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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Johanna Schmitt: Climate Change and Plant Life

We sometimes ignore the effects of climate change on plant life, but the potential severity of these effects isn’t something that should be ignored for long (Image Credit: Pisauakan, CC0)

From the California wildfires to the recent strikes across Australian primary schools, climate change is a topic that only seems to grow in its ubiquity. Yet whilst humans are increasingly focused on more obvious repercussions, such as extreme weather events, animal extinctions and shifting coastlines, we sometimes forget that climate change will have severe repercussions for plant life as well.

I spoke to Professor Johanna Schmitt of the University of California earlier this year to discuss some of those repercussions. Johanna’s team is working to determine how well certain plant species will be able to adapt in the face of rapid climate change.

Sam Perrin (SP): The term climate change is ubiquitous these days, yet we often don’t talk about plants in relation to its effects. What will some of the effects of climate change be on plant life?

Professor Johanna Schmitt, Department of Evolution and Ecology, University of California (JS): Well from a North American perspective, let’s start with seasonality. The growing season is longer, spring is coming earlier, summers are hotter, winters are warmer. And so in a lot of temperate areas trees are leafing out earlier. And in colder areas, there’s potential that they won’t be adapting to the warmer weather, and will continue to act on temperature cues, which would be bad. There’s definitely evidence of changes in phenology, in seasonal timing of phylogenic effects. There certainly is already evidence of shifts northward in some plant species, and local extinction of species in their southernmost populations.

Looking at California, we’ve just come out of a mega-drought. We have cyclical droughts, and they’re getting worse because the temperature’s rising. Among other things, it means the snow packs are much lower in California. That means water supplies are lower, because there’s less and less water from the melting snow pack. If precipitation all comes as rain in the winter, then that reservoir of snow is not there, so there’s no water in the summer for the farmers. And that also means the species in the mountains which previously relied on the water from snow melt can’t get through the summer. So we’re seeing pretty massive forest die-offs. And then in addition to that you have the bark beetles, which decimate trees. In parts of the western United States, these bark beetles can produce an extra generation if the winters aren’t cold enough and so the populations expand. I was hiking in the Rocky Mountain National Park a few years ago and the trees had been torn to shreds by these bark beetles.

And off the back of all this we’ve obviously had huge fires. This last fire year in California was record horrible. That’s something that affects plant life that then affects humans big time.

SP: Will the agriculture industry have to start adapting?

JS: There’s a group at Stanford who have been trying to figure out if there’s a signature of temperature affecting crop yields by looking at historical data. And it appears that higher temperatures are affecting crop yields and they expect that to become an issue in the future. This idea that if there’s more carbon dioxide, that will help fertilise the crops and they’ll do fine doesn’t seem to hold if you go beyond critical temperatures. Bottom line is, yes, people are concerned about crop yields being affected.

SP: Things like drought and forest die-off have become more extreme these days. But there’s a danger of this becoming the new norm for people. How do we fight those shifting baselines?

JS: It’s a really interesting concept. Because the younger generation doesn’t remember stuff that my generation does. For kids today, these California wildfires will be the new normal. When I was a little girl growing up outside of Pennsylvania we used to go ice-skating on the ponds all the time after they would freeze in winter. Nobody does that anymore because the ponds don’t freeze.

You look at the record of temperatures. I take Introduction to Biology lectures, and I show the carbon dioxide curve from Mauna Loa in Hawaii, and I show them that when I was born, CO2 was 320 parts per million, and then show them the increase just in their lifetime. So now, being over 400ppm is the new normal. Kids today won’t ever remember it being less than that. People are getting more used to extreme heat events which we just didn’t have 50 years ago.

Arabidopsis thaliana, which Johanna's lab works with, is a handy model species for looking at the effects of climate change on plant life

Arabidopsis thaliana, which Johanna’s lab works with, is a handy model species for looking at the effects of climate change on plant life (Image Credit: Dawid Skalec)

SP: To what extent can we predict the adaptation of some of these species to climate change?

