The role of trade-offs in the evolution of senescence

剧透警告：我们都会死！死亡在所有生物体中都是不可避免的：从细菌到我们人类，再到千年的狐尾松。然而，衰老研究的关键问题并不是终点——死亡，而是在我们到达终点之前，我们的身体发生了什么。具体来说，为什么我们在死前会变得更加脆弱和衰老？死亡风险的增加和生育率随着年龄的增长而下降，即所谓的衰老，对我们的一生议程产生了强烈的影响：我们从学校毕业、结婚生子、找到一份固定工作并退休的年龄，仅举几例。所有这些都是我们生活中的关键事件，由政府根据每个国家人口的衰老率估计而确定。当衰老稍微慢一些，就像北欧国家那样，政府开始考虑减少每周工作时间，同时推迟退休年龄的想法，就像德国和丹麦目前正在激烈讨论的那样。准备好嫉妒吧：事实证明，衰老并非普遍存在！有些动物和植物没有这种感觉。然而，从衰老研究的早期开始，解释衰老发生的主要理论都将衰老本身视为不可避免和不可避免的。我和我的同事最近在《自然》杂志上发表了一篇文章，反驳了生命史理论的这一基本原则。我们已经证明，事实上，大多数植物和许多动物物种并没有随着年龄的增长而变得更加衰老。这一发现彻底改变了老龄化研究的历史方向。参与衰老研究确实是一个特别激动人心的时刻，因为我们的发现引发了范式转变，迫使衰老研究从“我们为什么会衰老”的问题转向“为什么以及如何一些物种会衰老，而另一些却不会？”你想知道人类为什么会衰老吗？我们先离开一下，看看其他物种是如何避免衰老的呢？我的研究将考察动物和植物物种衰老或逃避衰老的机制。我将确定一个物种的解剖学、生理学、栖息地和进化历史的各个方面，这些方面使它或多或少容易衰老。为此，我将研究生理和宏观进化权衡在整个生命之树的进化或衰老逃避中的作用，从我在过去十年中开发的数据库中检查2000多种动植物物种的衰老轨迹，以及一组具有复杂生活史的物种的长期人口统计数据集，如食肉植物或具有长期休眠能力的兰花（如熊）。这项研究的发现可能会精确地指出栖息地、非生物条件和分类群的特征，这些特征使物种能够在更长的时间内以高绩效水平运作。

Spoiler alert: we are all going to die! Death is certain in all organisms: from bacteria, to us humans, and to the millenarian Bristlecone pines. However, the driving question in ageing research is not so much the end point, death, but rather what happens to our bodies before we reach that destination. Specifically, why do we become more fragile and decrepit prior to death? This increase in mortality risk and decline in fertility with age, known as senescence, has a strong influence on our lifetime agenda: the age at which we graduate from school, are expected to get married and have babies, get a permanent job and retire from it, to mention just a few. All of these are critical events in our lives that are established by governments using, among others, estimates of senescence rates of each country's human populations. When senescence is a bit slower, as in Northern European countries, and governments start to contemplate the idea of reducing the number of work hours per week while postponing the age at retirement, as it is currently being hotly debated in Germany and Denmark.Get ready to be jealous: it turns out that senescence is not universal! Some animals and plants out there do not experience it. Yet, since the early inception of ageing research, the main theories to explain the occurrence of senescence have treated senescence itself as unavoidable and unescapable. My colleagues and I have recently disproved this fundamental tenet of life history theory in a publication in Nature. We have shown that, in fact, most plants and many animal species do not become more decrepit as they age. This finding drastically reshapes the direction that ageing research has taken historically. It is indeed a particularly exciting time to partake in ageing research because our finding has provoked a paradigm shift, forcing ageing research to move on from the question "Why do we senesce?" towards "Why and how do some species senesce but others do not?".Do you wish to understand why we humans age? How about stepping away for a bit and examining how other species manage to escape senescence? My research will examine the mechanisms by which animal and plant species senesce or escape senescence. I will determine the aspects of a species' anatomy, physiology, habitat and evolutionary history that make it more or less vulnerable to ageing. To do so, I will examine the roles of physiological and macro-evolutionary trade-offs in the evolution or escape of senescence across the tree of life examining senescence trajectories in over 2000 animal and plant species from a database that I have developed in the last decade, and a set of long-term demographic datasets of species with complex life histories such as carnivorous plants or orchids with the ability of long-term dormancy (like a bear). Findings from this research are likely to pinpoint the habitats, abiotic conditions and features of taxonomic groups that allow species to operate at high performance levels for longer.