Month: September 2022

NON-ADAPTIVE TRAITS. "Charles Darwin observed that many traits are a consequence of descent from a last common ancestor that are themselves the products of earlier, presumably adaptive evolution. Darwin maintained that currently adaptive traits can and do co-exist with highly conserved traits having no apparent adaptive purpose." http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

TRAIT GHOSTS. "It is undeniable that some shared ancestral traits have been conserved long after their initial adaptive significance has vanished." http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

LETHAL LOSS OF TRAITS. "The typical explanation for the conservation of ancestral body plan traits is the presence of pivotal developmental processes whose mutation would be difficult or impossible for process so basic to how an organism achieves its organized growth that any significant deviation would result in death or severe impairment." http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

LETHAL TRAIT LOSS IN PLANKTON. "The so-called spiral determinate cleavage of many planktotrophic spiralian species so rigidly casts the fate of each embryonic cell early in the four- and eight-cell stage of embryo development that it is difficult (although not impossible) to imagine that mutations causing this embryology to deviate from the norm would be anything but lethal." http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

GENETIC SUPER-HYBRIDS. "The evolution of plant body plans is far more complex than that of animals because the organisms called plants are polyphyletic" (from many origins genetically). http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

MASSIVE ENDOSYMBIOSIS. "Rather than constituting a single clade that can be traced back to a single last common ancestor, plants (i.e. eukaryotic photoautotrophs) have multiple evolutionary origins presumably as a consequence of primary endosymbiotic events, giving rise to lineages like the Chlorophyta, or as a result of secondary endosymbiotic events, giving rise to others like the euglenids and chromists." http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

MASSIVE LATERAL GENE TRANSFERS. "This early phase in plant evolution, which involved extensive lateral gene transfer among pro- and eukaryotic unicellular organisms, was followed by one characterized by increased genetic isolation and divergence." http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

MAJOR RADIATION COMPLETED. "By late Mesoproterozoic or early Neoproterozoic time, the major radiation events distinguishing modern-day eukaryote lineages had already taken place." http://aob.oxfordjournals.org/content/85/4/411.full.pdf View in LinkedIn

SO ENDS this first of two weekends on plant body plans. Plants may as well have come from Mars biologically speaking, for they differ from animals so markedly. And although it is unfortunate that the animal maze term ‘plant intelligence’ has been used to describe their ability to predict, anticipate, and react to circumstances, which has caused an uproar in the Luddite community, these creatures without neurons clearly have the ability to cogitate in sophisticated ways. View in LinkedIn

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