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Evolutionary biologists invert the scientific principle

In science, methodological neutrality is expresed by the null hyptothesis, namely that every relationship between phenomena is, by default, the fruit of chance. The burden of refutation weighs on the researcher. You don’t have to prove innocence of justify chance.

Evolutionary biologists invert the principle: being selected is the default state, and a chance result is the outlier. There is a presumption of selection in nature, so a biologist is exempt from proving it. Instead, the burden of the proof lies on whoever claaims that a trait or a size was not selected. The time is ripe for biologists to embrace the ways of their fellow scientists and accept the null hypothesis: chance, which is to day, neutrality. Doing so does not imply rejection of natural selection, an indefensible stance. What it does imply is the rejection of natural selection as the default state in nature.

Der intuitive Geist ist ein Geschenk...

Einstein:

Der intuitive Geist ist ein Geschenk und der rationale Geist ein treuer Diener. Wir haben eine Gesellschaft erschaffen, die den Diener ehrt und das Geschenk vergessen hat.

Darwinian bias toward natural selection is baked into popular understanding

Because the Darwinian bias toward natural selection is now baked into popular understanding of evolution, it is not enough to tell the truth, nothing but the truth, but also to tell the whole truth. Rather than presume and seek out a selectionist explanation for what most likely are neutral traits, biologists might presume the ubiquity of the latter even as they marvel at the exceptions. And they might talk about it in public. Doing so would make an immense difference. Differential algebra, organic chemistry, and optical physics have no impact on our worldview; the theory of evolution does. When specialists in these other fields realize that they have been operating on the basis of unsound presuppositions, the corrections tend to stay “in house.” Their fields are torn down and rebuilt, but the rest of us are unperturbed. By contrast, Darwinian and neo-Darwinian ideas such as survival of the fittest, optimization, adaptation, and Malthusian competition reverberate in the way we experience reality, society, and ourselves. It follows that when these ideas misrepresent nature, they weigh heavily on our self-representation.

Darwin would not be published in Nature today

“Scientists apply themselves to what they believe to be the most important of the problems that seem tractable,” the Nobel Prize-winning biologist Francois Jacob wrote; “those that rightly or wrongly they think they will be able to solve.” Peter Medawar, another biology Nobelist, calls science “the art of the soluble.”

From the pre-Socratics to Bacon to Darwin, natural philosophers have not been so constrained. Philosophy begins in wonder, Socrates and Aristotle said, and whatever fills us with wonder deserves to be explored. Or, to use Martin Heidegger’s terminology, philosophers need not be limited to questions that are answerable (fraglich) via a consensual protocol of proof and refutation. They can work on questions worth asking (fragwürdig) even in the absence of such a protocol.

It is regrettable that only answers to fraglich questions get published in scientific journals, because the fragwürdig questions are the sort that set and reset paradigms. Democritus had no way to prove the atomic theory, and Darwin had no way to prove the common ancestry of all organisms. Democritus inferred his theory from the differential solidity of substances: since iron is more solid than water, the two must comprise different components. Darwin relied on analogy, a fortiori arguments, deduction, common sense, and personal experience. Particularly imprtant to him was a maxim learned from his mentor, the geologist Charles Lyell: The present holds the key to the past; the same process now governing nature have always done so. Democritus’s inference could never grace an issue of Science. Nature, founded in 1869 by Darwin’s inner circle to promote the master’s ideas, would not publish his papers because they were based on random observations, secondhand information, and primitive experiments.

The mycorrhizal tragedy of the commons

Abstract

• trees trade C for N with mycorrhizal network
• this network is the “commons”, part of the tragedy
• trees gain additional N et the expense of neighbours by supplying more C to fungi
• this can lead to increased N immobilization (in fungal biomass)

Introduction

• ectomycorrhizal fungi (EMF) hold N back from trees when they are in need
• when N supply is amended by fertilization, also EMF give away greater proportion
• further supply of EMF with C makes them diminish N returns
• fungus competes with other EMF symbionts of the same plant, can gain more C by exporting more N, until personal N matches its received C
• receiving more C makes EMF use more N for itself
• enhanced EMF growth initially increases N uptake, but eventually N immobilization in fungal biomass; negative feedback on plant’s N uptake

• How can this negative feedback made it through evolution?

