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FRATRICIDE. "Developing sinks export a factor that triggers senescence in target leaves." Sink leaves suck out the very last of the leaf nutrients from source leaves before the source leaves are allowed to be recycled in leaf litter. https://lnkd.in/dPac2Jv View in LinkedIn

COOPERATIVE STRATA. "We break down major transitions into two steps: the formation of a cooperative group and the transformation of that group into an integrated entity." http://www.pnas.org/content/112/33/10112.full View in LinkedIn

THREE IN THE BED. "Progressive or sequential senescence occurs during vegetative growth in herbaceous species when continued leaf production at the stem apex is frequently at the expense of the senescence of preceding leaves on the shoot. For example, in certain temperate pasture grasses, each vegetative branch (tiller) generally carries about three mature leaves at any given time, and every new leaf that appears must be balanced by senescence of the lowermost leaf." https://lnkd.in/dPac2Jv View in LinkedIn

ALL ABOUT INFORMATION. "A major evolutionary transition has been most broadly defined as a change in the way that heritable information is stored and transmitted." Think this over. http://www.pnas.org/content/112/33/10112.full View in LinkedIn

SHUNTING THE GOODIES. "Internal redistribution of N between sources and sinks can also account, at least in part, for other patterns of senescence. Before leaf fall in deciduous species, salvaged N is transferred to bark tissues, where it accumulates as defined storage proteins that will be mobilized to provide amino acids to support the resumption of growth in the spring." https://lnkd.in/dPac2Jv View in LinkedIn

REPETITIVE CHALLENGE. "The major transitions approach provides a conceptual framework that facilitates comparison across pivotal moments in the history of life. It suggests that the same problem arises at each transition: How are the potentially selfish interests of individuals overcome to form mutually dependent cooperative groups?" http://www.pnas.org/content/112/33/10112.full View in LinkedIn

AUTO-DIGESTION. "Young, actively growing vegetative sinks, and storage organs accumulating reserve proteins, have a rapacious appetite for N. When the demand cannot be met by import from the rhizosphere alone, N is withdrawn from older tissues. In extreme cases – monocarpic reproduction, for example – N remobilization from older tissues can occur on such a scale that the plant ‘self-destructs’." https://lnkd.in/dPac2Jv View in LinkedIn

LIFE AS A SERIES OF COLLABORATIONS. "In each transition, a group of individuals that could previously replicate independently cooperate to form a new, more complex life form. For example, genes cooperated to form genomes, archaea and eubacteria formed eukaryotic cells, and cells cooperated to form multicellular organisms." http://www.pnas.org/content/112/33/10112.full View in LinkedIn

TRANSITIONS. "Twenty years ago, Maynard Smith and Szathmáry revolutionized our understanding of life on earth by showing how the key steps in the evolution of life on earth had been driven by a small number of “major evolutionary transitions.” http://www.pnas.org/content/112/33/10112.full View in LinkedIn

SO ENDS this peek at falling leaves. The numerous variables that plants assess each autumn all go into the calculation of which date to start and to end the process of dropping the leaves. Each plant does its own mathematics. But what really is impressive is that while the dates of start and end vary each year, the species synchronization in that large habitat does not, and the autumnal march is invariably orderly. Not a single research paper can touch this hugely complex subject. View in LinkedIn