Facts that seem both important and underappreciated. There's not much here yet.

Physiology, Ethology

Obesity often has an viral origin (infectobesity).

Adenovirus serotype 36 (AD-36) is present in around 30% of obese people and 11% of non-obese Americans, and is known to cause obesity in multiple species, including chickens, mice, rats, and monkeys. It is thought to increase preadipocytes by inducing cell differentiation.

Crows are capable of self-reflection, and show signs of consciousness.

Quote: "Research unveiled on Thursday in Science finds that crows know what they know and can ponder the content of their own minds, a manifestation of higher intelligence and analytical thought long believed the sole province of humans and a few other higher mammals."

Psychology, Neuroscience

No congenitally blind person has ever been diagnosed with schizophrenia.

Link, referenced study. Low sample size for the relevant finding, but significant.

Congenital and/or early peripheral blindness (loss of side vision) is highly protective as well, though not completely.

Over 90% of schizophrenic Americans smoke.

Overview, Wikipedia. Statistic is taken from 2006, and base rate was 20%.

It is thought to be related to an increase of nicotinic receptors found in smoking, as well as a method of correcting the lowered dopamine levels found in the prefrontal cortex.

Genetics, Microbiology

Genes compete within organisms for reproductive dominance.

The takeaway: evolution happens on multiple levels of organization simultaneously. One manifestation of intragenomic conflict is meiotic drive, where "one or more loci within a genome will effect a manipulation of the meiotic process in such a way as to favor the transmission of one or more alleles over another, regardless of its phenotypic expression" (violating the principles of Mendelian inheritance).

Viruses can be altered so as to become "invisible" to immune systems, and therefore near 100% fatal.

Overview, paper. Demonstrated in mice, obviously not tested in humans.

When mousepox is modified by adding code for the cytokine (protein used in cell signaling) interleukin 4 (IL-4), it is capable of killing mice vaccinated against mousepox. IL-4 is thought to serve as a possible "protein cloak" for viruses; it is likely that research on this cloak is ongoing, but kept from the public. Try it at home!

The most common organism in the world is also the simplest.

Pelagibacter ubique is thought to be the most common (non-viral) organism in the world, and, aside from intracellular symbionts and parasites, has the smallest genome, at 1.3M base pairs. Because nitrogen is difficult to acquire, P. ubique uses the A/T base pairs more often than C/G (70% of all), as they have less nitrogen.

If you're willing to call viruses organisms, then this isn't true anymore: we have to look at bacteriophages, which outnumber all other organisms combined. Pelagibacter ubique has its own bacteriophage, HTVC010P, but this is not the smallest virus; porcine circovirus is composed of only 1759 nucleotides. But there are smaller self-replicating elements, such as viroids.

Life evolves to get better at evolving.

A common mechanism for this is life finding new ways to undermine "simplicity assumptions", such as the assumption that DNA is fixed in place in the genome, becoming efficiently rhizomatic.

• Examples

Mathematics, Physics

Every cohomology theory reduces to the study of connected components in the hom-space of some $(\infty,1)$-topos.

This is straightforward for representable cohomology theories such as singular cohomology (by Brown representability, all generalized cohomology theories w/ spectra), but holds for more complex things such as motivic cohomology, which classifies connected components in the $(\infty, 1)$-topos of $\infty$-stacks on the Nisnevich site.

All major diagonalization arguments are subsumed by Lawvere's fixed point theorem.

nLab.

This includes Gödel's incompleteness theorem, the halting theorem, and Cantor's theorem. The theorem: if in a Cartesian closed category there is a morphism $\phi: A \to B^A$ such that every point $q: 1 \to B^A$ is given by $\phi \circ p$ for some $p: 1\to A$, then every morphism $f: B \to B$ has a fixed point $s: 1\to B$ with $f \circ s = s$. From this we can infer, for instance, a generalized Cantor theorem: in a topos $\mathcal E$ with subobject classifier $\Omega$, there is an epic $X \to \Omega^X$ only if $\operatorname{true} = \operatorname{false}$ in $\mathcal E$'s internal logic.

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