’t part of the duck family (Anatidae). But they were originally thought to be carnivores, and when someone foisted the nickname ‘Demon Duck of Doom’ on them, it stuck.
This swan on the right is still a massive creep though.
2. Are chickens reptiles?
Ok, so birds being reptiles is something that Adam has covered, and damned if it doesn’t draw the crowds. I include this one because of an conversation with my kid earlier this year. We were at a zoo in central Norway and he insisted that chickens couldn’t be reptiles, because LOOK AT THEM.
Totally fair enough. The disconnect between our traditional ideas of birds and reptiles is hard to overcome. But if you ever find yourself baulking at the fact that birds belong in the Reptilia family, just look at their feet.
3. Pseudo science annoying
If any year presented the perfect example of just how damaging pseudoscience could be, it was 2020. Pseudoscience and poor understanding (and communication) of legit science killed people in 2020 on a very visible scale. Let’s hope that the public’s relationship with science improves in the near future. Drinking bleach won’t help in the fight against climate change either.
4. Did Ross believe in evolution?
I enjoy this one so much because Ross would have been fuming at the idea that someone could believe or not believe in evolution. He’s got a point to be honest. We might call it the theory of evolution, but the distinction between a ‘law’ and a ‘theory’ in science is a lot fuzzier than you might think.
BUT that doesn’t mean Ross isn’t still the worst friend.
5. What are the evil work of marmade spirit in human body?
Last year Adam and I recorded an episode of Cinematica Animalia concerning the ecology of mermaids, in which we discussed some speculative mermaid reproductive and evolutionary ecology. So naturally some people looked up ‘mermaid sex’ and found this site, which went into the 2019 ‘Best Ecology Search Terms’ article. This inadvertently doubled the number of people winding up on our site looking for ‘mermaid sex’.
I’m not describing it here you perv. Go and listen to the episode.
6. How to prevent evil birds?
Chickens are probably the most evil birds, seeing as 70% of bird life today is poultry. So in direct opposition to my advice in this article last year, stop eating them.
7. Define herbivores. And write down the names of herbivores from the Lion King movie.
This hands-down wins “most-obvious-primary-school-homework-task” for 2020. I really hope that the teacher set the follow-up question “WHY does all the vegetation disappear” (and given that “why does the landscape change lion king” was another search term, they did). And potentially also “why didn’t anyone explain trophic cascades to Jon Favreau”.
8. Cats are destroying the planet
Look outdoor cats are just the worst. They spread disease, kill native species at incredible rates and probably do other awful things in their spare time like leaving their mobile phones on the table while people are having dinner and talking loudly about CrossFit. But I don’t know if you can necessarily add ‘planetary destruction’ to their list of ambitions.
9. Ate outdoor cats bad?
Yes you are bad. Outdoor cats are bad, but please do not eat them. As well as this being unlikely to go down well with your neighbours, there’s a reason that carnivores know not to eat the carcasses of other carnivores. Do yourself a favour and forego eating cats.*
Sam Perrin is a freshwater ecologist currently completing his PhD at the Norwegian University of Science and Technology who is looking forward to another year full of variants of ‘IS BIRZ REPTALE’ filling the search terms. You can read more about his research and the rest of the Ecology for the Masses writers here, see more of his work at Ecology for the Masses here, or follow him on Twitter here.
Evolution and maintenance of microbe-mediated protection under occasional pathogen infection (2020) Kloock et al., Ecology and Evolution, https://doi.org/10.1002/ece3.6555
Microbes are everywhere in nature, and I don’t just mean out in the wild. They live inside of every plant and animal, including humans. These microbes can be harmful, beneficial, or do nothing to their hosts. When they help us, microbes take part in what’s called “defensive mutualism”, which is where they help their hosts fight off parasites. Benefiting from this mutualistic relationship depends on whether or not there are parasites around to defend against, as microbial defense mechanisms can harm not only the parasite but also the host itself.
For this symbiotic relationship to continue and not be selected against over time, the benefits of hosting the microbe must outweigh the costs. This is all well and good when there are always a lot of parasites to defend against, but that is not always the case. Today’s authors wanted to test how changes in parasite pressure over time affected the relationship between a defensive microbe and its host.Read more
Endless forms most stupid, icky, and small: The preponderance of noncharismatic invertebrates as integral to a biologically sound view of life (2020) Jesse Czekanski‐Moir & Rebecca J. Rundell, Ecology & Evolution, https://doi.org/10.1002/ece3.6892
When we think about evolution, too often our perception is that it drives species towards larger, more complex, more beautiful forms. It’s driven by popular media in part, but also by the way we teach it and the organisms we choose to focus on. This goes right back to early conceptions of evolution, with Darwin’s seminal text The Origin of Species referencing “endless forms most beautiful and most wonderful”, instead of “most basic and abhorrent”.
