Extreme warming events may sound like bad news to reindeer, but they could help increase population stability (Image Credit: Christopher Michel, CC BY 2.0, Image Cropped)
More frequent extreme climate events stabilize reindeer population dynamics (2019) Hansen et al., Nature Communications, https://doi.org/10.1038/s41467-019-09332-5
Whilst climate change has been causing (and will cause) a myriad of environmental problems, it’s important to remember that not all species will be negatively affected by more extreme weather events. One example is reindeer on the Arctic island of Svalbard, according to this week’s paper.
Taken at face value, an increased frequency of extreme warming events may not sound like a good idea for a cold-adapted species. But despite the fact that it can lead to rain falling and freezing over snow, rendering massive patches of food inaccessible, the authors show that this can actually lead to increased population stability.
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, Pixabay licence, Image Cropped)
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
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.