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IMMORTAL BACTERIA. "Bacteria are said to be biologically immortal, but only at the level of the colony. An individual bacterium can easily die. The two daughter bacteria resulting from cell division of a parent bacterium can be regarded as unique individuals or as members of a biologically "immortal" colony. The two daughter cells can be regarded as "rejuvenated" copies of the parent cell because damaged macromolecules have been split between the two cells and diluted. In the same way stem cells and gametes can be regarded as "immortal"." http://en.m.wikipedia.org/wiki/Biological_immortality View in LinkedIn

SO ENDS this second weekend contemplating the curious orchid family. The exacting fieldwork that has gone into teasing out these nuanced features of orchid deceptive reproduction are exemplars of excellent observation skills and hypothesis testing, in often uncomfortable conditions. The results, spread over hundreds of publications, are quite dazzling. The orchid has proved Darwin to be right. They were worth the effort. View in LinkedIn

POLLINATION LIMITED. "We reaffirm that orchids are primarily pollination limited, the severity of which is affected by resource constraints. Fruit set is higher in temperate than in tropical species, and in species which offer pollinator rewards than those that do not. Reproductive success is skewed towards few individuals in a population and effective population sizes are often small." https://lnkd.in/dXXbjhY View in LinkedIn

FAILSAFES. "In the absence of an effective pollinator some orchids use autopollination (10–15%) and very rarely apomixis (asexual propagation). Unlike many other flowering plants, orchids place the pollen on the pollinators in specific microsites to reduce cross pollination between species rather than using chemical inhibition. As a result most orchids are self compatible, with self-incompatibility being rare." http://www.sciencedirect.com/science/article/pii/S0960982208001723 View in LinkedIn

THE INBREEDING LINE. "Recent population genetic and phylogenetic investigations suggest gene-flow within subgeneric clades, but pollinator-mediated selection may maintain species-specific floral traits." http://link.springer.com/article/10.1007/s00114-005-0636-y View in LinkedIn

THE PARADOX. “But this explanation turns out to be wrong. Since the cost of death to individuals likely exceeds the benefit to the group or species, and because long-lived individuals leave more offspring than short-lived individuals (given equivalent reproductive output), selection would not favor such a death mechanism.” http://www.nature.com/scitable/knowledge/library/the-evolution-of-aging-23651151 View in LinkedIn

GROWTH HORMONE MUTANTS. “Multiple other growth hormone signaling-deficient mouse mutants exhibiting longevity have since been reported.” http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0072255 View in LinkedIn

CLEARING THE WAY. “The famous 19th century German biologist, August Weissmann, for instance, suggested – similar to Lucretius – that selection might favor the evolution of a death mechanism that ensures species survival by making space for more youthful, reproductively prolific individuals.” http://www.nature.com/scitable/knowledge/library/the-evolution-of-aging-23651151 View in LinkedIn

LONGEVITY GENE. “The hypopituitary Ames Dwarf Mouse was the seminal example of single-gene regulation of mammalian longevity. The mice homozygous for a hypomorphic df mutation in the Prophet of Pit1, paired-like homeodomain transcription factor (PROP paired-like homeobox 1) (Prop1) gene have deficient development of the anterior portion of the pituitary gland. Consequently, they are deficient in the production of growth hormone, thyroid stimulating hormone, and prolactin.” http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0072255 View in LinkedIn

2,000 YEAR OLD VIEW. “The Roman poet and philosopher Lucretius, for example, argued in his De Rerum Natura (On the Nature of Things) that aging and death are beneficial because they make room for the next generation, a view that persisted among biologists well into the 20th century.” http://www.nature.com/scitable/knowledge/library/the-evolution-of-aging-23651151 View in LinkedIn