contingo

Joined 9 years ago

Karma
95
Submissions
36
Member since
Jun 28
evolutionary biologist into lifeform imaging and design (in a 3D graphics context)
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Comment · 3 years ago
But it's not a "hitherto conjectured form of symbiosis". It's just another example of facultative lichenization, which has already been observed in species quite widely scattered across the fungal kingdom. That to me doesn't count as a "new type of coexistence". The actual research behind the headline is valuable and entirely worthy of publication (I've made similar contributions myself), my critique relates to the headline, the angle of the reportage.
Comment · 3 years ago
I'm skeptical that this discovery amounts to a "new type of coexistence". Fungi that are facultatively lichenized (having growth forms that include or exclude algae) have been known about for a long time, as have various stages of sophistication of the lichenized condition. I can find references dating back to at least the 1980s that describe various kinds of facultative lichenization. The authors' insistence that the symbiosis is not a lichen just because the mycobiont (fungal partner) has a free-living form is suspect: previous literature makes no such distinction. The relevant distinction here is not between lichen vs. non-lichen, but facultative vs. obligate lichenization. The observation that the mycobiont can be free-living and "does not depend on its alga for nourishment" does not imply that it doesn't derive nourishment from its algal partner once the partnership is established.

There's no major news here that I can see. The main value of this research is simply that it provides the first description of facultative lichenization occurring in a particular group of under-studied fungi (corticioid basidiomycetes).

Comment · 3 years ago
From the article:

>The donated shoes that ended up in Indonesia have added to a flood of illegal second-hand clothing pouring into that developing country, according to a senior government official there, who said such cast-offs pose a public health risk, undercut its local textile industry and often pile more waste into its already bulging landfills.

Comment · 3 years ago
Comment · 3 years ago
It's woefully wrong for something in the primary literature. Yes, I understood what information they were sloppily failing to be precise about. If I were refereeing this paper I'd insist on a correction.
Comment · 3 years ago
From the introduction, which starts by trying to give some wider taxonomic context:

>The genus Ilex comprises about 450 species growing in the tropical regions of South America and Asia. Ilex trees are located exclusively in South America...

The roughly 500-600 species in the genus Ilex are commonly called hollies and include the European Christmas holly, I. aquafolium. The genus overall has a worldwide distribution over both tropical and temperate regions, there is no particular concentration of diversity in the South American tropics. Strange to get basic facts so wrong in the opening sentences.

Comment · 4 years ago
Comment · 4 years ago
The biological term "symbiosis", by itself, in the strict sense, doesn't imply a benefit for both parties, it just describes a persistent and physically close association between two species. Hence parasitism or commensalism are also forms of symbiosis and so are associations which are not obligate, but facultative (both bionts can live without the other, however prevalent the association). "Obligate symbiotic mutualism" is the category for what you're describing. "Endosymbiosis" implies such an integrated relationship that it is at least obligate for the endosymbiont. In this human-mite case there are various claims of benefits and drawbacks to humans from the relationship, and the symbiosis is certainly already obligate for the mites.
Comment · 4 years ago
Psilocybin-producing mushrooms are widely dispersed across the clade of all other true mushrooms and their genomes clearly show there is no great mystery about their evolutionary history or relationships to other fungi. Modern phylogenetics completely discredits panspermia as an origin for particular species or groups of fungi: they all share a single common ancestor and they are all connected to our single Tree of Life as with every other known lifeform on Earth.
Comment · 4 years ago
Tunicates evolved long before animals that you would recognize as typical vertebrates. In their free-swimming larval state, tunicates do have a "notochord", or nerve chord, running along their head-tail axis. This structure is a kind of proto-spine. The evolution of true vertebrates proceeded from this condition by neoteny, the retention of larval traits in the adult body plan. Pyrosomes look so bizarre compared to a layman's notion of what a chordate should look like because they are colonial aggregations of lots of individual adult tunicates that have resorbed their notochords (I'm pretty sure that's the case, despite what the photo description says).
Comment · 5 years ago
OK, I looked at some piano roll layouts in DAWs, and found examples with equal spacing between semitones, you're right.

I looked at some music mapped onto this layout. The layout allowed for speedy recognition of lone intervals and simple chords, but no more so than standard notation, and it was far worse than standard notation at showing any higher level musical content (the harmonic function of those intervals and chords in the context of the whole piece or local progression, polyphony and independent voices in general, counterpoint, organization of rhythms and cross rhythms, phrasing, larger compositional structures...). Also, because it's just a homogenous field of repeating piano octaves there is much less to positionally anchor the eye on as it reads through, like a staff with ledger and bar lines and key signature would provide to a fluent sight reader. All this musical meaning is stripped away and to reinstate it would be a case of painstakingly decoding the piano roll rather than just fluently reading the music.

I can see how this layout is really useful in a DAW for MIDI input and editing. As for learning the absolute basics of harmony, yeah it's accessible, if you can't be bothered to learn the basics of standard notation. After which point it's a dead end.

Comment · 5 years ago
It makes sense in the context of tonal harmony. An octave is the interval between the 1st and 8th notes of a major or minor scale. I.e. a major or minor scale repeats itself (at double the frequency) every eight notes. A major third is the interval between the first and third notes of a major scale, and so on.
Comment · 5 years ago
OK, I looked at some piano roll layouts in DAWs, and found examples with equal spacing between semitones, you're right.

I looked at some music mapped onto this layout. The layout allowed for speedy recognition of lone intervals and simple chords, but no more so than standard notation, and it was far worse than standard notation at showing any higher level musical content (the harmonic function of those intervals and chords in the context of the piece or a progression, polyphony and independent voices in general, counterpoint, organization of rhythms and cross rhythms, phrasing, larger compositional structures...). Also, because it's just a homogenous field of repeating piano octaves there is much less to positionally anchor the eye on as it reads through, like a staff with ledger and bar lines would provide to a fluent sight reader. All this musical meaning is stripped away and to reinstate it would be a case of painstakingly decoding the piano roll rather than just fluently reading the music.

I can see how this layout is really useful in a DAW for MIDI input and editing. As for learning the absolute basics of harmony, yeah it's accessible, if you can't be bothered to learn the basics of standard notation. After which point it's a dead end.

Comment · 5 years ago
I don't trust you. You're just used to thinking in terms of the piano keyboard. As I said before, the distance between two adjacent white keys on a piano roll could be a major second, or it could be a minor second. In other words the same distance encodes different intervals. You don't know which it is until you also examine the position of the black keys. A keyboard where the twelve semitones were actually equally spaced would not have groupings of two vs. three black keys. Looking at the adjacency of the keys trivial to do, but so is reading an accidental, which gives you additional information about the functional role of the pitch it alters.
Comment · 5 years ago
A piano roll visualization gives a somewhat more immediate depiction of intervallic information. But it isn't absolutely proportionately spaced, it's mapped to keyboard topology. Two neighboring white keys could be a major or minor second apart, etc. (And if real piano topology is shown, asymmetric positioning of black keys mean that identical intervals with one white key and one black key are different in span.)

In relation to the staff, pitches in standard notation are just as "proportionally spaced". Instead of squeezing in black keys, you have to squeeze in accidentals, but then accidentals are an extremely useful way of "showing how chords work", especially in the context of progressions in tonal harmony, which a piano roll gives you no meta-information about. It's less intuitive only in that you need some study to parse it fluently, at which point you gain the advantage of being untied to the layout of a particular physical instrument.

In any quest to "understand how music actually works", as soon as you take some baby steps beyond the basic alphabet of intervals, a piano roll visualization is going to hold you back.

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