Protagoras said that man is the measure of all things and, although he was wrong, his sentence rings true, because we cannot deny that we like to take ourselves as a reference for everything.. What is bigger than us is great and what we surpass is small, for example, and, in a way, it is because we live on our own scale. We surround ourselves with objects made to measure, prepared for humans. Our companion animals are “manageable” and, whether small or large, do not occupy extremes on the tree of life. No one has a whale or bacteria as pets. So here we live, not paying too much attention to the fan of reality that falls outside our bubble.
That is why it is so complex for us to estimate certain things. For example, you may have heard that most of the world’s biomass is made up of plants and insects, and it’s true in a way, but it’s not exactly true. A new study has revealed that, if we take into account the added weight of different sets of life forms, microorganisms would predominate, well above insects and, along with them, trees, not plants in general, but trees. . Suddenly, life appears as two extremes of size, that of the tiny and that of the enormous, two realms between which stretches a wasteland of the mediocre, much less frequent and in which, in a way, we are. . Our scale is no longer the scale of life, we are not the measure of all things, far from it, we are an anecdote in the immensity of the biosphere.
All of this is true, although we may have been too hasty with those last statements. They are partly correct, we are not at those extremes of size that stand out for their contribution to biomass. However, we’re not particularly close to the middle ground between the microscopic and the titanic, either. In any case, we would be closer to that upper limit and we could consider ourselves part of that group of great beings that populate the Earth. It all depends on where we put the limits and what we want to study (or compensate). This is possibly the first truly exhaustive study in this line of research, and this strange trend raises questions for which we still don’t have answers. For example: why this strange preference for extremes?
In theory, what would be expected would be that life forms would be distributed more or less evenly among the different possible sizes. More than anything because we do not know factors that can tip the balance for some scales over others. So what is happening? What detail are we missing? In fact, the study reveals another disturbing detail, because it seems that this tendency to extremes also occurs among other groups of living beings and, what is more, it seems that the largest species crowd around a kind of limit. , a maximum measure above which we do not find other forms of life. There we find marine mammals, trees, giant mushrooms, etc.
We could sketch any number of hypotheses as to why these size extremes represent so much biomass of life, but all of that would be speculative. There are too many possible explanations and not enough data to make us decide between them. Could it be due to a question of energy efficiency? Could be. And, in part, we may clarify it if we do similar studies where, instead of relating size to biomass, we relate it to the number of individuals of each species and, on the other hand, to the number of species in each size range. . In the article they suggest that there are certain limits to the size of organisms and, in part, it is so.
It’s hard to imagine anything much smaller than a microbe. And, at the other extreme, it must be recognized that it is structurally complex to reach sizes equivalent to those of a sequoia, as well as exceeding them. In this sense, it is logical that, of the infinity of possible sizes, they crowd around the extremes, because they are incapable of transgressing those limits by becoming larger or smaller. Added to this question are others such as that, apparently, this tendency to extremes is more pronounced in terrestrial organisms than in marine ones. Other aspects of this size distribution will have to be studied and, possibly, along the way we will discover unexpected aspects of our own nature.
DON’T GET IT:
- Biomass is an interesting way of studying how life is distributed based on resources, how much each species consumes. It is not perfect, but it is indicative. Because, in that way, we can more or less establish a conversion between billions of ants and a hippopotamus. However, it is not everything, and it is interesting to analyze this size distribution from other perspectives.
- The sizes of life PLOS ONE 10.1371/journal.pone.0283020