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SELECTION OF THE FITTEST. "We argue that competition between genetically identical cells could improve the fitness of a multicellular organism by directing fitter cells to the germ line or by eliminating unfit cells, and that cell-competition mechanisms have been conserved in multicellular organisms. We propose that competition between genetically identical or highly similar units could have similar selective advantages at higher organizational levels, such as societies." https://lnkd.in/dXdwAzF View in LinkedIn

NUTRIENT COMPETITION. "To grow faster, plants must allocate more resources, primarily nitrogen, to photosynthesis. Nitrogen is one of the most important limiting resources for plant growth in nature, and most leaf nitrogen is allocated to photosynthesis. Small changes in nitrogen allocation can greatly influence light-saturated photosynthetic rate (Pmax) and photosynthetic nitrogen-use efficiency (PNUE), and therefore plant performance. Leaf nitrogen that is not allocated to photosynthesis is generally used structurally in cell walls, a component of plant defense and chemical defenses." https://lnkd.in/dM3QBWR View in LinkedIn

SINKS TRUMP SOURCES. "A semelparous plant dies because its sink tissues kill its source organs by a kind of starvation, by induction of senescence in response to nutrient diversion or by export of a ‘death hormone'." (Semelparous organisms have only one reproductive episode before death). https://lnkd.in/dPac2Jv View in LinkedIn

NUTRIENT SOURCES. "Organs that supply the precursors for sink metabolism are sources. Sources and sinks communicate through the vascular system. During development of the endosperm of cereal grains and the parenchyma of potato tubers, large amounts of starch are accumulated. These organs are supplied via the phloem with assimilated C mostly fixed by current photosynthesis." (C = carbon), https://lnkd.in/dPac2Jv View in LinkedIn

NUTRIENT SINKS. "A sink is defined as a net importer of nutrients (nitrogen (N), phosphorus (P), potassium (K), sulfur (S) and other minerals) and assimilates carbon (C) derived directly or indirectly from photosynthesis. Developing seeds, bulbs, tubers and other structures that accumulate storage compounds are strong sinks, as are expanding leaves and branches during vigorous vegetative growth." https://lnkd.in/dPac2Jv View in LinkedIn

BASIC DOGMAS. "For more than a century the basic tenets for the advantages of sexual reproduction have been that it can serve to (i) generate progeny with a diversity of novel genotypes and (ii) purge the genome of deleterious mutations, such as transposable elements, which otherwise would accumulate inexorably via Muller’s Ratchet to degrade the integrity of the genome." http://www.mycologia.org/content/105/1/1.full View in LinkedIn

COST-BENEFIT RATIO. "Most higher eukaryotes engage in sexual reproduction, at least part of the time." http://onlinelibrary.wiley.com/doi/10.1002/ece3.1516/full View in LinkedIn

BENEFITS OF SEXUAL REPRODUCTION. "Given the ubiquity of sexual reproduction, combined with the fact that the few known truly asexual lineages appear to be of relatively recent origin and therefore may be doomed to more rapid extinction, it is expected that sex must confer benefits." http://www.mycologia.org/content/105/1/1.full View in LinkedIn

SPECIES AS UNIT OF SELECTION. "However, despite numerous experimental studies, such pressures in favor of sexual lineages have never been demonstrated. It would thus be a selection at the species level: a selection for species unable to lose sex because of constraints, and not a short-term advantage of sex." https://lnkd.in/dV7ZdGm View in LinkedIn

THE FECUNDITY OFFSET. The conundrum for facultatively sexual organisms: “Why engage in sex if very few of your progeny might even attain the well adapted genotype of either parent? One way to obviate this cost is to have very many progeny, such that at least one approximates the fitness of the most fit parent." http://www.mycologia.org/content/105/1/1.full View in LinkedIn