JS: Not very well, that’s really the take-home message. Foresters have the best ability to do that because they’ve been doing large scale trials, taking genotypes from across a species’ range and growing them in different climates across that range. By doing that you can ask how different genotypes perform in different climates. And that allows you to say how much variation is there within the species across the range, and you can also look at how much variation is there within populations. Take something like budset, the timing of when to set your buds and cease growth, shut down, and go dormant so you don’t get killed by the frost. It’s a pretty hard deadline for conifer trees. But from year to year the frost comes at slightly different times. So some years genotypes that are more risk-averse do better and some years others that are more risk-prone do better, so they’d have alternate good years. And this means variation can help a species persist in a changing climate

So for forest trees there may be a fair amount of potential for adaptation. And now people are starting to look at small endemic plant species. Jill Anderson at the University of Georgia has been doing some really interesting work of late on adaptation to elevation across an altitudinal gradient. They combined genotypes at low, medium and high elevations, and combined those mixed gardens with snow manipulation. They either removed or added snow, and they found was evidence of adaptation for the species which were exposed to snow. So that suggested that the population may have trouble keeping up if we have a declining snow pack.

SP: Why is predicting these changes so difficult?

JS: Well for one thing we don’t really know what scenario we’ll be looking at in a few years. I’m pretty pessimistic given events of the last few years that we’re going to have anything but an aggressive carbon emissions scenario. I think it’s going to depend upon the species. We’re going to have to help out. I think many species are not going to be able to evolve fast enough in place. So we’ll have to intervene with assisted gene flow, but how do we choose which ones we want to assist?

SP: Can you take me through the concept of assisted gene flow?

JS: So we want to find out which climate a species likes and where’s that climate going to be in the future. There’s some cases where in fact the species range in the future will be almost non-overlapping with the range it’s in now. So how’s it going to get there? After the last glacial maximum, when the glaciers retreated the trees were able to keep up, but that was happening in orders of magnitudes slower than the rate that the climate is changing now.

The idea is for crucial keystone species, species that are important to the ecosystem, that we should be helping them to move. And that’s very controversial. Because are you essentially engineering species invasions, with limited knowledge of what that will do to the community that is already there. Assisted migration isn’t that aggressive. The idea is that within an existing species range, you move genotypes around to maximise the genetic variation to cope with the climate that’s coming. So in general that would be making sure you’re saving all the genotypes you can from that southernmost edge before they go extinct. And then moving them polewards to provide genetic material for the new climate.

To read up on the work that Johanna’s lab does, click here.

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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Misinformation in Ecotourism: An Example from the Great Barrier Reef

Miscommunication concerning ecosystems like the Great Barrier Reef can be extremely harmful to their future. I recently encountered a frustrating example of such misinformation. (Image Credit: Workfortravel, CC BY-SA 4.0)

Scientific communication is at the forefront of what we do here at Ecology for the Masses. We like to celebrate good examples of SciComm whenever we can. But every now and then it’s misused so overtly that you have to talk about it. So today I want to share a recent example of scientific communication that confused and worried me.

In the last month I’ve been lucky enough to travel around Australia with my partner and our son. We’ve seen rainforests, reefs and the outback, and we’ve had a great time. The Great Barrier Reef was a definite highlight; it was number one on my partner’s bucket list and I have great memories of it from when I was a kid. And it was on the reef that this misuse of scientific communication occurred.

We went out on the reef twice. The first time was with Ocean Safari, a group who I won’t hesitate to recommend. We saw a green sea turtle, stingrays, and more fish species than I could count. And when the tour ended, the guide spoke briefly about mass bleaching and why minimising our impact on the climate was so important to ensure the future of the reef. Perfect.

But on our second trip out, we used a different company. During the trip out to the reef, my partner was at a talk held by a marine biologist on the reef. I missed quite the show apparently, as my partner came back looking slightly confused. The biologist had told people that the temperatures on the reef for the last two years had been ‘perfect’, that the coral reefs would easily recover from bleaching, and that they would plant new ‘supercoral’ to restore the reefs.

Now I don’t want to spend too much time arguing that the guide was wrong. If you need convincing, please read my interview with Sean Connolly. In short, extreme warming events in 2016 and 2017 led to mass bleaching (in 2016 on a global scale). Temperatures were NOT ‘perfect’. Some coral does re-uptake algae after bleaching, but they often starve to death before they are able to do this, which happened on a massive scale over the last two years. And whilst coral restoration can work on a small scale, it is costly and time-consuming.

But why did this irritate me so much? In Australia we’re constantly faced with misinterpretation and downright lies about the reef from anti-conservation politicians all the time. Why is this worse?

