Tag Archives: evolution

Are Animals Doing the Wrong Thing?

The great tit (Parus major) needs to gain more than 10 % of its body weight in pure fat every evening, in order to survive a cold winter night (Image Credit: Ian Frank, CC BY 2.0)

Short-term insurance versus long-term bet-hedging strategies as adaptations to variable environments (2019). Haaland, T.R. et al., Evolution, 73, 145-157.

The Crux

Why do animals behave the way they do? Behavioral ecology is a field of research trying to explain the ecological rationale of animal decision making. But quite often, it turns out the animals are doing the ‘wrong’ thing. Why don’t all animals make the same choice, when there clearly is a best option? Why do animals consistently do too little or too much of something?

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The Ecology of a Mermaid

Adam regales us with one of the weirdest stories I’ve ever heard, and in case you were wondering, yes we do talk about how mermaids have sex. Jesus. Also there’s some cool ecology. Like how did mermaids evolve? Was it from a mutated baby tossed overboard? Probably not.

05:19 – Mermaids in Cinema
16:35 – Ecology of the Mermaids
33:25 – Mermaid Copulation (you were warned)
38:07 – The Mermaids vs. Jaws

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Blending In

In nature, it often pays to blend in to your background, especially if you’re a prey species like the deer mice used in this study. (Image Credit: David Cappaert, CC BY 2.0)

Linking a mutation to survival in wild mice (2018) Barret et al. Science, 363, p. 499-504.

The Crux

A big part of ecological studies involves investigating how certain traits or behaviors work (adapted) or don’t work (maladapted) in a specific environment, while scientists who study genetics may investigate specific parts of the DNA that are under selection for specific values of a given trait. Surprisingly, not many studies investigate these two aspects of natural selection simultaneously, instead they will attribute selection to a specific trait value without knowing the genetic mechanisms behind it.

The authors of this study used a well-studied model system of deer mice (Peromyscus maniculatus) to link these two aspects of ecology together, tying a mutation in a gene that codes for coat color into selection in the wild. The study took place in the Sand Hills of Nebraska, a relatively young region (in geological terms) where these mice are expected to have recently adapted to the environment due to strong selection for traits that promote their survival.

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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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