$$ Eubacteria

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Well, I admit it: I am just not as interested in microscopic organisms as visible ones, and thus am as guilty as anyone of taxonomic chauvinism. I just want to be able to look at stuff and draw it; that’s my excuse. What’s yours?

Couldn’t find any MICROBES so I drew some cashews

But I am working on it. I’m learning and/or relearning lots of fascinating stuff about Eubacteria and Archaea, two of the three domains of life. For one thing, some of them engulfed others of them to create the ancestors of the third domain, the more interesting one that includes everything from algae to avocado to fungi to fish to humans. Eukarya!, as Archimedes remarked, or something like that.

Before I bring this note to a close, I know what you're thinking. Why is the hybrid domain called Eukarya, when “Euchaea” would have made a much better portmanteau of the words Eubacteria and Archaea? It is too bad that we are not in charge.

Climbing around the tree of life

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Quercus rubra

I’m systematically studying systematics—how all living things on Earth are related in a tree of life.

I claim to have a system. But I’m not one to stick to recipes. Rather than ascending the tree in an orderly fashion, I tend to backtrack and change directions, jump squirrel-like to distant branches, and sometimes fall off. More time is spent on tangents than actual taxonomy.

But I know the tree is there; I can come back to it. It’s a guidepost, a framework. It keeps contained and organized a vast realm of biological inquiry that would otherwise be completely overwhelming. It’s a lot like my 3,400-item hierarchical to-do list, which I edit and reshuffle ad nauseam while only occasionally completing an actual task. As mighty as my “Workflowy” list undoubtedly is, the tree of life has it beat with something like 1.8 million species described and 10 million estimated—or maybe 3 trillion, if that makes a difference—not counting untold oodles of extinct ones.

Something I find exciting about this tree is that it’s a new way to orient oneself as a naturalist, despite the fact that the biodiversity it encapsulates is 4 billion years in the making. We may have been identifying and categorizing living things for the entirety of human existence, but we have only had the concept of an evolutionary tree since around the time of Darwin. And the tree itself has evolved dramatically as taxonomists hone the ability to compare organisms at a molecular level. Only within my lifetime has it grown into its current triadic shape, dividing life on earth into three major superkingdoms or domains or whatever you want to call them: Eubacteria, Archaea, and Eukarya. (I’ll elaborate on this somewhat in the next post, if I stick to the recipe, at least.)

Tamiasciurus hudsonicus

As we speak, phylogeneticists in our midst are pooling information from 4,185 studies and 148,876 species and counting in the effort to refine not only the branching patterns of the tree but also the timing of those splits between lineages, some of which diverged hundreds of millions of years ago. Regardless of how accurate all of that is at this point, I like having such a tree to think about. It lends an expansive dimension of time to the landscapes and living things I see spread out over global space. It gives me a sense of the familial relationships that intersect with the ecological ones I can observe myself. It’s a Y axis to my X axis of wandering around outside sketching stuff. Lest we fall out of the tree prematurely, I’ll stop here.

Mismatches from climate changes

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I drew this to illustrate another Forum paper for the scientific journal Oikos. Here is a summary of the study, “Why sex matters in phenological research” (by Nakazawa et al.):

As climate change shifts the timing of the seasons, it messes with different organisms in different ways—which can disrupt the way they interact. A predator might emerge before its prey does, for example, creating a trophic mismatch. Males and females of the same species can get out of whack, too, to the potential detriment of the next generation.

These Forum authors confront that idea of “sexual mismatch,” pointing out that males of many species gear up for mating before females do—or vice versa—as each sex responds differently to environmental cues. Their model shows that both sex-specific timing and trophic timing play important roles in the dynamics of a population.

But their literature reviews find that sex-specific information from the real world is scarce. Among other data limitations, studies of breeding cues tended to be male-biased for birds and mammals and female-biased for fish and insects. Notably, males had more variable timing than females for several species where the two sexes look different from each other—contrary to a conventional view that females are more likely to shift their timing.

Speculating that sexually dimorphic species may be especially vulnerable to a changing climate, the authors outline a more sex-conscious research agenda for the future (including collecting sex information during population monitoring, and using eDNA to gauge sex ratios) to better understand the ecological impacts of climate change.