Tag Archives: evolution

The Root of Disease

Fields full of herbaceous plants such as these can be incredibly diverse and complicated ecosystems, and the multitudes of species that inhabit them can influence the magnitude of disease that the organisms that inhabit it may encounter (Image Credit: LudwigSebastianMicheler , CC BY-SA 4.0)

Past is prologue: host community assembly and the risk of infectious disease over time (2018) Halliday, F.W. et al., Ecology Letters, 22, https://dx.doi/10.1111/ele.13176

The Crux

Everything in ecology is based around the environment that a focal organism inhabits, including the interactions it has with other organisms and the non-living aspects of the habitat itself (temperature, water pH, etc.). That being said, it’s no surprise that disease dynamics are likely to depend on the environment that a host inhabits, and that the environment itself is a product of what came before. That is to say, the group of organisms that originally populate a given ecosystem can have an effect on how that ecosystem will look in the future (lakes with freshwater mussels will have clearer water than those without).

The scientific literature is full of experiments, observations, and hypotheses about which environmental conditions lead to fluctuations in disease dynamics. As such, it is difficult to come to a consensus with a “one-size-fits-all” rule for disease dynamics and community structure. The authors of today’s study used a long-term experiment to determine what exactly moderates disease over time.  Read more

Getting Older is Favored in Choosy Species

One of the timeless (get it?) questions in biology is why did we evolve to age? What benefit is there to getting older and deteriorating before we die? (Image Credit: medienluemmel )

Evolution favours aging in populations with assortative mating and in sexully dimorphic populations (2018) Lenart, P. et al., Scientific Reports, 8, https://doi.org/10.1038/s41598-018-34391-x

The Crux

We as humans are familiar with aging as the slow deterioration of our bodies and minds over time, and we can see this in other animals as well (think of the old family dog with white around its muzzle). The interesting thing is that not every species ages in the way that we do, that is to say that they stay forever “young” until they die. In a biological sense that means that while these organisms can and do die, their risk of death remains the same throughout the course of their lives. This would be akin to your grandparents, in their old age, having the same risk of death as you during the prime of your life. Or, conversely, you being just as likely to die in your sleep as a senior citizen.

The authors of this study note that, while theories for the evolution of aging abound in the scientific literature, they are not broadly applicable and some of them even require the existence of aging for the evolution of aging to even happen. They wanted to find out in what situations aging individuals could outcompete non-aging individuals, and vice-versa.

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Birds are Reptiles

When one looks at birds like this puffin, it can be hard to reconcile its cute appearance with its place in the animal kingdom. The thing is, this adorable puffin has something in common with a rattlesnake, in that it’s a reptile (Image credit: Ray Hennessy CC-0).

You read that correctly, birds are reptiles. Now, I can hear you saying “but we learned that they are a different group of organisms, and that reptiles are just those scaly animals that have cold blood?” While reptiles don’t have cold blood per se, some of them DO have feathers. And can fly. In this post I hope to convince you of the fact that the puffin pictured above, and all of its avian relatives, belong with the snakes, lizards, crocodiles, and turtles in the reptile group.

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The Effects of City Life On a Species’ Body

Species like the anole exist in natural and urban environments. So how does where they live affect their body shape? (Image Credit: RobinSings, CC BY-SA 4.0)

Linking locomotor performance to morphological shifts in urban lizards (2018) Winchell, K. et al., Proceedings of the Royal Society of Biological Sciences, 285, http://dx.doi.org/10.1098/rspb.2018.0229

The Crux

We know that human construction leads to displacement of many species, regardless of the ecosystem. But just because we put up a city, doesn’t mean that all the species that lived there go disappear. Some stay and adapt to their new surroundings. Understanding how certain types of organism respond to new environments is important when considering our impact on a species.

Today’s paper looks at the response of lizards, in this case anoles, to living in the city. The authors wanted to find out, among other things, whether individuals of the selected species showed different locomotive abilities on natural and man-made surfaces based on whether or not they came from the city or the forest, and whether these corresponded to morphological differences.

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It’s All in Your Mind

Rodents and primates are periodically cited as some of the more intelligent animals on the planet, but it turns out that the large brains that these mammals possess have evolved more than once in their history. (Image Credit: Arjan Haverkamp CC BY-SA 4.0 

Encephalization and longevity evolved in acorrelated fashion in Euarchontoglires but not in other mammals (2018) DeCasien, Alex R., Evolution, DOI: doi:10.1111/evo.13633

The Crux

Some of the most striking footage from documentaries like the recent “Blue Planet II” involve organisms that display remarkable intelligence (the octopus that uses shells to disguise itself and hide from its shark predators was a particular favorite of mine). As humans, we sometimes assume that we have the best brains on the planet and have somewhat of a monopoly on intelligence, so it’s always fascinating and maybe even surprising to see other animals using their own brains to solve problems. In mammals, brains that are larger than expected have evolved more than once, which is somewhat of a surprise given how costly a big brain is. For example, your brain needs 20% of the oxygen that your body uses, so one out of every five breaths is exclusively for your brain.

Larger brains are also correlated with longer lives, relative to the group that the organism in question belongs to. Historically, studies on brain size and longevity have been dominated by primate species, so the concern was that this long life/large brain trend may only be a primate trend, instead of generalizable to all mammals. The authors of this study wanted to analyze this trend across more mammal groups, in addition to studying the relationship between larger brains and longer lives.

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Episode 8: The Gremlins/Mogwai

We kick down the kitchen door and go to bloody war with the Mogwai, from 1984’s Christmas classic Gremlins. Dave gives China tips for invasion, Sam says the word ‘tarsier’ too much and Adam can’t resist showing off how much Mandarin he doesn’t know.

5:52 – History of the Gremlins
18:02 – Movie Any Good?
21:40 – Physiology of a Mogwai
44:11 – Ecology of a Mogwai
1:02:32 – The Gremlins vs. Gollum

You can also find us on iTunes and Google Play.

The Changing Face of Ecology: ASFB Edition

I speak to another group of influential researchers on how ecology has changed over the recent decades

I speak to another group of influential researchers on how ecology has changed over the recent decades (Image Credits: Jarod Lyon, Gretta Pecl, CSIRO, CC BY-SA 2.0)

I’m 29. It’s not like that makes me uniquely qualified to give me the youth’s perspective on ecology today. But it does make me 100% unqualified to talk about how ecology has changed in recent decades. So when I was at the recent Australian Society for Fish Biology Conference (a line you’ll surely be sick of if you’ve been keeping up with my recent interviews), I decided to get some uniquely fishy perspectives on how our discipline has changed over the last 20-30 years.

The following commentaries are naturally from fish biologists. If you’d like a broader perspective on the changing face of ecology, check out Part One and Part Two of this series. You can also find the full interview with all the scientists below by clicking on their names.

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