But the authors of today’s paper want to challenge that preconception of evolution as favouring larger or more complex or beautiful organisms, and they have some truly magnificent examples to do so with.Read more
A katydid, proudly displaying the front legs in which it houses its ears (Image Credit: Charlie Woodrow, CC BY 2.0)
Insects are famously one of the most diverse groups of organisms, with over one million species discovered, adapted to nearly every niche on the planet. This diversity has allowed for the evolution of an incredible mix of shapes and sizes, behaviours, and other features. Perhaps the most frequently re-occurring of these traits are their ears, with current estimates stating they have evolved up to 20 times independently, on almost every imaginable part of the body. So just what makes it so easy for insects to evolve ears? And why should we study them?Read more
The evolution of crocodilian nesting ecology and behavior (2020) Murray et al., Ecology and Evolution, https://doi.org/10.1002/ece3.5859
One goal of evolutionary ecology is to understand the links between microevolution and macroevolution, meaning evolution in the short term (multiple generations) and how that scales up to the long term (millions of years). In macroevolution, a group of organisms is thought to be successful if it not only exists for a long period of time, but if it also boasts a large number of species. With those criteria in mind, crocodilians (alligators, crocodiles, gharials, and caimans) are one of the most successful lineages to have ever existed on the planet. Though they may not be the most diverse group of organisms with only 25 species, they have been around for about 100 million years. To put that into perspective, dinosaurs went extinct about 65 million years ago, meaning that the crocodilians not only lived with dinosaurs, but they survived the mass extinction that the dinosaurs didn’t.
This longevity as a lineage raises some questions as to what it is about the crocodilians that made them so successful, when their cousins the dinosaurs died out. An interesting aspect of crocodilians is that there is very little variation among these organisms, as they are all generalist carnivores, live aquatic lives, exhibit mating vocalizations, their sex is determined by the temperature of their eggs (see Did You Know?), and they care for their eggs and young. Despite these similarities, there are some notable differences in the reproductive ecology and behavior of the different species, specifically how they build and care for their nests. Because of these differences, the authors of today’s study asked if variation in how crocodilians reproduce may have been the cause of their success.Read more
The silver lining of extreme events (2018) Coleman & Wernberg, Trends in Ecology and Evolution, https://doi.org/10.1016/j.tree.2020.08.013
We here at Ecology for the Masses recognize the harm of climate change and the danger that it poses to countless species the world over. Part of climate change involves extreme climate events such as floods, droughts, unusual cold spells, or cyclones, all of which can be devastating to natural systems. By and large these events are seen as negative, and rightfully so! But today’s paper offers another perspective on extreme climate events: their potential for driving evolution towards increased resilience.
Now, I’m not saying that these extreme climate events are good. I dislike them just as much as the next person with a shred of concern about the natural world. That being said, the authors raise some interesting points about the evidence that exists for these events being a positive force for evolution and adaptation. As such, I want to touch on a few of those points, address some issues with this ‘silver lining’, and talk about what it means going forward.
What Evidence Exists
Extreme climate events result in massive losses of organic life, local extinctions, and can drive range shifts. This is quite costly from not only an ecological point of view, but also a social and and an economic one. Due to these costs, a significant amount of effort and money has been dedicated to working on issues associated with these events. Interestingly enough, despite the negative connotations and costs associated with extreme climate events, there is emerging empirical evidence for a “benefit” in that they can cause non-random mortality (see Did You Know?), driving rapid evolution and adaptation.
Scientific theory has predicted that when extreme climate events occur in such a way that they select against weak individuals, but aren’t so extreme that “tougher” individuals cannot live, then these more tolerant and stronger individuals can persist in populations/areas undergoing extreme events. If these tougher individuals can pass on their genes, then a population can rapidly adapt to these extreme conditions. For example, a study showed that a severe cold snap selected for cold tolerance in green anoles (Anolis carolinensis), and similar work has shown that heatwaves selected for thermal tolerance in kelp. While plenty of the lizards/kelp didn’t have the proper traits to survive these extreme temperatures, some of them did. And because they passed on those genes to the next generation, the population is better-suited to survive future extreme temperatures.
Did You Know: Non-Random Mortality
Evolution is a fact of life, and the driving force behind the persistence of life on our planet. However, what you may not know is how evolution actually results in changes in a population/species over time. Individual organisms don’t evolve, species do. So how does that work? Well, it all has to do with how often certain individuals pass on their genes. “Survival of the fittest” refers to the biological concept of “fitness”, which is how good a given organism is at passing on its genes. So in order to be the most fit, you have to pass on the most genetic material, relative to other members of the population. This is where non-random mortality comes into play. Non-random mortality means that there is a pattern behind the death rates. Put into other words, the individuals that survived had something that the ones that died did not. This is how evolution works slowly over time, non-random mortality means that individuals with a given trait tend to die less often than those that don’t have that trait, which means that that trait gets passed on more often than others. Eventually, that trait will become the new normal for that population/species, and evolution has occurred.
