Month: September 2022

SO ENDS this contemplation of the anatomical structures underlying the human face that are responsible for the nuanced human expressions, and the function of these expressions in humans and other primates for social cohesion. This is a prime example where “nothing makes sense except in the light of evolution.” Comparative phyolgenetic studies illuminate the reasons behind things and how muscles that started life for orifice control, end up with a social role later in evolution. View in LinkedIn

CONCEPTUAL ROOTS. “The multi-cellular eukaryote concepts of “species” and “individual” are deeply embedded in most efforts to characterize and measure biodiversity. Most multi-cellular eukaryote diversity metrics are defined in terms of “species diversity” over some spatio-temporal range, and much raw biodiversity-measurement data consists of observations of the occurrence of a single individual of a particular species at a specific point in space and time.” https://standardsingenomics.biomedcentral.com/articles/10.1186/s40793-016-0180-8 View in LinkedIn

WRONG TEMPLATE. “Multi-cellular eukaryotes-oriented concepts of species and individual cannot be applied meaningfully to prokaryotes.” https://standardsingenomics.biomedcentral.com/articles/10.1186/s40793-016-0180-8 View in LinkedIn

WRONG SCALES. “The case can be made that prokaryote populations operate on such incomparably different spatio-temporal scales that it is difficult to describe a “specific point in space and time” in a way that applies equally effectively to multi-cellular eukaryote and to prokaryote populations.” https://lnkd.in/ewnQ9Vg View in LinkedIn

TWO TIME SCALES. “If one were to go into any multi-cellular eukaryote ecosystem, pick a species at random, kill off 99.9 % of its population, and then measure how long it would take the species to recover, the result might be a year or more for a mouse, and a century or more (if then) for elephants. For some prokaryotes, the time to recover from a 99.9 % population cull could be 24 h or less.” https://standardsingenomics.biomedcentral.com/articles/10.1186/s40793-016-0180-8 View in LinkedIn

DOMINANT POPULATIONS. “From a biodiversity perspective this means that, in principle, a rare prokaryotic species (say, 0.1 % of the population) could become the dominant species (say, 90 % of the population) in a very short period of time. Some recent reports suggest that this does in fact occur in natural populations.” https://standardsingenomics.biomedcentral.com/articles/10.1186/s40793-016-0180-8 View in LinkedIn

ECOSYSTEM SUCCESSIONS. “These findings suggest that microbial ecosystems may routinely and rapidly undergo profound changes in community structure that, for multi-cellular eukaryotes, would be described as a major ecological succession. Among multi-cellular eukaryotes, however, a major ecosystem succession may take years, decades, or even centuries, whereas dynamic changes in microbial communities may well occur over hours or days.” https://standardsingenomics.biomedcentral.com/articles/10.1186/s40793-016-0180-8 View in LinkedIn

GENE PARADIGM SHIFTS. “Biology is no stranger to paradigm shifts. Before the advent of molecular biology, classical genetics was based on the notions that genes are the fundamental units of mutation, of recombination, and of heredity, and that they are arranged on the chromosomes like beads on a string. New insights, generated by molecular analysis, forced a recognition that there were, in fact, no fundamental units, no beads, and no string.” https://lnkd.in/ewnQ9Vg View in LinkedIn

UNIT PARADIGM SHIFTS. “Similarly, before metagenomic tools allowed us to see the prokaryotic world, classical biology held that individual organisms are the fundamental units of ecology, of evolution, and of biodiversity, and their evolutionary history could be explained by arranging them into objectively real, lineage-defined groups, with the groups composed into a single-rooted tree.” https://lnkd.in/ewnQ9Vg View in LinkedIn

NEW WORLD VIEW. “New insights from molecular analysis are forcing a recognition that there are, in fact, no completely objective individuals, no unique lineages, and no one true tree, at least in the quantum realm of prokaryotic dark matter,” and no fundamental gene units, no gene beads, and no gene strings. https://standardsingenomics.biomedcentral.com/articles/10.1186/s40793-016-0180-8 View in LinkedIn