• dual scale of ectomycorrhizal symbiosis: one tree, many fungi and many trees, one fungus
• trees have optimize individual benefit, this has consequences for other trees connected through the fungal network
• combined efforts of trees to increase individual N gain aggravates N immobilization in fungal biomass

Hypothesis

• fungus shares greater N proportion with trees that deliver more C
• tree delivers more C to fungi that supply more N
• tragedy from tree viewpoint: total C export to all fungi so high that it leads to N immobilization
• tragedy from fungus viewpoint: exporting more N would reduce own growth, exporting less N reducec competitiveness for plant C
• plants share common N pool, optimizing for individual gain hampers comunity gain
• experiments with plant strangling and shading

Materials and methods

Seedling experiment

Field experiment

Model description

Results

• shaded less biomass than sun, strangled no effect
• shaded plants more N than sun plants, strangled plants way less: decreased C export to fungi mobilizes soil N to the plant and vice versa
• maximum network-scale N mobilization occurs at intermediate level of network-scale C export
• at individual tree level: 1 more C supply leads to 0.95 more N return, hence there is competition among trees which will eventually make network-scale N mobilization drop

Discussion

• tragedy of the commons: individual gain reduces community gain
• there is one common N pool all trees draw from (common EMF network, in which multiple fungi connect the host plants)
• elevated atmospheric CO$_2$ levels should lead to higher N immobilization, more fungal biomass growth, maybe less tree growth

The carbon costs of global wood harvests

Abstract

• counting newly grown wood from harvested forests as extra is wrong because this growth would also happen without harvesting
• harvesting forests leads until 2050 to additional eCO$_2$ in the realms of land use change due to agricultural expansion

Main text

• depending on how you count, harvesting wood might not be just C neutral but even benefit the climate
• reporting at national level allows countries to look C neutral
• harvesting should decrease this benefit, but is not reported separately
• net increase in forest C makes countries appear to have no emissions
• reporting net effects of new wood harvests and regrowth from previous harvests leads to similar effects (no identification of effects of new wood harvests alone)
• appears that harvesting in temperate countries is beneficial and in tropical countries it is costly (in terms of climate)
• wrong accounting: Growth that would occur anyway cannot offset harvesting costs.
• so far: mostly spatial offsetting, or offsetting with past growth
• possible: offsetting with what grows in the same place after the harvest
• harvests lead to short-term emissions and undermine Paris Agreement

Accounting for time in estimation of GHG costs

• CHARM (carbon harvest model): new global forest C model
  • live vegetation, roots, slash, different wood products and landfills
• computes annual difference in scenarios: forest would have grown, forest is harvested
• emissions discounted with 4% per year: the earlier the heavier
• SCC (social carbon costs): for instance cost for mitigation might decreaste with better technology
• mitigation now is more valuable (costly), already included in the discount
• discount can be seen as interest rate for companies on today’s emissions, they will have to pay back more later

Growing wood demand

• long-lived wood products (LLP): sawn wood, wood panels, and other industrial roundwood
• short-lived wood products (SLP): paper and papaerboard products
• very-short-lived products-wood fuel (VSLP-WFL): wood harvedted deliberately for energy
• very-short-lived products-industrial (VSLP-IND): waste from manufacture of other wood products, burned for energy
• wood harvests will increase by 54% globally between 2010 nd 2050, mostly SLP; VSLP-WFL most uncertain
• substituton effects for steal and concrete
• “clear-cut-equivalents”: area necessary by clearcutting to get the same amount of wood
• nice flow-chart of wood products

Robustness of results

• 3-5 GtCO$_2$e per year
• probably conservative: effects of harvests on soil C not counted: meta-analyses show quite some soil C loss
• indirect effects such as road building ignored (can be several times direct effects)

Insensivity to discount rate

• robust if society has a small preference for short-term over long-term mitigation

Meaning of economic effects

• Compare harvesting with no human activity instead of another human activity such as land use change, otherwise you are covolving numbers.

A potential mitigation option

• harvesting comes with carbon costs, offsetting is usually done in wrong ways
• comparing them with land-use change due to agricultural expansion makes costs disappear, because costs are about equal
• No harvesting mitigates climate change.
• Later, mature forests might sink in C slower, but no harvesting now would buy us time.

Thank you. This I'm used to.

And then you are here. You are simultaneously engaged in her conversation and thinking about something else; she both gives herself to you and does not give herself to you; you find her objectionable and you deeply love her; she worships you and wonders what she might have missed with someone else.

“Thank you,” you tell the angel. “This I’m used to.”

The secret codes of life

The secret codes of life - whether presented as a gift or a burden - go totally unapreciated. And once again the Rewarder and the Punisher skulk off, struggling to understand why knowing the code behind the wine does not diminish its pleasure on your tongue, why knowing the inescapability of heartache does not reduce its sting, why glimpsing the mechanics of love does not alter its intoxicating appeal.

Scales

And God suddenly bolts up in His bed with a revelation: everything that creates iself upon the backs of smaller scales will by those same scales be consumed.

Meaning varies with spatial scale

Do you think it would have any meaning at all if you displayed of of your your Shakespearian plays to a bacterium? Of course not. Meaning varies with spatial scale. So we have concluded that communicating with her is not impossible, but it is pointless.