What This Means
The potential for extreme events to select for resilience and drive rapid adaptation means that groups dedicated to conservation and preservation of species and ecosystems may be able to proactively anticipate future events. The authors highlight the difficulty inherent in studying non-model organisms for traits/genes that may promote persistence to future climate events, as it involves a LOT of background research to understand the mechanisms behind such persistence. However, to use the anoles from earlier as an example, there are better ways. If one was to go to an area that recently suffered a cold snap like those anoles did and collect the survivors, chances are that most of those survivors have the cold-tolerance trait. By selectively breeding/relocating those survivors conservation workers could prevent future die-offs due to cold snaps.
Problems With These Approaches
This all sounds great, right? No issue? Well, not quite. Just because a given trait may promote persistence to one stressor (the environment) does not mean that it promotes persistence to all others (like disease). Another issue with this silver-lining of adaptation and rapid evolution is the bottleneck effect: extreme events cause mass die-offs. Though the survivors may have a trait that allows them to persist in extreme events, the reduced population size of the survivors may result in such a marked decrease in genetic diversity that the population fails eventually anyway due to the issues associated with inbreeding.
Extreme climate events are an unfortunate reality, and they are only predicted to get worse and become more frequent. Today’s paper offers a pleasant silver lining to that very grim reality, as it highlights the potential for these events to drive evolution and selection to extreme conditions. It may not be as good as not having these events in the first place, but the authors bring up an important point by drawing attention to the evidence that exists for populations adapting to these extreme conditions, many of which seem to be driven by human-induced climate change. I’ve recently re-read Michael Crichton’s Jurassic Park, and I can’t help but think of a quote from the character Dr. Ian Malcolm’s as I was reading this paper: “The planet has survived everything, in its time. It will certainly survive us”.
Adam Hasik is an evolutionary ecologist interested in the ecological and evolutionary dynamics of host-parasite interactions. You can read more about his research and his work for Ecology for the Masses here, see his personal website here, or follow him on Twitter here.
Of poisons and parasites—the defensive role of tetrodotoxin against infections in newts (2018) Johnson et al., Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.12816
Many organisms in nature produce powerful (and sometimes deadly) toxic substances, often taken as evidence that prey evolved chemical defenses against predators. Interestingly, these chemical defenses are deadly not only to predators, but also to parasites. This complementary defense, in addition to the ubiquity of parasites themselves, indicate that parasites may have had a hand in the evolution of host toxicity.
One particularly potent toxin found in the animal kingdom is tetrodotoxin (TTX). It can cause paralysis, difficulty with breathing, and even death in some cases. Newts in the genus Taricha are notorious for having high concentrations of TTX in their skin and eggs, and this has long been thought to have evolved as a defense against predators. In particular, Taricha newts and garter snakes (Thamnopholis spp.) are a classic example of arms-race dynamics (see Did You Know). Despite this relationship, newt toxicity and snake resistance to the toxin don’t always match up perfectly in nature, suggesting that other factors may influence newt toxicitiy. The goal of today’s study was to study parasitic infection and compare it to variation in toxicity among two newt species, the rough-skinned newt (T. granulosa) and the California newt (T. torosa).
Local Adaptation to Biotic Interactions: A Meta-analysis across Latitudes (2020) Hargreaves et al., The American Naturalist, https://doi.org/10.1086/707323
Local adaptation is a process whereby individuals native to a given area are better-suited to live in that environment than foreign individuals, and those local individuals will out-compete foreign individuals. This adaptation to local conditions can range from a predator that is better at finding and catching prey, to a plant that is more efficient than another at taking nutrients from the soil, or to a host that has evolved defenses against a local parasite. Despite a wealth of literature and science that has been dedicated to the study of local adaptation, it is not clear what it is about the environment that commonly drives it.
Early studies of local adaptation measured abiotic (non-living) factors like temperature and the amount of light, but this ignores the fact that all environments include biotic factors like other species and any interactions with them. A small amount of studies have shown that biotic interactions (i.e. interactions with other species) can drive local adaptation, but there isn’t a consensus on how common of a pattern that is. Today’s authors used a meta-analysis of previous studies to test how these biotic interactions affect local adaptation. Read more
Macroevolutionary convergence connects morphological form to ecological function in birds (2020) Pigot et al, Nature Ecology & Evolution, https://doi.org/10.1038/s41559-019-1070-4
There are an astounding amount of different forms that the animals on our planet take. Likewise, there are a multitude of diverse functions that animals serve in the environment, such as that of a herbivore, a predator, or scavenger. In some cases it’s a clear link between the form of a given animal and its function in the environment, like that of the beak of a hummingbird that allows it to feed on nectar and their role as a pollinator. But whether or not there is a reliable way to predict the function of an animal based off of its form is has been the subject of considerable controversy.
Deciding on how many morphological traits to use to predict ecological function is a difficult prospect. One could argue that it’s impossible to pick a finite number of traits, as there are infinite possible niches that organisms can fill so there’s no way that a set of traits could fill those infinite possible niches. Mapping animal form to function has major implications for quantifying and and conserving biodiversity, and the authors of today’s paper wanted to to determine just how many traits are needed to do that.