It’s because the guide was someone posited as an ‘expert’, and asked to speak in front of people who were assumed to have little knowledge about the concept of coral bleaching. Most Australians are aware at least of the fact that the reef is in danger, but the group on the boat were mostly from overseas. So they hear a marine biologist speak, and assume that those words are fact. The take-away message from the talk becomes one of negligence; nothing to worry about here, nothing needs to be done to help. At worst, that attitude even spreads to people they talk to later on.

It also angered me because talks like the one given are excellent opportunities for scientific communication. You have a group of people who are obviously interested in seeing an ecosystem and are about to enter it, so it’s the perfect moment to engage them in the ecological and conservation issues surrounding that ecosystem. It’s a great way to spread ecological awareness. Unfortunately it was used here to spread misinformation. I can only get so angry at the biologist here though, as the message has clearly been condoned by the company, and they need to take responsibility. Confusing, seeing as there future livelihood depends on that of the reef.

The Great Barrier Reef, along with countless other ecosystems worldwide, are not doing well. But with a concerted effort from the scientific community and the public we hope to keep informed, they’re hopefully not beyond repair. But the damage done by misinformation in this sort of forum needs to be mitigated, as quickly as possible.

The Perfect as the Enemy of the Good in Sustainable Living

Eating beef isn't great for the environment. But ca someone who occasionally snacks on cows still be in favour of conservation and other ecological causes?

Eating beef isn’t great for the environment. But can someone who occasionally snacks on cows still be in favour of conservation and other ecological causes?

Today I want to talk about a tweet. Or more accurately, the attitude to sustainability that this tweet represents. It occurred during the recent Ecological Society of Australia conference, and went roughly thus*.

Good to see only vegetarian food at ESA2018. We know that it’s not possible to be truly in support of conservation unless you cut meat out of your diet.

Now for starters, I want to make it clear that I am 100% in support of eating vegetarian. For those of us fortunate enough to be living in relative affluence, vegetarian diets are easy to maintain, generally cheaper (based on personal experience), and have a proven positive impact on the climate. I’m not completely vegetarian, but I take a lot of steps to minimise my diet’s climate footprint. It doesn’t take much.

What I am not in support of is the idea that a person cannot possibly be a proponent of conservation and other ecological causes, or that their other efforts in support of a better world are futile, if one facet of their life does not align perfectly with minimising their climate impact. This attitude can come in many forms, from the above tweet, to your friends who yell “HA, hypocrite!” when they discover a stray plastic bag in your room or see you take a taxi instead of biking one day.

To underline my frustration with this attitude, let’s look at a now somewhat-famous study that came out in mid-2017. The paper was a meta-analysis which drew up a list of lifestyle changes in developed countries which had the highest carbon footprint. You can read a few summaries of the paper here and here, and the paper itself here.

In the study, switching to a vegetarian (or ‘plant-based’, as the study refers to it) diet was listed as the step with the sixth-highest impact. To highlight the problems with the attitude I’m arguing against here, let’s rephrase the above tweet using the step with the third-highest.

Good to see that everyone put the effort in and drove to ESA2018. We know that it’s not possible to be truly in support of conservation unless you find an alternative to flying wherever physically possible.

If this were true, then there would be a lot less attendees at conferences like this every year. Now for the step with the highest.

Good to see more non-parent ecologists at ESA2018. We know that it’s not possible to be truly in support of conservation unless you don’t have children.

No comment needed, I feel.

Now admittedly, the two above are substantially more impactful on an individual’s lifestyle that turning vegetarian. But I know a few ecologists who have several children, and I would never dream of accusing them of not being in support of ecological causes.

Furthermore, I believe the propagation of the idea that anything less than perfect is insufficient can dissuade people from making lifestyle changes. The following quote is from Voltaire, and I think it applies here quite well.

Don’t let the perfect be the enemy of the good.

Whether you’re an environmentalist, a conservationist, or an accountant, if you want to support the environment, absolutely you should encourage lifestyle changes to help reduce our impact on the planet. But please, let’s not spread the idea that anything less than total commitment is worthless.

*The tweet itself has been somewhat paraphrased. I do not wish for the ecologist who wrote it to be googled or messaged for obvious reasons. I have been assured by colleagues that they are a brilliant ecologist, and by no means intend to disparage their person by my disagreement with this one opinion.

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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